COLUMBIA LIBRARIES OFFSITE HEALTH SCIENCES STANDARD HX64103919 QP471 .B99 On the physiology of QP^Tl COLUMBIA UNIVERSITY EDWARD G. JANEWAY MEMORIAL LIBRARY Digitized by the Internet Archive in 2010 with funding from Columbia University Libraries http://www.archive.org/details/onphysiologyofseOObyrn ON THE PHYSIOLOGY OF THE SEMICIRCULAR CANALS AND THEIR RELATION TO SEASICKNESS ON THE PHYSIOLOGY OF THE SEMI CIRCULAR CANALS AND THEIR RELATION TO SEASICKNESS BY JOSEPH BYRNE, A.M., M.D., LL.B. NEW YORK J. T. DOUGHERTY LONDON H. K. LEWIS MDCCCCXII Copyright, 1912, by JOSEPH BYRNE New York Entered at Stationers' Hall, London, 1912 All Rights reserved Printed in the United States of America The Book Composition Company, 155 East Twenty-third Street, New York TO DAVID FERRIER A PIONEER IN THE PHYSIOLOGY OF THE NERVOUS SYSTEM, WHOSE CAREFUL EXPERIMENTS, ACCURATE OBSERVATIONS, AND SOUND DEDUCTIONS RENDER HIS WORK A GUIDE AND INSPIRATION FOR STUDENTS OF GENERATIONS TO COME PREFACE Six years ago the author undertook to write an arti- cle on the etiology of seasickness. Not satisfied with a mere expression of views without appeal to experimental fact, and believing that the semicircular canals were in some way involved in the causation of the malady, he undertook of his own suggestion and forethought, a series of experiments using rotations, aural irrigations, stimula- tion of the retina by strong light, galvanism applied to the mastoid areas, etc., to determine whether by such means phenomena resembling those of seasickness could be experimentally reproduced. The results of his earliest experiments fulfilled his expectations to such an extent, that he proceeded to a thorough study of the semicircular canals, as affected by rotations, aural irrigations and gal- vanism. The phenomena of nystagmus and the displacements of the head that occur in rotations, aural irrigations, and galvanism applied to the mastoid areas, were observed by him independently and the mechanisms involved in their production studied and worked out before he had any information of the work done by Barany, Neumann and others. He makes therefore, no pretensions for this part of his work on the score of priority in time, but submits it to the profession in the hope that the work will speak for itself. Armed with the knowledge and experience gained from a thorough study of the sickness produced by rotations, v vi PREFACE aural irrigations, etc., he next proceeded to the experi- mental study of seasickness, the results of which are de- tailed in Part III. Although numerous volumes were consulted the author owes special acknowledgment to the works of Ferrier, Sherrington, Piersol, Risien-Russell, and Ewald. The description of the labyrinth and of the eighth nerve is taken mainly from Piersol' s Human Anatomy. The author wishes to thank Dr. Bailey and Messrs. William Wood & Co. for permission to reproduce three figures from Dr. Bailey's work on Histology. He also wishes to thank his friend Mr. Hugh J. Smith for the patience and fortitude with which he submitted to the various tests, as well as for the intelligent assistance given in describing the subjective phenomena. The author has always been an acute sufferer from sea- sickness, and the time and labour devoted to these inves- tigations, which were conducted in private, he considers well spent if his efforts tend to a better understanding of this distressing malady, with consequent alleviation of unspeakable human misery. J. Byrne. 29 West 61st Street, New YorK City, January, 1912. CONTENTS PART I GENERAL ANATOMICAL AND PHYSIOLOGICAL CONSIDERATIONS CHAPTER PAGE I. Anatomy of the Labyrinth 3 XL The Eighth Nerve . 12 III. The Remaining Cranial Nerves .... 22 IV. Blood-supply of the Labyrinth and of the Cranial Nuclei 37 V. Synopsis op Anatomical Connections . . 40 VI. The Sympathetic or Autonomic Nervous System 98 VII. The Paths Involved in Pupillary Move- ments 105 VIII. Further Anatomical and Physiological Con- siderations 114 PART II PHYSIOLOGY OF THE SEMICIRCULAR CANALS IX. Physiology of the Semicircular Canals FROM THE Standpoint of Animal Experi- mentation 125 X. The Effects of Passive Rotation . . . 130 vii viii CONTENTS CHAPTER PAGE XL The Effects of Rotation upon the Digestive Apparatus 164 XII. The Effect of Drugs and Other Measures UPON Derangements of the Alimentary System Caused by Rotation Sickness . . 183 XIII. The Effect of Rotation upon Equilibrium 192 XIV. The Effects of Rotation upon the Eyes . 198 XV. The General Effects of Aural Irrigations 207 XVI. The Effects of Aural Irrigations upon the Digestive Apparatus 233 XVII. The Effects of Aural Irrigations upon the Eyes 250 XVIII. The Effects of the Galvanic Current upon the Semicircular Canals 268 XIX. How Rotations, Aural Irrigations and Gal- vanism Affect the Labyrinthine Recep- tors and the Related Effectors . . .273 XX. Mechanism of the Nystagmus of Rotations, Aural Irrigations and Galvanism . . . 288 XXI. Relations of the Semicircular Canals to the Oculo-Motor Nuclei and their Bear- ing UPON THE Results of Certain Experi- ments 306 XXIL On Ocular Movements and Nystagmus . . 315 XXIII. On the Occurrence of Nystagmus . . .331 PART III SEASICKNESS XXIV. Studies in Seasickness 339 XXV. Further Studies in Seasickness During a Transatlantic Trip 345 XXVI. Studies in Seasickness (Continued) . . .357 CONTENTS ix PAGE CHAPTER XXVII. Studies in Seasickness (Continued) . . .379 XXVIII. Studies in Seasickness (Continued) . . .384 XXIX. General Conclusions from Studies in Sea- sickness. Protocols 417 XXX. History and Literature of Seasickness . 473 XXXI. Etiology of Seasickness 4S6 XXXII. Etiology of Seasickness (Continued) . . 496 XXXIII. On the Occurrence of Seasickness . . .508 XXXIV. The Effects of Seasickness and Their Re- lation TO Diseased Conditions . . . .512 XXXV. How Recovery from Seasickness Takes Place. Outlines of Treatment . . .518 BIBLIOGRAPHY ^^7 INDEX „ ... 537 PART I GENERAL ANATOMICAL AND PHYSIOLOGI- CAL CONSIDERATIONS CHAPTER I ANATOMY OF THE LABYRINTH The long axis of the internal ear measures about 20 mm, and corresponds with that of the petrous bone. The cavity of the bony labyrinth is divided into an ante- rior portion, the cochlea, a middle portion, the vestibule, and a posterior portion, the semicircular canals. The vestibule is an irregularly elliptical cavity measuring about 5 mm from before backward, the same from above downward, and about 3 — 4 mm from without inward. The outer wall constitutes that part of the inner wall of the tympanic cavity in which the oval window is situated. The medial or inner wall is directed toward the bottom of the internal auditory canal, and has two depressions sepa- rated by a ridge — ^the crista vestibuli, the upper pointed end of which forms the pyramidalis vestibuli. The anterior, the smaller of these depressions, is the spherical recess and lodges the saccule. In the lower part of this fossa a number of perforations (about a dozen) mark the macula cribosa media, through which pass, from the bot- tom of the internal auditory canal, the branches of the vestibular nerve to the saccule. The posterior, larger depression, is the elliptical recess, which lodges the utricle. Behind the lower part of the spherical recess the crista vestibuli divides into two limbs, between which is the recessus cochlear is, which lodges the beginning of the ductus cochlearis, and is pierced by a number of small openings for passage of the nerve filaments to this duct. The openings in the crista vestibuli and the elliptical recess collectively form the macula cribrosa superior, and transmit branches of the vestibular nerve to the utricle and to the ampullae of the superior and horizontal semi- circular canals. Below and behind the recessus ellipticus lies a groove, the fossa sulciformis, which deepens pos- 4 SEMICIRCULAR CANALB teriorly into a ven^ small canal — the aqugeductus vesti- buli, and runs in a slightly curved course to the posterior surface of the petrous bone, where it ends in a slitlike opening — the apertura externa aqugeductus vestibuli, situ- ated between the internal opening of the internal auditory- canal and the groove for the lateral sinus. The canal transmit-s the ductus endolymphaticus and a small vein. The anterior wall of the vestibule is pierced by the large opening leading into the scala vestibuli of the cochlea. Near this opening is seen the beginning of the lamina spiralis ossea, which lies on the floor of the vestibule be- low the oval window. Posteriorly the vestibule communi- cates with the semicircular canals by five small openings. The semicircular canals are three small bony tubes, of a shape indicated by their name. They constitute the posterior division of the bony labyrinth. The direction of each canal corresponds roughly with one of the funda- mental planes of the body, viz., the superior canal corre- sponds with the coronal or frontal, the posterior with the sagittal, and the horizontal with the transverse. The plane of their direction is such that each canal is at right angles to the direction of each of its fellows. At one end of each canal there is a dilated portion — the ampulla. The superior canal lies farthest front, and in nearly a ver- tical plane at right angles to the long axis of the petrous bone. The plane of the posterior, which is the longest of the canals, is approximately parallel to the long axis of the petrous bone. The external portion of the horizontal semicircular canal forms a prominence in the inner wall of the middle ear, behind the facial canal, while the upper part of the superior semicircular canal produces a conspicuous elevation — the eminentia arcuata, seen on the superior surface of the petrous bone. The canals open into the ]:)ost(3rior part of the vestibule by five open- ings, the undilated ends of the superior and posterior canals uniting U) form a common trunk, the crus com- mune. The iKjrizontal canal alone has two distinct open- ings into the vestibule. Its ampulla is at its outer end, and lir'H at the iippnr ))ait of the v(?stibule, above the oval window, from wliich it is sf^mrated by a groove corre- sponding with the facial canal. The ampullary end of the posterior canal lies on the ANATOMY 5 floor of the vestibule, near the opening of the undilated end of the horizontal canal and that of the canalis com- munis. The ampulla of the superior canal lies in the vicinity of the ampulla of the horizontal canal, but is situated somewhat mesial to it. This is an important relation in view of the fact that stimuli by means of irri- gations in the external auditory canal, or by means of galvanism over the mastoid area, usually affect the am- pulla of the horizontal canal only; but if thermic irrita- tion be long continued, or if there be structural changes due to long-continued disease of the middle ear, pheno- AmjpuUas Ampulla The Bony Labyrinth. {From " Histology," by Dr. Bailey. X3. (Heitzmann.) Wm. Wood & Co., Publishers) mena indicating irritation of the ampulla of the superior canal may appear simultaneously with those from irrita- tion of the ampulla of the horizontal canal, or may even be present to the exclusion of the latter. In the wall of the ampulla of the posterior canal a number of small openings constituting the macula cribrosa inferior provide for entrance of the special branch of the vestibular nerve, destined for this canal. Sappey ^ states that the superior canal bends somewhat upon itself, so that the anterior (external) half inclines a little inward {e7i dedans), and the posterior (internal) half inclines a little outward (e7i deJiors). Poirier and Charpy^ follow Sappey 's descrip- tion, which is undoubtedly accurate. 6 SEMICIRCULAR CANALS The membranous labyrinth lies within the bony laby- rinth, and resembles it in general form. This agreement is least marked in the vestibule, since here the bony cap- sule is occupied by two compartments of the membranous sac — the utricle and saccule. The membranous labyrinth comprises : 1. The utricle and saccule, which, with the ductus endolymphaticus, lie within the vestibule. 2. The three membranous, semicircular canals, which lie within the bony canals. 3. The membranous cochlea enclosed within the bony cochlea. The membranous labyrinth is attached especially at certain places by connective tissue to the inner wall of the bony capsule. The space between the membranous and bony labyrinths — largest in the scala tympani and scala vestibuli of the cochlea and in the vestibule — consti- tutes the spatium perilymphaticum, and contains a modi- fied lymphatic fluid, the perilymph. The fluid which fills the interior of the membranous labyrinth is called the endol}mi23h, and can pass from one part of the laby- rinth to another, although the saccule and utricle are only indirectly connected through a narrow channel — the duc- tus endolymphaticus. The utricle occupies the recessus ellii:)ticus in the uj^per and back part of the vestibule. Larger than the saccule, it communicates with the three membranous semicircular canals. It is attached to the upper and inner walls of the vestibule by connective tis- sue. It extends from the roof of the vestibule backward and downward to the opening of the j^osterior ampulla (5.5 to G mm). The utricle has three subdivisions, the uppermost a blind sac (3 to 3.5 mm in length and breadth), called the recessus utriculi, whilst the two lower divisions form the utriculus proprius, which measures 8 mm by L 5 to 2 mm. The lower part of the utricle proper is prolonged into the tube-shaped sinus posterior, which connects the ampulla of posterior canal with the utricle. The openings of the semicircular canals into the utricle are as follows : (a) Into the recessus utriculi : the ampulhe of the superior and horizontal canals, (b) Into the utriculus proprius : ANATOMY T 1. The sinus superior, which lies within the crus com- mune, and receives in turn the non-ampullated ends of the superior and posterior canals. 2. The non-ampullated end of the horizontal canal. 8. The ampulla of the posterior canal through the sinus posterior. On the antero-lateral wall of the recessus utriculi is placed the macula acustica of the utricle, whilst from its antero-mesial wall springs the canalis utriculo-saccularis, the small canal from the utricle that joins a still smaller passage from the saccule to form the ductus endolym- phaticus. The saccule is an irregularly oval compartment, about 8 by 2 mm, occupying the recessus sphsericus in the lower and anterior part of the vestibule, to w^hich it is attached by connective tissue. It is somewhat flattened laterally, and at its lower end gradually narrows into a passage — the canalis reuniens, which connects the saccule with the ductus cochlearis. Its upper end bulges back- ward, forming the sinus utricularis, the wall of which comes in contact with that of the utricle. The small canal that helps to form the ductus endolymphaticus springs from the posterior wall of the saccule. The duc- tus endol}miphaticus passes through the aquseductus ves- tibuli to end in a blind dilated extremity, the saccus endol}Txiphaticus, lying between the layers of the dura mater below the opening of the aqueduct. Through open- ings in the recessus sphsericus branches of the vestibular nerve enter and pass to the macula acustica sacculi on the anterior wall of the saccule. The canalis reuniens is the very small tube passing from the lower part of the saccule into the upper wall of the cochlear duct, near the caecum, as its blind vestibular end is called. The membranous semicircular canals (ductus semi- circulares) occupy about one-third of the diameter of the osseous canals, and correspond with them in number, name, and form. They are closely united along their convex margins with the bony tubes, whilst the opposite concave margins lie free in the perilymphatic space, being attached only by irregular vascular connective-tissue bundles (ligamenta labyrinthi canaliculorum) , which stretch across this space. Each of the membranous tubes 8 SEMICIRCULAR CANALS has an ampulla, which is relatively much larger than the osseous ampulla, being three times the size of the rest of the tube. The part of the ampulla corresponding to the convexity of the semicircular canals is grooved on the Diagram of the Perilymphatic and Endolymphatic Spaces of the Inner Ear. (Testut.) Endolymphatic spaces in grey; perilymphatic spaces in black. 1, Utricle ; 2, saccule ; 3, semi- circular canals; 4, cochlear canal; 5, endolymphatic duct; 6, subdural endolymphatic sac; 7, canalis reuniens; 8, scala tympani ; 9, scala vestibuli ; 10, their union at the helicotrema; 11, aqueduct of the vestibule; 12, aqueduct of the cochlea; 13, periosteum ; 14, dura mater ; 15, stapes in fenestra ovalis ; 16, fenestra rotunda and secondary tympanic membrane. {From "Histology," by Dr. Bailey. Wm. Wood & Co., Publishers) outer surface at the entrance of the ampullary nerves. On the corresponding inner surface is a projection — the septum transvorsum — which practically divides this space inUj two parts, and is surmoimtod by the crista acustica, which contains the ampullary endings of the vestibular ANATOMY 9 nerves. The crescent-shaped thickening beyond each end of the crista is called the planum semilunatum. Structure of the Utricle^ Saccule^ and Semicircular Canals. The vestibule and the bony semicircular canals are lined by a very thin periosteum, composed of a feltwork of resistant fibrous tissue containing pigmented connect- ive-tissue cells. Endothelium everj^where lines the peri- lymphatic space between the membranous and osseous canals, covering the free inner surface of the periosteum, the fibrous trabeculae, and the outer or peril}Tnphatic sur- face of this part of the membranous labyrinth. The walls of the utricle, saccule, and membranous semicircular canals are made up of (a) an outer fibrous connective- tissue lamella, and (b) an iimer epithelial lining, the latter consisting throughout the greater part, of its extent of a single layer of thin, flattened, polyhedi-al cells. Beneath the epithelium, in the region of the maculae and cristae, is (c) a thin, almost homogeneous, hyaline membrane with few cells. This middle layer presents, in places, on its inner surface small papillary elevations covered by epithelium. On the concave side of the semicircular canals is a strip — ^the raphe — of thickened epithelium, in which the cells become low, cylindrical in type. In the plana semilunata the cells are cylindrical in type. Over the regions receiving the nerve fibres — the maculae acus- ticse and the cristae acusticae — the epithelium undergoes a marked alteration, changing from the indifferent covering cells into the highly specialized neuro-epithelium. The maculae acusticae are about 3 mm long by 2 mm broad, the macula of the saccule being a little narrower (1.5 to 1.6 mm) than that of the utricle (2 mm). At the margin of these areas the cells are at first cuboidal, next low columnar, and then they abruptly increase in length until they measure from 0.30 to 0.3o mm, in con- trast with their usual height of from .003 to .004 mm. The acoustic area includes two kinds of elements — the sustentacular or fibre cells and the hair cells. The susten- tacular cells are long, rather narrow, irregularly cylindri- cal elements, and extend the entire thickness of the epi- 10 SEMICIRCULAR CANALS thelial layer, resting upon a well-developed basement membrane by their expanded or divided basal processes. At a variable distance from the base they present a swell- ing enclosing an oval nucleus, and terminate at the surface in a cuticular zone. The cylindrical hair cells are broader but shorter than the sustentacular cells, and reach from the free surface only as far as the middle of the epithelial layer, where each cell terminates usually in a rounded or somewhat swollen end, containing a spherical nucleus. The end next to the free surface exhibits a differentiation into a cuticular zone, similar to that covering the inner ends of the sustentacular elements. From the free border of each hair cell a stiff, robust hair, .020 to .025 mm long, projects into the endolymph. This, however, is resolvable into a number of aggluti- nated, finer hairs or rods. The free surface of the neuro- epithelium within the saccule and utricle is covered by a remarkable structure, the so-called otolithic mem- brane. This consists of a gelatinous membrane, in which are imbedded numberless small, crystalline bodies, the otoliths. Between it and the cuticular zone is a space, about .020 mm in width and filled with endolymph, through which the hair cells pass to the otolithic mem- brane. The otoliths are minute crystals, usually hexa- gonal in form, with slightly rounded angles, and from .009 to .011 mm in length. They are composed of cal- cium carbonate, with an orgjinic basis. On reaching the macula the nerve fibres form a subepithelial plexus, from which fine bundles of fibres pass toward the free surface. The fibres usually lose their medullary substance in pass- ing through the basement membrane, and enter the epithe- lium as naked axis-cylinders. Passing between the sub- cuticular cells to about the middle of the epithelium, they break up into fine fibrilla), which embrace the deeper ends of the hair cells, and give off fine threads tliat pass as free axis cylinders between the cells to higher levels. The crista acustica and planum soinilimatum are cov- ered with neuro-epitheli urn, similar to thatof the macula). The hairs of the hair cells, however, are longer and con- verge to, and are imbedded witliin, a peculiar domelike structure known as the cupola, regarded by some anato- mists as an artefact formed by coagulation of the fluid ' ANATOMY I 11 in which the hair cells are bathed. Otoliths probably do not exist in the cristse acusticse. In some lower animals, besides the maculae of the utricle and saccule, there is also a third structure similar to these — the lagena — which likewise contains otoliths. In certain fishes the otoliths are stones of 1 cm in size. The plane of the macula utriculi corresponds roughly with that of the external semicircular canal. In the uj)right position it is inclined backward at an angle of 45°. Ac- cording to Ketzius 3 the long axis of the macula utriculi in men is directed from in front upward and inward and (the short axis) backward, downward, and outward, the general plane being about horizontal. The long axis of the saccule is almost vertical, and is directed from with- out upward and inward, the short axis being directed from before backward. The macula is situated upon its mesial surface (Retzius). The plane of the macula sacculi runs from above and behind forward and down- ward in an antero-posterior direction, at about an angle of 45°. The lagena of lower animals permits vertical dis- placement of its otolith, while the maculae of the utricle and saccule are roughly horizontal, and at right angles to each other (Piersol*). The hairs of the maculae of the utricle and saccule are stiffer and shorter than those of the cristae of the ampullae, and are held together by a stiffer mass of otoconium, which, however, is not gelati- nous, but of otolithic composition. Yerworn ^ proposed the name staloliths for the otoliths of the utricle and saccule, and called the analogous organs in certain lower forms statocysts, thus assuming that the function of these organs is exclusively static, as distinguished from the dynamic function of the semicircular canals. Clarke,^ after a comparative study of the otolithic and related structures, concludes that whilst the otolithic structures are mainly statical in function, they are not exclusively so, and may function dynamically as well. With the exception of the maculae of the utricle and saccule no part of the vestibular wall is supplied with nerve terminals of the eighth nerve, CHAPTER II THE EIGHTH NERVE The eighth nerve consists of two portions — the coch- lear, or true nerve of hearing, and the vestibular, which is concerned with equilibration. Traced from the brain toward the ear, the eighth nerve arises at its superficial origin by two roots : a mesial — radix vestibularis — and a lateral — radix cochlearis — which embrace the inferior cerebellar peduncle, the mesial root passing to the inner, and the lateral root to the outer side of the peduncle. The nerve thus formed by the union of these two roots leaves the surface of the brain-stem at the posterior bor- der of the pons, where it is adherent to the middle cere- bellar peduncle. To its inner side, and closely associated with it, are the motor and sensory roots of the facial nerve, which lie within a groove on the mesial surface of the eighth, and with it enter and traverse the internal auditory canal. Within the latter the eighth nerve sepa- rates into two divisions, of which the superior and larger is the vestibular nerve (n. vestibuli), and the inferior and smaller the cochlear (n. cochleae). Although in a general way these divisions continue the corresponding roots, this agreement as to the source of their fibres is not complete, since strands of the vestibular fibres are incor- porated with the cochlear nerve. On reaching the bottom of the internal auditory canal, the facial nerve enters the facial canal, whilst the fibres of the eighth nerve disap- pear through apertures in the lamina cribrosa, to reach the several parts of the membranous labyrinth. In the internal auditory canal the vestibular and facial trunks are connected (fila anastomica) by a branch, which passes from the pars intermedia to the vestibular nerve, and by one from the latter to the geniculate ganglion. These apparent communications between the seventh and eighth 12 ANATOMY 13 nerves are, in fact, only aberrant strands of facial fibres that return to the seventh after temporary association with the eighth. The vestibular nerve divides into three terminal branches, which pass through the apertures in the cribri- form plate, above the falciform crest, and supply the utri- cle and the superior and external semicircular canals. Not all the fibres of the vestibular root, however, are in- cluded in these branches, since of the three branches given off by the vestibular nerve, two, viz., those of the saccule and posterior semicircular canal, are incorporated v/ith the cochlear fibres, and seemingly are derived from the cochlear nerve. The remaining branch of the cochlear nerve contains the cochlear fibres proper, which traverse the numerous foramina of the tractus spiralis foraminosus and the central canal of the modiolus, to supj^ly the organ of Corti. The fibres of the eighth nerve are afferent. Hence they are processes (axones) of nerve cells, situated some- where along the course of the nerve. The real origin of the nerve fibres, therefore, is to be sought in the ganglia, occurring in the divisions of the nerve. The true cochlear fibres arise within the cochlea as axones of the cells of the spiral ganglion, or ganglion of Corti (g. spirale). This structure consists of a series of bipolar neurones, which occupies the spiral canal in the base of the lamina spiralis. The dendritic processes of these cells begin as fine fibrils, which lie in close relation with the neuro-epithelial cells, comprising the inner and outer hair cells of the organ of Corti. Leaving the hair cells as non-medullated fibres, they traverse the foramina nervosa of the labium tympanicum, at which point they become medullated when they interlace to form a flat feltworkthat lies between the layers of the lamina spiralis, and soon assemble to form bundles which pass to the cells of the ganglion spirale, each fibre probably joining its individual cell. Leaving the ganglion, the axones of its cells enter the bony canals within the modiolus, from which they emerge as the tractus spiralis foraminosus, and are collected into a single bundle — the cochlear nerve proper. This latter, however, soon receives two acces- sions, one of which consists of fibres from the saccule, the 14 SEMICIRCULAR CANALS other from the posterior semicircular canal. These accessions are in reality parts of the vestibular nerve and, beyond their temporary companionship have nothing to do with the cochlear root. On reaching the medulla the cochlear fibres come into relation with their nucleus of reception, which includes two superficial aggi-egations of nerve cells that collectively constitute the acoustic nucleus. The latter consists of two parts, of which one — the ventral cochlear nucleus, also called the accessory acoustic nucleus — lies ventral to the inferior cerebellar peduncle ; and the other — the lateral cochlear nucleus, or tuberculum acusticum, rests upon the dorso-lateral surface of the peduncle, and occupies the extreme outer part of the triangular acoustic area, seen in the lateral angle of the floor of the fourth ventricle. The greater number of cochlear fibres end in arborizations around the stellate cells of the ventral ganglion, whilst others terminate in relation with the more elongated fusiform cells of the lateral nucleus. From the neurones of these subdivisions of the reception nucleus, the audi- tory pathway is continued as two chief tracts — the axones of the cells of the ventral nucleus passing for the most part ventral to the restiform body and the special root of the trigeminus to form the corpus trapezoides, whilst those from the lateral nucleus sweep around the outer surface of the restiform body, and then medially beneath the ependyma of the floor of the fourth ventricle, where they show with varying degrees of distinctness as the striae acusticse. The corpus trapezoides — the conspicuous trans- verse tract that separates the tegmental from the ventral region of the pons in its superior part — is formed chiefly by the axones of the cells within tlie central cochlear nucleus, supplemented by a limited number of fibres that spring from the lateral nucleus. In addition it contains axones from the large cells found within the trapezoid body on each side of the middle line that constitute the nucleus trapezoideus. In close relation with the dorsal surface of the corpus trapezoides, within the superior olive and on either side of the median raphe, lies the superior olivary nucleus (nuc. olivarius superior) , a col- lection of nerve cells around which many of the cochlear fibres, chiefly from the opposite but also from the same ANATOMY 15 side, end and from which the tract of the lateral fillet principally takes origin. Not all the fibres arising from the superior olivary nucleus, however, enter the lateral fillet. A considerable number leave the dorsal surface of the nucleus, and as its peduncle pass to the abducent nucleus (v. Bechterew considers these fibres as cerebello- fugal paths to the abducens nucleus) , and by way of the posterior longitudinal fasciculus to the nuclei of the other ocular nerves. In this manner it is asserted the reflex paths are established, by which the motor nerves, including probably the facial, are brought under the influence of auditory impulses. There are reasons, however, for rejecting this simple, almost direct relation between the eighth nerve and the nuclei of the eye muscles. Movements of the eyes in response to a loud sound are not simple reflex movements, but complex, coordinated movements, associated usually with other movements, e.g., turning of the head and eyes to the source of the sound, accompanied by a general movement of withdrawal of the head and upper part of the body. Such complex purposive movements could hardly take j)lace through direct paths from the auditory to the ocular and other nuclei without the intervention of some higher harmonising mechanism. Moreover, in Ferrier's^ experiments, stimulation of the auditory area in the temporal lobe caused the animal to turn the head and eyes in the direction of the ear of the opposite side. This interesting experiment shov»"s that the main relation between the auditory nerve proper and the cerebral cortex is a crossed one. It also shows that reflex, coordinated turning of the head and eyes in response to auditory stimuli may take place along other ]3aths than the direct one mentioned; that is, in a downward course, possibly through the medium of the cerebellum. Within the tract of the fillet, a short distance beyond the superior olive, is encountered a group of nerve cells, the nucleus of the lateral fillet (nucleus lemnisci lateralis) . Whilst numerous additions to the fillet are received from these cells, their relation to the cochlear fibres is uncer- tain. The lateral fillet will be more fully described later on. It is sufficient to note here that in so far as the auditory (cochlear) fibres are concerned, the tract termi- 16 SEMICIRCULAR CANALS nates chiefly in the inferior collicuhis of the quadrigemina and in the median geniculate body. In addition to its constituents through the corpus trapezoides the lateral fillet receives considerable accessions of cochlear fibres by way of the striae acusticse. These strands consist, for the most part, of the axones of the cells lying within the tuberculum acusticum ; but to a limited extent also of the axones of the ventral cochlear nucleus, which wind over the latero-dorsal surface of the inferior cerebellar peduncle, pass medially beneath the ependyma of the floor of the fourth ventricle, as far as the median groove; and, cross- ing to the opposite side, sweep ventrally through the dorsal region of the medulla or pons, to join the tract of the lateral fillet, and so proceed in company with the other cochlear fibres to the higher levels. Not all the component fibres of the acoustic strise follow the lateral fillet; some of them, after decussation, turn brainward, possibly joining the mesial fillet, whilst others may enter the posterior longitudinal fasciculus to assist in establishing the reflex paths, influencing the motor nerves. The auditory paths, by which impulses from the organ of Corti, travelling along the cochlear fibres reach the cerebral cortex, are as follows : 1. Peripheral neurones of the ganglion spirale whose axones — the cochlear fibres — pass to the reception nu- cleus, composed of the ventral and lateral cochlear nuclei. 2. The neurones of the cochlear nuclei send their axones — (a) By way of the corpus trapezoides to the superior olivary nucleus, chiefly of the opposite side or to the lateral fillet, or its nucleus without interruption in the olive, (b) By way of the stria3 acusticse through the tegmentum, to join the trapezoidal fibres. 3. The neurones of the superior olivary nucleus, or of the fillet nucleus, whose axones pass by way of the lateral fillet, (a) To the cells within the inferior colliculus, or (b) without interruption through the inferior brachium to the cells within the median geniculate body. 4. The neurones of the inferior colliculus and of the median geniculate body whose axones pass as the audi- tory radiation to tlie auditory cortical area within the temponil loho of the cerebrum. The exact limitations of ANATOMY 17 tne auditory area are still uncertain, but the most im- portant part of it includes the superior temporal and the subjacent part of the middle temporal convolution. The cochlear fibres that do not undergo decussation ascend through the lateral fillet of the same side, and eventually establish cortical relations with the corre- sponding cerebral hemisphere. From the foregoing it is manifest that the auditory area is chiefly connected with the cochlea of the opposite side. This crossed relation is emphasized, for there are sufficient reasons for asserting positively the existence of a similar crossed relation be- tween the cerebellum and the semicircular canals and vestibule, as will appear later. The fibres of the vestibular portion of the eighth nerve are the axones of the bipolar nerve cells situated within the small vestibular (g. vestibulare) or Scarpa's ganglion, which lies at the bottom of the internal auditory canal. The dendrites of these cells constitute the five branches of distribution of the vestibular nerve, and pass through the various openings in the inner wall of the bony labyrinth, as above described, to reach the maculae acusticse within the saccule and utricle and the cristse acusticse of the ampullae of the semicircular canals, where the nerve fila- ments are in intimate relation with the neuro-epithelium. The centrally directed axones of the neurones supplying the utricle and the superior and external semicircular canals become consolidated to form the vestibular nerve of descriptive anatomy. Those from the saccule and pos- terior semicircular canal join the cochlear fibres, and with these course within the cochlear nerve until the latter unites with the vestibular to form the common auditory or eighth nerve trunk. Where the common trunk sepa- rates into its two roots the vestibular fibres leave the cochlear, and permanently assume their natural com- panionship with the remaining fibres of the vestibular root. The vestibular fibres enter the brain stem at a slightly higher level than those of the cochlear root lying mesial to the latter and the ventral cochlear nucleus, and pass dorsally within the pons, between the inferior cerebellar peduncle and the spinal trigeminal root. On reaching a level dorsal to the latter, the vestibular fibres divide into 18 SEMICIRCULAR CANALS short upward and longer downward coursing branches which, after condensing into an ascending and descend- ing root respectively, end in arborizations around the cells of the vestibular nucleus of reception. The exact extent a.nd constitution of this nucleus which underlies the area acustica in the floor of the fourth ventricle are uncertain, since the neurones directly related to the ves- tibular fibres contribute only a part of those contained within a large diffuse complex of cells and fibres, many of whose constituents probably have only an indirect con- nection with the vestibular nerve. Sabin^ successfully reconstructed this complex, which comprises two general parts: 1. An extended, irregularly triangular mass of cells lying for the most part mesial to the tract formed by the ascending and descending branches of the vestibular fibres and, 2. A smaller mass of cells which lies above the larger one, and partly to the outer side of the tract of the vestibular fibres. The apex of the large triangular mass approaches the middle line, and its superior and inferior basal angles are prolonged upward and downward along the vestibular tract. Examined microscopically the large mass is found to include three subdivisions : (a) A tapering, caudally directed nucleus, which con- tinues the inferior angle along the descending vestibular root. (b) An extended triangular nucleus that includes the greater part of the large triangular mass. (c) An irregular pyramidal nucleus that prolongs up- ward the superior angle. The first of these subdivisions (a) is known as the spinal vestibular nucleus (nuc. spinalis n. vestibularis) ; the second (b) as the median vestibular nucleus (nuc. medialis n. vestibularis) , also as the chief nucleus or the triangular nucleus; and the third (c) as the superior vestibular nucleus, or the nucleus of V. Bechterew. The small mass (2) corresponds with the lateral vestibular nucleus (nuc. lateralis n. vestibularis), or the nucleus of Deiters. The fibres of the descending root end around the neurones within the spinal nucleus in a manner similar AMATOMY 19 to that in which-the constituents of the spinal root of the trigeminus terminate in relation with the neurones within the substantia gelatinosa, whilst those of the ascending vestibular root end around the cells within the remaining vestibular nuclei. Ferrier and Turner, however, observed that after section of the eighth nerve the descending ves- tibular root did not degenerate, whilst Bruce traced the fibres to the cuneate nucleus. (See Vestibular connec- tions.) Although much uncertainty and conflict of opinion exist as to the details of the secondary paths by which the impulses carried by the vestibular fil^res are dis- tributed, it may be accepted that fibres pass from the nuclei of reception: (a) To the cerebellum, chiefly to the roof nucleus of the o]3posite side, and possibly to the nucleus globosus and emboUiformis as constituents of the nucleo-cerebellar tract, by which impulses of equilibration are carried to the great coordinating centres. (See note to Vestibular connections.) (b) As arcuate fibres ventro-medially into the tegmen- tum of the pons across the middle line, bending upward or downward to reach other levels, some fibres, however, remaining on the same side. From the character of the impulses it is probable that only relatively few vestibular fibres join the median fillet to ascend to the optic thala- mus. Other connections of the nuclei include: (c) Commissural fibres between V. Bechterew's nucleus of either side. (d) Fibres to the abducent nucleus. (But see sum- mary of Vestibular connections.) (e) Crossed and uncrossed fibres fromDeiters' nucleus to the posterior longitudinal fasciculus ; and (f) Fibres from the same nucleus to the spinal cord. Not all the neurones of Deiters' nucleus are concerned in transmitting afferent impulses to the cerebellum, for many are links in the path by which cerebellar cells exer- cise coordinating influence over the root cells of the spinal nerves. Starting in the cerebellum such efferent impulses are carried by fibres that descend through the median part of the inferior cerebellar peduncle, and probably end around certain of the cells within Deiters' nucleus. 20 SEMICIRCULAR CANALS Fr.om these cells in turn originate the fibres of the vesti- biilo-spinal tract which, after traversing the medulla, enter the antero-lateral column of the cord, and end in relation with the motor root cells. A shorter and more direct path for vestibular reflexes may probably be formed by the collaterals of the vestibular fibres that end around the spinal neurones of Deiters' nucleus; but the objection already put forward against the simple direct connection between afferent cochlear fibres and the oculo-motor centres holds as well here as in the case of vestibular fibres. Such connections cannot account for the more complex coordi- nated movements of equilibration which postulate a higher coordinating mechanism. The vestibular and cochlear nuclei are nutrient relay centres — coordinating centres of a lower order perhaps but related to, and acting in accord with, higher coordinating centres that regulate and con- trol the more complicated movements consequent on coch- lear or vestibular irritation. In those cases where there seems to be a direct connection between the vestibular fibres and the motor centres, e.g., those fibres mentioned as going to the abducent nucleus, it is probable that such fibres are mainly efferent and carry impulses from the cerebellum or other higher centres, which coordinate the movements of the eyes with the movements executed by other muscles in response to labyrinthine stimulation. The same has to be said of many fibres in the posterior longitudinal fasciculus, which, undoubtedly, convey co- ordinating impulses that harmonise the actions of motor nerve centres situated at some distance from each other, a notable instance being that of the abducens centre, which works in harmony with the centre for the internal rectus muscle of the opposite side. In the nystagmic movements observed in irrigations of the external audi- tory canal, undoubtedly the fibres from Deiters' nucleus to the posterior longitudinal fasciculus play an important role; but, as before stated, these fibres probably do not represent a direct immediate connection between the ves- tibular fibres and the posterior longitudinal fasciculus, but are to be considered in part at least as efferent fibres from the cerebellum or other coordinating centre. In fishes the vestibular nerve is in close functional relation with the mesencephalic centres of the opposite ANATOMY 21 side (Loeb ^^) , whilst almost all the optic fibres pass to the same centres (Parsons *^) . In fishes, therefore, and in the lower forms of animals generally it is reasonable to assign important functions in the maintenance of equili- brium to the mesencephalic centres. CHAPTER III THE REMAINING CRANIAL NERVES Of the remaining cranial nerves the first or olfactory- is the only sensory nerve in man in which the neurones (cell bodies) of the first order are situated on the surface, like tlie sensory cells of some of the invertebrates. These latter cells represent the cell bodies of the posterior spinal ganglia, which have wandered to the surface epithelium (Retzius*^). For the central relations of the olfactory nerve see "the rhinencephalon" in the synopsis of ana- tomical connections. The second or optic nerve is not a true nerve, but a part of the brain substance. The true optic nerve com- ponents are the sensory neurones of the first order lying within the retina itself. As the dorsal-spinal-ganglion cells emigrate from the neural crest at an early age to form the neurones of the first order of the sensory spinal nerves, and lose their connection with the cord to regain it later on, it is manifest that the analogy between the optic and the sensory spinal elements is incomplete, since the retina develops entirely from the invaginated optic vesicle. For the central connections of the optic nerve see "Anatomical Synopsis." The third, fourth, and sixth nerves are purely motor, and arise from their respective nuclei. As neuro-tendi- nous organs, similar to the Golgi-Mazzini corpuscles, have been demonstrated in the tendons of the external ocular muscles, and as the degree of convergence of the eyeballs has much to do with accommodation reflexes, it is prob- able that the third nerve has afferent paths for accommo- dation reflexes and for purposes of reciprocal innervation. The nucleus of tlie third nerve is medially situated deep within the gnjy matter of the aqueduct of Sylvius, near the dorsal surface of the posterior longitudinal fasci- 22 ANATOMY 23 cuius. The nucleus is 6-8 mm long, and extends from the level of the caudal pole of the superior colliculi (from underneath superior colliculi and part of third ventricle, according to Quain^^) almost to the level of the fourth nucleus, from which it is separated by a narrow interv^al. The grouping of the nerve cells of the third nucleus is as follows : 1. A paired group, consisting of long columns of cells — the chief nuclei — extending along the dorsal surface of the posterior longitudinal fasciculi. These chief nuclei are subdivided into (a) dorsal (lateral) and (b) ventral (mesial) cell groups. Dislocated groups of cells of the chief nucleus lie scattered among and beneath the fibres of the posterior longitudinal fasciculus. 2. Dorsal to the chief nucleus and overlying the pos- terior-median surface is the tapering column of small nerve cells — the Edinger-Westphal nucleus. The mass of this nucleus is thicker above than below (caudad) , and is divided into dorso-lateral and ventro-median portions at the caudal pole, though fused at the cephalic extremity. There is question as to whether the Edinger-Westphal nucleus is related to the third nerve. In the dorsal (inferior) group of cells maybe distinguished six second- ary groups. Two of. these lie lateral to the others, and somewhat dorsally. The remaining four are placed more mesially and one, which is in the middle line — the nucleus medialis — is common to the oculo-motor nerve of each side. Experiments on animals and pathological observations in man seem to show, that the oculo-motor centres are grouped as above; that is, that they are divided into a superior and an inferior or dorsal group, and again into a mesial and a lateral group. The ante- rior (superior) part of the oculo-motor nucleus has smaller cells than the rest of the nucleus, and extends forward into the wall of the third ventricle. Hensen and Volck- ers ^^ have shown by direct application of the electrodes in the dog that most anteriorily in the wall of the third ven- tricle is the centre for accommodation. Behind this, and more laterally situated than the former, is the centre for constriction of the iris. At the junction of the third ventricle with the aqueduct of Sylvius is the centre for the rectus internus, behind which, in order backward, are the 24 SEMICIRCULAR CANALS centres for the rectus superior, levator palpebrse superioris, rectus inferior, and lastly that of the obliquus superior. The clinical observations of Kahler and Pick, and those of Starr, indicate that the levator palpebrae, rectus supe- rior, and obliquus inferior are innervated from the dorsal (dorso-lateral) group, and the rectus internus and rectus inferior from the ventro-mesial group in order from above downward (caudad). v. Bechterew ^' from his observations following irrita- tion of the posterior wall of the third ventricle and of the floor of the aqueduct of Sylvius concluded that the third nucleus consists of two larger groups — one paired and one unpaired — and of two smaller paired accessory groups. The former — larger groups — contain the main nucleus, and are laterally and ventrally in relation with the pos- terior longitudinal fasciculus. About the level of the junction of the middle with the anterior third of the nucleus is the median unpaired group and the dorso- lateral paired groups. The anterior (superior) groups are related to accommodation and pupillary constriction. The posterior group is subdivided into a lateral group for the levator palpebrse, superior rectus, and inferior ob- lique, and a median group for the internal and inferior rectus. From the uniformity of the findings given above the grouping of the centres in the third nucleus may be accepted as proven. Tsuchida,^'* who recently (1906) investigated the whole subject, denies the constant exist- ence of a well-marked, unpaired, median group, as described by Perlia and others, but admits the existence of broken groups of medially placed cells, especially in the upper and lower thirds of the nucleus. The oculo- motor fibres, according to Tsuchida, originate from vari- ous portions of the third nucleus without limited relations to distinct groups. The nucleus of Darkschweitsch, which is a laterally situated group of cells beginning in the floor of the third ventricle and extending caudallyas far as the upper third of the chief nucleus, is no longer regarded as having direct relations with the third nerve. It is in intimate relation with the posterior longitudinal fasciculus, amongst the fibres of which its cells to a great extent lie. ANATOMY 25 Hence it is often called the nucleus of the posterior longi- tudinal fasciculus. It is stated as probable that the oculo-motor fibres decussate in the caudal portion of the chief nucleus. Tsuchida^* and others maintain that some decussation takes place throughout the greater part of the nucleus. The connections of the third nucleus are as follows: 1. With the cerebral cortex : (a) With the posterior por- tion of the second and third frontal convolutions, chiefly of the opposite side. This connection is direct via the corona radiata, internal capsule, and cerebral peduncle, and was first demonstrated by Ferrier,^and independently byMunk. (b) With the occipital cortex about the visual area. This connection is also mainly crossed, and repre- sents a motor ocular path, as demonstrated by Schafer and Brown. ^^ The path is indirect via the optic radia- tion, superior brachium, and su^^erior colliculi. Ferrier also got ocular movements from this area, but considered them as associated movements (synkineses) . 2. With the primary visual centres via the superior colliculi. 8. With the nuclei of the fourth and sixth cranial nerves and with Deiters' nucleus. These connections are supposed to be by way of the posterior longitudinal fasciculus. 4. With the nucleus of the facial nerve via the pos- terior longitudinal fasciculus. This connection is assumed to explain the associated action of the third and seventh nerves in contractions of the orbicularis palpebrarum and corrugator supercilii muscles. As previously stated, the simple direct communication between the ocular nuclei and Deiters' nucleus cannot be accepted as fully explaining the coordinated actions of the various functionally related structures. Thus Duval and Laborde ^^ showed that irritation of the sixth nucleus caused lateral conjugate movements of the eyeballs, and explained the results by asserting that the sixth nucleus sends fibres through the posterior longitudinal fasciculus to the centre for the opposite internal rectus in the third nucleus. But Schafer ^^ whilst admitting that fibres from the posterior longitudinal fasciculus enter the sixth and third nuclei, insists that such fibres end in these nuclei, 26 SEMICIRCULAR CANALS and that no fibres from the sixth or third nucleus enter the posterior longitudinal fasciculus. The fibres of the posterior longitudinal fasciculus to the sixth nucleus more probably represent efferent cerebellar or other paths which, with similar fibres or collaterals passing from the cerebellimi or other centre to the third and fourth nucleus, afford a more rational explanation of the coordinated action of these nuclei. Moreover, v. Bechterew^^ con- siders the cerebellar superior olivary tract which, through the superior olives, makes connection with the sixth nucleus as an efferent cerebellar jy-cith for ocular move- ments. In a similar way, perhaps, may be explained the coordinated relation of the seventh and third, as well as of the other cranial nerve nuclei. 5. With the cerebellum. These paths have not been satisfactorily demonstrated, v. Bechterew states that a continuous connection exists between the third nucleus and the cerebellum, by which the latter becomes in- structed as to the position of the eyeballs and the condi- tion of the pupil. These pathways lie in the superior peduncle of the opposite side. The relation, therefore, between the oculo-motor nucleus and the cerebellum is a crossed one. V. Bechterew, ^^ however, in discussing the centrifugal function of the spinal bundle of the middle peduncle and of the cerebellar superior olivary tract, states that the fibres passing in the superior peduncle to the oculo-motor nucleus of the opposite side are also cerebello-efferent for the control of reflex ocular movements. The relations of the third nucleus to the seventh and to the other cranial nerve nuclei are probably mainly through the cerebellum via the superior peduncle, and thence through efferent cerebellar paths, including those in the posterior longi- tudinal fasciculus. The fourth nucleus lies near the middle line, just caudad to the third nucleus, from which it is separated by a small intfjrval. It seems to lie in a distinct depres- sion on the posterior longitudinal fasciculus. It is 2 mm long, and ext(m(ls from a point oy)posite the superior fxjrder of the inferior colliculus. to the lower ])ole of the colliculus. It is in relation with the cortex of thf? inferior ANATOMY 27 frontal convolution of the opposite side through fibres that pass by way of the corona radiata, internal capsule, and cerebral peduncle. It is stated that this nucleus is in relation with the third and sixth nuclei through the posterior longitudinal fasciculus. For reasons already stated, it is preferable to consider these relations as made mainly through the cerebellum or other coordinating cen- tre, and not directly by fibres passing between the nuclei. The fibres arising in the nucleus pass laterally and ven- trally in the tegmentum for a short distance, and then course in a median direction and dorsalward. They totally, or almost totally, decussate in passing through the anterior end of the superior medullary velum, and emerge from the surface of the latter at the side of the frenulum veli in two small bundles, which pierce the pia and unite to form the trunk of the nerve. The fourth nucleus does not seem to bear any close functional or anatomical rela- tion to that of the seventh. The sixth nucleus consists of multipolar cells lying in the dorsal part of the tegmentum of the pons, and under- neath the floor of the fourth ventricle. It is situated anterior to the striae acusticse, beneath the eminentia teres, and ventral to and within the loop formed by the fibres on their way to form the seventh nerve. The sixth, like the third and fourth nuclei, is related to the frontal oculo-motor area of the cerebral cortex of the opposite side. The decussation of the cortical paths takes place at the level of the nucleus, and, according to some observers, through the nucleus. The nucleus, it is stated, is in rela- tion with the third nucleus of the opposite side, and with the superior olive, and the cochlear and vestibular nuclei through the posterior longitudinal fasciculus. For rea- sons already stated, these connections probably represent in the main, efferent cerebellar paths, i.e., part of the common paths originating in the cerebellum, and sending fibres or collaterals to each of the associated nuclei. The sixth nerve makes its exit through the posterior part of the pons, between the latter and the medulla oblongata. In the cavernous sinus it is situated first above and then to the outer side of the carotid artery, and passes through the superior orbital fissure, to join the external rectus muscle. The sixth is the longest of the cranial nerves. 28 SEMICIRCULAR CANALS Owing to its length and the course it takes it is, of all the cranial nerves, the most liable to pressure from exuda- tions, syphilitic or other, occurring at the base of the brain. The fifth is a mixed nerve. It has two nuclei. The sensory nucleus is a columnar mass of grey matter within the lateral part of the tegmentum, extending from the middle of the pons through the entire length of the me- dulla, and into the spinal cord, as low as the second cer- vical segment, where it becomes continuous with the sub- stantia gelatinosa. Though the rounded upper part of this tapering column is called the sensory nucleus of the fifth nerve, the whole mass receives fibres. The fibres of the fifth nerve as they approach this nucleus divide into ascending and descending bundles. The latter are coarser than the former, and form the descending or spinal root. The Gasserian ganglion contains the cell bodies of the primary neurones of the sensory part of the fifth nerve, this ganglion being the analogue of the dorsospinal-root ganglia of the spinal nerves. The connections of the sensory part of the fifth nerve are: 1. By axones which cross the raphe from the nucleus to the opposite mesial fillet, ascend to the thalamus and, after interruption, proceed to the cortex cerebri. It is probable that some fibres pass to the fillet of the same side, and reach the brain as uncrossed paths. Collaterals of the crossed and uncrossed paths from the nucleus prob- ably reach the motor nuclei of the fifth, seventh, ninth, and twelfth nerves of both sides. For reasons already stated it is probable that many of the functional relations between the cranial nuclei are mainly established through paths that pass by way of the cerebellum. 2. By axones from the cells of the fifth nucleus that enter the inferior peduncle and pass to the cerebellum as constituents of the nucleo-cerebellar tract. These paths are mainly crossed 3. By collaterals or stems of the arcuate paths with the sensory nuclei of the fifth, seventh, ninth, and tenth nerves of the opposite side. The chief motor nucleus of the fifth (nucleus mastica- torius) is a short column of grey matter lying in the, ANATOMY 29 upper part of the pons, close to the median side of the sensory nucleus. The nucleus consists of large stellate cells, the axones of which pass through the tegmentum to the surface of the pons as the motor fibres of the fifth nerve. From the mesial portion of the nucleus a number of fibres pass dorsally in a curv^ed manner toward the raphe, which they cross beneath the floor of the fourth ventricle to reach the opposite nucleus. A smaller constituent of the fifth motor root — the descending mesencephalic root — includes fibres that spring from cells lying within the lateral part of the grey matter in and about the Sylvian aqueduct. These fibres descend to join the larger tract from the chief motor nucleus. Some fibres that spring from the pig- mented cells of the substantia ferruginea of the same and opposite side join the descending mesencephalic root of the fifth ner^^e. The connections of the motor part of the fifth nerve are: 1. With the cortex of the lower third of the prsecen- tral convolution of the o^^posite side mainly, but to some extent of the same side. The pathway is via the corona radiata, internal capsule, and cerebral peduncle into the pons, where, for the most part, the fibres decussate and end about the motor nucleus. The fibres from the cere- bral cortex to the cranial motor nuclei, especially those to the seventh and twelfth, join the fillet, constituting what is known as the crustal fillet. (See Fillet.) The seventh is now^ considered a mixed ners^e. The cells of the primary sensory neurones of the seventh lie in the geniculate ganglion, situated in the knee of the facial canal and lying above the eighth and below the seventh nerve. The dendrites of these sensory neurones constitute the sensor}^ peripheral fibres of the seventh, which course in the pars intermedia or ner\^e of Wrisberg. The axones of the geniculate neurones form the sensory root of the seventh. The sensory nucleus of reception of the seventh nerve is shared in common with the ninth and tenth nerv^es. The fibres of the seventh nerve on approaching this nucleus divide like those of the fifth into short ascending and long descending branches. They terminate about the neurones of the nucleus, the paths being con- 30 SEMICIRCULAR CANALS tinned by axones that pass to the mesial fillet of the opposite side, and eventually to the cerebral cortex. The afferent fibres of the seventh nerve are distributed chiefly through the chorda tympani, which emerges from the tympanic cavity through the Glasserian fissure, to join the lingual nerve. They mediate sensations of taste from the anterior two-thirds of the tongue. As these fibres end in part, at least, in the same nucleus of reception as the ninth nerve, they are considered by some authors as an aberrant x^ortion of the latter. Because removal of the Gasserian ganglion has been followed by complete loss of taste in the corresponding side of the tongue (according to some surgeons in the anterior two-thirds only) , it has been assumed that all the fibres of taste pass by way of the fifth nerve, or at least that those fibres of taste run- ning in the chorda tympani Ijelong in reality to the fifth nerve. However, the results of Cushing,^^ following removal of the Gasserian ganglion, show that in no case was the sense of taste in the posterior third of the tongue affect- ed, whilst that of the anterior two-thirds, though at first diminished or even lost, was subsequently completely restored. It seems, therefore, that the loss of taste fol- lowing removal of the Gasserian ganglion was merely a bye-result of the operation. Gushing attributes the tem- porary loss of taste to post-operative degeneration and swelling of the fibres of the lingual nerve, which affected the conductivity of the intermingled fibres of the chorda tympani. The taste fibres of the chorda t3nnpani, there- fore, do not originate in the Gasserian ganglion, and the opinion given above referring their origin to the genicu- late ganglion seems, if anything, to be substantiated. Hunt'*^ has shown that inflammation of the geniculate ganglion is accompanied by herpes zoster of the tym- panum, external auditory canal, and concha, often accom- panied by peripheral facial palsy, tinnitus, deafness, and vertigo. The latter symptoms are due to the close rela- tions of the seventh and eighthnerves within the temporal bone. Hunt farther pointed out the association of in- flammations of the Gasserian ganglion and the ganglia of the second, third, and fourth dorso-spinal cervical ganglia with herpes of the face and of the occipito-collaris region ANATOMY 81 respectively, thus establishing the homology between the Gasserian and geniculate ganglia and those of the dorso- spinal roots. Head and Campbell ^Uiad previously shown that herpes zoster was due to a specific inflammation of the dorsal spinal root ganglia. The motor nucleus of the seventh nerve lies in the teg- mental region of the pons, ventral to the sixth nucleus, beneath the middle of the fourth ventricle. The connec- tions of this nucleus are: 1. With the motor cerebral cortex of the opposite side by way of the corona radiata, internal capsule, crus cere- bri, and the crustal fillet. The decussation takes place about the level of the nucleus of the j)ons. 2. With the nucleus of the opposite side. This con- nection has not been satisfactorily demonstrated. From clinical and pathological observations it has been assumed that a special group of cells in the nucleus is related to the orbicularis palpebrarum and frontalis muscles. This group of cells is closely associated with the portion of the third nucleus innerv^ating the levatores palpebrarum, and is bilaterally represented in the cerebral motor cortex. Hence the absence of paralysis of volun- tary motion of the muscles that close the eye in hemi- plegia from one-sided cerebral lesion, e.g., hemorrhage. Ferrier ^ pointed out similar instances of bilateral cor- tical innervation by way of contrast with the one-sided cortical representation of speech in Broca's centre. The seventh nerve supplies motor innervation to the muscles of the face, of part of the scalp, and of the ear, including its intrinsic muscles. The secretory and vaso-dilator fil^res (bull3ar autono- mics) for the submaxillary and sublingual salivary glands pass by way of the chorda t}Tnpani which, emerging from the tympanic cavity through the Glasserian fissure, joins the lingual nerve. After coursing a short distance with this nerve the secretory and vaso-dilator fibres for the salivary glands mentioned, branch off and pass to the glands along the ducts of the latter. The cells of the so- called submaxillary ganglion receive only fibres destined for the suljlingual gland, as shown by Langley, who sug- gests that the ganglion be called the sublingual. The fibres to the submaxillary gland connect with nerve 32 , SEMICIRCULAR CANALS cells lying within the hiliis of the gland; The ^yn4-» pathetic autonomics reach the glands by way of the supe- rior cervical ganglion. The ninth is also a mixed nerve. The cells of the primary sensory neurones lie in the superior and petrous ganglia (g. superius and g. petrosum) , situated upon the upper part of the nerve trunk as it emerges from the skull. The sensory root traverses the formatio reticularis grisea, and just before reaching the dorsal nucleus divides into a mesial and a lateral bundle of fibres. The former and smaller bundle ends about the cells of the sensory part of the dorsal nucleus (nuc. alee cinerese) . It is sup- posed that the cells in the upper part of the nucleus are related to the sense of taste, and it is about these cells that the taste fibres of the chorda tympani end in part at least. The second and larger bundle of fibres forms the chief constituent of the fasciculus solitarius along the surface and l^etween the fibres of which lies a slender column of grey matter. The cells of this grey matter constitute the spinal reception nucleus of this part of the ninth nerve. The motor portion of the ninth nerve springs from cells lying in the dorsal nucleus and in the nucleus am- biguus. It is in relation with the cortex of the lower part of the prsecentral gyrus of the opposite side. The ninth nerve mediates sensations from the mucous membrane of the tongue and pharynx (in part), and from the tym- panic cavity and Eustachian tube. It sends motor fibres to the nuiscles of the pharynx and base of the tongue and secretory fibres to the parotid gland. The dorsal nucleus, which is the nucleus of origin and reception for the ninth and tenth nerves, and for the taste fibres of the chorda tympani passing in the seventh, lies just lateral to the median vestibular and upper part of the twelfth nucleus. Its upper portion is covered })y the spinal vestibular nucleus and its lower portion overlies the twelfth nucleus. The middle portion of the nucleus — the fovea vagi — is in intimate relation with the floor of the fourth ventricle. The median portion of the nucleus constitutes the dorsal motor nucleus and the remaining portion the dorsal sen- sory nucleus. The nucleus ambiguus (nucleus ventral is) lies in the formatio reticularis grisea, midway between ANATOMY S^ the substantia gelatinosa and the dorsal accessory olivary nucleus. It consists of a small group of cells, giving origin to motor fibres, which unite with the fibres from the dorsal motor nucleus. The motor nuclei of the ninth are in crossed relation with the cerebral cortex, like the other cranial motor nerves. The sensory part of the dorsal nucleus (nuc. alse cinereae) and the spinal nucleus (nuc. tractus solitarii) , which resembles the corresponding nucleus of the fifth nerve, are reception nuclei for the lateral mixed nerves (VII, IX, and X). The fasciculus solitarius extends from the upper border of the medulla to the lower limit of the decussation of the fillet, and is related to the sensory fibres of the seventh, ninth, and tenth nerves. The largest part of this tract consists of the root fibres of the ninth nerve ; in fact, the tract itself is in reality only the continuation of the larger bundle of fibres of the ninth nerve on its way to join its nucleus of reception, the lat- ter consising of cells lying upon and within the fasciculus solitarius. The tenth (vagus, pneumogastricus) is a mixed nerve. The cell bodies of the primary sensory neurones of the vagus lie within the ganglion of the root in the jugular foramen and the ganglion of the trunk outside the jugular foramen, both ganglia being situated upon the upper part of the nerve. The centrally directed processes pass into the medulla in company with the motor strands, and divide into two sets of fibres, of which the larger set ends about the lower portion of the dorsal sensory nucleus, whilst the smaller set bends downward and enters the fasciculus solitarius to end about the cells of the reception nucleus, situated upon and between the fibres of the fasciculus. The sensory fibres, therefore, of the ninth and tenth nerves, as well as part, at least, of the seventh (chorda tympani fibres) have a more or less common nucleus of reception in the sen- sory part of the dorsal nucleus (nuc. alae cinereae) and in the spinal reception nucleus of the fasciculus solitarius (nuc. tractus solitarii). The central connections of the vagus, like those of the other mixed nerves, include : 1. Fibres to the median fillet, chiefly of the opposite 34 SEMICIRCULAR CANALS side, which pass to the optic thalamus. From the latter they are relayed to the cerebral cortex. 2. Fibres that pass to the cerebellum, mainly of the opposite side, as part of the nucleo-cerebellar tract. Ross^'^ considered the cells of the sensory part of the Tagus as the analogues of the vesicular cells of Clarke's column. 8. Fibres to various other nuclei and centres in the medulla, such as the vaso-motor and respiratory centres. The sensory portion of the vagus mediates sensation from the mucous membrane of the pharynx (branch from the ganglion of the trunk), larynx, trachea, oesophagus, stomach, intestines, gall-bladder, gall-ducts, and from the lungs and pericardium. The auricular branch from the ganglion of the root supplies the skin of the posterior portion of the auricle and the posterior inferior portion of the external auditory canal. Besides the above there are special fibres to the heart, liver, spleen, pancreas, kidneys, adrenals, and possibly to the intestinal blood-vessels. The bulbar or accessory portion of the eleventh nerve is generally admitted to be an integral part of the motor division of the tenth. It is still a question as to the ultimate distribution of these fibres as well as to that of some of the motor fibres of the tenth nerve proper. Van Gehucten ^^ believes that the accessory fibres are distributed chiefly to the larynx via the inferior laryngeal nerve, a branch of the tenth, and do not reach the heart or stomach. Brunton^^ concluded that the inhibitory cardiac fibres originate in the accessory nucleus. The efferent fibres to the heart from the tenth nerve proper are most probably inhibitory, and it is still a question whether they reach the heart muscle directly or end about neurones within the heart structure. The efferent fil^res of the tenth to the stomach and intestines include motor, inhibitory, and secretory fibres. It is stated that some of the fibres affect the calibre of the blood-vessels of the stomach and liver, but Burton-Opitz ^^ has si 1 own that no vaso-motors for the stomach or liver run in the pneumogastric nerve. The motor fibres of the tenth nerve originate in the cells of the motor portion of the dorsal nucleus, and in those of the nucleus ambiguus, ANATOMY 35 more or less in common with the motor fibres of the ninth nerve. The accessory fibres spring from cells located within the nucleus ambiguus only. The fibres from the nucleus ambiguus at first pass backward toward the floor of the fourth ventricle, and then bend sharply outward, and become condensed into compact strands that receive motor fibres from the dorsal nucleus. From this point they proceed ventro-laterally with the sensory fibres to the superficial origin of the nerve. The eleventh or accessory nerve is a purely motor nerve supplying the sterno-mastoid and trapezius muscles. Its upper medullary roots spring from the cells of the motor portion of the dorsal nucleus, which gives origin to the vagus, whilst its lower, spinal roots spring from the anterior horn of the grey matter of the cord, as low as the fifth or seventh segment. The relation of the upper por- tion of this nerve to the vagus, of which it is considered to be a part, has already been discussed. The twelfth or hypoglossal is also a pure motor nerve supplying the muscles of the tongue, the extrinsic mus- cles of the lar}mx, and those attached to the hyoid bone. Its fibres originate in a distinct nucleus lying in the floor of the fourth ventricle near the middle line. The eleventh and twelfth nerves, like the other motor cranial nerves, are related to the cerebral cortex of the opposite side. They are also related to the other cranial nuclei to some extent through the cerebellum. It is stated that the third, seventh, and twelfth nuclei are in intimate relation. The objections urged against the simple direct re- lations between the cranial nuclei render it probable that the chief relation between these three nuclei is an indirect one through the medium of a common coordinating centre, such as the cerebellum. Gaskell ^^ has shown that every spinal segment has a somatic and a splanchnic root. Each somatic root is divided into a ganglionated and a non-ganglionated por- tion springing from the cells of the posterior (dorsal- spinal-root ganglion) and anterior horns respectively. The splanchnic root is also divided into ganglionated and non-ganglionated portions, which spring from the cells of the lateral horn and those of Clarke's column respect- ively. The ganglia of the splanchnic root are the ganglia 36 SEMICIRCULAR CANALS of the sympathetic chain, and are the homologues of the ganglion trunci vagi. Thus in the eleventh nerve the somatic root, besides sending a branch to the cervical plexus, is distributed to the sterno-mastoid and trapezius muscles, whilst the splanchnic root from the lateral horn is distributed to the viscera. CHAPTER IV BLOOD-SUPPLY OF THE LABYRINTH AND OF THE CRANIAL NUCLEI The labyrinth is supplied by the internal auditory artery, a branch of the basilar, which accompanies the auditory nerve. This vessel supplies the vestibule, semi- circular canals, cochlea, and their membranous contents. The internal auditory divides into the common cochlear (Siebenmann) and the internal vestibular artery. The latter vessel supplies the vestibule. The former divides into two branches, one of which, the cochlear artery proper, supplies the two superior spirals of the cochlea, whilst the other — the vestibulo-cochlear artery — supplies the inferior spiral of the cochlea and the vestibule. The blood is returned by the internal auditory vein into the superior petrosal sinus, and by small veins which pass through the cochlear and vestibular aqueducts to the inferior and superior petrosal sinuses. Siebenmann found that the veins from all the semicircular canals united in a common trunk, which leaves the labyrinth along the aquseductus vestibuli ; but Shambaugh ^ found that in the sheep, calf, and pig the venous blood from the vestibule and semicircular canals drained into the canaliculi cochleae, but that in the calf the vein from the crus commune often leaves the labyrinth along the aquse- ductus vestibuli. The labyrinthine artery is thus a part of the central brain system, and susceptible of similar pathological changes. The branches to the cochlea, vestibule, and semicircu- lar canals form delicate convolutions in intimate relation with the cochlear and vestibular nerve elements. Wit- maack,^^ discussing the causation of senile deafness, attributes the latter to disturbed nutrition of the cochlear 37 38 SEMICIRCULAR CANALS nen^e, caused byarterio-sclerosis. The "elective vulnera- bility" of the cochlear branch of the auditory nerve is due, in part, to the fact that this nerve is imbedded in a bony capsule, partly surrounded by broad, lymphatic spaces. The blood-vessels are end arteries, whilst the ganglion cells of the cochlear ganglion are bipolar, and are much smaller than all other ganglion cells found in vertebrates. The vessels of the labyrinth are not affected by intra- cranial pressure like those of the retina, because most of the venous blood and lymph passes from the aquseductus cochleae into the jugular vein. In conditions like tumor of the brain the ear presents no sign analogous to the retinal choked disc. The region of the third nucleus is supplied by small delicate branches of the posterior cerebral artery. These branches are end arteries; that is, they form no anasto- moses, and have no communication with the vascular sys- tem of bordering regions. Moreover, these branches change from a horizontal to a vertical course, and they, as well as the superior and middle cerebellar arteries (branches of the basilar) originate at a point where the carotid and basilar blood-streams meet. These facts have been adduced to explain the momentary nystagmus, vertigo and disturbances of vision which attend sudden stooping and rising to the erect position, the chief factor in the causation of these symptoms being sudden altera- tion in the blood-supply of the ocular, cerebellar, and other centres. The pons and medulla are supplied by the vertebral arteries and by branches springing from them, viz. , the basilar and anterior si)inal. The latter supplies the medulla oblongata and the nuclei situated in its lower region, including the eleventh and twelfth. The fifth, sixth, and seventh nuclei are supplied by branches of the basilar. The medulla oblongata receives further blood- supply from branches of the dorsal spinal, posterior cere- bral, and inferior and posterior cerebellar arteries. The central artf^ry of the medulla, a branch of the basilar, sends delicate branches to the cochlear and vestibular nuclei. A branch of the posterior communicating artery furnishes a terminal to the red nucleus. The vermis of ANATOMY 39 the cerebellum receives a branch from the superior cere- bellar artery, whilst the nucleus dentatus is supplied by a branch from the middle cerebellar. The cerebral peduncle, through which pass the bulbo-cerebral and cerebello-cere- bral paths receives branches from the posterior cerebral arteries. Branches from the posterior communicating and from the anterior choroid arteries reach the internal capsule. It is stated (Kyle ^') that affections tending to obstruct the vessels supplying the cortical centres and the nuclei and paths related to the vestibular system may cause ver- tigo and other sjmiptoms usually referred to disturbances within the labyrinth. In general, it may be said that the vascular supply of the base of the brain is faulty from the standpoint of collateral circulation. Hence the persistence of sjmiptoms from small vascular lesions of areas adjoining the base, lesions which, if they occurred upon the convexity of the hemispheres, would easily be compensated by collateral blood-supply. The area of the third nucleus having the poorest blood-supply of any part of the brain, every serious disturbance of the circulation has its effect upon the innervation of the ocular muscles. Thus in profound anaemic states from loss of blood or other cause, and in the cachexia of wasting diseases, it is common to find disturbances of vision, some nystagmus, and vertigo. These symptoms are similarly encountered when a person who has lain in bed some time first assumes the erect posture. Here the vaso-motor mechanisms have become disordered from disuse, and there ensue, when the patient first attempts to stand up, temporary, irregularities in the blood-supply of the ocular and possibly other centres. CHAPTER V SYNOPSIS OF ANATOMICAL CONNECTIONS Co7inections of the Vestibular Nerve The vestibular nerve ends in the vestibular nuclei of reception. From the nuclei fibres pass : (a) To the cerebellar roof nucleus of the opposite side as the vestibulo-cerebellar tract. Risien-Russell ^^ and Ferrier and Turner ^ showed that this is an efferent path between the vermis and Deiters' nucleus, but Kolliker, from embryological studies, concludes that some of the fibres are axones of Deiters' cells a few coming from the chief auditory nucleus. (b) As arcuate fibres passing ventro-medially into the tegmentum of the pons to cross the middle line, and so bend upward and downward to reach other levels. Some fibres, however, remain on the same side. Of the crossed fibres some are said to join the mesial fillet to reach the thalamus and superior colliculi, while others are said to join the lateral fillet and so reach the inferior colliculi, and possibly the auditory cortex. (c) Commissural fibres between the nucleus of Bech- terew or superior vestibular nucleus on either side. (d) Fibres to the abducent nucleus. Gordinier and others believe that each vestibular nucleus sends fibres to the abducent nucleus on either side. Duval and Laborde showed that the sixth nucleus was connected with the third and fourth nerve nuclei of the opposite side, and stimulation of the area of the sixth nucleus caused the eyes tcj turn to the side of stimulation. This, however, does not prove that the sixth nucleus coordinates these movements. Schafer insists that no fibres enter the pos- terior longitudinal fasciculus from the sixth or third nucleus. Moreover, it is not apparent why the fibres to the sixth nucleus are necessarily the direct continuations 40 ANATOMY 41 of vestibular fibre-paths, and not the continuation of descending paths from the cerebellum. The posterior longitudinal fasciculus is in intimate relation with the nuclei of the sixth, third, and fourth nerves, and receives numerous fibres, both crossed and uncrossed, from the vestibular (including Deiters') and from other nuclei. Moreover, when eye movements take place in response to vestibular stimulation movements of other parts take place concurrently and in a coordinated manner. Hence but little importance is to be attached to this connection between the vestibular nerve and the sixth nucleus, unless it be distinctly understood as an indirect connection through the medium of the cerebellum or other coordina- ting centre via the vestibular (Deiters') nucleus or the posterior longitudinal fasciculus, or both. (e) Crossed and uncrossed fibres to the posterior longitudinal fasciculus. (f) Fibres to the spinal cord. These fibres com- municate with the olivary body and lateral columns. The descending vestibulo-olivary tract passes to the olivary body of the same side (Van Giesen ^^) , whilst the vestibulo- spinal tract passes through the periphery of the lateral field of the formatio reticularis, and descends in the lateral column of the cord. Its ultimate distribution is unknown, but it probably ends in relation with the ventral horn cells. The fibres to the spinal cord and superior olive are not altogether to be considered as mainly continuations of paths direct from the vestibular nerve. For the reasons given in discussing the fibres to the sixth nucleus these fibres are to be regarded as coming in part from the cere- bellum via Deiters' nucleus. The latter has many affer- ent and efferent neurones, and is, therefore, properly con- sidered as a relay station for both afferent and efferent impulses, rather than a coordinating centre of the higher order. More recent investigations show that part of the ventral (anterior) marginal fasciculus (vestibulo-spinal tract) comes from the roof nucleus of the cerebellmn (Morris ^^) . The same author states that the fibres from the vestibular nucleus to the abducent nucleus travel by way of the posterior median (longitudinal) fasciculus of both sides. 42 SEMICIRCULAR CANALS The vestibulo-olivary tract is best regarded as being in part at least the continuation of vestibular paths after interruption in Deiters' nucleus. Reaching the olive on the same side the fibres cross to the opposite olive and proceed in part to the cerebellum by way of the restiform body. This view seems to be supported by v. Bech- terew's experiments, in which lesions of the inferior olive caused rotations and ocular deviations, exactly like those following section of the vestibular nerve on the same side. The tract may, therefore, be called the crossed vestibulo-olivo-cerebellar tract, whilst the descending ves- tibulo-spinal tract may be called the cerebello-vestibulo- spinal tract. The olivary fasciculus, or Helweg's bundle, connects the spinal neurones with the olive and indirectly with the cerebellum (Morris). Much confusion is created by anatomical writers retaining the term, "direct sensory cerebellar tract of Edinger. " This tract was described by Edinger in his earlier work, viz., "Twelve Lectures on the Structure of the Central Nervous System." In his later work, "The Anatomy of the Central Nervous System of Man and of the Vertebrates in General," Edinger himself discards the term, "direct sensory cerebellar tract," saying: "It is wiser at present to designate the system as tractus cere- bellaris acustica, etc." We may, therefore, conclude that the direct sensory cerebellar tract contains nothing more by way of afferent paths than what is included in the sensory nucleo-cerebellar paths (q.v.). According to Cunningham, ^^ botli the principal nucleus and the nucleus of Deiters are in intimate relation with the superior worm of the cerebellum. Deiters himself, as well as Ferrier and Turner, believe that Deiters' nucleus is an internode between the cerebellum and the cord. Ferrier and Turner adduce strong evidence to support this view. But Kolliker has shown that some of the paths are afferent, i.e., to the cerebellum. Klemoff^ believes the axones of Dieters' nucleus form the ventral (anterior) tract of Lowenthal, i.e., the tractus vestibulo-spinalis of Monakow, descending in the anterolateral column of the cord. Ferrier and Turner observed that after section of the eighth nerve, the descending vestibular root did not ANATOMY 43 degenerate. They believe, therefore, that this root forms an internodal connection between Deiters' nucleus and the cuneate nucleus. Bnice saw the lower end of the descend- ing vestibular root terminate in the cuneate nucleus. It seems probable, therefore, that the descending vestibular root is a continuation of afferent cerebellar paths repre- sented in the dorsal fasciculi (columns of Goll and Burdach) . Cerebellar Connections 1. Through the inferior peduncle by: (a) The direct cerebellar tract (dorsal spino-cerebel- lar fasciculus or tract of Flechsig) continues, after in- terruption, the afferent paths from the posterior nerve roots of the same side to the superior worm of the same and opposite side, i.e., in the monticulate and lingual lobules. (b) The arcuate fibres — anterior and posterior super- ficial — from the gracile and cuneate nuclei of the same and opposite side. The fibres of the so-called descending root of the vestibular nerve may be grouped here. (See Vestibular connections.) (c) The olivo- cerebellar fibres, chiefly from the oppo- site inferior olivary nucleus, but to a limited extent from the nucleus of the same side. These constitute the bulk of the latter part of the restiform body, and end within the cortex of the hemisphere and worm, and also within the fibre complex enveloping the nucleus dentatus. The fibres are mostly afferent (v. Bechterew ^^) . The atrophy, however, of this nucleus, which is jDresent in failure of development of the opposite half of the cerebellum or fol- lowing its removal, seems to show that many of the cere- bello-olivary fibres are efferent paths. The further links of connection are uncertain. Kolliker maintains that some of the olivo-cerebellar fibres are axones of the cells of Purkinje from the oppo- site side, and that fibres from some olivary cells pass downward into the anterior ground bundle. The possi- bility of some of the olivo-cerebellar fibres being continu- ations of vestibular afferent paths should be remembered. The route in such a case would be along the vestibular nerve to Deiters' nucleus, thence to the olive on the same 44- SEMICIRCULAR CANALS side, thence cross the midline to the opposite olive and through the rest i form body to the cerebellum. Such a connection would explain the phenomena observed by v. Bechterew ^^ following destruction of the olive and many other experimental phenomena which otherwise are not readily explicable. From the manifestly important connections between the olive and the cerebellum it would seem that the olive is a great relay station for afferent and efferent cerebellar paths, if not a coordinating centre of equilibrium on its o^Mi account, v. Bechterew believes the inferior olive is related closely to tactile sensibility. (d) Fibres from the nucleus lateralis of the medulla to the cortex of the cerebellar hemisphere. The nucleus lateralis is a collection of cells in the formatio reticularis grisea near the periphery and ventral to the spinal trigeminal root. The nucleus is regarded as the analogue of the lateral horn cells. (e) Fibres from the arcuate nucleus (a collection of cells in the paths of the anterior superficial arcuate fibres) to the cerebellar cortex. (f) The nucleo-cerebellar tract, i.e., fibres from the reception nuclei of the trifacial, facial, vestibular, coch- lear, glosso-pharyngeal, and vagus. This tract occupies the middle of the peduncle, and ends chiefly in the roof nucleus (nucleus fastigii) of the same and opposite side. This tract includes the direct sensory cerebellar tract of Edinger. (See Vestibular connections.) (g) Fibres from the cerebellar roof nucleus to Deiters' nucleus, and thence by tlie vestibulo-spinal tract to the antoro-lateral column of the cord (ventral marginal fasci- culus and the fasciculus from the formatio reticularis). (h) According to some anatomical writers, additional vestibular, and possi})ly other sensory fibres, pass with- out intf3rruption byway of the restiform body to the cere- bellar roof nuclei, constituting the direct sensory cere- bellar tract of Edinger. As before noted, Edinger's direct sensory cerebellar tract, considered as an afferent cerebel- lar pathway, is in reality identical with the nucleo- cerebellar tract. ANATOMY 45 Connections of tlie Cerebellum Through the Middle Peduncle Afferent paths, i.e., to the cerebellum. 1. Fibres from the cells of the pontine nucleus as con- tinuations of the fronto-cerebellar and of the temporo- occipito-cerebellar tracts. These paths connect the cells of the frontal, temporal, and occipital lobes with the cor- tex of the opposite half of the cerebellum, ending chiefly in the cortex of the hemisphere, in the worm, and pos- sibly in the nucleus dentatus. The tracts are chiefly crossed. 2. Collaterals from ]3yramidal tracts to the pontine nuclei. Efferent paths, i.e., from the cerebellum. 1. Fibres — the axones of the Purkinje cells in the cerebellar cortex — which cross the middle line to end in relation with the cells of the nucleus tegmenti (red nucleus) , close to the raphe (v. Bechterew ^^) . The tract is mainly uncrossed, owing to a double decussation, viz., in the superior peduncles and in Forel's decussation. 2. Fibres from the cells of Purkinje to the nucleus pontis of the same and opposite side have been assumed to exist. Ferrier maintains that the cerebello-pontine fibres of the middle peduncle, after crossing the middle line, join the pyramidal tract, to recross in the pyramidal decussation. Such a pathway would establish efferent relations between each half of the cerebellum and the structures of the same side of the body. Ferrier 's experi- ments undoubtedly establish a marked functional relation- ship between these parts, but recent observations seem to show that the efferent cerebello-pontine fibres do not end in the nucleus pontis but, after crossing the middle line, are believed to end within the tegmentum in the red nucleus (v. Bechterew). Ferrier, however, makes no mention of the nucleus pontis, nor of interruption of the efferent paths at this point. V. Bechterew 's assumption may be accepted, and there is still provision for a possible recrossing of this efferent cerebellar path by fibres which emerge from the ventro-medial surface of the red nucleus, and cross the 46 SEMICIKCULAR CANALS middle line as the decussation of Forel bending down- ward as the rubro-spinal tract. The middle cerebellar peduncle, according to v. Bech- terew, contains: (a) Cerebral fibres which originate in the superior and lateral parts of the cerebellar cortex, and in the area of the upper worm and central nucleus, and pass to the upper half of the pons, where some of the fibres from the cerebrum along the medial and lateral divisions of the cerebellar peduncles are interrupted. The motor tracts of the cerebrum are joined m the ganglia of the pons by impulses from the cerebellum conveyed in the middle peduncle. (b) The spinal fibres, which are cerebello-fugal, arise from the anterior and middle parts of the cerebellar cor- tex, and end in the grey matter of the lower half of the pons on both sides. From this point fibres pass as the fasciculus verticalis to the region of the nucleus reticu- laris and the lateral area of the formatio reticularis, and finally to the antero-lateral ground bundles of the cord (fasciculus to and from the formatio reticularis) . A few fibres reach the corpora quadrigemina with the lemniscus. From the above it is manifest that v. Bechterew agrees with Ferrier in the main facts. 2. Fibres to the corpora quadrigemina via the spinal bundle and the median fillet (v. Bechterew) . Connections of the Cerehellum Through the Superior Peduncle Afferent imths, i.e., to the cerebellum. 1. Fibres from Gowers' tract (ventral spino-cerebellar tract), arching over the fifth nerve to reach the superior peduncle and thence to reach the dentate nucleus and cerebellar cortex of the same side (Hoche). As some of the posterior root fibres, of which Gowers' tract is a con- tinuation, decussate in the anterior commissure, this tract is, in part, crossed. Mott believes the fibres of Gowers' tract taking this course end in the posterior portion of the vermis, whilst the remaining fibres of Gowers' tract end in the corpora quadrigemina and the thalamus. ANATOMY 47 2. Fibres from the red nucleus to the dentate nucleus. This path is mainly crossed. 8. Fibres to the cerebellum from the oculo-motor nucleus — afferent ocular and pupillary paths (v. Bech- terew). This path is crossed. Efferent paths, i.e., from the cerebellum. 1. Fibres of the cerebello-tegmental tract, which spring from the dentate nucleus with probably augmenta- tions from the roof nucleus and cortex of the worm. At the decussation of the superior peduncles most of the fibres cross. Above this decussation the fibres are in large measure interrupted in the red nucleus, those not so interrupted passing through the subthalamic region to end in relation with the cells of the thalamus. Most of the fibre-paths ending in the red nucleus are continued by rubral neurones to the thalamus. From the thalamus the uninterrupted paths, as well as those interrupted in the red nucleus, are continued to the cerebral cortex by the thalamo-cortical paths. Many of the fibre-paths ending in the red nucleus are, however, diverted into the rubro- spinal tract which, for the most part, crosses the median line in the decussation of Forel, and traverses the brain stem and antero-lateral columns of the cord to reach the ventral root cells. The connections of the cerebellum through the rubro-spinal tract are, therefore, chiefly un- crossed. The axones of the red nucleus neurones, which form the rubro-spinal tract, emerge from the ventro-medial surface of the nucleus, cross the middle line at the decussation of Forel, and bend downward within the tegmentum of the mid-brain and pons to reach the medulla, finally entering the lateral columns of the cord as an important but uncer- tainly defined descending tract, which may be fairly rep- resented as the intermediate fasciculus. The cerebello- rubro-thalamico-cortical paths are mainly crossed, while the cerebello-rubro-spinal tracts, owing to a double decus- sation, bring the cerebellum into relation mainly with the motor root cells of the same side. 2. Fibres to the oculo-motor nucleus of the opposite side. These fibres contain the afferent pupil reflex path (v. Bechterew ^^) , but they also contain efferent paths, 48 SEMICIRCULAR CANALS probably concerned in the conjugate movements of the eves. This tract is crossed. The dorsal zones of the early metencephalon besides providing the reception nuclei of the sensory cranial nerves, and perhaps of the pontine nuclei, contribute the neuroblasts, which become the nervous elements of the cerebellmn. The ventral zones play an active part in producing the tegmental portion of the pons and nuclei of origin of the fifth, sixth, and seventh cranial nerves. As in the medulla so in the pons, the ventral tracts are relatively late additions to the tegmentum, which is the primary and oldest part of this segment of the brain stem. The bulky ventral nervous masses take fonn only after the appearance of the cerebro-spinal and cerebro-cerebellar paths. The hmnan cerebellum is, therefore, developed from the roof-x:)late and adjacent parts of the dorsal zones of the lateral walls of the metencephalon. The posterior longitudinal fasciculus contains : 1. Fibres from the nucleus of the posterior commissure (Darkschewitsch's nucleus) in advance of the third nerve nucleus in the grey matter, about the upper end of the Sylvian aqueduct. The fibres cross to join the fasciculus of the opposite side. 2. Fibres, also crossed, from the nucleus fasciculi longitudinalis dorsalis in the grey matter of the floor of the third ventricle in the vicinity of the corpus mam- millare. 3. Fibres crossed and uncrossed from the vestibular (Deiters') nucleus. For reasons already stated in dis- cussing the vestibular connections, it is highly improbable that the paths lying between Deiters' nucleus and the posterior longitudinal fasciculus merely represent the con- tinuations of paths from the semicircular canals to Deiters' nucleus, and thence to the ocular and other nuclei. Many of the fibres undoubtedly are continuations of paths from the cerebellum and other higher centres, perhaps, and carry efferent impulses, whilst others are afferent — the continuations perhaps of vestibular paths, but their main o])jective ])oint is not the sixth nucleus, but rather some higher coordinating centre. Either of these suppositions makes it possible to explain the phenomena observed on stimulating the area corresponding to the location of the ANATOMY 49 Bixth nerve nucleus without according this latter centre the dignity of a coordinating centre for the other ocular muscles, and also without encountering the awkward ob- jections the latter hypothesis entails. 4. Fibres from the abducens nucleus to the oculo- motor nucleus. The existence of these or of any fibres leaving the abducens nucleus to enter the posterior longi- tudinal fasciculus is denied by Schafer.^^ 5. Fibres from the reception nuclei of the remaining sensory nerves of the brain stem of the same and opposite sides. These fibres are probably all afferent, their objec- tive point being the higher coordinating centres, and perhaps also centres at other levels, which by their means — through the posterior longitudinal fasciculus — may be brought into relation for reflex movements of a lower order. 6. Fibres traversing the commissura hypothalamica (Edinger ^) , to reach probably the mammillary body of the opposite side. 7. Fibres probably also to the thalamus, subthalamic region, the corpora quadrigemina, the red nucleus, and the cerebellum. The connections of the posterior longitudinal fascicu- lus are important and far-reaching, but they have been only imperfectly worked out. The connection with the cerebellum is undoubted, and yet no definite path of any importance has been traced. The same has to be said of its connections with other higher centres. Connections of the Mesial Fillet or Lemniscus 1. Fibres from the nucleus gracilis and nucleus cunea- tus which, for the most part, cross the middle line as the arcuate filDres making the sensory decussation about the upper border of the pyramidal decussation in the lower part of the medulla oblongata. This sensory decussation marks the lowest limit of the fillet and the fibres compos- ing it are continuations of the paths represented in the posterior fasciculi of the cord, viz., those of Goll and Burdach derived from the posterior nerve roots of the same side. The fillet tract is mainly crossed. 2. Fibres from the reception nuclei of all the sensory 50 SEMICIRCULAR CANALS cranial nerves connected with the brain stem. These fibres are mainly crossed. 8. Fibres from the cells of the more extensive nuclei, e.g., from those of the substantia gelatinosa. Accom- panying the spinal root of the fifth nerve, numerous fibres sweep toward the raphe and, with few exceptions, cross to join the fillet of the opposite side. These three sets of fibres constituting the bulbo-tecto- thalamic tract course upward through the tegmentum. Many of the fibres end around the deeper grey stratum of the superior coUiculus, some passing over the aqueduct of Sylvius to the opposite colliculus. The remaining fibres pass on to reach the cells in the ventral part of the optic thalamus, thence the paths are continued to various parts of the cerebral cortex. Other fibres said to be derived from the cuneate nucleus end in the corpus subthalami- cum and the lenticular nucleus. From the cells of the latter, fibres proceed through the commissure of Meynert — a strand j^laced just above the optic chiasm — to the lenticular nucleus of the opposite side. Still other fibres can he traced into the posterior commissure of the brain and into the mammillary body. The fillet has also strands running in an opposite direction. Some of these are probably: 4. Fibres from the cells of the optic thalamus and corpora quadrigemina. 5. Efferent strands which establish connections between the cerebral cortex and the nuclei of the motor cranial nerves, especially the seventh and twelfth. These cortico- bulbar tracts join the median fillet in the upper part of the pons, and descend with it as far as the upper limit of the twelfth nucleus. This part is often called the crustal fillet. On reaching the levels of the various nuclei, the fibres destined for them undergo decussation for the most part. 6. Fibres from the cerebellum via the spinal bundle of the middle peduncle to the corpora quadrigemina (v. Bechterew). ANATOMY 51 Connections of the Superior CoUiciiU of the Corpora Quadrige7nina Afferent paths, i e., to the coUiciili. 1. Fibres from the optic tract through the superior brachium directly, or after interruption in the lateral gen- iculate body. Probably some fibres cross to the opposite colliculus through the commissure of the superior col- liculi. 2. Possibly fibres from the lateral geniculate body as continuations of the paths from the occipital cortex to the lateral geniculate body. These latter run in the optic radiation, but are centrifugal. 3. With the posterior sensory tracts of the cord through the median fillet. Probably some fibres cross to the opposite colliculus by way of the commissure. 4. With the cochlear nuclei by way of the lateral fillet. 5. Fibres between the superior colliculi and the pos- terior longitudinal fasciculus connecting the nuclei of the third, fourth, and sixth cranial nerves with the superior colliculus. These are part of the undemonstrated fibres mentioned in the connections of the posterior longitudi- nal fasciculus. 6. Probably spino-tectal fibres travelling with the tecto-spinal tract, but in the reverse direction. 7. Fibres from the substantia nigra by way of the fillet (v. Bechterew ^^) . 8. Fibres from the cerebellum by way of the spinal bundle of the middle peduncle through the median fillet (v, Bechterew ^^) . Note. — The fibre paths grouped under 5 and 8 are probably the afferent cerebellar paths which control the reflex conjugate movements of the eyes and the various forms of physiological nystagmus. Efferent paths, i.e., from the superior colliculi. 1. The tecto-bulbar and tecto-spinal tracts. These fibres emerge from the ventral borders of the colliculi. The more medially situated fibres cross the raphe to form, with the corresponding fibres of the opposite side, the fountain decussation of Meynert, just ventral to the pos- 52 SEMICIRCULAR CANALS fcerior longitudinal fasciculus. The destinations of the fibres of these tracts are (1) the nuclei within the brain stem; (2) undetermined nuclei in the spinal cord, most probably the ventral root cells. The fibres to the spinal cord pass by way oft the anterior column of the cord (fas- ciculus sulco-marginalis) , whether directly or after inter- ruption being undetermined. The tracts are partly crossed. 2. Some of the fibres as they emerge from the colliculi can be traced through the tegmentum, passing to the outer side of the red nucleus, piercing the median fillet and entering the substantia nigra. 3. Fibres in the commissure of the superior colliculi as axones of the cells of the colliculi. 4. Possibly fibres to the lateral geniculate body, the path being continued thence to the occipital cortex. Connections of the Lateral Genimilate Body Afferent paths, i.e., to the geniculate body. 1. Fibres of the outer division of the optic tract. 2. Fibres (cortifugal) from the occipital cortex by way of the optic radiation. Efferent paths, i.e., from the geniculate body. 1. Fibres to the superior colliculus through the supe- rior brachium. Some fibres probably reach the opposite colliculus through the commissure of the superior col- liculi. The superior brachium contains also fibres from the optic tract that reach the superior colliculus without interruption in the lateral geniculate body. 2. Fibres to the occipital cortex by way of the optic radiations. Connections of the Lateral Fillet or Lemniscus Lateralis Afferent paths, i.e., toward the cerebrum. L Fibres from the superior olivary nucleus of the same side, which represent the continuation of the coch- lear paths, chiefly from the opposit(3 auditory nuclei to ANATOMY 58 the inferior colliciilus and median geniculate body, and through these latter by way of the auditory radiation to the cortex. Some fibres from the superior olivary nucleus pass to the sixth nucleus, and by way of the posterior longitudinal fasciculus to the nuclei of the third and fourth cranial nerves. But see observations on the simi- lar connections of the vestibular nucleus. 2. Fibres from the cells of the nucleus of the lateral fillet, and possibly fibres from the nucleus tegmenti lateralis of Kolliker. 3. Fibres from the acoustic striae after mesial decus- sation. The fibres of the lateral fillet end partly in the cells of the inferior coUiculus, and in those of the median genicu- late body, the paths being continued by axones from the cells of these bodies to the auditory cortical areas. Some fibres of the lateral fillet probably reach the inferior col- liculus of the opposite side through the commissure of the inferior colliculi. The lateral fillet mainly represents a crossed afferent cochlear path. Connections of the Inferior Colliculi Afferent paths, i.e., to the colliculi. 1. Fibres from the lateral fillet ending about the cells of the nucleus of the inferior colliculus of the same side, some fibres probably reaching the opposite colliculus by way of the commissure of the inferior colliculi. 2. Fibres from the cerebral cortex, especially from the temporal lobe through the inferior brachium. Efferent paths, i.e., from the colliculi. 1, Fibres — axones of the cells of the inferior colliculi — which continue the paths of the lateral fillets interrupted in the colliculi. These fibres joining with those con- tinued from the lateral fillet are the chief constituents of the inferior brachia. 2. Fibres to the tecto-bulbar and tecto-spinal tracts. 8. Fibres also pass by way of the superior medullary velum to the medulla of the worm. 54 SEMICIRCULAR CANALS Coimections of tlie Median Geniculate Bodies Afferent paths, i.e., to the geniculate bodies through the inferior brachium. 1. Fibres from the lateral fillets which end about the cells of the nuclei of the median geniculate bodies. These are the fibres that have not been interrupted in the in- ferior colliculi. 2. Probably fibres from the auditory cortex. Efferent paths, i.e., from the geniculate bodies. 1. Fibres forming the lateral root of the optic tract known as the inferior commissure of Gudden. After decussation many of these fibres probably are directed toward the lenticular nucleus. Some fibres may possibly end in the subthalamic nucleus of the same side. The existence of fibres from the median geniculate body to the median root of the optic nerve has been demonstrated. These fibres are not concerned in vision, and do not atrophy after enucleation of the eye as do retinal fibres. They probably represent in us older and little used paths for protective reflexes analogous to those paths which enable the frog, deprived of its cerebrum, to "see" sufficiently to escape objects in jumping, although it is unable to recognize anything. Similar unused paths can be traced in the olfactory organs. It is possible that these paths may still function to some extent in abnormal conditions of heightened irritability, as in the nausea of seasickness. 2. Fibres — the axones of the cells of the median gen- iculate bodies — which continue the paths of the lateral fillet, not interrupted in the inferior colliculi, to the audi- tory cortex. Connections of the Inferior Olivary Nucleus Afferent paths, i.e., toward the nucleus. 1. Fibres from the cerebellar cortex, the worm, and the nucleus dentatus through the restiform body, through the nucleus of the same side, mainly without interruption, across the middle line, to end in the nucleus of the oppo- ANATOMY 55 site side. These fibres constitute an efferent cerebellar path, continued, perhaps, by fibres which spring as axones of the olivary cells, and which descend in the anterior ground bundle of the cord (Kolliker). It is probable that the paths represented here cross the middle line twice. (See "Efferent paths" below.) 2. Fibres from Deiters' nucleus, which pass to the olive of the same side, thence across the middle line to the olive on the opposite side, and through the restiform body to the cerebellum. These fibres represent, in part at least, the continuation of vestibular paths interrupted in Deiters' nucleus, and are generally known as the descend- ing vestibular olivary tract. It seems more correct to call them the crossed vestibulo-olivo-cerebellar tract for reasons stated in discussing the vestibular connections. 3. Fibres from Helweg's fasciculus, probably an affer- ent cerebellar pathway. Efferent paths, that is, from the inferior olivary nucleus. 1. Fibres as axones of the olivary cells passing down in the anterior ground bundle of the cord (Kolliker). These fibres in part may represent the continuations of efferent cerebellar paths, beginning in the roof nucleus, thence to Deiters' nucleus of the opposite side, thence w^ith or without interruption they descend to the inferior olive on the same side, and crossing to the opposite olive end about the neurones of the olivary nucleus. Such a pathway crosses the middle line twice, bringing thus each half of the cerebellmn into relations with the structures on the same side of the body. See "Olivo-cerebellar fibres," under the connections of the inferior peduncle. Another possible means of double decussation of these paths is discussed under the vestibulo-sj)inal tract in the cord (q.v.). 2. Fibres from the inferior olive to the opposite olive, thence through the restiform body to the cerebellar cortex, the worm and the nucleus dentatus. Some fibres ascend to the cerebellmn from the olive of the same side. This set of efferent olivary fibres consists mainly of afferent cerebellar fibres, and represents most probably the con- tinuation of vestibular paths, interrupted in Deiters' nucleus, and perhaps also in either one of the olivary 56 SEMICIRCULAR CANALS nuclei. This set of fibres is mentioned under both afferent and efferent paths, because, owing to the peculiar relations of the olives to each other, the fibres that are afferent to one olive are frequently efferent in relation to the other. The accessor}^ olivaiy nuclei are two irregular, plate- like masses of grey matter that lie respectively mesially and dorsally to the chief olive. Their connections are in the main those of the chief olivary nuclei. Connections of the Superior Olivary Nucleus Afferent paths, i.e., to the nucleus. \. Fibres from the cochlear nuclei, mainly of the opposite side. The continuation of these paths, after interruption in the superior olive, represents the chief source of the lateral fillet. The axones of the ventral cochlear nucleus and, to some extent, those of the lateral cochlear nucleus, as they traverse the upper part of the pons toward the superior olive on the opposite side form a conspicuous transverse tract — the corpus trapezoides — that separates the tegmental from the ventral region of the pons. Some large cells found within the corpus trape- zoides are known as the nucleus trapezoideus. These cells give off axones to the trapezoid body paths, and probably in part to the superior olivary nucleus. 2. Fibres from the lateral half of the cerebellum of the same side as the cerebello-superior olivary tract. Accord- ing to V. Bechterew these fibres, after decussating in the middle line, pass from the cerebellar roof nucleus, and go directly or through the fibres of the trapezius to the superior olive. There is reason for believing that this is a cerebellar centripetal tract, Vjut v. Bechterew l^elieves it to be centrifugal because of the direct communication of the superior olive with the abducent nuclei, and because of the relation of the latter to reflex ocular movements. Efferent paths, i.e., from the nucleus. 1. Fibres, as axones of the nucleus, which are the chief source of origin of the lateral fillet. Th(?y represent the continuation of cochlear paths t/) the inferior colliculus, median geniculate) body, and auditory cort(3x. 2. Fibres to the nucleus of the sixth nerve and other ANATOMY 57 fibres by way of the posterior longitudinal fasciculus to the other oculo-motor nuclei. For reasons stated in dis- cussing the vestibular connections with the sixth nucleus, these fibres are not to be considered as altogether mere continuations of cochlear paths, but are rather to be taken in the main as a part of many efferent paths from higher coordinating centres, e.g., the cerebellum. V. Bechterew ^^ considers these fibres as the continua- tion of a cerebello-superior olivary tract, carrying cere- bellar centrifugal impulses, and analogous to the fibres in the superior cerebellar peduncle to the oculo-motor nucleus of the opposite side. This opinion is in harmony with the views repeatedly expressed in these pages con- cerning the relations between the various cranial nerve nuclei, and notably between the vestibular, sixth and third nerve nuclei. The cerebellum consists of two lateral lobes or hemi- spheres connected by a median lobe, the vermis. All these divisions are subdivided into various lobules, the surfaces of which are marked by parallel transverse folds or laminse, which give off secondary and tertiary laminae. The general appearance presented on section is known as the arbor vitae. The surface of the cerebellum is com- posed of grey matter, the cortex, enveloping the white matter. There are also masses of grey matter — the in- ternal nuclei — within the cerebellum imbedded in the white matter. The fibres that enter the cerebellum are : 1. From the restiform body, (a) from the dorsal spino-cerebellar tract to the cortex of the vermis; (b) olivo-cerebellar fibres to the whole cortex; (c) fibres from the lateral nucleus, and possibly from other nuclei in the reticular formation. 2. The continuations of vestibular root-fibres to the vermis. 3. Fibres from the ventral spino-cerebellar tract to the vermis. 4. Fibres from the nucleus pontis to the cortex of the hemispheres. The internal cerebellar nuclei are: (1) the dentate nucleus; (2) the roof nucleus or nucleus fastigii; (8) the nucleus emboliformis; and (4) the nucleus globosus. The globosus is connected by uncertain and limited 58 SEMICIRCULAR CANALS attachments with the roof nucleus and embolus. It is also connected with the postero- inferior part of the den- tate nucleus. Hence these nuclei are more or less con- tinuous masses of grey matter. The globosus and emboli- fomiis are but incompletely separated parts of the nucleus dentatus. The cortical cells do not send axones outside the cerebellum, all efferent paths being interrupted in the internal nuclei. The dentate nucleus receives fibres from the cortex of the hemispheres. The globosus and emboli- formis receive fibres from the cortex of the vermis, whilst the nucleus fastigii receives fibres from various parts. The axones of the nucleus fastigii (fastigio-bulbar fibres), for the most part as crossed paths, pass to the vestibular and, possibly, to other reticular formation nuclei. The axones of the remaining internal cerebellar nuclei pass in the superior peduncle. There may be some efferent fibres in the middle peduncle to the reticular formation nuclei, but the greater part of this peduncle consists of ponto- cerebellar fibres. The inferior and middle peduncles are thus largely afferent, whilst the superior peduncle is effer- ent in great part to the red nucleus, thalamus, and nucleus of the third nerve. The commissural tracts constitute part of the white matter of the cerebellum. The anterior (superior) commissure is the larger, and lies in front of the dentate nucleus, whilst the posterior (inferior) commissure lies behind the nucleus. Each crosses the middle line to pass into the opposite hemi- sphere, thus constituting the anterior and posterior cere- bellar decussations. Connections of the Worm ( Verynis) Within the substance of the worm are: \. The superior cerebellar commissure. This consists of fibres passing in front of the roof nucleus. Beyond the worm on either side the fibres expand into the main limbs of the medullary tree. This commissure is the main link between the cortical areas of the cerebellar hemisphere. 2. The inferior cerebellar commissure passes behind the roof nucleus as a number of email transversely cours- ing bundles. ANATOMY 59 8. The decussation of the roof nuclei. This differs from the commissural tract just mentioned. It consists of rounded bundles traversing the roof nucleus, especi- ally its anterior (superior) part. More distally the fibres skirt the dorsal margin, and still farther backward they invade the beginning of the medullary limb. 4. The median sagittal bundle extends from the supe- rior medullary velum, beneath the roof nucleus into the medulla of the worm. Above, these fibres are continued upward through the medullary velum and into the inferior colliculus. The separate extra-cerebellar connections of the worm * have not been successfully traced. Various experiments, however, point to the worm as containing most important coordinating centres with wide peripheral relations. The superior medullary velum is a sheet of white mat- ter extending from beneath the corpora quadrigemina to the medullary substance of the cerebellum. Laterally, it is attached to the superior cerebellar peduncles, thus forming the roof of the upper part of the fourth ventricle, where its ventral surface is lined by ependpna. Dor- sally, it is overlaid by the rudimentary folia of the lingula. Its connections are: 1. Fibres of the median sagittal bundle passing be- tween the medulla of the worm and the inferior coUiculi. The function of these fibres has not been detennined. The inferior medullary velum also consists of white matter, and is attached for some distance to the front and lower surface of the nodule. Its connections, so far as known, are merely mechanical. The fourth ventricle communicates freely with the subarachnoid space of the cord through the foramen of Magendie, situated in the median part of the roof of the * fourth ventricle, and also through the foramina of Luschka in the lateral recesses of the ventricle. Connectiofis of the Pontine Nucleus Afferent paths, i.e., to the nucleus. 1. Fibres from the cortex of the frontal, temporal, and occipital lobes of the same side as constituents of the fronto-cerebellar and temporo-occipito-cerebeUar tracts. 60 SEMICIRCULAR CANALS 2. Collaterals from the pyramidal tracts, thus estab- lishing connections between the motor areas of the cortex and the pontine nuclei. Efferent paths, i.e., from the nucleus. 1. Ponto-cerebellar fibres — the immediate constituents of the middle peduncle — which, for the most part, cross the middle line to reach all parts of the cortex of the cerebellar hemisphere and of the worm, and possibly the nucleus dentatus. According to some authors the assumption that the * efferent cerebello-pontine fibres end about the cells of the pontine nucleus lacks the support of more recent observa- tions. (See note on the Connections of the middle cere- bellar peduncle.) The red nucleus consists of an ovoid reticulated field on either side of the median line in the upper half of the mid-brain, extending from the lower border of the su- perior colliculus to a short distance within the subthala- mic region. Each nucleus consists of a complex of gxey matter and fibres. Connectio7is of the Bed Nucleus (Nucleus Ruber, Nucleus Tegmenti) Afferent paths, i.e., to the nucleus. 1. Fibres from the superior cerebellar peduncle. As the decussation of this peduncle begins about the upper third of the inferior colliculus, and is best marked oppo- site the superior colliculi, it is evident that the red nucleus receives fibres as follows: (a) uncrossed fibres from the peduncle of the same side; (b) crossed fibres from the peduncle (;f the opposite side. 2. Fibres of the efferent cerebello-pontine tract in the middle peduncle (v. Bechterew). These fibres represent a crossed path from the half of the cerebellum on the oppositf3 side. 8. Fibres that enter the nucleus on its lateral aspect from the cerebral cortex (Dejerine^^) and probably also from the corpus striatum (Edinger), e.g., fibres included in the tractus strio-thalamicus, which pass from the ANATOMY 61 caudate nucleus and putamen to the thalamus, subthala- mic body, and the red nucleus. Efferent paths, i.e., from the nucleus. 1. Fibres to the optic thalamus as axones of the rubral neurones. These fibres represent the continuation of the paths of the superior cerebellar j^eduncle, inter- rupted in the nucleus. From the thalamus the path is continued to the cerebral cortex. 2. Fibres — the axones of the rubral neurones — which join the rubro-spinal tract, having crossed in the decussa- tion of Forel. These represent the continuation of the paths from the cerebral cortex and corpus striatum, and are to be considered as indirect motor paths supplemental to the cortico-spinal pyramidal tracts. 8. Fibres — the axones of the rubral neurones — which emerge from the ventro-medial surface of the nucleus, cross the middle line in the decussation of Forel, and turn downward as the rubro-spinal tract. This latter descends within the tegmentum of the mid-brain and pons, traverses the medulla, and finally enters the lateral column of the cord. The rubro-spinal tract, therefore, carries efferent im- pulses as follows : 1. From the cerebral cortex and corpus striatum of the opposite side, the path crossing once in the decussation of Forel. 2. From the cerebellum of the same side, (a) by way of the superior peduncle, the path crossing in the pedun- cular decussation and recrossing in Forel's decussation; (b) by way of the middle peduncle, the path crossing in the pons to reach the red nucleus and recrossing in Forel's decussation. Ferrierheld that the middle pedun- cular fibres, after crossing the middle line, join the py- ramidal tracts and recross in the decussation of the latter. The optic thalamus is mainly a great ganglionic inter- node in the corticipetal paths. Most of the afferent paths from the cord, brain-stem, and cerebellum end about its cells, thence corticipetal fibres pass to all parts of the cerebral cortex and to the corpus striatum. The thala- mus also receives fil^res from all parts of the cerebral cor- tex, and from it efferent fibres proceed to the lov^ex cer^tre^ 62 SEMICIRCULAR CANALS in the brain-stem and cord. The stratum zonale is a thin layer of nerve fibres on the superior surface of the thala- mus. The fibres can be traced to the optic tract on the one hand and to the optic radiations on the other. The thalamus is connected with its fellow by a bridge of grey matter with few white fibres, the massa intermedia. Lat- erally the thalamus blends with the internal capsule. The reticulated stratum on the ventro-lateral surface consti- tutes the medullary lamina. It consists of numerous fibres to and from the thalamus. The ventral surface of the thalamus rests on the prolongation of the tegmental part of the cerebral peduncle, and is called the subthalamic tegmental region. The ventral nucleus receives the great sensory paths. This nucleus and the ganglion habenulse are the oldest of the thalamic nuclei, being found in all vertebrates (Edinger^^). The optic thalamus, subthalamic body, and the lateral geniculate body constitute the main divisions, in regard to function, of the diencephalon. The thalamus itself contains some twenty grey nuclei (Nissl, v. Monakow). The subthalamic body and the lateral geniculate body may be regarded as grey nuclei, somewhat analogous to the nuclei of the thalamus, only more distinctly separable from the latter structure. Relatively to its bulk the region sends few fibres caudally, but it sends numerous fibres to the telencephalon (c. striatum and cortex) . Connections of the Optic Thalamus Afferent paths, i.e., to the thalamus. 1. Fibres directly from the cord as the spino-thalamic and probably some from Gowers' tract. The relation is mainly a crossed one. 2. Fibres from the cerebellum, (a) directly, as cere- bello-thalamic fibres from the same and opposite side; (b) indirectly, after interruption in the red nucleus, as the rubro-thalamic fibres. 3. Fibres from the various nuclei by way of the median fillet, i.e., (a) from the gracile and cuneate nuclei, con- tinuing upward the paths of the posterior fasciculi of the •cord after decussation for the most part; (b) from the jeception nuclei of all the sensory cranial nerves, as well ANATOMY 63 as from the more extensive nuclei. (See Median fillet connections.) 4. Probably fibres of other '^tracts which arise within the tegmental area of the brain-stem, e.g., undemon- strated fibres from the posterior longitudinal fasciculus. 5. Fibres from all parts of the cerebral cortex, which pass in the thalamic radiation as cortifugal paths. 6. Fibres of the tractus strio-thalamicus, from the caudate nucleus and putamen. Some fibres from the caudate nucleus reach the thalamus directly by way of the internal capsule. 7. Fibres as a strand from the cortex of the olfactory bulb. 8. Fibres (thalamocipetal) from the optic tract, and from the optic radiation. These fibres constitute the stratum zonale — a layer of white matter on the superior aspect of the thalamus. The fibres from the lateral root of the optic tract are superficial, and cross the external geniculate body to spread over the thalamus. The fibres from the occipital cortex, by way of the optic radiation, invest the pulvinar. 9. Fibres of the stratum zonale from the temporal cor- tex via the ventral stalk. 10. Fibres in the mammillo-thalamic tract being a continuation of the paths leading from the olfactory cortical areas in the uncus and hippocampus to the mam- millary nuclei. Efferent paths, i.e., from the thalamus. 1. Fibres — the thalamo-cortical — which issue from the latero-ventral surface of the thalamus, and proceed to all parts of the hemisphere, some crossing to the opposite side by way of the corpus callosum. The fibres are con- ventionally grouped into bundles, called the stalks of the thalamus. Each stalk is named according to its rela- tions. Thus there is a frontal, a parietal, an occipital, and a ventral stalk. The frontal stalk traverses the internal capsule between the caudate and lenticular nuclei, to which it gives fibres and ends in the frontal cortex. The parietal stalk enters the internal capsule, and fre- quently the lenticular nucleus in its course to the parietal cortex. Other fibres destined for the parietal lobe and 64 SEMICIRCULAR CANALS the adjacent parts of the frontal lobe, are continuations of the paths of the mesial fillet. These fibres emerge mostly from the ventral tlialamic nucleus, pass outward to the under surface of the lenticular nucleus; then, bending upward, traverse the lenticular nucleus by way of the medullary striae, or the globus pallidus to reach the cor- tex. Other fibres possibly continue the fillet path by entering the internal capsule, and thus, perhaps, reach the coi-tex directly. The occipital stalk connects the thalamus with the visual cortical areas of the occipital and parietal lobes. The fibres issue from the lateral surface of the pulvinar and as the optic radiation sweep outward and backward around the posterior horn of the lateral ventricle to reach the cortex. The ventral stalk emerges from the fore part of the ventral surface of the thalamus, arising from the lateral and mesial nuclei. It passes dowTiward and outward beneath the lenticular nucleus, and includes two systems of fibres. Its lower part — ansa peduncularis — continues laterally into the cor- tex of the temporal and central lobes. Its upper part — ansa lenticularis — skirts the adjacent border of the len- ticular nucleus, which it enters to gain the putamen; or, continuing through the lenticular nucleus via the medul- lary laminse, it reaches the caudate nucleus. The efferent fibres, i.e., from the thalamus are, therefore: \. To the frontal cortex and to the caudate and len- ticular nuclei. 2. To the parietal cortex and lenticular nucleus. 3. Fibres to the parietal and frontal lobes as continua- tions of the paths of the mesial fillet via the lenticular nucleus, the medullary striae, or the globus pallidus to the cort<3X. 4. Fibres that possibly continue the fillet path to reach the cortex directly, via the internal capsule. 5. Fibres to the cortex of the occipital and parietal lobes. 6. Fibres of the ventral stalk, (a) to the cortex of the temporal and central lobes via the ansa peduncularis ; (b) to the putamen as fibres of the ansa lenticularis through the lenticular nucleus, or to the caudate nucleus through the lenticular nucleus and the medullary laminae. ANATOMY 65 7. Fibres in the thalamo-mammillary tract, the paths possibly being continued thence to the olfactory cortex by way of the anterior pillar of the fornix, or by way of the mammillo-tegmental strands to the tegmentum of the mid-brain and to lower levels. In every instance where the thalamus is connected with the cortex, i.e., where there are cortico-thalamic paths, there are also paths in the reverse direction, i.e., thalamo-cortical paths. The epithalamus — a subdivision of the thalamencepha- lon — includes the trigonum habenulse, the pineal body, and the posterior commissure. In the trigonum habenulse the striae mark the site of the taenia thalami and the still deeper ganglion habenulse. The source of the fibres of the striae medullares is uncer- tain. Probable constituents of the striae medullares. 1. Fibres — the olfactory habenular — arising 'from the cells within the septum lucidum and the olfactory area. 2. Fibres — the cortico-habenular — from the cortical cells within the hippocampus and the adjacent area, and by way of the fornix and its anterior pillar, reaching the fore end of the thalamus to pass backward within the medullary striae. Many fibres of the striae medullares end about the cells of the ganglion habenulse. Some, however, reach the pineal body through the peduncle of the latter, cross in the commissura habenulae, and end about the cells of the opposite habenular nucleus. The ganglion habenulae in turn gives origin to the fasciculus retroflexus of Meynert, which arches backward and downward, passing between the central grey matter of the third ventricle and the thalamus proper, then to the mesial side of the red nucleus to reach the base of the brain, where it ends about the cells of the interpeduncular ganglion. This nucleus is a well-defined collection of cells in many animals. In man it consists of a scattered median cell group within the posterior perforated space, close to the anterior border of the pons. The fasciculus, also called the habenulo-peduncular tract, receives fibres from the ganglion habenulae of both sides, some fibres having crossed in the habenular commissure. The ma- 66 SEMICIRCULAR CANALS jority of its nbres, mostly crossed, end in the interpedun- cular ganglion. Many, however, may be traced farther caudally within the tegmentum of the brain stem (Ober- steiner^^), as may also fibres from the ganglion inter- pedunculare. The pineal body is situated just over the superior col- liculi. Its stalk is continuous with the medullary striae. The body contains laminated particles of carbonate and phosphate of lime. Structurally it resembles the inverte- brate visual organ. It is highly developed in reptiles. The posterior commissure (commissura posterior cere- bri) provides paths by which fibres from various sources undergo median decussation. It is a small cordlike band of white matter overlying the superior entrance of the aqueduct of Sylvius. It is partially covered by the habenular commissure and the pineal peduncle above. Behind and laterally it is continuous with the superior colliculi. It is present in all vertebrates, and becomes myelinated early (Edinger ^^) . The probable constituents of the posterior commissure are : 1. Fibres from the nucleus of the posterior commis- sure. 2. Fibres from the nucleus of the posterior longitu- dinal fasciculus, located in the grey matter of the third ventricle near the mammillary bodies. 3. Fibres from the posterior tract of the thalamus of the opposite side, which descend within the tegmentum, lateral and ventral to the posterior longitudinal fasciculus. 4. Fibres which cross to join the fasciculus retro- flexus. 5. Fibres from the median fillet. 6. Fibres from the superior cerebellar peduncle to the thalamus on the opposite side. 7. Perhaps fibres from the deeper grey stratum of the corpora quadrigemina to the cerebral cortex of the oppo- site side. The subthalamic region occupies, on each side of the middle line, a triangular area between the thalamus above and the internal capsule and its prolongation — the crusta of the peduncle — below. It is a link between the mid-brain and the diencephalon, and contains the up- ward prolongation of the tegmentum of the cerebral pedun- ANATOMY 67 cles, the thalamocipetal paths of the fillet and of the superior cerebellar peduncles, the upper extremities of the substantia nigra and of the red nucleus, and a new mass of grey matter — the corpus subthalamicum. _The- substantia nigra extends through the mid-brain from the upper borders of the pons, almost to the level of the mammillary body in the subthalamic region. It separates the tegmentum from the crusta of the peduncles, and contains numerous irregularly scattered nerve cells, which are pigmented. Along its ventral border lie the nuclei of origin of the third and fourth nerves, and within its lateral parts the nuclei of the mesencephalic roots of the fifth. The functions and connections of the neurones within the substantia nigra are but little known. ProhabU Connections of the Siihstantia Nigra Afferent paths, i.e., to the substantia nigra. 1. Fibres from the caudate nucleus and the putamen, and perhaps from the frontal cortical areas. Efferent paths, i.e., from the substantia nigra. 1. Fibres passing into the tegmentum and the crusta, and thence to lower levels. 2. Fibres to the fillet to reach the superior coUiculus (v. Bechterew ^3) . The corpus subthalamicum, or nucleus of Luys, lies just dorsal to the crusta, and lateral to the red nucleus and substantia nigra. Superiorly it extends considerably beyond the red nucleus, and consists of a network of fine medullated fibres, enclosing pigmented, multipolar nerve cells. The dorsal surface of the nucleus is defined by the overlying lateral parts of the field of Forel, which consists of a stream of fibres passing between the red nucleus and the thalamus and internal capsule. Connections of the Corpus SuUhalamicum 1. Fibres from the ventral surface of the nucleus, which pierce the adjacent crusta and join the ansa len- ticularis to gain, probably, the globus pallidus. 2. Fibres — perforating — which connect the nucleus 68 SEMICIRCULAR CANALS with Meynert's and Gudden's commissures (Ober- steiner ^^) . The commissura hypothalamica traverses the floor of the third ventricle above the mammillary bodies, and con- nects the ventro-mesial ends of the two subthalamic bodies. The commissura hypothalamica contains also: 1. Fibres — decussating — from the anterior pillars of the fornix. These fibres reach the mammillary body as a crossed tract. 2. Fibres from the posterior longitudinal fasciculus (Edinger ^^) . The corpora mammillaria mark, by their posterior surfaces, the anterior limit of the ventral surface of the mid-brain. Each body consists of an outer layer of white matter, enclosing a core of grey substance — ^the nucleus mammillaris. Connections of the Mammillary Nucleus Afferent paths, i.e., to the nucleus. 1. Fibres from the downward arching anterior pillar of the fornix, as well as fibres through the commissura hypothalamica from the anterior pillar of the fornix of the opposite side. These fibres form part of the path connecting the cortical olfactory centres in the uncus and hippocampus with the thalamus. 2. Fibres to the mammillary nucleus — as the thalamo- mammillary tract in the mammillo-thalamic strand. 3. Possibly fibres from the posterior longitudinal fas- c ^>ulus by way of the hypothalamic commissure. Efferent paths, i.e., from the nucleus. \. Fibres — the mammillo-thalamic tract or bundle of Vicq d'Azyr — which course upward and forward to end in the anterior nucleus of the thalamus, thus completing the path connecting the cortical olfactory centres of the uncus and hippocampus with the thalamus. Beginning in the hippocampus major this path follows the fimbria, body, and antf3ri(jr pillar of the fornix to the mammillary nucleus, and thence, after interruption, proceeds via the mamniillo-tlialamic strand to the anterior nucleus of the ANATOMY 69 thalamus. This latter strand contains fibres running in both directions, between the thalamus and the mammil- lary body. 2. Fibres of the mammillo-tegmental tract which arch backward and downward, and are traceable into the teg- mentum of the mid-brain to the vicinity of the inferior colliculli. 3. Fibres of the pedunculus corporis mammillaris. These constitute another mammillo-tegmental tract. They spring from the lateral mammillary nucleus, and course backward and downward along the medial margin of the crusta to enter the tegmentum. Their destination is not known. Kolliker believes they end in the central grey matter about the aqueduct of Sylvius, near the fourth nerv^e nucleus. 4. Strands from the peripheral layer of the mammil- lary body over the tuber cinereum (v. Lenhossek ^) . 5. Possibly fibres to the posterior longitudinal fascicu- lus by way of the hypothalamic commissure. The telencephalon or end-brain consists of: (1) the hemisphserium, which includes the pallium, rhinencepha- lon, and corpus striatum; and (2) the pars optica hypo- thalami, which includes the lamina cinerea, optic com- missure, tuber cinereum, and pituitary body. The lamina cinerea consists of a thin layer of grey substance extending backward above the optic commis- sure, from the termination of the corpus callosum to the tuber cinereum. On either side it is continuous with the grey matter of the anterior perforated space, and forms the anterior part of the inferior boundary of the third ventricle. It connects the corpus callosum, and is some- times called the grey root of the optic nerves (Sappe^). The functions of the lamina cinerea, if other than me- chanical, are unknown. The optic chiasm lies in the optic groove of the sphenoid bone in front of the tuber cinereum, and beneath the lamina cinerea with the anterior perforated space on either side. The paths of optic chiasm are : 1. The visual fibres proper which, in animals below the rabbit, e.g., guinea-pig, fishes, reptiles and most birds, undergo complete decussation. In man and the 70 SEMICIRCULAR CANALS higher animals only the fibres from the inner portion of each retina cross in the chiasm to enter the opposite optic tract. Tlie fibres from the outer side of the retina do not decussate, but pass into the optic tract of the same side. 2. Fibres that pass from one optic tract to the other along the posterior border of the chiasm (Gudden's inferior commissure) . These fibres — the median root of the optic tract — connect the two internal geniculate bodies, and possibly also the inferior colliculi. They seem related more to the auditory than to the visual system, but it is possible that they are protective reflex paths. 8. Fibres that pass from the chiasm into the floor of the third ventricle, possibly to reach the third nucleus. These are the afferent paths for pupil constriction (v. Bechterew ^^) , but this view seems to lack the support of evidence from the histological structure of the retina. 4. Fibres along the anterior margin of the chiasm connecting one retina or optic nerve with the other (com- missura arcuata anterior of Hannover; bogen-commissure of Stilling) . Lesions of one retina- cause degeneration in the opposite optic nerve, due to the presence of collaterals of the optic nerve which course backward from the chiasm (Parsons ^^), The paths in the optic tract are : 1. Fibres in the lateral root constituting the greater part, 80% in maia, of the optic tract, which end in the extern^ geniculate body, the paths being continued to the occipital cortex by new neurones passing in the tha- lamo-occipital radiation in company with fibres from the pulviuar a^nd the superior colliculi (optic radiation of Gratiolet) , 2. Fibres to the thalamus (pulvinar) and superior colliculi, the paths being continued to the occipital cortex by fibres that pass in the thalamo-occij^ital radiation. Borne of the fibres from the pulvinar and external genicu- late body pass as main stems or give off collaterals on their way to the occipital cortex. Of these main stems or collaterals some go to the corpus striatum, whilst others descend to the tegmentum to reach the cerebellum prob- ably and the centres and motcjr nuclei of the muscles of the eyes, head and neck. These are the fibres most ANATOMY 71 probably that mediate the physiological nystagmus, which, by means of retinal impressions, facilitates the visual fixation of rapidly passing objects. It is exceed- ingly probable that these optic pathways are closely related functionally to the labyrinthine jDaths, and that in many instances they impinge with the latter on the same final common path. In the lower animals the optic lobes, which are the analogues of the corpora quadrigemina in the higher animals, are the main visual organs. Almost all the optic nerve fibres end in the mesencephalic nuclei (analogues of the superior colliculi) and in the dien- cephalic nuclei (external geniculate bodies) . This latter is the first evidence of real visual representation in the occipital cortex (Parsons^). The optic nerve, in addition to the paths already mentioned, has fibres w^hich spring from cells situated in the primary optic centres, viz., the external geniculate bodies, the pulvinar, and the superior colliculi. Though the function of these fibres is unknown, they are not necessarily centrifugal paths as Parsons sug- gests, but may, in part, represent afferent paths, the cell bodies of whose neurones lie in structures central to the optic tracts. It may be observed that in fishes the vestibular nerve is in close relation w^ith the mesencephalic centres (Loeb^^). This shows that the mesencephalon in the lower animals at least probably contains important coor- dinating centres for movements of station and equilibrium. The tuber cinereum is an outpouching, at the base of the brain, of a thin sheet of grey matter, an extension of that surrounding the cavity of the mid-brain and fourth ventricle. It contains the nucleus tuberis and the supra- optic nucleus. The connections of these nuclei are un- knowm. The rhinencephalon — the oldest part of the hemisphere — includes (1) the olfactory lobe, consisting of the olfac- tory bulb, the olfactory tract and roots, the olfactory trigone, and the parolfactory area; (2) the uncus and a •number of accessory parts. The fornix is the chief fibre tract connecting the olfactory cortex in the uncus and hippocampus with the thalamus. The olfactory cortex is, therefore, not represented in the corona radiata, but has its own special projection fibres in the cortico-mammillary 72 SEMICIRCULAR CANALS tract within the fornix. In the brain the sensory paths are the first to acquire the myelin sheath, beginning with those of smell and ending with those carrying auditory impulses to the cortex. By observing the first appearance of the myelin sheath in various paths, the olfactory fibres have been traced to the uncinate gyrus, whilst the auditory and visual fibres have been traced to the temporal and occipital lobes respectively. New paths have similarly been traced from the areas in the cortex in which these sensory fibres terminate down to the medulla and motor nuclei of the cord. Connections of the Rhmencephalon Afferent paths, i.e., carrying impulses from the periphery. 1. To the thalamus by a strand from the cortex of the olfactory bulb to the antero- ventral part of the thalamus. 2. To the cortex (a) by the inner olfactory root, which joins the mesial aspect of the anterior extremity of the gyrus fornicatus ; (b) by the outer root to the gyrus hippocampus. 8. Possibly by paths from the posterior longitudinal fasciculus, by way of the hypothalamic commissure to the mammillary body. 4. Possibly by the thalamo-mammillary pathway. Efferent paths. 1. From the cortex by the cortico-mammillary tract from the uncus and hippocampus through the fimbria, body, and anterior pillar of the fornix to the mammillary nuclei, each mammillary body receiving fibres from the cortex of both sides, owing to a decussation in the com- missura hypothalamica of some fibres from the anterior pillars of the fornix. From the mammillary nuclei the paths are continued by fibres (A) to the thalamus by the Vnammillo-thalamic strand or bundle of Vicq d'Azyr; and (B) to the tegmentum of the mid-brain, and possiJDly to lower levels, as the mammillo- tegmental tracts, of which there are: (a) The mammillo-tegmental tract proper, the fibres of which have been traced to the teg- mentum of the mid-brain in the vicinity of the inferior colliculi. (b) Possibly a mammillo-tegmental tract ANATOMY 73 through the pedunculus corporis mammillaris. (c) Pos- sibly fibres to the posterior longitudinal fasciculus from the mammillary body via the hypothalamic commis- sure. Such a connection with the posterior longitudinal fasciculus would be a possible means of bringing the olfactory centres into relation with other centres in the mid-brain, pons, and medulla, (d) Possibly strands connecting the mammillary body with the tuber cine- reum. 2. From the thalamus, (a) The thalamo-mammillary tract may be an efferent path from the thalamus, along which impulses, received directly from the cortex of the olfactory bulb, may pass after interruption in the thala- mus. From the mammillary body the path is continued by way of the mammillo-tegmental paths, or perhaps through the posterior longitudinal fasciculus to other centres in the mid-brain, pons, and medulla, which are thus brought into relation with the olfactory centres. (b) Possibly by fibres from the thalamus to other portions of the cerebral cortex, and perhaps to lower centres in the brain-stem and cord. The corpus striatum is a mass of grey matter supple-, mental to the cortical substance. It receives fibres con- veying sensory impulses, and gives off fibres, probably motor in function, which arise from its cells. Connections of the Corpus Striatum Afferent paths, i.e., to the corpus striatum. 1. By way of the tegmento-striate fibres, chiefly con- tinued from the mesial fillet, and perhaps from the red nucleus and the thalamic region via the internal capsule, to end around the cells of the putamen and head of the caudate nucleus. 2. By the thalamo-striate fibres, which pass from the thalamus (a) by way of the internal capsule to the caudate nucleus; or (b) by way of the ansa lenticularis to the putamen; or (c) by traversing the medullar}^ laminae to the caudate nucleus. 8. By cortico-striate fibres. Dejerine denies the exist- ence of these paths, but Edinger says some bundles of fibres can be demonstrated. 74 SEMICIRCULAR CANALS Efferent paths, i.e., from the corpus striatum. 1. By the strio-thalamic fibres, consisting of (a) those from the caudate nucleus to the thalamus direct; (b) those which, traversing the internal capsule and medul- lary laminae and joining fibres from the putamen, pass by way of the ansa lenticularis to the thalamus ; (c) those from the putamen, which reach the thalamus partly by way of the globus pallidus and partly by the ansa lenti- cularis. 2. By the strio-peduncular fibres, well seen in the lower animals (Edinger) , as the continuation of the basal tract of the fore brain. The fibres pass from the caudate, and probably from the lenticular nucleus into the subtha- lamic region and the cerebral peduncle, joining in the latter the stratum intermedium, closely related to the substantia nigra. The medullary substance of the brain consists of fibres with their supporting neuroglia. The fibres are of three kinds, viz. (1) association fibres linking the different portions of the same hemisphere together, and which, with the exception of those situated about the fissure of Rolando, are not meduUated at birth; (2) commissural fibres; and (8) projection fibres. The association fibres are divided into the short and the long. The short association fibres stretch from one convolution to another, some loops — the intracortical association fibres — being buried in the grey matter, while others — the subcortical association fibres — lie in the adja- cent white matter. There are also fibres limited to con- volutions of the same lobe, the intralobar association fibres. The long or interlobar association fibres include (1) the uncinate fasciculus; (2) the cingulum; (8) the superior longitudinal fasciculus; (4) the inferior longi- tudinal fasciculus; and (5) many other long association fibres which cannot be satisfactorily demonstrated. The uncinate fasciculus connects the orbital surface of the frontal lobe with the anterior portion of the temporal. The inferior longitudinal fasciculus transmits visual im- pulses to other parts of the cortex (Dejerine) . The anterior commissure contains: 1. Fibres connecting the end of one temporal lobe with the end of its fellow of the opposite side, ANATOMY 75 2. Fibres from one olfactory lobe to the other. 3. Fibres from the olfactory lobe on one side to the hippocampal convolutions of the opposite side. 4. Fibres from the olfactory lobe through the commis- sure to reach the taenia semicircularis, and to proceed with it along the roof of the inferior horn of the lateral ventricle to end in the amygdaloid nucleus. The hippocampal commissure joins the two hippo- campi. These fibres cross in the psalterium, and some, after decussation, join the longitudinal fibres of the for- nix and proceed to the thalamus via the mammillary body and mammillo-thalamic strand. The corpus callosum — the largest commissural tract in the brain — joins the t\^^o hemispheres. Little is known definitely of the individual fibre paths or of the parts associated through them. The projection fibres are few in the frontal, parietal, and latero-inferior part of the temporal regions. The function of these areas is not well understood. Flechsig believes them to be association centres. The olfactory cortex, as before stated, is not represented in the corona radiata, having its own projection fibres in the cortico- mammillary tract within the fornix. The projection tracts are divided into (1) the short; and (2) the long. The short projection tracts include: 1. The cortico-thalamic, consisting of (a) fibres from the frontal lobe to the anterior end of the thalamus; (b) fibres from the region of the fissure of Rolando, and the adjoining part of the parietal lobe to the lateral and mesial nuclei of the thalamus ; (c) fibres from the occipi- to-temporal region to the medio-ventral part of the thala- mus ; (d) fibres from the posterior part of the parietal lobe, and from the occipital lobe to the pulvinar. The thalamo-cortical tracts are associated with the foregoing. They leave the thalamus as its stalks or peduncles, and reach the various areas of the cortex. They represent continuations of the sensory paths from the cord, brain-stem and cerebellum. In these tracts are represented the median fillet, the spino-thalamic tract, and probably part of Gowers' tract and the cerebello- rubro-thalamic tract. The optic radiation represents the 76 SEMICIRCULAR CANALS continuation of the visual paths of the optic tract after interruption in the pulvinar, lateral geniculate bodies and superior colliculi. 2. The cortico-geniculate and cortico-quadrigeminal tracts. These are accompanied by corticipetal fibres from the superior colliculi and lateral geniculate bodies. 3. The auditory radiation which contains cortifugal as well as corticipetal fibres running between the inferior coUiculus and median geniculate body and the auditory centres in the middle portion of the superior temporal convolutions, and probably the adjoining part of the operculum. The path passes through the retro-lenticular portion of the posterior limb of the internal capsule be- neath the lenticular nucleus. 4. The cortico-rubral, which is a supplementary motor tract. The origin of these fibres is probably in the cortex of the parietal lobe. The long projection tracts include: L The cortico-pontine. The continuation of these paths after interruption in the pontine nucleus completes the link between the cerebral cortex and the cerebellum. The cortico-pontine tracts include (a) the fronto-pontine fibres; and (b) the temporo-occipito-pontine fibres. Through these tracts fibres from the cerebral cortex of either side reach the cerebellum on both sides. 2. The motor tracts which include : (a) The cortico-bulbar tracts. The fibres for the movements of the eye muscles spring from the posterior portion of the middle frontal convolution (Mills ^^), ad- joining the lower part of the precentral gyrus, in which are the centres for the cortico-bulbar trar^ts. The exact location of the strands is known only for the twelfth nerve in the posterior part of the knee, and for the seventh, which is in advance of the twelfth. Within the cerebral peduncle, the cortico-bulbar strand occupies the lateral part of the inner third of the crusta, and the fibres for the third and fourth nerves soon turn dorsally and cross the raphe to end, for the most part, in the nuclei of the opposite side. The fibres for the remaining nuclei pass near the middle line, and cross as they approach the levels of the nuclei for which they are destined. (b) The cortico-spinal tracts or pyramids^ occupy the ANATOMY 77 middle third of the crusta, with the sensory paths on their outer side. They decussate for the most part at the lower boundary of the medulla. The fibres that do not decussate here are continued down the cord as the direct pyramidal tracts, but they also cross the middle line through the white commissure on reaching the level of their destination, although there is evidence tending to show that part, at least, of these fibres do not cross the middle line. (See Pyramidal tracts in the cord. ) The rolandic region is concerned in sensation as well as motion. It includes the precentral and postcentral convolutions and the paracentral lobe. The sensory fibres from the periphery to this area carry impulses which excite sensations of touch, pain, and temperature, as well as those associated with impulses from the muscles and tendons, and possibly those associated with certain phases of acts of equilibration. Excluding the sensori- motor and the various sensory areas, about two-thirds of the cerebral cortex has no known connection with the periphery. Flechsig believes these regions of the cortex to be association centres. The motor centres are mainly located in front of the central fissure. Those for the face and tongue are in the lower third of the motor zone. In the posterior parts of the second frontal convolution and in a portion of the third frontal convolution are the cen- tres for the associated lateral movements of the eyes, and for the lateral movements of the head (Beevor and Horsley ^) . The centres for stereognostic perception and muscular sense are in the superior and inferior parietal convolutions. The speech centres in right-handed people are in the posterior part of the third left frontal convolution, in the first left temporal convolution, and perhaps in the left angular gyrus. Broca's convolution — the third left frontal — is the motor speech centre. Destruction or disability of this centre causes motor aphasia, i.e., inability to transform concepts into words, though the patient be con- scious and the tongue capable of being moved. A minor part in speech is played by the posterior part of the right third frontal convolution, but it is the chief motor centre in left-handed people. In the first left temporal convolution is the auditory 78 SEMICIRCULAR CANALS centre for speech. Lesion of this area produces loss of memory of word-sounds, though the hearing in the ordinary sense may be sufficiently good. Thus distinction is made between hearing as conceptualization and hearing in the ordinary sense of becoming conscious of sound im- pressions originating al) externo. A similar distinction holds for visual acts, and as we shall see later, there is a third manner in which individuals "see" and probably also hear and smell, and which forms the basis for pro- tective reflex acts through the medium of centres and paths placed below, and sometimes widely separated from the cerebral cortex. The centre for memory of printed words is probably in the left angular gyrus. Lesions limited to this region are rare. They render a person unable to understand writing, though ordinary vision may be good. The existence of a motor writing centre is doubtful (Oppenlieim) , but if it exists it is probably located in the posterior portion of the second left frontal convolution. The centre for smell is probably somewhere near the anterior portion of the gyrus fornicatus. There is no definite knowledge about the location of the cortical centre for taste. The auditory centre is in the upper temporal convolution. Each centre is probably connected with both cochlear nerves. The frontal lobes will stand much destruction on one side without giving rise to marked physical signs. This has been frequently noted in experiments, and is a matter of common clinical ex- perience in tumours of the frontal region, where the chief symptoms may be merely hysteroid manifestations. The cuneus and calcarine fissure — ^the white line of Gennari — together constitute a primary and lower cortical or visuo-sensory centre. The lateral aspect of the occipi- tal lobe is a visuo-psychic area, containing subareas or centres concerned in higher visual processes. Lesions of the lateral occipital lobe, especially if large and in the left hemisphere, or lesions on both sides, cause mind- blindness analogous to word deafness. Lesions of the cuneo-calcarine cortex cause lateral homonymous hemi- anopsia. This may also be produced by lesion of the lateral part of the occipital lobe if it extends far enough inward to interrupt the optic radip^tions (Schafer and Brown ^^) , ANATOMY 79 Pathways in the Spinal Cord In a cross section of the cord the area bounded by the posterior median sulcus (dorsal septum) and the dorsal root is designated as the posterior funiculus, the area bounded by the dorsal and ventral roots is called the lat- eral funiculus, and that bounded by the ventral root and the anterior median fissure the anterior funiculus. The term fasciculus is intended to cover any fairly defined bundle of fibres connecting one centre or level with another centre or level, without intermption of the path- way. A fasciculus consists therefore of but one set of neurones, e.g., the dorsal-spino-cerebellar fasciculus (direct cerebellar tract) . Tract is a physiological rather than an anatomical term. It indicates a pathway for the conduction of impulses without regard to anatomical in- terruptions. A tract, therefore, may consist of two or more sets of communicating neurones, forming physio- logical continuity, e.g., the cerebello-vestibulo-spinal tract. The term column is now reserved by many authors to designate the projections of grey matter within the white surrounding substance, e.g., the ventral grey column (ventral cornu), the dorsal grey column (the dorsal comu) . The ascending tracts of the cord include : 1. The dorsal fasciculi (columns of Golland Burdach). 2. The dorsal spino-cerebellar fasciculus (direct cere- bellar tract, or tract of Flechsig) . 3. The ventral spino-cerebellar fasciculus (Gowers' tract) . 4. The spino-tectal and spino-thalamic tracts. 5. Helweg's fasciculus or bundle. The dorsal fasciculi consist mainly of the ascending arms of the central processes of the dorso-spinal or pos- terior root ganglia. Cajal, in 1889, by means of the Golgi method, demonstrated the bifurcation of the posterior root fibres on entering the cord. In animals after section of the dorsal root in one of the sacral nerves, it was seen by means of the Marchi stain that a great part of the dorsal fasciculi (Burdach's column chiefly) consisted of the descending arms of the T-bi furcations of the posterior 80 SEMICIRCULAR CANALS root fibres. These descending arms are destined for lower segments in the cord, and give off collaterals at various levels. Some of them constitute long pathways for spinal reflexes, e.g., the well-known scratch reflex in which clonic movements of the hind leg are evoked by scratching the region behind the shoulder of the normal dog. The paths involved in this reflex have been demonstrated by Sher- rington and Laslett^^ by the method of successive de- generation, as scattered fibres in the lateral ground bundles of the cord. The ascending arms of the T-bifurcation of the pos- terior nerve roots send fibres or processes and collaterals to the different segments of the cord at various levels. The remaining posterior root fibres constitute the long ascending paths of the dorsal fasciculi. These as they ascend are gradually displaced toward the middle line and away trom the grey matter, in accordance with the general law of the eccentric position of the long fibre paths. Few, if any collaterals are given off from the dorsal median fasciculus (Goll's column) . The zone of Lissauer consists of the bifurcation of the finer fibres of the pos- terior nerve root. The terminations of the fibres and collaterals of the posterior nerve-roots are as follows : 1. Some, including part of the fibres from Lissauer's zone, end about cells in the substance of Rolando. From this point the pathway is continued by intermediate neu- rones to the lateral ground bundle and so to the cells of the grey matter of other segments. 2. Some pass directly through the substance of Rolando to terminate in tract cells, the axones from which pass as the spino-thalamic tract in the white matter of the same and of the opposite side. The fibres that cross the median line pass in the anterior commissure. 3. Fibres that end in relation with the ventral horn cells of the same side (reflex paths). Some reflex paths are relayed to the ventral horn cells of the opposite side. 4. Fibres that end in the tract cells of the dorsal nucleus and in other cells, the axones of which form the dorsal spino-cerebellar fasciculus (direct cerebellar tract) and the ventral spino-cerebellar fasciculus (Gowers' tract) . ANATOMY - 81 5. Some fibres enter the posterior aspect of the dorsal comu, and bend upward to end in the substance of Rolando. 6. Some fibres of the dorsal root also pass in the pos- terior commissure to reach the cells of the grey matter of the opposite side. The collaterals and terminals of the posterior nerve root may, therefore, terminate in any part of the grey matter. The collection of marginal cells (dorsal nucleus) situated near the mesial surface, close to the base of the dorsal cornu, extends from the cervical to the first and second lumbar segments, and is known as the column of Clarke (Clarke's vesicular column, or the nucleus of Stilling) . From these cells the pathway is continued by means of neurones of the second order to the dorsal spino- cerebellar fasciculus (direct cerebellar tract) of the same side, and so to the vermis of the cerebellum. This origin of the dorsal spino-cerebellar tract has recently been dis- puted, but apparently upon insufficient grounds. It must be remembered, however, that the Golgi stain picks out only a few elements, and it is impossible to know what elements are omitted. The small cells in the substance of Rolando also send axones into the lateral ground bundle. The cells of origin of the ventral spino-cerebellar tract are not definitely known. It is known, however, that some fibres of this tract cross in the anterior commissure, and it is probable that these fibres spring from cells situ- ated in the dorsal horn. The tract does not degenerate after section of the dorsal nerve roots (Mott) . The dorsal spino-cerebellar fasciculus is, therefore, an uncrossed pathway, whilst the ventral spino-cerebellar tract is both crossed and uncrossed. Mott believes this fasciculus con- sists of two afferent bundles, one of which the ventral cerebellar, situated at the periphery, passes to the cere- bellum in the superior peduncle, whilst the other — the crossed afferent tract of Gowers and Edinger — passes up on the outer side of the lemniscus to the corpora-quadri- gemina and optic thalamus (Gordinier ^^) . The spino- tectal and spino-thalamic tracts spring from cells about the base of the dorsal cornu, and pass up on the inner side of the ventral spino-cerebellar fasciculus to the teg- 82 SEMICIRCULAR CANALS mentum and thalamus. The tracts continue the paths of the posterior nerve root of the opposite side mainly. The fasciculus of Helweg is seen only in the upper cervical cord. Its cells of origin and destination are un- known, although it has been assumed that the path is in relation with the inferior olive. The dorsal fasciculi, viz., the fasciculus gracilis and the fasciculus cuneatus (columns of Goll and Burdach) are interrupted in the posterior nuclei of the medulla, the fasciculus of Goll ending in the nucleus gracilis and that of Burdach in the nucleus cuneatus. The fibres from these nuclei for the most part cross the middle line as the arcuate fibres about the level of the upper border of the pyramidal decussation in the lower part of the medulla oblongata. This sensory decussation marks the lowest limit of the fillet, the fibres of which continue the paths represented in the dorsal fasciculi. (See Connections of the fillet.) There is question as to whether some of the component fibres of the dorsal fasciculi are directly continued to the cerebellum and mesial fillet without interruption in the posterior nuclei of the medulla. Kolliker, Solder, Hoche, and others maintain the affirmative. The dorsal fasciculi are mainly pathways for impulses related to the so-called deep sensation (muscle and ten- don) . There are also in the median fibres of the dorsal fasciculi some fibres for the transmission of tactile im- pulses. Some authors maintain that the pathway for tactile sensation is uncrossed and interrupted in the grey matter. It is most probable, however, that the paths for tactile sensation are both crossed and uncrossed, and that in the dorsal fasciculi they travel to a variable extent, many passing all the way up to the medulla to join the mesial fillet after interruption in the posterior nuclei of the medulla, whilst others, after travelling a variable dis- tance, pass into the grey matter. The dorsal spino-cerebellar and the ventral spino-cere- bellar paths convey those afferent unconscious impressions that underlie coordination and cerebellar muscle tonus. The dorsal spino-cerebellar path is uncrossed, whilst the ventral spino-cerebellar path is both crossed and uncrossed. Both pathways are interrupted in the cord. ANATOMY 83 The spino-tectal and spino-thalamic pathways convey impulses concerned in the sensation of pain and tempera- ture and to some extent those of touch. These are inter- rupted pathways and are mainly crossed in the cord. They join the mesial fillet above the sensory decussation in the medulla. Helweg's fasciculus probably conveys, through the inferior olive to the cerebellum, impulses akin to those that travel by way of the dorsal and ventral spino-cere- bellar pathways. Some fibres of the ventral spino-ce- rebellar fasciculus probably reach the thalamus, and perhaps may be considered as stray fibres from other path- ways, e.g., spino-tectal, spino-thalamic. (See Connections of superior and middle peduncles of the cerebellum.) Gowers believed that part of the ventral spino-cerebellar fasciculus conveys impulses related to pain and tempera- ture. The cerebellar fibres of this tract pass by way of the inferior and superior peduncles, some fibres passing also, according to Hoche, by way of the superior medul- lary velum. The fasciculus has been traced as low as the fifth lumbar segment (Mott, ^°^ Russell ^^^) , while above, the tract was traced by Rossolimo ^^^ to the inferior collic- uli, substantia nigra and the globus pallidus. The term Gowers' tract, as originally applied, included the spino- thalamic and spino-cerebellar tracts. At the present time it is restricted to the ventral spino-cerebellar fasciculus proper. Peripheral Terminations of the Affere^it Paths The afferent or sensory paths commence at the periph- ery. The bodies of the afferent peripheral neurones are separated from the neural tube, and are located in the posterior spinal ganglia or their analogues in the cranial nerves. The first, second, and eighth cranial nerves have a peripheral apparatus of peculiar structure. In the olfactory nerve the primary afferent neurone re- mains in the peripheral epithelium. In the eighth nerve the path originates in the neuro-epithelium, but the cell body remains permanently bipolar. The optic nerve is in reality not a nerve, being developed from an invagination of the brain wall. 84 SEMICIRCULAR CANALS The peripheral endings of the sensory neurones are : 1. Free endings, in which the nerve fibres lose their medulla and end between (not within) the epithelial cells of the skin and mucous membrane, and also between the connective-tissue strata. The finer threads often terminate in end knobs. These endings are believed to be the receptive organs for painful stimuli. I 2. Fibres from the spinal ganglia, ending in the sali- , vary glands. These fibres probably constitute part of the afferent paths for the reflex increase of salivary secretion. I 3. Fibres from the Gasserian ganglion, ending in the teeth pulp. ■ 4. Modified forms of diffuse termination, e.g., the fibres of the glosso-pharyngeal ending in clusters of cells known as the taste buds of the tongue. Taste buds rep- resent endings of the neuro-epithelial type, having special connections with the nerves, e.g., wrappings of the nerve fibres about the taste-bud epithelia. It is believed that these accessory structures and the peculiar disposition of the nerve fibres in relation to them render the nerve fibres accessible to certain kinds and degrees of stimuli only. 5. Touch cells. In the simplest form the nerve fibres form a cuplike expansion for the reception of one end of a single cell. This form represents the beginning of the development of Meissner's corpuscles, the second stage of which is represented by the nerve fibres forming a flat disc-like expansion containing neuro-fibrils between two epithelial cells. These endings are found in the papillae of the skin and in other parts of the body. 6. End bulbs, consisting of a granular core of cells surrounded by connective-tissue lamellae, the nerve fibre ending in a snarl of fibrillse twisted about the core. These endings are in the conjunctiva, glans penis, serous membranes, mesentery, etc. 7. Corpuscles of Vater-Pacini. These bodies consist of a capsule composed of crescentic lamellae which are covered with endothelial plates. Inside the capsule is the core containing cells and naked axis cylinders. These corpuscles are always located deeply, e.g., in the deeper portions of the connective-tissue layer of the skin of the palmar and plantar aspect of the fingers and toes, in the pancreas, and in the mesentery. They are assumed to be ANATOMY 85 Organs adapted for heavy pressure stimuli, whilst Meiss- ner's corpuscles are looked upon as the organs for lighter pressure sensation. 8. In tendons the Golgi-Mazzini organs, which consiert of rich arborizations of nerve fibres, forming varicosities between the tendon fibres, the whole being enclosed in a connective-tissue capsule. These organs aid in the per- ception of the position and movement of the limbs in space. 9. Muscle spindles which are modified muscle fibres, receiving a special nerve ending. These are widely dis- tributed in the body and are probably present in all skeletal muscles. They are especially numerous in the small muscles of the hand and foot. None have been found in the intrinsic muscles of the tongue, nor in the eye muscles, although in the tendons of the latter Golgi- Mazzini organs have been demonstrated. Each spindle consists of a capsule composed of half a dozen concentric layers of fibrous tissue, enclosing a group of from three to ten or more muscle fibres with medullated nerves, blood- vessels, and interspersed connective tissue. The muscle fibres of the spindle are embryonic in structure, having more nuclei than the ordinary muscle fibres, and contain- ing some undifferentiated sarcoplasm. Sherrington has shown that these structures are afferent in function, since they do not degenerate after section of the motor nerves. 10. It is still a question as to whether sensory im- pulses from the periphery pass into the cord by way of afferent sympathetic fibres that enter the posterior spinal ganglia. The descending paths in the cord include : 1. The pyramidal tracts consisting of (a) the crossed or lateral cerebro-spinal fasciculus; (b) the uncrossed or mesial cerebro-spinal fasciculus. 2. The tecto- spinal tract. 3. The rubro-spinal tract. 4. The tract from the interstitial nucleus of Cajal. 5. The tract from Deiters' nucleus. 6. The tract of Thomas. 7. The septo-marginal tract. 8. The comma tract of Schultze. The fibres of the pyramidal tracts end about the cells 86 SEMICIRCULAR CANALS of the ventral horn (ventral grey column). Some ob- servers, however, believe they terminate about the cells of the intermediate grey matter, the impulses being relayed by short neurones to the ventral horn cells. It is often stated that all the fibres of the direct pyramidal tract cross the median line at their levels of destination, but this point cannot be considered as proven, since lesion of the direct pyramidal tract causes some impairment of function in the muscles on the side of the lesion. More- over, even in the crossed pyramidal tracts, there are some homo-lateral, i.e., uncrossed fibres. The fibres of the tecto-spinal tract spring from the roof of the mid-brain. After decussation the fibres pass downward into the cord, where they lie according to some observers near the ventral sulcus, whilst according to other observers, they are scattered through the antero-lateral ground bundle. The fibres are believed to end in relation with the ventral horn cells. The presence of any tecto- spinal fibres in the cord has been disputed. The fibres of the rubro-spinal tract (von Monakow's tract) spring partly from cells in the red nucleus located in the tegmentum of the mid-brain, and partly from other cells in the formatio reticularis in the region of the pons. The path is mainly crossed. In the cord the tract lies ventral to the lateral pyramidal tract, its fibres partly mingling with those of the latter. The fibres of the rubro-spinal tract end in the dorsal part of the ventral horn. This tract is part of an important cerebellar effer- ent path, composed of three sets of neurones, viz.: (1) from the cerebellar cortex to the nucleus dentatus; (2) from the nucleus dentatus to the red nucleus ; (3) from the red nucleus (rubro-spinal tract proper) to the ventral root c(3lls. As previously stated, owing to a double decussation, viz., in the superior peduncles and in the rubral neurones of the rubro-spinal tract, efferent cere- bellar impulses, transmitted via the cerebello-rubro-spinal tract, are mainly distributed to the ventral root cells of the homo-lateral side. The tract from the interstitial nucleus of Cajal is un- crossed and lies near the ventral sulcus. Its fibres terminate in the ventral horn, some having been traced into the lumbar region of tlie cord. The interstitial ANATOMY 87 nucleus of Cajal is located in the formatio reticularis of the tegmentum of the mid-brain anterior (cephalad) to the III nucleus. The fibres of this tract, however, are believed by some to originate in the nucleus of Darksche- witsch, and by others in the nucleus of the posterior longitudinal fasciculus, and by still others in the nucleus of the posterior commissure. It is a question whether any of these nuclei is identical with the interstitial nucleus of Cajal. The tract from Deiters' nucleus occupies the ventral and mesial periphery of the cord. The more lateral fibres are imcrossed, w^hilst those near the ventral sulcus spring from the nuclei on both sides. It is probable that with the fibres of this tract other fibres descend from other portions of the vestibular nucleus, and from other nuclei in the formatio reticularis grisea of the medulla (reticulo- spinal fibres). The fibres all terminate in the ventral horn cells. As previously stated, Deiters' nucleus is an important relay station for afferent labyrinthine impulses to the cerebellum. It is possible that Deiters' nucleus may serve as an immediate coordinating centre for labyrinthine impulses ; but for reasons often reiterated in the preceding pages this is highly improbable in man and the higher animals, in whom the chief coordinating centres for laby- rinthine impulses are located in the cerebellimi and pos- sibly in the mid-brain. On the other hand, Deiters' nucleus receives fibres from the cerebellum and relays the paths dow^n the cord. Again some fibres from Deiters' nucleus, probably the continuation of vestibular paths, pass to the homo-lateral inferior olive, and directly, or after interruption, pass to the contra- lateral olive which sends numerous fibres to the cerebellum via the inferior peduncle (restiform body). The inferior olive and Deiters' nucleus are thus in intimate relation with the cerebellum by means of afferent and efferent paths. The afferent vestibular paths from Deiters' nucleus to the nucleus fastigii are mainly crossed. The efferent cere- bellar paths from the nucleus fastigii to Deiters' nucleus are also mainly crossed, but, as many of the fibres of the vestibulo-spinal tract near the ventral sulcus are crossed, provision is thereby made for bringing each half of the • I I a I I I5 ANATOMY 89 cerebellum into functional relationship with the homo- lateral half of the body by means of a double decussation, as in the case of the cerebello-rubro-spinal paths. For reasons previously stated, it is perhaps better to call the vestibulo-spinal tract the cerebello-vestibulo- spinal tract and the vestibulo-olivary tract the vestibulo- olivo-cerebellar tract. (See Vestibular connections. ) All the fibres of the tract from Deiters' nucleus, taken collec- tively, are sometimes called the antero-lateral descending tract or the marginal bundle of Lowenthal. The tract from the interstitial nucleus of Cajal and the mesial portion of the tract from Deiters' nucleus consti- tute the major portion of the descending fibres of the median longitudinal fasciculus an important bundle in the segmental brain. Some observers hold that some fibres from the cerebellum pass down the cord without interruption in Deiters' nucleus. The fibres of the tract of Thomas originate in the formatio reticularis of the medulla, and pass downward in the lateral column, to end in the grey matter of the cervical cord. The septo-marginal tract is a small bundle of fibres lying next to the posterior septum. In the sacral cord it forms a small dorso-medial triangle, whilst in the lumbar region it forms a superficial bundle, and the oval bundle of Flechsig at the middle of the posterior septum. In the thoracic and cervical regions the fibres are scattered. The fibres of this tract are probably the descending axones of cells in the cord, forming short, intersegmental (spino- spinal) tracts. The "comma" tract of Schultze consists of a small bundle of descending fibres, lying about the middle of the posterior column. It is a well-marked feature of the dorsal cord. The fibres probably spring from the column cells of the grey matter of the cord, forming short inter- segmental (spino-spinal) tracts, although they are believed by some to be descending branches of the dorsal root fibres. Many descending tracts contain also ascending paths. The peripheral terminations of the efferent paths are : 1. The motor end plates of striated muscle. These consist of flattened expaijgions of undifferentiated sa^rcQ^ 90 SEMICIRCULAR CANALS plasm. Here the nerve fibres ramify in close relation with the muscle fibre. It is a question whether the nerve terminals are located outside or inside the sarcolemma. . Section of the motor nerve fibre is followed by atrophy of the muscle. ' 2. Axones which form the preganglionic fibres of the sympathetic nervous system. These axones always end^ in a sympathetic ganglion. From this point the path- ways are continued by the axones of spnpathetic neurones (post-ganglionic fibres of Langley) , to end in the muscle of the intestines, blood-vessels, heart, etc., or in the glands, etc. , of the skin. In glands the fibres end about the lumen. Some endings occur in the follicular cells of the ovary but none reach the ovum itself. In the kidney the endings are mainly in the walls of the blood-vessels. There are peripheral ganglia in the plexuses of Auerbach and Meissner, situated between the coats of the gastro- intestinal tract, mainly in the small intestine. These ganglia, which are not of the sympathetic type (Lang- ley^), contain multipolar cells the dendrites of which lie in the connective-tissue layers. There are also, in the stroma of the mucous membrane, cells from which fibres pass between the epithelial cells. The spinal pregan- glionic fibres become pilo-motor, vaso-motor, or secretory fibres, according as their post-ganglionic continuations end in the erector muscles of the hairs, in the muscles of the blood-vessels, or in the sweat-glands, etc. It is prob- able that some sympathetic afferent paths reach the pos- terior spinal ganglia. In the heart muscle the sympa- thetic fibres ramify and often end in expansions. The central nei-vous system may be divided into (1) a segmental part, comprising the spinal cord and the basal part of the brain; and (2) a suprasegmental part, com* prising the expanded portions of the dorsal wall of the neural tube, viz., the pallium, corpora quadrigemina and cerebellum (Bailey ''^^'''). Tracts which connect one region of the cord or seg- mented brain with another region are known as interseg- mental tracts, whilst tracts that pass to or from the supra- segmental parts are called suprasegmental tracts. The intersegmental tracts are mainly located in the antero- lateral ground buiajdle. close to the grey matter^ some being; ' ANATOMY 91 found also in the ventral portion of the posterior columns (oval bundle, etc. ) . The existence of reflex spino-spinal paths is shown by the familiar extensor-thrust reflex described by Sherring- ton.^' In a spinal dog, slightly stroking the skin behind the plantar cushion with the edge of a piece of paper, or . pushing the finger-tip between the plantar cushion and the toe-pads causes the leg on that side to extend powerfully for a short period. The pathway for this reflex is via the posterior root fibres direct to the ventral horn cells of the same side. The stimulation passes to neurones which innervate all the extensor muscles of the leg and there is but one synapsis between the afferent fibres and the body and dendrites of the efferent neurones. Reference to the schalt-zellen of v. Monakow, which are probably interposed between the afferent and efferent neurones, is omitted for the sake of simplicity. The extensor thrust reflex is probably an important element in the reflex mechanism of locomotion. In cer- tain cases irritation of the foot causes extensor thrust in the opposite leg. Here an intermediate spino-spinal neurone carries the stimulus to the ventral horn cells of the opposite side. In this reflex, therefore, three neu- rones are involved, viz. : (1) An afferent peripheral; (2) a heteromeric spino-spinal neurone; and (3) an efferent neurone Longer spino-spinal neurones have been shown to exist by means of the scratch reflex. The pathway for this reflex is a long and uncrossed one. The fibres of the intermediate neurones actually involved, lie scattered in the lateral part of the lateral column, i.e., in the lateral ground bundle, as demonstrated by Sherrington and Laslett^^ in the following manner: The cord was tran- sected between the second and third thoracic segments. This caused degeneration of all fibres entering the cord from the brain, mid-brain, bulb, and cervical and first and second thoracic segments. The dog was kept alive for one year, which allowed time for complete degenera- tion of the severed tract and for absorption of the products of degeneration. The cord was then transected again between the fourth and fifth thoracic segments and the secondary degeneration in the divided tracts studied 92 SEMICIRCULAR CANALS by the ordinary methods, e.g., Marchi, etc. By means of this method of "successive degeneration" the scratch reflex chain was shown to consist of (1) a receptive neu- rone from the skin to the spinal grey matter of the corre- sponding spinal segment for the shoulder; (2) a long descending proprio-spinal neurone from the grey matter of the shoulder segment to that of the leg segments via the lateral part of the lateral column; (8) a motor neurone to a flexor muscle. This chain has three neurones, enters the grey matter twice, and has two synapses exclusive of the schalt-zellen. The motor neurone is the final common path the rest of the arc being afferent (Sherrington^^). The efferent paths of the cord convey impulses which may be grouped as follows : 1. Motor, including (a) voluntary and reflex motor, muscle tonus, etc. ; (b) vaso-motor; (c) viscero-motor; (d) cardio-m.otor; (e) pilo-motor. 2. Secretory to the various glands — gastric, salivary, pancreatic, sweat, etc. 3. Inhibitory for each of the foregoing. The impulses . conveyed in the afferent paths of the cord may be grouped as : 1. Sensory, including all impulses affecting conscious perception, e.g., visual, auditory, olfactory, gustatory pressure, pain, temperature, hunger, thirst, etc. 2. Reflex, including those impulses which evoke various motor and secretory reactions. The impulses which originate in the specialized nervous structures of the semicircular canals and vestibule of the internal ear fall within this group. 3. Inhibitory. Little is known definitely of the nature of the impulses of this group. It has not been demonstrated that afferent impulses inhibit conscious sensations, although unconscious re- flexes, e.g., sneezing may in some cases be inhibited by afferent impulses (Howell ^^). The impulses that originate in the semicircular canals and vestibule of the internal ear can unquestionably inhibit certain efferent motor (tonus) paths, as may be seen in cold irrigations of the external auditory canal, and in Qertain forms of rotation. But this effegt ^hQwld ANATOMY 93 in some instances be classed as a depression of function in the afferent elements of the ordinary reflex tonus mech- anisms, rather than as an instance of positive inhibition. This subject will be discussed more fully in a later chapter. The tonus of the muscles of the body is partly main- tained by a constant stream of afferent impulses from the periphery to the related cells in the ventral horns and in other centres of coordination and tonus, e.g., the cerebel- lum, mesencephalic centres, etc. The grouping of the various cells in the ventral horn has only been partially determined in regard to their functions. The ventral group is probably related to the long flexors and extensors of the limbs and the central group to the muscles for the finer movements of the fingers and toes. In the third to the fifth cervical seg- ments the central group contains the cells related to the phrenic nerve. The dorsal mesial group seems to be related to the muscles of the vertebral column. Extra groups of cells are found in the dorso-lateral region. These cells are probably related to the muscles of the limbs. Touch, pain and temperature are grouped as super- ficial sensibility, as compared with muscle and tendon sense and deep pressure, w^hich are classed as deep sensi- bility. Head and Rivers ^^ have found in the skin two systems of sensory fibres. One system, the protopathic, is related to sensations of pain and of extreme changes of tempera- ture. The sensations, however, are imperfectly localized, and the sensibility is low, i.e., the threshold of stimula- tion is high. The kind of sensation present in the viscera, also mediated by this system of nerve fibres, is called protopathic sensibility, and may be regarded as a defensive agency against pathological changes. It com- prises sensations of pain, of heat above 37° C, and of cold not above 26° C. It is assumed that three different sets of nerve fibres mediate each of these three sensa- tions. The second system of fibres, the epicritic, mediates sensations from light pressures and from small differences in temperature between 26° and 37° C. 94 SEMICIRCULAR CANALS Epicritic fibres regenerate much more slowly after lesions than protopathic fibres. They enable us to make exact discriminations of touch and temperature. They are found only in the skin, and include separate fibres for heat, cold, tactual localization and tactual discrimina- tion. Some authors assume that the peculiar structure of the various sensory terminals (receptors) have much to do in determining the adequate stimulus for the various nerve fibres ; and, indeed, there is evidence that the doctrine of specific nerve energies applies to the cutaneous senses, i.e., that each sense has its own nerve fibres capable of mediating only its own quality of sensation. There is also evidence that the peripheral terminals of the efferent paths (effectors) determine the effect of effer- ent impulses. Thus Langley^^ caused fibres from the chorda tympani, which are vaso-dilators (inhibitory) for the submaxillary gland, to grow down into the peripheral end of the divided cervical sympathetic, which carries vaso-constrictors for the same gland, and found, after regeneration had taken place, that stimulation of the chorda tympani then caused vaso-constriction in the sub- maxillary gland. Erlanger^ cut the fifth cervical nerve, and sutured the proximal stump to the distal stump of the sectioned vagus. Later he found that stimulation of the fifth trunk caused typical vagus phenomena. In the following pages we shall have occasion to revert to this subject, when it will be shown that the ampullary nerve terminals of the semicircular canals and of the maculae acusticse of the vestibule may be affected by various forms of stimulation, e.g., galvanic, thermic, rotation and always with the same constant specific result. Recapitulation of the Cerebellar Paths Afferent cerebellar tracts, i.e., to the cerebellum. Paths through inferior peduncle 1. By way of the vestibular reception nuclei (includ- ing Deiters') to the roof nucleus of the opposite side. Mainly crossed. ANATOMY 95 2. By way of the vestibulo-olivo-cerebellar tract. Mainly crossed. 8. Dorsal spino-cerebellar fasciculus (direct cerebellar, or tract of Flechsig) . Mainly uncrossed. 4. The ventral spino-cerebellar fasciculus (Gowers' tract). Partly crossed. 5. Arcuate fibres from the nuclei of the posterior tracts; partly crossed; and some fibres from the arcuate nucleus, partly crossed. 6. Olivo-cerebellar fibres; mainly crossed. These fibres include the vestiMlo-olivo-cerebellar tract for part of its extent. (See 2 above.) 7. Fibres from the nucleus lateralis; partly crossed. 8. Nucleo-cerebellar tract; mostly crossed. This tract includes No. 1 above, as well as the fibres formerly in- cluded under the term direct sensory cerebellar tract of Edinger. 9. Fibres from the third nucleus to the opposite half of the cerebellum (v. Bechterew). Paths through the middle peduncle 10. Fronto- and temporo-occipito-cerebellar tracts. Mainly crossed. 11. Possibly collaterals from the pyramidal tracts — - mainly crossed. Paths through the superior peduncle 12. Some fibres of the ventral spino-cerebellar fasci- culus (Gowers' tract) ; mainly crossed (Gordinier ''^) . 18. Fibres from the red nucleus to the dentate nucleus ; mainly crossed. Through undefined paths 14. Fibres from various sources, bringing various centres of the brain-stem, medulla and cord into relation with each other under one common coordinating centre; fibres from the eyes directly or indirectly, whereby these aid in the maintenance of equilibrium through the opera- tion of the cerebellum. The fibres from the eyes include pupillary paths (v. Bechterew ^^) , but this point can hardly be considered as settled. Other fibres are supposed to bring the visceral movements under cerebellar control, 96 SEMICIRCULAR CANALS though it is probable that the cerebelhim exerts but little direct control upon visceral movements. These fibres are said by some anatomists to pass in the dorsal spino-cere- bellar tracts. Fibres, especially those from the various organs of special sense, convey impressions from the audi- tory, vestibular, visual and olfactory organs to the cere- bellum. Efferent cerebellar tracts, i.e., from the cerebellum. By way of the inferior peduncle 1. Part of the cerebello-olivary fibres, the paths being continued into the anterior ground bundle of the cord (Kolliker). The destination of the fibres is uncertain, but most probably it is the ventral horn-cells. 2. The cerebello-vestibulo-spinal tract. Uncrossed probably because of double decussation. (See Vestibulo- spinal tract in the cord. ) Through the middle peduncle 3. The cerebello-rubro-spinal fibres. Relations mainly uncrossed because of a double decussation. 4. The cerebello-ponto-pyramidal or cerebello-pyra- midal fibres. Relations uncrossed because of a double decussation. Through the superior peduncle 5. The cerebello-tegmental tract, which includes (a) the cerebello-thalamo-cortical paths crossed and uncrossed ; (b) the cerebello-rubro-thalamico-cortical paths, partly crossed; (c) the cerebello-rubro-spinal tract proper, the relations of which are mainly uncrossed because of a double decussation. 6. Fibres to the oculo-motor nuclei of the opposite side (v. Bechterew ^^) . These fibres are concerned prob- ably in the conjugate movements of the eyes. Through undefined paths 7. Fibres to the posterior longitudinal fasciculus. 8. Fibres to the various centres in the mid-brain, pons, medulla, and cord, which insure coordinated action of ocular, skeletal and perhaps of the visceral muscles as ANATOMY 97 well as of the great centres in the medulla, e.g., the vagus, glosso-pharyngeal vaso-motor, respiratory, etc. Marchi traced degenerating fibres from the cerebellum to all the cranial nerves, but Ferrier and Turner, ^ as well as Risien-Russell, have not been able to confirm his find- ings. CHAPTER VI THE SYMPATHETIC OR AUTONOMIC NERVOUS SYSTEM The sympathetic or autonomic nervous system (Lang- ley) is comi)osed of neurones, the cell bodies of which lie in various sympathetic ganglia. The chief of these ganglia are : 1. The s}Tnpathetic chain from the superior cervical to the ganglion coccygeum. 2. The outlying ganglia, ¥/ith or without names, but related to the former group as follows : (a) In the abdo- men; the prevertebral ganglia, viz., the semilunar or coeliac, from which arises the coeliac plexus and the inferior mesenteric giving rise to the hypogastric nerve. These ganglia lie ventral to the sympathetic chain, but are in direct connection with it. (b) In the region of the head other ganglia of the same type are found, viz., the ciliary, spheno-palatine, otic, submaxillary, sublin- gual, etc. To these, perhaps, should be added the cardiac ganglia and those ganglia located in the plexuses of Meissner and Auerbach between the coats of the intestinal tube, although Langley ^Moelieves that the cells of the ganglia of the Meissner and Auerbach plexuses are not of the sympathetic type. The continuity of the sympathetic with the central nervous system is effected by efferent fibres which leave the latter for the most part by way of the anterior spinal nerve roots, or their analogues in the cranial nerves. It is possible that some efferent fibres may leave the cord by way of the posterior nerve root. Such fibres, however, must suffer interruption in the dorsal root ganglia which contain some sympathetic cells, since they do not degen- erate after section of the posterior nerve root. Cf. the antidromic impulses of Bayliss.'*^ 98 ANATOMY 99 The efferent paths from the central nervous system are, in every instance, interrupted once at least in the sympathetic ganglia. From the point of interruption the pathway is continued by synrpathetic neurones to the peripheral tissues. The sympathetic j^^thway consists therefore of two or more neurones, one of which belongs to the central nervous system, constituting the pregangli- onic fibre. The path is completed by the post-ganglionic fibre that springs from a cell of one of the sympathetic ganglia. "The fibres from the S23inal cord to the sympa- thetic ganglia connect certain cells of the spinal cord with the cells of the sympathetic ganglia in the same way as the fibres of the pyramidal tracts connect certain cells of the brain with the cells of the spinal cord. These spinal fibres become pilo-motor, vaso-motor, or secretory fibres, according as the fibres from the sympathetic cells, with which they are connected, end in the erector muscles of the hairs, muscles of the blood-vessels, or in the sweat- glands" (Langley^^). The sympathetic system is also connected with the central nervous system by means of afferent pathways which pass by way of the posterior root ganglia, forming the afferent path for ceii:ain re- flexes, and exceptionally, perhaps, for conscious sensa- tions. The sympathetic reflexes in the normal individual are carried on below the level of consciousness, but in certain disordered states, e.g., neurasthenia, cardiac pal- pitation, disorders of digestion, etc., afferent influences from the sympathetic system reach the level of conscious perception. The preganglionic fibres of the sympathetic system spring from four regions, viz. : (1) From the mid-brain, emerging in the third cranial ner^^e, and passing to the ciliary ganglion; (2) from the bulbar region, emerging in the seventh, ninth, tenth, and eleventh cranial nerves; (8) from the thoracic nerves, viz. , from the first thoracic to the fourth or fifth lumbar nerves and passing in general to the s}mipathetic chain, many fibres, however, passing without interruption to the abdominal ganglia; (4) from the sacral regions by way of the nervous erigens supplying the descending colon, rectum, anus and geni- tal organs. 100 SEMICIRCULAR CANALS The connections between the anterior nerve roots and the chain of sympathetic ganglia are known as the rami communicantes. These are divided into (a) white rami, or those possessing a medullary sheath and which consist of preganglionic fibres; and (b) grey rami, which are non-medullated, or are but slightly medullated and con- sist of post-ganglionic fibres. In the cervical, lumbar and sacral regions, the rami are exclusively grey whilst in the thoracic and upper lumbar regions both white and grey rami are found. The fibres of the white rami (preganglionic fibres) may pass up or down the chain for some distance before ending in a sympathetic ganglion. The grey rami represent post-ganglionic fibres return- ing from the sympathetic chain to join the anterior spinal nerves, which they accompany to their areas of distribution, especially the cutaneous areas, since the branches to the skin supply the sweat-glands, blood-ves- sels and pilo-motor muscles. The paths which pass as post-ganglionic fibres in the grey rami to any one spinal nerve do not necessarily rep- resent continuations of the paths that pass as pregan- glionic fibres in the white rami from the same nerve. In general, there is a great outflow of preganglionic fibres, including vaso- motor, secretory (sweat) and pilo-motor in the white rami from the first and second thoracic to the second, and even to the fourth, lumbar nerve. The continuations of those paths destined for the skin areas of the head, limbs, and trunk, return by the grey rami to the anterior spinal nerves and run with them to their destination. The fibres for the blood-vessels, glands and walls of the abdominal and pelvic viscera, after entering the sym- pathetic chain, emerge without suffering interruption, and pass still as preganglionic fibres of the splanchnic nerves, to the coeliac ganglion, or in the branches that connect with the inferior mesenteric ganglion. From these points the paths are continued as post-ganglionic fibres. The fibres for the glands, blood-vessels and plain muscle of the head region after entering the sympathetic chain pass upward along the cervical sympathetic to end in the superior cervical ganglion. From this point the paths are continued by postganglionic fibres, which ANATOMY 101 emerge in the various plexuses that spring from this ganglion. The course of the various preganglionic fibres is as follows : 1. Those from the third cranial nerve end in the cil- iary ganglion, thence the path is continued as postgangli- onic fibres that pass in the short ciliary nerves to the iris and ciliary muscle. 2. The fibres that emerge by the VII and IX cranial nerves probably supply the glands and blood-vessels (vaso- dilator fibres) of the mucous membrane of the nose and mouth. Some of these fibres reach the fifth nerve by anastomosing branches and are distributed with it. The preganglionic fibres of the VII and IX cranial nerves end in the ganglia of the sympathetic type of this region, viz. , the spheno-palatine, otic, submaxillary, sub- lingual. 3. The preganglionic fibres of the X cranial nerve (representing also fibres from the X nucleus) are viscero- motor for the oesophagus, stomach, small intestine, and large intestine as far as the descending colon. They also supply motor fibres for the bronchial musculature, inhibi- tory fibres for the heart, and secretory fibres for the gas- tric and pancreatic glands. It is well known that the central nervous system can inhibit and augment the gen- eral contractions of the stomach and intestines. The ganglia in which the preganglionic fibres of the vagus end have not been definitely located, but probably these comprise the small, and for the most part unnamed ganglia distributed in and near the organs innervated. Burton- Op itz *^ has demonstrated by means of the strohmur that the vagus contains no vaso-motor fibres for the stomach. 4. The preganglionic fibres from the sacral cord pass in the anterior roots of the second to the fourth sacral nerves. The branches from these roots unite to form the nervus erigens (pelvic nerve) which loses itself in the pelvic plexus without connecting with the sympathetic chain. The pelvic plexus is also formed in part from the hypogastric nerve arising from the inferior mesenteric ganglion. Through this pathway sympathetic fibres from the upper lumbar region enter the plexus. 102 SEMICIRCULAR CANALS The sympathetic fibres of the nervus erigens supply vaso-dilator fibres to the external genitals causing erec- tion in the male. They also supply vaso-dilator fibres to the rectum and anus, and motor fibres to the plain muscle of the descending colon, rectum and anus. The pregan- glionic fibres of these pathways end in small sympathetic ganglia in the pelvic plexus or in the neighborhood of the organs supplied. The accelerator fibres for the heart emerge from the anterior roots of the second, third and fourth thoracic spinal nerves (according to some authorities from the first and fifth thoracic, and even from the lower cervical nerve roots as well) . The fibres pass by the white rami to the stellate or first thoracic ganglion, some ending in the inferior cervical ganglion, and thence by way of the annulus of Vieussens to the inferior cervical ganglion. Many branches leave the sympathetic system and vagus in this region and pass to the cardiac plexus and so to the heart. Hence in some of these branches accelerator fibres are found mixed with vagus inhibitory fibres. No accelerator fibres are found in the cervical sympathetic above the inferior cervical ganglion. The vagus contains some accelerator fibres as stimulation of that nerve after atropin causes acceleration of the heart. The accelerator centre has not been definitely located. Stimulation of the upper cervical region causes cardiac acceleration, but this merely shows that the centre may be situated in this region or above it. Certain nerve fibres carry afferent impulses to the vaso- motor centres whereby reflex constriction or dilatation of the peripheral vessels is effected with consequent tendency to elevation or lowering of the general blood-pressure. Such fibres are known as pressor or depressor nerves re- spectively. In the dog the afferent depressor fibres for the heart run in the vagus, but in other animals these fibres form a separate bundle — the depressor nerve — dis- covered by Ludwig and Cyon in 1866. In man the depressor fibres most probably run in the vagus, and originate between the cardiac muscle fibres or in the walls of tlie aorta. These fibres are merely sensory, and, when stimulated, cause inhibition of the vaso-constrictor centre. ANATOMY 103 The normal mode of stimulation of the sympathetic system is reflex. This portion of the nervous system is, therefore, mainly concerned with involuntary action. Apparently the only reason that can be assigned for this fact is that the ultimate points of origin of the paths are located in regions other than the voluntary motor cortex (Howell ^^) . However, as before stated, in certain abnor- mal conditions afferent impulses from the sympathetic system may give rise to conscious sensations. Animals, as Goltz and others have shown, live after severance of the nerve connections of the abdominal viscera with the spinal cord. After some primary disturbances the func- tions of the alimentary canal go on as usual, but the gen- eral vital resistance is much impaired, necessitating great care in the preparation and selection of food. This indicates that whilst the cerebro-spinal system normally exerts control over intestinal movements, and presumably over other visceral functions, the latter nevertheless can be, and perhaps normally are, mainly executed under the influence of mechanisms belonging to the diffuse as dis- tinguished from the cerebro-spinal nervous system. Bay- liss and Starling ^^ concluded that peristalsis is a compli- cated reflex carried out through the intrinsic ganglia. Summary of the Vaso-motor Nerves Efferent fibres : 1. Vaso-constrictor fibres distributed chiefly to the skin and the abdominal viscera (splanchnic area) . The blood-vessels of this area are all governed by the general constrictor centre in the medulla as well as by their own particular centres in the cord or elsewhere. They are normally in a state of tonic contraction. 2. Vaso-dilator fibres, distributed especially to erectile tissue, glands, the bucco-facial regions and muscles. The blood-vessels of these structures and areas are not under the control of a superior governing centre in the medulla, and the dilator fibres are not normally in a state of tonic activity. Afferent fibres : 1. Pressor fibres which cause a rise in blood-pressure 104 SEMICIRCULAR CANALS by reflex stimulation of the vaso-constrictor centres, e.g., sensory nerves of the skin or any sensory nerve when powerfully stimulated. 2. Depressor fibres which cause vaso-dilatation and fall of blood-pressure by inhibition of the vaso-constrictor centre in the medulla oblongata, e.g., depressor fibres of the heart. 8. Depressor reflex vaso-dilator fibres which cause vaso-dilatation and fall in blood-pressure by stimulation of the related vaso-dilator centres, e.g., erectile tissue, congestion of glands in functional activity. CHAPTER VII THE PATHS INVOLVED IN PUPILLARY MOVEMENTS The mechanism of pupillary constriction consists chiefly in contraction of the sphincter muscle accompanied by relaxation of the dilator and dilatation of the blood- vessels. Dilatation, on the other hand, is effected mainly by contraction of the dilator muscle, accompanied by inhibition of the sphincter and contraction of the vessels of the iris. The part played by the blood-vessels is a relatively unimportant factor, as it has been shown (Budge and Waller ^^^) that dilatation can occur without variation in the blood-supply of the iris, whilst Sal- kowski '^^ showed that actual constriction of the vessels may accompany pupillary dilatation. Langley and An- derson, ^^ however, state that constriction of the arteries with contraction of their longitudinal fibres might be a possible factor in dilatation, but do not believe that vas- cular changes have much influence on pupillary move- ments. The pupil is not directly under control of the will. Its movements originate (1) by reflex stimulation, or (2) by synkineses, i.e., the pupillary movement is associated with other voluntary or reflex movements. There are two chief reflexes and two chief sjmkineses, giving in all (1) the light reflex; (2) the accommodation synkinesis; (3) the sensory reflex; and (4) the cerebral or psychic synkinesis. The optic ners^e contains fibres from all parts of the retina. The pupillar)^ fibres decussate partially in the chiasm and pass into the optic tract. Since destruction of the lateral geniculate body does not destroy the light reflex (v. Bechterew, "^ Henschen "5) , the pupillary paths evidently do not enter this body. Flourens^^ believed the pupillary constrictor centra m 106 SEMICIRCULAR CANALS was in the corpora qiiadrigemina; but Knoll, "^ who was confirmed by v. Bechterew and by Ferrier and Turner,"^ showed that the superior coUiculi might be removed with- out abolition of the light reflex. According to Bogroff and Flechsig "^ a tract passes from the optic tract directly into the stratum griseum centrale. v. Bechterew"^ be- lieves the pupillary fibres leave the optic tract at the level between the corpus cinereum and the root fibres of the third nerve, near the entrance of the optic tract into the external geniculate body, and run thence to the posterior part of the third ventricle, where they end about neurones that send axones to the third nucleus of the same side. V. Bechterew ^^o also believes that pupillary fibres pass in the superior peduncle between the third nucleus and the cerebellum. The paths are crossed and convey impulses in both directions. Darkschewitsch ^21 believes the pupillary fibres leave the optic tract near the external geniculate body and pass, through the thalamus to the ganglion habenulae, being relayed thence through the posterior commissure to the nucleus bearing his name. But v. Bechterew and others showed that this nucleus is not related to the third nerve. Bernheimer ^22 thinks the pupillary fibres pass directly to the third nucleus. Bach,^^^ however, could not con- firm this view. It is still a question as to what the defin- ite path of the pupillary fibres is. It seems most likely (Parsons*^) that these fibres pass by the superior brachium into the superior colliculi, and by means of new connec- tions the jmths i)ass to the third nucleus of the same and opposite side. The difficulty about this is that extirpa- tion of the colliculi does not abolish the light reflex. Par- sons, however, states that the pupillary fibres end in the lateral portion of the colliculi which was not removed in the experiments of Ferrier and Turner."^ According to Sacki and Schmaus,^'^^Shaeffer,i25 Argyll- Robertson, ^^e Wolff, 127 Ruge^^s and others, pupillary con- striction is caused in part by inhibition of dilatation. Parsons, ^'-^ Anderson "^ and others maintain that pupillary constriction is solely effected by the constrictor centre. The grounds for such a view are: (1) After section of the third nerve variation in tin; ilkimination does not affect the pupil; (2) paradoxical pupil dilatation may arise and ANATOMY 107 persist for one minute in strong sunlight; (3) the irregu- larity of the pupils consequent on sympathectomy is not diminished, but rather increased, by bright illumination of the eyes. These reasons are scarcely sufficient to elimi- nate dilator inhibition in the light reflex. It is generally accepted that the centre for pupil con- striction is located in the third nucleus. Marina ^29 thinks the ciliary ganglion contains the centre for the light reflex. His experiments, however, are not con- vincing. The efferent pupillo-constrictor path passes via the third nerve (branch to the inferior oblique) to the ciliary ganglion where, after interruption, the paths are continued in the short ciliary nerves to the iris. Langley and Anderson, ^^^ Apolant, ^^ Langendorff ^^^ and others have shown that the third nerve fibres enter- ing the ciliary ganglion end about the cells of the latter as preganglionic fibres, the paths being continued through postganglionic fibres into the short ciliary nerves and so to the iris. The exact nature of the cells in the ciliary- ganglion has been a matter of much investigation and controversy. Langley and Anderson^^^ and Langendorff ^^2 have shown that the ganglion contains no spinal ganglion elements. The more recent work of Anderson ^^^ showed that after removal of the ciliary ganglion there was no degeneration of medullary fibres in the HI, IV, V, or VI nerves. Jegerow ^^^ found that after section of the third nerve removal of the ciliary ganglion increased the dilata- tion of the pupil. And since excision of the superior cervical ganglion reduces the number of cells in the ciliary ganglion (Bumm^'*^), and eserine does not con- trol the pupil so efficiently after sjTiipathetic ganglionec- tomy (Levinsohn ^^^) , we may conclude that some con- strictor paths find their way to the ciliary ganglion through the s}Tnpathetic. (See also Onuf and Collins ^o^. ) Anderson ^^^ removed the ciliary ganglion in kittens, and after a few days found that by partially asphyxiating or killing, or by dividing the third nerve, the dilated pupil became smaller than the control. This phenome- non, known as paradoxical pupil contraction, he attribu- ted to increased excitability of the paralyzed muscle. The phenomenon is not of as frequent occurrence as the 108 SEMICIRCULAR CANALS parallel phenomenon paradoxical pupil dilatation occur- ring sometimes after removal of the superior cervical ganglion. The pupillo-dilator tract begins probably in the mes- encephalon near the third nucleus. Passing caudad by unknown paths it descends in the lateral tract of the cord. In the cat, dog and ape the paths leave the cord by the ventral roots of the three upper thoracic nerves, enter the rami communicantes, and pass to the first thoracic or stel- late ganglion. From this point most of the fibres pass by way of the anterior limb of the annulus of Vieussens, some fibres also passing in the posterior limb, up the neck in the cervical sympathetic to the superior cervical ganglion. From the latter the tract enters the skull by the cervico-Gasserian strand, and runs independently of the carotid plexus to join the Gasserian ganglion; pass- ing thence into the first or ophthalmic division of the fifth nerve, following the nasal branch, the tract finally leaves the latter to enter the long ciliary nerves, thus avoiding entrance into the ciliary ganglion. The long ciliary nerves enter the eye on each side of the optic nerve, and pass forward between the chorioid and sclerotic, through the ciliary body, to be distributed to the iris. In the course of this path lie the superior-cilio-spinal centre which is a hypothetical centre in the medulla near the XII nucleus, and the inferior cilio-spinal centre of Budge, ^^^ which lies in the cord between the sixth cervical and fourth thoracic vertebrae. Schiff,^" however, showed that the inferior cilio-spinal was not an independent automatic centre. It may be noted that the above includes only efferent paths, or at least, it does not include afferent paths lead- ing to the mesencephalic centre, although it is probable that the exclusion of light acts as a positive stimulus to the dilator mechanism (Howell ^^) . The existence of a pupillo-dilator muscle has been much studied and discussed. Maunoir ^^^ first propounded it, but no uniformity of opinion so far prevails. The difficulty seems to attach itself chiefly to the histological differentiation between the radial fibres and the blood- vessels of the iris, and to the interpretation of the nature of the cells in the posterior layer of the iris (Parsons ^^). The present state of the question seerns to be that ttie aii- ANATOMY 109 terior layer of the retinal pigmented epithelium acts as a dilator muscle (Grunert ^'^^) . The cells on bleaching look like plain muscle fibres and stain in the same manner. Whatever be the state of the question from the anatomi- cal point of view, Langley and Anderson ^^^ have demon- strated conclusively the existence of a dilator of the pupil. Homolateral pupillary constriction following section of the cervical sympathetic was first pointed out by Par- four du Petit. ^^° Removal of the superior cervical gan- glion was found to cause wider pupillary dilatation than simple section of the nerve trunk (Frangois-Franck ^^^ and others) . The general effect of sjmipathectomy or of ganglionectomy are : miosis, narrowing of the palpebral aperture, projection of the nictitating membrane, retrac- tion of the globe (Langendorff ^^^) , hyperaemia of the con- junctiva (Heese^^^), temporarily increased secretion of tears due to hyperaemia (Levisohn^^^), diminution of intra-ocular tension (Adamiik,^^^ Selenkowski and Rosen- berg^s^), degeneration of the retinal ganglion cells and optic nerve (Lodato^^^^^ vascular injection of the eye- ground upon the side of operation (Sinitzen ^^^) and perhaps trophic disturbances. Galvanic or faradic stimulation of the cervical sympa- thetic causes : homolateral pupillary dilatation with pu- pillary constriction on the opposite side (Schenk and Fuss ^^^) ; change in the color of the iris because of dis- placement of its fibres; retraction of the nictitating membrane and widening of the palpebral fissure with protrusion (retraction in the rabbit, Heese) of the eyeball (Katschew^^^) ; constriction of the vessels of the conjunc- tiva, iris and retina (Heese ^^^) ; increased intraocular tension (Adamtik^^^) and diminished lachr}mial secre- tion (Wolferz and Demtschenko ^9°) the last effect being the result of vascular changes (Campos "^ and Levisohn^^^) . Lodato found that slow irritation of the sympathetic, e. g. , by implantation of a foreign body, causes dilatation of the homo-lateral pupil. This pupil reacts slightly to light, but more so to light flashed in the opposite pupil, Lodato attributed the phenomenon to retinal anaemia, Schenk and Fuss^^^ confirmed Dogiel's observation that stimulation of the cervical sympathetic tended to cause Qonstriction of the opposite pupil, but showed that it 110 SEMICIRCULAR CANALS was due to the consensual reflex. As the latter is absent in rabbits the authors did not observe the phenomenon in these animals. Under certain circumstances after sympathetic gan- glionectomy, e.g., excitement, dyspnoea, anaesthesia, or death, the pupil may dilate instead of contracting (Lan- gendorff,^s3 Anderson, ^^^ Lewandowski,^^^ and others). This phenomenon is known as paradoxical pupillo-dila- tation. The cause is attributed by Anderson ^^^ to in- creased automatic excitability of the dilator contractile tissues, this latter condition being in turn attributed by Langendorff ^^^ to degeneration of the nerve elements. The accommodation synkinesis is considered to be merely a constrictor effect accompanying accommodation, or rather convergence. The phenomenon is not consid- ered to be a true reflex. Weber, ^^^ however, proved by means of prisms that constriction occurred in convergence without accommodation and not vice versa^ and it is well known clinically that the accommodation phenomena are absent in paralysis of the third nerve. Moreover, even when the pupil is very small, it can be made to contract by convergence, whereas in fixation for distance in these instances the degree of dilatation corresponds exactly with that of the previous constriction. These considera- tions coupled with the presence of Golgi-Mazzini end- organs in the tendons of the ocular muscles tend to show that accommodation constriction resembles a true reflex mediated through varying tension in the different ocular muscles. Clinical observation shows that with one eye closed and held firmly so as to prevent convergence, efforts at accommodation cause little, if any, constriction. The dilatation observed by Hensen and Volkers ^^ on stimulation of the VI nucleus can be accounted for by inhibition of the internal rectus, coupled perhaps with active dilatation, as Sherrington 212 has shown by cortical stimulation that reciprocal innervati(m obtains between these muscles. Langley ^^3 ^^s shown that the superior cervical ganglion sends post-ganglionic fibres to the III and VI nerves. The function of these fibres is not known. Thoy were formerly supposed to be vaso-motor for the ocular muscles, but subsequent experiments have dis- proved this. ANATOMY 111 • The sensory pupil reflex consists in dilatation induced by tactile, pathic and other sensory stimuli. Upon the application of any of the stimuli named, there is at first a rapid, short-lived, primary dilatation due to reflex augmentation of the dilator tone. This is followed by a second dilatation rapid in onset but slow in disappearing, and due to inhibition of constrictor tone (Anderson ^^^) . The sensory reflex was first obtained on stimulation of the posterior fasciculi of the cord by Chauveau, who found that the effect was abolished by section of the cord above Budge's inferior cilio-spinal centre. Later Bernard ^^^ showed that stimulation of any sensory nerve evoked the reflex, and Balogh ^^^ that it could be evoked after removal of the superior cervical ganglion, v. Bechterew main- tained that the sensory reflex was entirely due to inliibi- tion, but Anderson ^^2 got well-marked dilatation from stimulation of the sciatic nerve after division of the pupillo-constrictor path. This dilatation, which was accompanied by the other phenomena associated with stimulation of the cervical sjmipathetic, was absent if the cervical sympathetic as well as the third nerv^e had been previously cut. The cerebral synkinesis (psycho-kinesis, Parsons) is the name given to alterations of the pupil induced by psychic stimuli, e.g., fear, the thought of a bright light, etc. It is also to a great extent an association of ocular movements which themselves may be the result of sen- sory impulses (Parsons ^^). Haab^^ first described the phenomenon. Pupil dilatation and constriction have been observed by Hitzig,2oi Ferrier,^ Braunstein, 202 and many other physiologists upon stimulation of various regions of the brain. It was generally found that dilatation was more easily produced than constriction, but no strict localiza- tion could be made out. Most observers considered the effects as complications rather than direct results from local stimulation of the cortex. The dilatation is usually accompanied by the other known effects of stimulation of the cervical sympathetic. Section of this latter abolishes all these effects but the pupillary dilatation, and this it diminishes. With both sympathetics intact, full dilata- tion of the pupils occurs in epileptoid convulsions result- 11^ SEMICIRCULAR CANALS ing from prolonged or frequently repeated excitation of cortical motor areas (Parsons ^^^) . In Parsons' experiments upon cats tlie following areas of the brain on stimulation caused pupil dilatation after destruction of all possible sympathetic paths : (1) A con- siderable area about the crucial sulcus; (2) the mesial surface of the hemisphere in the occipital region near the crucial sulcus ; (3) the anterior part of third or median convolution. Ferrier^ got constriction and divergence from this latter area in the dog. In exceptional cases transitory constriction preceded dilatation. In the occipital region, in the posterior part of the third or median convolutions, Ferrier got constriction, but Parsons could not confirm the observation upon the cat whilst Frangois-Franck got temporary constriction followed by dilatation. Parsons got, upon the dog, re- sults similar to those obtained upon the cat, and con- cluded that there probably exist in the frontal and occipi- tal areas foci for constriction, but that these are masked by the dilator effects, which are more easily produced. Section of the third nerve after previous division of the cervical sympathetic, left the puj)il immobile and three-quarters dilated. Stimulation of the cortex was then without effect. Section of the corpus callosum was without effect upon dilatation from cortical stimulation. Hence the bilateral effect was not due to stimulation acting through the opposite cortical areas, but to its effect upon the lower centres. Stimulation of the anterior and posterior part of the corona radiata and internal capsule, i.e., fibres from the frontal and occipital areas, caused bilateral dilatation of the pupils. In one case there was constriction and con- vergence from stimulation of the posterior part of the internal capsule. Sherrington, 2^^ after vagus and spinal transection which cut off impulses from above and those from below via the cervical sympathetic, found the pupils dilated as if in anger. This indicates that in pupil dilatation from stimulation of the cerebral cortex after section of the sympathetic, the mechanism consists in inhibition of the constrictor mechanism. Another theory bases the mech- ANATOMY llg anism of this dilatation upon vascular changes in the iris. But all the vaso-motors for the iris run in the cer- vical sympathetic, and Langley and Anderson ^'^ have shown that vaso-motor changes whilst they may affect the pupil, do not do so to such an extent as to make them independent factors to any important degree. It may be remarked that Onuf and Collins, ^^^ Frangois- Franck and others believe that all the mydriatic paths are not confined to the cervical sympathetic. Ferrier ^ obtained pupil constriction from the anterior and posterior limbs of the angular gyrus in the monkey, and from the third external or coronal convolution in dogs. Parsons ^"^ failed to confirm these observations, but Frangois-Franck and Pitres ^^ saw transitory con- striction from stimulation of the former area. In pigeons Ferrier observed intense pupil constriction on irritation of the middle of the convexity of the hemi- sphere. Schafer ^^ got marked constriction from stimula- tion of the quadrate lobule, whilst in monkeys Ferrier also got fairly constant homolateral pupil constriction from irritation of certain areas of the cerebellum. Parsons concluded that the phenomena of pupil dilata- tion and contraction from irritation of the cerebral cortex are mere associations, since they do not occur in the absence of ocular movements. The movements obtained from the sensory areas, e.g., from the visual centres in the occipital cortex are due to ill-defined visual sensations leading to appropriate movement of the head and eyes. The mere fact of association with ocular movements tends to show that movements of the iris, like other ocular movements, have higher representation than that of merely spinal or analogous motor nuclei. CHAPTER VIII FURTHER ANATOMICAL AND PHYSIOLOGICAL CONSIDERATIONS Before approaching the study of the semicircular canals it is proper to note further a few fundamental facts concerning the anatomical and physiological relations of the cerebellum with other structures. The following may be accepted : 1. The cerebellar hemisphere is in close anatomical and physiological relation with the cerebral hemisphere and inferior olivary body of the opposite side. In Fer- rier's^^ case marked atrophy of the cerebellar hemisphere was found in a criminal lunatic with atrophy of the contra-lateral cerebral hemisphere. Starr has a similar specimen from a weak-minded child who had always been irregular in gait and balanced with difficulty. The child died when three years old from measles. There was found almost complete absence of the cerebellum on one side with marked atrophy of the fibres of the pons and inferior olive of the opposite side. Gudden ^^ found on extirpation of one-half of the cerebellum ensuing atrophy of the opposite olive. Many instances of cerebellar defect have been discovered at autopsy in individuals who, in life, were considered to be fairly normal. 2. Each half of the cerebellum controls for the most part the movements of muscles on the same side of the body. Ferrier's^ experiments showed that stimulation of one side of the cerebellum was always accompanied by move- ment of the muscles on the side stimulated, and by certain characteristic movements of the eyes. This proposition seems a corollary of the first. Each cerebral hemisphere controls the muscles of the opposite side of the body, and at the same time is in intimate relation 114 ANATOMY 115 with the cerebellar hemisphere of the opposite side. Further developraents will show that this relationship is the one best calculated to aid the function of equilibra- tion. 3. The cerebellum acts wholly in a reflex manner, i.e., beneath the level of consciousness. This is generally ad- jnitted by investigators. Hence afferent and efferent paths are required. The afferent paths place the cerebel- lum in relation with the specialized sensory organs of equilibration, the chief of which are the semicircular canals, the eyes, and those structures in which kinsesthetic impulses originate, viz., the skin, muscles, tendons, articular surfaces, etc. The cerebrum, however, besides being capable of exerting control over the muscles in- volved in equilibration and in ocular movements has, in man, to be reckoned as an important source of afferent cerebellar impressions in acts of equilibration. The phenomena of conjugate deviation observed by Schafer and Mott,^^ and by Kisien-Russell ^^ on stimulation and ablation of the ocular centres in the frontal lobe and the similar phenomena that sometimes accompany cerebral hemorrhage, closely resemble those observed on stimula- tion (Ferrier^), or ablation (Luciani^^), of parts of the cerebellum or section of the cerebellar peduncles, or of the auditory nerve. These phenomena are best explained by assuming the existence of cerebral and cerebellar tonus balanced mechanisms, working in harmony and in a reflex manner, the cerebral motor mechanisms of one side acting in harmony with the corresponding mechanisms of the opposite half of the cerebellum. In addition to the direct tonus influence which the cerebral centres exert upon the ocular and other muscles itVould seem that the cerebrum is an important source of afferent cerebellar impressions whereby it influences the actions of the cerebellar mechanisms upon the ocular and other muscles. In other words, afferent cerebellar paths conduct im- pulses from the various parts of the cerebral cortex to the cerebellum. Such cerebro-cerebellar paths are somewhat analogous to those from the semicircular canals, and from the peripheral kinsesthetic end organs. The im- pulses conveyed by them act probably after the manner of 116 SEMICIRCULAR CANALS those conveyed by the vestibular or kinaesthetic paths in influencing cerebellar action. In a large cerebral hemorrhage confined to one hemi- sphere not only is the independent action of the cerebral centres for the head and eyes suspended, but the cerebral influence exerted through the cerebro-cerebellar paths is in abeyance. The consequent conjugate deviation results from removal of the direct cerebral tonus, as well as of the associated, indirect, cerebro-cerebellar tonus on one side of the body, leaving the opposing mechanisms of the opposite side in free and unopposed control. The phenomena following section of the superior and middle peduncles of the cerebellum seem to afford grounds for this assumption. It may, therefore, be concluded that the cerebrum besides exerting tonic influence directly on muscle, can also affect muscle tone indirectly through the medium of the cerebellum. The anatomical relations strongly corroborate this view. The fact that removal of the cerebral hemispheres of the frog does not disturb the functions of equilibration to any extent, does not contra- vene this view because the hemispheres are relatively unimportant structures in the frog, as compared with man, and bilateral lesions tend to counterbalance each other, leaving the remaining elements of the balanced mechanisms to control acts of equilibration. The turn- ing of the eyes to the side of the lesion in cerebral apo- plexy accords with Ferrier's^ experiments, in which stimulation of the cerebellum on one side was invariably followed by turning of the eyes toward that side. These matters shall receive further discussion in a later chapter. The cerebellum by means of its afferent and efferent peripheral relations constantly holds the muscles involved in equilibration in a state of tone ever ready to respond to impulses originating from change of j^osition (Ewald) or other stimulus. This tonic influence is bilateral, each half of the cerebellum controlling in the main the muscles on the homolateral side. Thus delicate cerebellar mech- anisms are constantly active in the reflex maintenance of equilibrium. Sometimes these mechanisms work unaided and at other times in conjunction with the higher volun- tary motor centres. Serious interference with the affer- ent, efferent, or central elements of the reflex arcs of ANATOMY 117 these mechanisms results in disturbances of equilibrium, incoordinated action of the muscles of dynamic equilib- rium and other phenomena. Such disturbances, if of mild degree, may be corrected by voluntary effort, but this latter is always awkward, very exhausting, and requires the constant attention of the individual, which is the opposite of what occurs in normal equilibration. Compare the results observed by Weir-Mitchell^^ in pigeons after injury to the cerebellum 4. The peripheral end organs of the vestibule and semicircular canals are mainly in crossed relation with the cerebellum through the vestibular nerve, v. Bech- terew maintains the contradictory of this proposition. The succeeding chapters, as well as careful study of the fibre-paths, will reveal this crossed relationship. Ferrier^ has shown that the cochlear apparatus is in relation mainly with the temporo-sphenoidal lobe of the opposite side. He found on stimulation of the auditory area in monkeys, cats, dogs and jackals, pricking of the oppo- site ear, wide opening of the eyes, dilatation of the pupils, and turning of the head and eye to the opposite side, thus indicating the direction of the source of the imagined sound. These experiments were repeated many times, and on both sides of the brain. Before proceeding further, it is proper to call attention to such terms as "rolling on the long axis to the side of operation" in animals, and to contrast it with "revolving to the right or left, or to the side of the lesion, on the long axis" in man. Owing to the difference in posture normally assumed by man and the quadrupeds, these expressions have altogether a different meaning. In the case of a dog ' ' rolling on the long axis toward the side of operation, ' ' means that the direction of the motion would be represented by a bent arrow passing transversely over the'dorsal aspect of the animal, whilst in the case of man the direction would be indicated by a bent arrow passing transversely across the ventral aspect of the body. The rotations in the two instances, though in the same direc- tion, would be, according to current forms of expression, absolutely in opposite directions. A similar difficulty is encountered in describing movements of the eyeballs oc- curring in nystagmus and ocular deviations. Thus, it is 118 ' SEMICIRCULAR CANALS said, that the eyeballs rotate inward or outward, or from left to right on the horizontal antero-posterior axis. Such statements afford opportunity for misinterpretation. Thus if the upper part of the visible portion of the eye- balls be held in mind as the point of observation, the direction will be indicated by an arrow pointing one way, whilst if the lower portion of the eyeball be taken as the point of observation, the direction will be indicated by an arrow pointing in the opposite direction. Hence it seems better to drop the terms rotating inward and out- ward, and substitute for them rotation in the direction of the hands of a watch or the reverse, the watch in every instance being considered as held facing the observer, and in a plane parallel to the vertical transverse mesial (coronal) plane of the subject's body. Similarly in rota- tions with the subject in the recumbent posture the watch is considered as placed on the subject's breast with the dial looking toward, the observer, and parallel to the coronal plane of the subject's body. The direction of certain forms of rotation can then be designated as with or against the hands of the watch, whilst the nystagmus, ocular deviations and subjective sensations of movement may be recorded in similar terms. The simple reflex arc comprises, according to Sher- rington, (1) a peripheral receptive portion (receptor), (2) a peripheral motor portion (effector) , and (3) a con- ducting part which consists of the afferent and efferent neurones. "At the commencement of every reflex arc the receptive neurone is the sole avenue for impulses generated at its receptive point. The path is therefore exclusive, and other receptive points cannot employ it. A single receptive point may play reflexly on a number of differ- ent effector organs, e.g., on many muscles and glands in different regions, yet all its reflex arcs spring from one single shank, i.e., from one afferent neurone which con- ducts from the recex:)tive point at the periphery into the central nervous organ. At the end of every reflex arc is the motor neurone, the last conductive link to an effector organ. This receives impulses from many receptive sources in various regions of the body. It is the sole path by which all impulses, no matter whence they come, reach the muscle fibres. The receptor neurone forms a private ANATOMY 119 path exclusively, serving impulses of one source only. The effector neurone is a public or common path for impulses arising at many sources of reception. A receptive field, e.g., an area of skin is analyzable into receptive points. An effector organ stands in reflex connection not only with many individual receptive points, but with many receptive fields. Impulses generated in manifold sense organs can pour their influence into one and the same muscle. Therefore, in reflex arcs the initial neurone of each is a private path, exclusive for a receptor point or group of points, and finally the arcs embouch into a path leading to an effector organ, and their final common path is common to all receptive points wheresoever they may lie in the body, so long as they have connection with the effector organ in question. ' ' But arcs converge to some degree before finally con- verging upon the motor neurone. Their private paths embouch upon internuncial paths common in various degree to groups of private paths. The terminal path is the final common path to distinguish it from internuncial common paths. The motor nerve to muscle is a collection of (parts of) final common paths. Internuncial paths conduct and converge to final paths or to further inter- nuncial paths. In the scratch reflex the long descending proprio-spinal neurone is connected with a whole group of afferent neurones — private paths from the scalptor re- ceptors in the skin field of the scratch reflex. Again, in the retina and olfactory bulb, Cajal and others have shown that the conducting fibres of whole groups of receptors impinge upon individual neurones of the next relay. The thalamic neurones form a path upon which the dorsal col- umns, fillet, and spino-cerebellar peduncular paths con- verge. Therefore, each internuncial path is, to some extent, a common path, just as the receptive neurone is common to a small number of receptors. The ultimate path, therefore, differs from the internuncial path only in that it exhibits communism in the highest degree" (Sherrington) . Because each instance of convergence of two or more afferent neurones upon a third which, in regard to them is efferent, affords, as shown, an opportunity for coalition or interference of their action, each structure at which it 120 SEMICIRCULAR CANALS occurs is a mechanism for co-ordination (Sherrington^). In simple reflexes using only one muscle it may be ac- cepted that the motor neurone is the final common path. In complex co-ordinated reflexes involving the simulta- neous action of several muscles, e.g., the reflex acts of equilibration, mediated by cerebellar neurones, the spinal motor neurones cannot be the final common path which in this instance must of necessity consist of efferent cere- bellar neurones, using, however, various spinal motor neurones to manifest its influence upon the effector organs brought into play. The receptor organs are divided (Sherrington) into three groups, as follows: L The exteroceptive field endowed with numerous receptive organs adapted to mechanical contact — cold, warmth, light, sound, injury (noxa) ; in fact, eveiy mode of stimulation whereby the environment can affect the ex- ternal surface of the body. 2. The proprio-receptive field with specific receptor organs adapted to modes of stimulation obtaining in the muscles, tendons, joints, walls of the blood-vessels, etc. 8. The interoceptive field, co-extensive with the inter- nal surface of the body (alimentary canal, etc.), and fur- nished scantily with receptor organs as compared with the exteroceptive field, though these are peculiarly adapted to chemical agencies. Receptors that respond to stimuli originating from an object at a distance from the body are known as projicient or distance receptors, e.g., those of vision, hearing, and smell. Such receptors tend to have a large cortical representation and to control the skeletal musculature as a whole. Receptors that respond to the action of noxious agents which threaten immediate harm to the skin are known as nociceptors. Furthermore, the reflex which these receptors excite is prepotent, protects by escape or defence, is im- perative and is accompanied by pain. There is no such thing as a purely simple reflex, be- cause the nervous system is never at rest, and no part of it is disconnected from the rest. Reflexes are more easily elicited from the skin (receptor organs) than from the afferent nerve trunk, and ^ome are only elicited from a ANATOMY 121 particular surface by particular Btimuli. One reflex may- combine harmoniously with another, so that their reac- tions mutually reinforce each other. Such reflexes are allied and their neural arcs are called allied arcs. On the other hand, some reflexes are incompatible and antagonistic, i.e., one inhibits the other or a whole group of others. The reflex or group that inhibits its oppo- nents is called prepotent for the time being. Nocicep- tive reflexes override (inhibit) all others and are there- fore prepotent. The type reflex, e. g. , the scratch reflex, etc. , results from the harmonious relation between allied reflexes and allied arcs. In a type reflex the whole motor centre potentially belongs to all and each of the groups of receptive organs proper to the reflex. The elements of the centre of the type reflex are combined and incapable of isolated excitation. In the decerberate dog a reflex that is accompanied by certain mimetic movements simulating certain affective states, e.g., anger, pain, etc., is called a pseudo-affective reflex. Pain is the psychic adjunct of a protective reflex. The reflex is always purposive. A receptive field frequently contains receptors of two different species, e.g., tangoceptive and nociceptive which may not both of them initiate reflexes belonging to the same type, i.e., related between themselves as allied reflexes. On simultaneous stimulation of these two kinds of receptors the nociceptive suppresses the tango- ceptive reflex. This is known as reflex complication. "The compounding of reflexes is a main problem in co-ordination. Hence the common path is a feature" (Sherrington ^^) . "In the scratch reflex there is an end effect of posi- tive sign followed by an inhibitory phase which is an end effect of negative sign. This succession in the reflex is repeated many times, the stimulus being continued. The scratch reflex is therefore of double sign, i.e., it develops first an excitatory and then an inhibitory end effect. "In the flexion reflex of the hind limb of a spinal dog or cat, the end effect is expressed by two groups of muscles whose contractions act in opposed direction at the same joints. This opposition is obviated at the end of the reflex by the end effect having the form of excitatory 122 SEMICIRCULAR CANALS state as regards the motor nerve to the flexor muscles, but suppression or withholding of excitatory state (central inhibition) as regards the motor neurones of the extensor. This is a reflex of double sign, whilst the scratch and eyelid reflexes are of successive double sign" (Sher- rington ^) . Although the intimate nature of inhibition is but little understood it has been clearly demonstrated by Sherrington ^^ that inhibition is an active process and an essential part of the reflex. By means of inhibition the motor neurones are precluded from the arc of one reflex whilst left open to another. In any type reflex, inhibi- tion of certain muscles appears as the negative aspect of positive excitation in other muscles. This phenomenon which seems to be an essential part of every reflex move- ment constitutes what is known as reciprocal innervation. The seat of inhibition seems to be, not in the afferent or efferent neurone, but in an internuncial mechanism between them, viz., the ultimate synapse. The objection made to the spinal motor neurone as constituting the final common path for complex co-ordinated reflexes o^ equilibrium seems to indicate that in these and similar reflexes the seat of inhibition is not placed at, or near the commencement of the spinal-motor neurone, but higher up, viz. , at the commencement of the cerebellar or other neurone which, in this instance, is the commencement of the final common path. Tonic reflexes of posture are the most readily inhibited. From the foregoing it is apparent that the most inti- mate functional relations obtain between the various parts of the nervous system. In the preceding chapters an at- tempt was made to trace anatomically these connections, the study of which may help toward an understanding of the physiological relations, though it must be under- stood that the tracts traced only crudely and indefinitely represent the actual paths employed in the various activi- ties of nervous system. Thus, whilst it is not possible to trace the minute anatomical connections it seems that every final motor neurone, or, at least, every common path is, to some extent, in relation with the receptive areas of all parts of the body through afferent arcs of greater or less resistance. PART II PHYSIOLOGY OF THE SEMICIRCULAR CANALS CHAPTER IX PHYSIOLOGY OF THE SEMICIRCULAR CANALS FROM THE STANDPOINT OF ANIMAL EXPERIMENTATION So much investigation has been devoted to the study of the semicircular canals that it would take more space than present circumstances permit to give even a cursory review of the work done. As early as 1693 Bannister, an English- man whose researches were perhaps the first experimental effort in this direction, observed the role of balancers in certain kinds of files, and noted disturbances of equilibrium after their removal. Since Bannister's time the literature of the semicircular canals teems with names familiar to every student of medicine. Only a few can be mentioned, such as Scarpa, Darwin, Jackson, Flourens, Goltz, De Cyon, Hogyes, Hitzig, Spamer, Brown-Sequard, Lucas, v. Bech- terew, Vulpian, Baginsky, Breuer, Mach, Crum-Brown, Laborde, Koenig, Lee, Sewall, James, Kreidl, Loeb, Biehl, Dreyfus, Schwartze, Wanner, Ewald, von Stein, Delage, Engelmann, Koryani, Steiner, Bruck, Barany, Neumann and hosts of others. Flourens was the first to point out the intimate relation- ship between the semicircular canals and the function of equilibration. He showed that injury of the membranous canals was followed by disturbances of equilibrium — vary- ing with the seat of the lesion. De Cyon, Goltz and others confirmed Flourens's observations. Flourens ^^ and De Cyon,^''' experimenting on the semi- circular canals of pigeons, obtained the following results: Division of the horizontal canal on one side caused a series of oscillations of the head in the horizontal plane on a vertical axis. These cease in a short time, but on section of the corresponding canal on the other side they reappear with greater intensity. The bird cannot now maintain it^ 125 126 SEMICIRCULAR CANALS equilibrmm, but falls or turns on a vertical axis or circles round and round. After eight to ten days the bird recovers and seems normal but for a certain awkwardness seen espe- cially in flight. Division of the posterior vertical canals causes similar but more violent disturbances of equilibrium. The move- ments of the head are in a vertical plane on a horizontal axis. The pigeon somersaults head over heels. The dis- turbances subside in fourteen days, but a certain brusquerie of movement remains, with an almost complete inability to fly. Division of the superior vertical canals causes move- ments of the head from behind forward and from right to left, or vice versa, with profound disturbances of equi- librium. The bird constantly tends to somersault heels over head. The plane of the movements of the head is diagonally around a horizontal axis. The movements on section of the canals seem therefore to take place in the plane of the canals operated on. In rabbits, section of the canals gave results similar to those obtained in pigeons, but more enduring and the oscilla- tions affected the eyeballs more than the head and trunk (De Cyon^"^). Section of one horizontal canal caused ten- dency to movements of manege (circus movements). Sec- tion of one vertical canal caused the animal to turn on the longitudinal axis. There was deviation of the eyeballs and nystagmus, the plane of the oscillations varying with the canal injured, but the oscillations of the eyeballs were more or less independent of the movements of the head. In frogs, section of the horizontal canals caused the head to turn on the long axis of the body, the animal falling to one side or leaping. Section of the posterior vertical canals caused the animal to fall on its back. Section of the other vertical canals caused complete somersaults and the utmost disorder of movement. On section of the superior vertical canals the frog swims in an upright position, pivoting round and round. Re- covery may follow destruction of all the canals on one side. At first there is a tendency to fall to the injured side, and the leg of this side gives way as if broken. In many animals the head assumes an unnatural position, e.g., in pigeons the PHYSIOLOGY 127 occiput going to the side of injury and the beak to the opposite side. After destruction of the canals on both sides equilibra- tion is extremely affected. Pigeons' after a time learn to walk, but the disturbances of equilibration recur if a hood be thrown over the eyes. After some months the birds begin to look normal, but they cannot fly, and when suddenly startled their confusion of movement returns and they tumble about helplessly. Animals with their semicircular canals destroyed can hear (Flourens), while those in which the cochlea alone has been destroyed cannot hear but can equilibrate. This accords with what is now kno^vn and accepted, viz., the complete anatomical and physiological distinction between the vestibular and auditory fibres and nuclei of reception of the eighth nerve. Section of the auditory nerve in frogs gave results simi- lar to those obtained on section of the semicircular canals (Goltz^^). Similar effects were observed in dogs by v. Bechterew ^^ on section of the eighth nerve, and in sheep and horses by Biehl.'^ The animals rolled round toward the side of operation and showed a skew deviation of the eyes, that on the side of operation looking downward and out- ward, whilst that on the other side looked upward and in- ward. The oscillations of the eyes were in the direction opposite to that of the deviation. Polling movements were most marked in the first few days, being almost incessant. When not rolling on itsaxis (longitudinal) the animal lies on the side of section with this side of the head downward. The legs on the side of section are doubled up close to the trunk, but flaccid, whilst those of the opposite side are rigidly extended outward. If the animal is placed in any other position than on its side, all the stiffness of the limbs ceases to be manifest (v. Bechterew ^^). The disturbances of equilibration gradually become less pronounced, but for many weeks the animal is unsteady. This unsteadiness is greatly increased by covering the eyes. A loud sound often causes the animal to fall on the side of section or to roll round once or twice. When both audi- tory nerves are cut the animal can neither stand nor walk. There is no paralysis of the limbs, but all movements of them are irregular and purposeless. The head and eyes 128 SEMICIRCULAR CANALS oscillate, but the eyes oscillate in a horizontal plane and there is no skew deviation as when one nerve is divided. Various theories have been put forward to explain the modus operandi of the semicircular canal apparatus. Thus actual currents of endolymph were at first believed to be the adequate stimulus of the ampullary nerve endings (Goltz^^); then, because the membranous canals are of capillary calibre this theory was displaced by that of partial pressures (Mach/^ Breuer ^^ and Crum-Brown '^^) of the endolymph in a certain direction that is to or from the ampulla. De Cyon "^^ differs from Crum-Brown, Mach and Breuer and considers the semicircular canals as a system of physiological coordinates to which we refer all our notions of space. Breuer'^^ and Ewald^^ showed that determination of an endolymph current toward the ampulla produced devi- ations and displacements of the head in a certain direction, while determination of an endolymph current from the ampulla toward the canal produced similar displacements, but in the opposite direction. The existence of bilateral labyrinthine tonus mechanisms which, in the erect position, constantly supply the muscles involved in equilibration with tonus impulses, makes the hypothesis of partial pressures exerted through the endolymph more acceptable without necessarily implying any gross actual movement of the fluid. Moreover, the delicacy of these mechanisms on either side of the body, each of which so nicely adjusts itself in bal- ancing its fellow of the opposite side under varying con- ditions, implies rapid alterations such as could be effected by means of pressure rapidly transmitted through compara- tively incompressible liquids rather than by means of the clumsy, slow movements of the liquid itself. It is not prob- able that in rotations the pressure exerted through the en- dolymph in one direction with reference to the ampulla upon one side of the body is reinforced by a pressure ex- erted in the opposite direction in the corresponding canal upon the other side. This phase of negative stimulation will therefore be omitted in the discussions that follow. The otoliths, which in mammifera are two, and in other vertel^rates three on either side, are, according toi Breuer '^^ the peripheral organs of specific sensations of PHYSIOLOGY 129 position and of movements of translation. They are dis- posed in two planes (three in animals possessing the lagena) perpendicular to each other, the physiological stimulus being the gravitation. For the sake of simplicity and to avoid confusion, little mention of these organs will be made in the discussions that follow, though undoubtedly they are affected in vari- ous forms of rotations and movements as well as in prolonged aural irrigations and in strong galvanic stim- ulation. CHAPTER X THE EFFECTS OF PASSIVE ROTATION Passive rotations were performed in various postures and in various planes. For rotation about the long axis of the body, the subject was placed in an arm-chair sus- pended from the ceiling. For rotation about the other axes of the body, a broad board, long enough to permit the subject to li@ in any position, was suspended after the manner of a boatswain's chair. Passive rotation in general caused various disturb- ances depending upon the duration (repetition) and rapid- ity of the rotation ; upon the axis of the body about which the rotation took place; but, above all, upon the abrupt reversal, retardation or acceleration of the movement. Mild rotations repeated a few times caused merely a transitory dizziness. If repeated sufficiently often with reversals, accelerations and retardations, rotations of mild degree, i.e., of short range and of a low rate of speed, grad- ually produced profound disturbances in the organism. Rotations more severe in grade caused disturbances of equilibrium with vertigo; displacements and deviations of the eyes, head and body; disturbances of the circulation and respiration; disturbances of the digestive apparatus with increased flow of saliva, nausea, wretchedness and vomiting; and finally, disturbances of the nervous system varying from a mild degree of irritability to the most pro- found degree of general physical and mental prostration. The position of the body during rotation, i.e., whether it is upright or horizontal, is an important factor because of the effects upon the circulation, but, chiefly perhaps, be- cause of the necessity of acts of equilibration mediated by the otoliths when the body is erect. Thus rotations about the long axis of the body with the subject sitting upright 130 PHYSIOLOGY 131 were very effective in causing sickness and distress and circulatory disturbances, whilst with the subject lying hori- .zontally, rotations in the sagittal and coronal planes caused lighter and more transient phenomena. It was notable, however, that rotation in the sagittal plane back- ward, i.e., occiput first, caused much more disturbance than rotation in the same plane forward, i.e., face first. For convenience, all rotations are to be considered as about the long axis of the body, with the subject sitting upright in an arm-chair unless otherwise specified. In general, the effect of mild rotation upon the cir- culation is a rise in blood-pressure dependent on contrac- tion of the blood-vessels. (See protocols 1-17 at the end of this chapter.) Frequently the rise is preceded by a pre- liminary fall in blood-pressure. If mild rotations be con- tinued at frequent intervals, the rise in blood-pressure may occasionally be absent, owing to fatigue, but on resting, and at times even without resting, it will manifest itself soon again. After repeated mild rotations, a close study of the circulation reveals the fact, not fairly represented in the protocols, that the blood-vessels are constantly con- tracting and dilating. In" severe rotations, the radial artery becomes at times so small and empty as to be impal|)able. Under such circumstances, of course, the blood-pressure by clinical methods would be nil. During such periods of radial pulselessness, the ear, or stethoscope, placed over the heart found the latter beating, with the sounds feeble, the second sound being relativeh^ accentuated. (See protocol 13). These pulseless periods occurred mainly in very rapid rotations during the actual rotation, and frequently just after reversal or sudden cessation. They lasted for a mo- m.ent or two when the pulse gradually returned. At the time that the pulseless periods were observed, the swing used consisted of a boatswain's chair. There was, conse- quently, no support for the back, so that the subject's head tilted backward during the rotation. In later trials when the swing used (an arm-chair) had a support for the sub- ject's back, no pulseless periods were observed. An approach to this phenomenon was frequently observed, both during and after rotations, when the pulse, at one moment large and with low blood-pressure, would almost immediately 182 SEMICIRCULAR CANALS disappear as the arteries contracted to an extreme degree. (See protocol 13.) After long, repeated, mild rotations, or after severe rotations with reversals or retardations, the general ten- dency is toward a decline in blood-pressure, with general prostration and with the pulse-rate in general stationary, or somewhat slowed. Vomiting restores the circulation so regularly in rotation sickness that it may be regarded as one of nature's defences against failing medullary circu- lation, rather than as a mere act intended to empty the stomach, though in doing the latter it unquestionably benefits the general condition materially. At times the blood-pressure and pulse-rate made sharp upward excur- sions before the vomiting actually occurred, and before the 'subject was aware that the abdominal muscles had become fixed in the act. This fact, not generally admitted by physiologists and clinicians, has been frequently observed by the author in other conditions. The increased blood- pressure seems to be caused by the same agency that sets the mechanism of nausea and vomiting going, and is not merely the result of muscular contraction. In general, the respiratory rate was increased during, and slowed after, rotation. Between rotations, the rate was slowed or about normal, never much above it. Severe and even mild rota- tions caused complete apnoea for short periods, followed by deep inspirations. (See protocols 8 and 10.) As a rule, the respiratory rate increases as the blood-pressure falls, and vice versa. When vomiting and deep breathing did not suffice to maintain or restore the blood-pressure, the pulse- rate occasionally became markedly increased, but increase in pulse-rate apart from vomiting was the exception, not the rule; in fact, the most striking general effect of re- peated rotations upon the pulse is a slowing of the rate. It was noted that covering the eyes and head had no appreciable effect in preventing the nausea and circulatory disturbances that attend rotations. (See protocol 2.) Rotations in the sagittal and coronal planes, with the subject lying horizontally, lowered the blood-pressure. (See protocols 17a and 17b.) The pulse-rate was also lowered. After the rotations, the blood-pressure rose somewhat, but not to the extent observed following rotations about the long axis with the subject sitting erect. PHYSIOLOGY IBB The conclusions are: 1. That rotations in the upright position about the long axis of the body, affect the circulation by irritation of the medullary vaso-constrictor centres. There are reasons for believing that the semicircular canals are not in direct re- lation with the medullary vaso-constrictor centres, and that the rise in blood-pressure that accompanies rotations, etc., is the result of the cerebral and cerebellar disturbances responsible for the vertigo, displacements of equilibrium, etc. On the other hand, the otolithic apparatus seems to be in direct relation with the medullary vaso-constrictor centres. These structures appear to be the chief factors in the mechanism which regulates the blood-pressure when the subject assumes the erect posture. However, inasmuch as rotations probably affect the otolithic apparatus of the vestibule, as well as the ampullary receptors of the semi- circular canals, it is probable that the otoliths are an im- portant factor in the mechanism involved in the circu- latory changes observed. 2. That by vaso-constriction, the blood-pressure is raised without a corresponding increase in pulse-rate, but when the rotations are frequently repeated over long periods, or when they are severe, with violent reversals or retardations, fatigue rapidly sets in, with failure of the circulation which, when profound, is met chiefly by en- hanced respiratory movements and by vomiting. The latter tends to restore the circulation in the vital medul- lary centres, and removes the stomach contents. 3. That the vagus (cardiac inhibitory) centre is stim- ulated, as evidenced by the slow pulse, and in certain extreme conditions is so irritated as to practically bring the heart to a standstill for a time. 4. That the respiratory centre is inhibited, making the rate lower, and causing, at times, complete apnoea. The subsequently increased depth of the respiration is to be attributed in part to a prolonged period of latency and accumulation of C 2 in the blood. 5. That the respiratory as well as the pulse-rate, ac- companies the blood-pressure in the sharp rise of the latter that occurs with vomiting. 6. That in rotation in the sagittal and coronal planes, with the subject lying horizontally, the vaso-constrictor 134 SEMICIRCULAR CANALS action with its resulting rise in blood-pressure, is wanting, not because the rotation does not stimulate the medullary vaso-constrictor centres, but because the stimulation of those centres is insufficient to cause appreciable effect on the blood-pressure on account of the diminished tonicity of the vessels and lowered pulse-rate that obtain in re- cumbency, these being due, in part, to the inactive state of the otolithic apparatus. 7. That in rotations in recumbency, the vagus centre is stimulated, as manifested by lowered pulse-rate, which is masked, to a certain extent, because of the lowered pulse- rate induced by recumbency. 8. That a condition simulating surgical shock may be present with extremely contracted arteries. This seems to favor Porter's view of the mechanism of shock, viz., arterial constriction, or Henderson's view, viz., venous relaxation, as opposed to Crile's view, which attributes shock to arterial relaxation. 9. That the emptying of the stomach is but one of the bye-results of vomiting, where the latter occurs as the re-' suit of anaemia and asphyxiation of the medullary centres in profound circulatory depression from whatever cause. Thus, vomiting is to be regarded as a response of the organism analogous to that which occurs in an animal upon which artificial increase of intra-cranial pressure is practised. In the latter instance, asphyxia occurs first, then follows arterial constriction, with contraction of the muscles all over the body, e,g,, increased peristalsis, arterial constriction, etc., phenomena which are fairly rep- resented in the act of vomiting as seen in rotations, Yom^ iting, therefore, or the condition that immediately precedes it and is responsible for the actual expulsion of food from the stomach, is to be regarded as a defence of the organism against threatened dissolution from lowered blood-pressure, and consequent asphyxia of the medullary centres. The Influence of Drugs upon the Circulatory Changes that Occur with Rotations Strychnin and atropin in combination had the effect of maintaining the blood-pressure without appreciable PHYSIOLOGY 135 change in severe swings with violent reversals. Protocol 3 shows how this was effected in part, i.e., by increased pnlse-rate. The sensitiveness of the cardiac mechanism to altered conditions of intra-cardiac pressure is also well known. Slight cardiac arh}i:hmia was also noted at times. The action of strychnin alone is shown in protocol 3. The blood-pressure was not so well maintained, nor were the effects upon the subject's general condition so favourable as when the combination of atropin and strychnin was used. Vagus stimulation effects are seen just after the rotation. It is fair to add that the subject's body was in a state of fatigue from the effects of a severe handball contest, engaged in on the previous day, without proper preparation. Protocol 8 shows the effect of atropin, which tends slightly to prevent the marked fluctuations of the respiratory rate incidental to rotations. Protocol 9 shows the effect of atropin in maintaining a good average stand- ard of blood-pressure. The subject (B), on whom the experiments in this instance were performed, was ex- tremely sensitive to rotation. The severe swings given after the atropin could not have been tolerated without the drug. It should be noted, however, that the stomach was empty, which is at times an important factor in rota- tion sickness. The pulse-rate was not quickened in the rotations after atropin. This shows that the action of the drug on the cardiac vagus terminals was insufficient to overcome the effects of central vagus stimulation. The blood-pressure was well maintained by arterial constriction under the influence of atropin. Protocol 10 shows, on a different subject (S), practically what was shown in protocol 9. It also shows the tendency of the respiratory rate to rise as the blood-pressure falls, and to fall as the latter rises. Protocol 11 shows the effect of nitroglycerin, both before and after atropin. Before atropin had been given, the typical nitroglycerin effect was not a con- spicuous feature, being overshadowed by the vaso-con- strictor effect from the rotations, and this, notwithstanding that the subject felt the usual nitroglycerin effects in the head. Xitroglycerin, administered after atropin, shows a marked rise in pulse-rate, illustrating one of nature's methods in combating lowered arterial tension. The large 136 SEMICIRCULAR CANALS fluctuations of pulse-rate and blood-pressure occurring be- tween the administration of the atropin and the second dose of nitroglycerin are to be attributed to exhaustion of the neuro-vascular mechanisms, which was, in turn, the immediate reactionary eifect of the struggle to maintain the blood-pressure, in spite of the relaxed musculature of the arterioles caused by the first dose of nitroglycerin. Protocol 12 shows the effects of strychnin and morphin. The pulse-rate was not increased, the blood-pressure being well maintained by vaso-constrictor action, and yet the rotations made the subject feel very dizzy, sick and nauseated. With these there were motor and mental de- pression, and a general feeling of wretchedness. Vomiting did not occur, because the rotations were suspended in order to forestall it, and to relieve the subject's wretched- ness, which persisted for over four hours, partly, perhaps, because of the well-known excretion of morphin into the stomach, protracting the period of nausea pending its re- absorption or elimination. Protocol 13 shows the effect of morphin when used alone. The drug was administered after many rather severe rotations, and at a time when there was a steady decline in blood-pressure, with a ten- dency of the pulse-rate to rise. Rotations after the mor- phin showed a fairly well-maintained blood-pressure with- out increase of the pulse-rate. Forty-two minutes after the administration of the morphin the subject was given gr ^/(5o of atropin crystals. Fourteen minutes after the atropin had been given, rotations so sickened the subject that he vomited. The blood-pressure and pulse-rate failed to show the usual atropin effect. With the vomiting, there was the usual sharp rise in blood-pressure and pulse-rate. A repetition of the rotation caused depression of the blood-pressure and pulse-rate, and the subject felt nause- ated, dull and heavy. During a rotation, given 26 min- utes after the administration of atropin, the pulse-rate at the wrist disappeared and the second sound of the heart was feeble or missing. The pulse disappeared frequently in the rotations given on this occasion, both before and after the administration of the drugs. The effect of bromid of potassium is shown in pro- tocol 14a, The rotations sickened the subject and caused PHYSIOLOGY 137 vomiting. Between rotations, the blood-pressnre was fairly sustained. It can be seen, however, that the pulse showed rather a tendency to slowing. The figures do not fairly represent the behaviour of the circulation, as extensive fluctuations occurred, which were so evanescent that there was not time to catch and record them. After vomiting, the efficiency of the circulation was enhanced. With bro- mid, although the subject was sickened quickly, there was undoubtedly less psychic wretchedness than was noted in rotations without the use of drugs, whilst between rota- tions there was absence of the usual dread of the next rotation. The effect of digitalon is shown in protocol 14b. The subject felt his susceptibility increased, if anything, for the sickening effects of rotations. The blood-pressure showed a downward tendency, as did the pulse-rate after an initial rise. The first rotation was performed two hours and eighteen minutes after the administration of the drug, which was not sufficient time for a digitalis preparation, given hypodermically, to show its characteristic effects on the circulation. The digitalon caused some local irrita- tion and edema, and a distinct increase of stomach irri- tability. The effect of hyoscyamin is shown in protocol 15. The drug evidently diminished the sickness and wretchedness that usually accompany rotations. There were wide fluctuations in the blood-pressure and in the pulse-rate. On the whole, with hyoscyamin the blood- pressure was not so well maintained as with atropin, and it is evident that the drug was not so potent as atropin in eliminating the effects of vagus stimulation, since the pulse showed no tendency to increase in rate, and was slowed, if anything, after the rotations. The drug was also found inferior to atropin in warding off stomach sick- ness, although it helped to a considerable extent in this direction, for the rotations were rather severe, with many reversals. The psychic and motor exaltation noted with atropin were missing. During some of the rotations an almost impalpable radial pulse was found, accompanying an accentuated second sound. This was found repeatedly. Of course, taking blood-pressures under the circumstances was out of the question. Protocol 16 shows the effect of 138 SEMICIRCULAR CANALS bromid in a subject very susceptible to the effects of rotation. "Whilst the latter tended to sicken, there was an absence of the usual wretchedness and psychic depres- sion. There was no fear of being made sick, and the thought of rotations to come did not worry. It was noted that in rotations after bromid the tendency to nausea, so readily excited by the odour of tobacco-smoke, was some- what lessened. The blood-pressure and pulse-rate showed effects similar to those shown in protocol 1-i. The effect of hyoscyamin is again shown in protocol 16. The train of symptoms set up in rotation sickness per- sists till physical and mental depression ensues. The stom- ach, once disturbed, ever remains a source of secondary irritation to the medullary, cerebellar and cerebral centres. Hyoscyamin counteracts or eliminates the effects of this secondary irritation by depressing the sensory nerve termi- nals in the stomach. The drug, however, also depresses the psychic areas in the cerebrum. The bromides act merely by depressing the cerebral psychic areas, thereby eliminating the element of apprehension and psychic dis- tress that is such a constant symptom in rotation sickness. Atropin has the advantage over bromides and hyoscya- min, in that it depresses the sensory nerve endings in the stomach and all over the body, and at the same time stimu- lates the psychic and motor areas of the cerebrum, as well as the respiratory and vaso-constrictor centres in the me- dulla. The protocols clearly show that atropin has a more potent effect than hyoscyamin in tending to paralyze the vagus nerve endings in the heart. However, a relatively larger dose of atropin was used. The effects of atropin and strychnin in combination are shown in protocol 17, where the rotations were per- formed with the subject lying horizontally. The effects are similar to those noted in the rotations performed with the subject sitting upright. jSTote the reflex slowing of the pulse induced by recumbency, and the slowing induced by vagus-centre irritation from the rotation, and counter- acted by atropin later on. (See protocol 3.) These observations show: 1. That the coniI)ination of strychnin and atropin is more potent tlinn cither of these drugs used alone, and ia PHYSIOLOGY 139 superior to any other drug or combination of drugs so far tried in combating the effects of rotation upon the stomach and cerebrum, and upon the mechanisms of the circulation. 2. That atropin, hyoscyamin and bromides are effi- cient in averting or ameliorating rotation sickness in the order named, atropin, however, being far more potent than hyoscyamin, as the latter is more potent than bro- mides, although the circulation seemed to be better main- tained with bromides than with hyoscyamin. 3. That morphin and nitroglycerin are a hindrance, rather than a help, in rotation sickness, and are contra- indicated in conditions akin to rotation sickness, although with morphin the circulation was well maintained. PROTOCOLS. 1.— On " S," a Subject with Fair Toleration. January 1, 1909. Pulse- Blood- Remarks. rate. press. 72 120 Normal before rotations. 76 100 Just after rotation (long axis). 76 120 1 min. after " 64 120 P < ( ( < < ( 64 95 Just after rotation. Artery small. 64 120 1 min. after " 56 120 2 60 115 3 60 115 Rotation. 96 140 Vomited as left swing". 84 145 1 min. after rotation. 76 115 2 72 105 3 72 110 4 '* «* 72 105 5 68 105 Rotation. 104 150 Vomited. 96 145 1 min. after rotation. 80 120 2 76 115 3 80 105 4 ** ** 80 100 5 72 105 Feels chilly. 76 90 Went to stove. 72 110 72 100 140 SEMICIRCULAR CANALS Pulse- Blood- Remarks, rate, press. 72 105 72 125 Danced to "warm up." 72 105 72 115 84 85 Just after rotation. Eyes open. 64 105 1 min. after rotation. 60 100 60 95 2 74 95 76 95 3 *'- " 72 100 76 95 4 72 100 72 105 5 84 105 Rotation. Eyes closed. 100 115 80 150 Vomited. 72 125 1 min. after rotation. 80 115 80 105 2 80 105 3 2. — On "B," a Very Susceptible Subject. January 1, 1909 84 120 Normal. 84 115 76 130 Standing in rowboat as latter was rowed in a circle. 88 135 Balancing efforts in cold air. 130 No sickening effect. 76 120 Normal. 88 135 After mild to and fro swing in different directions. 88 140 88 140 76 130 Just after rotation long axis. 76 140 Nauseated. 72 ' 125 After mild rotation. 68 140 1 min. after rotation. 72 140 2 72 130 3 72 130 Resting. 68 130 72 135 After mild rotation, eyes closed and covered. 72 125 Nauseated. Odours sicken. 72 140 80 125 After brisk rotation. 68 120 Lump-sensation in stomach. 140 Odour of tobacco-smoke offensive. PHYSIOLOGY 141 3.— On "S," January 2, 1909 Time, Pulse- Blood- Remarks. a.m. rate, press. *»%-"i=u.a.B. 76 120 Normal. 76 115 68 110 Mild rotation (long axis). 72 115 1 min. after. 68 115 2 80 110 Mild rotation. 88 110 1 min. after. 84 110 2 80 90 After brisk rotation. 76 95 1 min. after. 76 110 2 72 95 After brisk rotation. 56 90 Just after rotation, lying supine. 56 95 64 110 1 min. after rot., lying down. 72 115 Standing after lying. Feels chilly. 68 100 1 min. after standing up. 68 100 68 100 2 min. after standing up. 60 100 10 : 00 Strychnin sulph., gr 1/20, hypo. 80 105 Resting. 80 100 72 100 10 : 10 68 90 Brisk rotation. 64 95 1 min. after. 64 95 64 95 2 min. after. 72 115 3 10 : zu 68 100 Brisk rotation. 60 100 1 min. after. 64 110 2 64 110 3 10 : 37 Atropin sulph. , gr 1/100, hyiK). 60 95 Resting. 64 105 10:43 76 105 10 : 45 72 105 Brisk rotation, dizzy during rot. no nausea. 60 105 1 min. after. 60 105 2 68 105 3 72 105 4 80 105 6 88 105 7 84 105 8 11 : 00 92 105 Brisk rotation, dizzy ; nauseated, headache. 88 105 1 min. after. 84 105 2 80 105 3 142 SEMICIRCULAR CANALS Time, Pulse- Blood- a.m. rate, press. 88 105 4 min. after. 88 105 5 Remarks. 4a .—On "S," January 3, 1909 72 110 Normal, standing. 68 105 < < << 56 95 Lying. 52 95 < < 56 100 Standing. 72 110 < < 72 110 After mild rotation (long axis) 68 115 68 105 60 105 64 100 64 95 72 95 64 105 •60 95 64 95 64 95 9 55 Atropin sulph., gr 1/100, hypo. 64 95 9 57 64 56 100 100 10 00 60 100 10 02 64 105 ' 10 :05 64 100 10 09 64 100 10 10 80 100 Brisk rotation ; slight momenta 80 100 Nervous ; dizzy ; weak at knees 76 105 72 105 84 105 88 100 88 95 84 95 Lay down. 56 95 Lying down. 64 100 < < 68 105 < < 64 105 < < 92 95 Standing after lying. 92 95 95 < < < < << < < 96 95 After a moderate rotation. 80 95 88 100 << < ( <( 84 100 tt << <« 80 95 << «< «< PHYSIOLOGY 143 4b.— On «B," January 3, 1909 Pulse- Blood- Remarks. rate. press. 76 115 Normal, standing. 76 115 < < 76 110 Lying. 72 115 < < 80 110 Standing. 80 110 < < 92 115 After a moderate rotation. 80 110 << < < < ( 80 110 << tt it 76 115 tt tt tt 80 115 tt tt tt 5.— On «S," January 10, 1909 72 110 Normal, standing, • 68 110 << 76 115 (« 76 115 (< 76 115 Lying down. ao 95 A 64 105 d d €) €) « (d 9 d © e ® (5) ® ® €> €> ^ '^ 'W w w '^ e e 9 <» ^ -^ "^W ^ # "^ '^ m m PHYSIOLOGY 291 IN DOGS 1. Pyramid, to the left of it. 2. Pyramid, to the right of it. 3. Upper vermiform process, posterior end of declive in midline. 4. Upper vermiform process, posterior end of declive on left of midline. 5. Upper vermiform process, posterior end of declive on right of midline. 6. Lateral lobe, posterior superior lobe on right side. 7. Flocculus region. IN CATS 1. Median lobe, right curve. 2. Median lobe, left curve. 3. Upper vermiform process, posterior end of declive in midline. 4. Upper vermiform process, posterior end of declive to left of midline. 5. Upper vermiform process, posterior end of declive to right of midline. 6. Lateral lobe, posterior superior lobule on the left. 7. Lateral lobe, posterior superior lobule on the right. Section of the right vestibular nerve in the ^i ^\ sheep (Biehl). V ^ R.E. L.E. 9 €) © di (^ 9 €) e w W ^^ €) e m (» 9 l>, same, two or tnree nours alter operation '/^^vV (Risien-Russell). \^} 18. Nystagmus just after section of eighth nerve (right) (Risien-Russell). 19. The same, two or three hours after operation 329 DIAGRAM TO SHOW THE OCULAR DEVIATIONS FOLLOWING REMOVAL OF PARTS OF THE OCU- LAR CEREBRAL AREAS AND OF PORTIONS OF THE CEREBELLUM. a. Narcosis ; eyes before operation. Cm (m b. Removal of frontal ocular area of right hem- isphere. c. Lapse of few days ; eyes in normal position. i#) uf^S d. Removal of left lateral lobe of cerebellum. © ® © a. Narcosis; eyes before operation. Cm TlW b. Removal of frontal ocular area of right hem- /^\ /C\ isphere. ^ ^ c. Lapse of few days ; eyes in normal position. Qfn (9j d. Excision of right lateral lobe of cerebellum. ^4|^ /^ a. Narcosis ; eyes before operation. Cm Cm €) 00 b. Removal of left lateral lobe of cerebellum. c. Lapse of some days ; eyes in normal position. d. Removal of frontal ocular area of right hem- isphere. a. Narcosis ; eyes before operation. b. Extirpation of left lateral lobe of cerebellum. c. Lapse of few days ; eyes in normal position. d. Removal of frontal ocular area of left hem- isphere. Q CHAPTER XXIII ON THE OCCURRENCE OF NYSTAGMUS Theoretically nystagmus can be produced only by in- terference with the co-ordinating mechanisms of ocular movement. As nystagmus is a highly co-ordinated move- ment effected by alternating reflexes in which inhibition plays such an important role, interference with the oculo- motor nerves as in the case of the spinal motor neurones of which they are the analogues, does not cause true nys- tagmus but paralysis of ocular movement. And similarly, since, in the two sets of reflex arcs involved in nystagmus, interference with the efferent arcs of the final common path (ultimate neurone) upon one side of the body would not cause nystagmus, but rather absence of the related element of the nystagmus, or in other words a paralysis. For these reasons, and because inhibition is so frequently de- pendent on stimuli originating in the receptive field and transmitted by way of the afferent neurones (Sherrington^^) we must look to the afferent arcs or co-ordinating centres in the cerebellum as the chief site of interference in the causation of nystagmus. As these afferent arcs originate in the labyrinthine and retinal receptors, and possibly in portions of the cerebral cortex, it is evident lesions of any extent within the cranial cavity interfering with the afferent paths as well as lesions of very limited extent, e.g., a tiny patch of sclerosis, a small exudate, or a tiny thrombus or embolus in the cere- bellar co-ordinating centres, may cause nystagmus. Hence nystagmus is set down in text-books as one of the gen- eral symptoms of disturbed cerebral function. The ques- tion arises, however, as to why nystagmus is so seldom produced by irritation or ablation of the cerebral cortex. The answer is that such nystagmus is occasionally seen (Beevor and Horsley *°) although ordinarily it is inhibited 331 832 SEMICIRCULAR CANALS by the conspicuous ocular deviations that accompany irri- tation and ablation of the cerebral ocular centres. It will be noted that these ocular deviations are of such direction as would inhibit the nystagmus that should accompany such a lesion, i.e., that they are in the direction opposite to that of the short elements. Destruction of the cerebellum or lesions destroying or causing suspension of function of the ocular co-ordinating centres to any great extent causes, not nystagmus, but nystagmoid movements in which the sharp differentiation of the short and long elements is wanting. Visible nystagmus most frequently results from lesion or interference with the ocular or labyrinthine mechanisms. Milder grades, however, readily detected by means of the ophthalmoscope, are of very frequent occurrence and are usually overlooked. These milder forms of nystagmus are generally caused by irritation of the cerebral cortex by toxines of various kinds circulating in the blood since the cortical centres seem to be more readily affected by various poisons than the purely reflex centres, cerebellar or other. On this ground may be explained the recurrence of ocular deviations in the experiments of Risien-Russell.^'' These mild ophthalmoscopic forms of nystagmus are important features in minor forms of disturbances of equi- librium. There are good reasons for believing that vertigo, with its attendant subjective distress, is seldom or never experienced in the absence of nystagmus, although it has been recorded that some persons suffered from vertigo even after removal of both eyeballs. The close relation between vertigo and vomiting makes it probable that the vertigo of gastric disorders may not wholly originate in toxemia of the cerebral centres, but may be mediated through affer- ent impulses initiated by direct irritation of the recep- tors in the alimentary canal. Miner's nystagmus seems to be caused by the strained and unusual position of the head, whereby certain sets of vestibulo- and oculo-cerebellar mechanisms are in constant and prolonged use, so that exhaustion of the neurones in- volved ensues with a condition of localized neurasthenia similar in every respect to an occupation neurosis. When the subject resumes his natural position the weakened por- tion of the oculo- or yestibulo-cerebellar mechanisms is no PHYSIOLOGY 333 longer capable of offering the adequate counteraction to the opposing mechanisms to secure a proper balance of reflex tonus innervation. The result is nystagmus. Pos- sibly a similar explanation, i.e., neurasthenia of certain sets of vestibulo-cerebellar mechanisms holds for Gertier's disease with its attacks of vertigo, paralysis (paresis) of the neck muscles allowing the head to fall forward, etc. This disease occurs frequently in France, Switzerland, and Japan, and is especially noted in those who are much fatigued and neurotic or emotional, and in those working in a lowered position (Starr ^26). The author has seen nystagmus occur in an infant of neurotic heredity upon the eruption of each of the first four teeth. The child was in fair general health, and fairly well up to the average in intelligence and development for children of her age. There was a distinct tendency for the tooth on one side to appear long before the corresponding tooth on the other side. With the eruption of the left, lower, central incisor, there was a deviation of the head toward the right, and a nystagmus of mixed type with a general direction toward the left. The child on looking at any object, held in a fixed position upon her left, lowered the head so that she could look at it out of the right corners of her eyes, a position in w^hich the nystagmus was at a minimum. The explanation of the teething nystagmus is afforded by the lack of development of the cerebral (inhibiting) centres and by the instability of the cerebellar mechanisms which responded to unilateral impulses reaching it by way of the trigeminus and the nucleo-cerebellar tract. Such abnor- mal responses to more or less ordinary stimuli are not un- common in neurotic individuals, and they may explain many forms of obscure vertigo as that from nasal polypus, contact of the skin with cold objects, e.g., the doctor's hand, etc. An interesting feature of this case w^as the fact that incision of the gum over an erupting tooth terminated rather suddenly an attack which, judging from previous experience, seemed destined to last for some weeks. Another interesting case of nystagmus was seen in the first days of an attack of erysipelas starting in an infant of five months over the mastoid area just behind the left auricle. The nystagmus, which was of the mixed t}^e, had a general direction toward the left and with the watch, 834 SEMICIRCULAR CANALS and was undoubtedly due to heightened irritability of the ampullary receptors of the superior and horizontal canals caused by the local inflammation. The local application of ice checked the nystagmus and helped to soothe the severe gastric irritability. The child went on with the struggle which was a prolonged one. The disease spread all over the scalp and body with the formation of numerous abscesses, but eventually ended in complete recovery. Here again, perhaps, we must recognize lack of cerebral development coupled with cerebellar instability as the fundamental factor resulting in a manifest quantitative disproportion between effect and cause, the latter in this instance being of necessity a trivial difference of tempera- ture in the two labyrinths aided perhaps by toxaemia. The nystagmus disappeared inside of forty-eight hours. Nystagmus more frequently occurs in children than is usually supposed. Osier and Peterson ^27 have reported three cases occurring in young children affected with diplegia. It is possible to differentiate nystagmus of central cere- bellar origin from that originating in labyrinthine dis- turbances. Nystagmus due to the latter has always a fast and a slow element, and the movements are executed about definite axes of the eyeball corresponding to rotations or movements in fixed and definite planes, whereas in cere- bellar nystagmus, e.g., from a gross destructive lesion in the vermis, the movements of the eyeball are apt to be irregular in that they occur, not about any axis of the eye- ball, but are more in the nature of irregular oscillations back and forth, or circumduction movements of the eyeball as a whole. There is an irregular inco-ordinated action of all or part of the muscles, but no set of opponents work tfjgether in such a way that the movements could be said to have a regular fixed direction as in true nystagnms. Moreover, vohmtarily turning the eyes in a certain direc- tion does not inhibit the movements as in labyrinthine nystagmus, though it may diminish them to some extent or develop abnormal movements. However, some cases of cerfibf.'llar nystagnuis due in part to destruction and in part to irritation, may have a definite direction and may be exaggerated by turning the eyes in a certain direction, thus resembling la})yrinthine nystagmus, but in the case of cerebellar nystagmus there is always some element whicb PHYSIOLOGY B85 would be atypical for labyrinthine nystagmus as shown by tlie reactions to aural irrigations, rotations and galvan- ism. Thus in one case due to a syphilitic deposit in the vicinity of the vermis, there being no cerebral or cranial nerve symptoms, the nystagmus was of the vertical type and was not affected by lying do\\'Ti. On looking up, the eyes were steady, but on looking toward the feet, the eye- balls began to jerk upward toward the vertex which is op- posed to all experience in the nystagmus of labyrinthine origin. With this nystagmus there was an "empty feel- ing" all over the body on the right side, but with no paralysis and no disturbance of the reflexes or loss of cutaneous sensation. There was slight inco-ordination in the right hand movements as compared with the left. Ly- ing in bed with the eyes closed and directed toward the feet, there was experienced a sense of rotation in the mesial plane "occiput first." Sitting up with the eyes closed, there was experienced a sense of rotation about the long axis from right to left. The hearing was good on both sides, and there were no noises in the ears. All combinations of aural irrigations were tried, with the subject in the supine posture. Bilateral irrigations at 61° F. caused the eyes to jerk furiously both on looking up and down, whereas bi- lateral irrigations at 116° F. caused the eyes to jerk upward upon looking toward the vertex, but absolutely stopped all motion upon looking toward the feet. These symptoms and signs made probable the diagnosis of a lesion affecting the posterior portion of the middle lobe of the cerebellum and extending somewhat to the left from the middle line, the paresis in the muscles being in this instance in the inferior recti. The peculiar numb empty feeling on the right side of the body extended from the head to the foot. A simi- lar feeling was noted in aural irrigations but it never ex- tended much below the head and neck. This symptom seems to be characteristic of cerebellar disturbance and should be carefully studied in every case before being classed as merely one of the parsesthesiae. Another curious symptom this patient presented was amenorrhoea for a period of one year. Her menstrual flow returned two weeks after the commencement of mercurial inunctions coupled with iodide of potassium internally. The amenorrhoea was probably only indirectly associated with the cerebellar lesion. Formerly the cereJjellum was supposed by physi- 836 SEMICIRCULAR CANALS ologists to be functionally related to the sexual organs. Ferrier ^ in his experiments found nothing to support such a view. In the present instance the amenorrhoea was merely the result of general ill-health and anaemia conse- quent upon the syphilitic infection. The importance of the labyrinthine mechanisms in equilibration has long been recognized by physiologists. We have seen the scope and nature of some of their rela- tions in this respect. We have also seen that they have important relations with ocular movements, and with cir- culatory and respiratory as well as with gastric and intes- tinal function. Their delicacy as evinced in the foregoing experiments, and the possibility of latent, hereditary, or acquired defect, coupled with their important and exten- sive relations, give these mechanisms a new importance in the etiolog}^ and treatment of neurasthenias, both local and general, as well as of the various neuroses, and espe- cially those associated with disturbed gastric function. The behaviour of the stomach in rotations and in aural irrigations, points to these cerebellar and labyrinthine mechanisms as a possible factor in the etiology of hyper- trophic stenosis of the pylorus in infants and adults. The relations of the cerebellum to the cerebrum, are not so clearly defined, but there is enough evidence to show the existence of impoitant afferent and efferent cerebellar paths between these two organs. This is a further reason for according the cerebellum and its mechanisms an im- portant role in the etiology of neuroses and neurasthenias, in which hurry and restlessness, both physical and psychic, are such features. Migraine also is undoubtedly related to some defect in the cerebellar mechanisms, and the fact that it is said to yield to hypnotic suggestion, can probably be explained by the afferent and efferent relations between the cerebellum and the cerebrum. The importance of the afferent cerebellar paths, especially those associated with the eye and ear, should be constantly remembered. A trifling defect in either of these organs, although in time it may be compensated, may be sufficient to impair the automatic mechanisms to such an extent that the individ- ual has to devote an undue amount of concentration, time, and energy, to the performance of ordinary acts. The result is a handicap for the individual, and perhaps im- pairment of the general health. PART III SEASICKNESS CHAPTER XXIV STUDIES IN SEASICKNESS On December 27, 1908, observations of the circulation and blood-pressure were taken aboard the steamship Taurus. The round trip lasted about eight hours. The weather was mild, but there was sufficient rolling and pitching to affect subject "B" who was very susceptible, and yet not enough to interfere directly with the correct observation of the blood-pressure, or indirectly by neces- sitating balancing efforts on the part of the subject. See protocols at the end of Chapter XXIX. Protocol 1 shows the results of observations made on this trip. After the start, there were signs of reaction on the part of the circulatoiy mechanisms resembling those seen after mild rotations and aural irrigations. The first portion of the protocol represents the condition of the cir- culation after the exertion and excitement of trying to catch the boat. After a time, however, the blood-pressure and pulse-rate fell steadily as the result of fatigue of the vaso-constrictor mechanisms (not well shown in the proto- col because the blood-pressure was not taken sufficiently often) and of stimulation of the vagus centre. The slow pulse-rate shown between 10 a.m. and 11 a.m. is very unusual fcr this particular subject, and undoubtedly rep- resents mild vagus stimulation. The recovery of the vaso- constrictor mechanism from 12.80 p.m. on, when the boat was at rest and the machinery stopj)ed is worthy of note. The chief symptoms experienced by the subject were a slight headache, and the familiar " queer feeling all over" which was present only at times. In addition to these there were slight disturbances of the nervous system, as manifested by disinclination for work, irritability of tem- per, and a consciousness of the respiratory movements. Long, deep inspirations were a matter of frequent occur- rence. 339 840 SEASICKNESS On April 4, 1909, another trip was made upon the steamship A ngler. On this occasion frequent observations on the pulse-rate and iDlood-pressure were made. The trip lasted about seven hours and a half. The weather was mild, but there was enough motion to produce the subjec- tive phenomena of seasickness in its early and milder phases. The nervous manifestations were headache, with fulness and lightness in the head, parsesthesise of the scalp, especially a sense of tension in the occipital region, psy- chic and motor depression, irritability of temper, disin- clination for work, perversion of sensory function, whereby the respiratory and gastro- intestinal movements were registered in consciousness, perversion of the sense of smell, whereby the odour of tobacco-smoke, agreeable under ordinary circumstances, became obnoxious, photophobia, and annoyance from the use of the eyes, especially in look- ing at the moving water (fatigue of the oculo-motor ap- paratus ) . The changes in the circulation, as shown in protocol 2, were not striking, nevertheless they show the characteristic reaction of the circulatory system to repeated irritation of the medullary centres, and though milder in degree, re- semble those changes so constantly met with in rotations and aural irrigations. All through the trip the vaso-motor mechanism was in a constant state of activity in response to mild stimulation of the labyrinthine receptors. The movements of the boat were not of sufficient abruptness and range to cause overirritation with subsequent exhaus- tion. Hence the protocol shows rather an enhancement of the circulation, with a slowing of the pulse, the latter in great part the result of mild stimulation of the cardiac vagus centre. These observations show that even in the presence of unimpaired circulation, all the subjective phe- nomena of seasickness may be present. It follows, there- fore, that the prime cause of seasickness is not impaired circulation, although profound changes in the circulation may, and usually do, occur in any given case. Digestive disturbances appeared early. The "lump- sensation" in the stomach — i.e., a feeling as if a foreign body were in that organ, is one of the early symptoms of seasickness, just as it is in the sickness of rotations and aural irrigations. This symptom results in part from SEASICKNESS 841 sensory perversion, and in part from overactivity of the muscles of the stomach, both of which are in turn to be attributed to irritation of the medullary and cerebral cen- tres. On different occasions the stomach was evacuated and irrigated, to determine the cause of this "lump-sen- sation. ' ' In many instances a mass of mucus was re- covered, but this, though of importance as a secondary factor, could not be considered the prime cause, as it fre- quently happened that no such disturbing element was to be found within the stomach, and where such was found, the symptom often persisted after its removal. In sup- port of this view, may be cited the concomitant slowing of the pulse in seasickness and in rotation- and irrigation- sickness, as well as the vaso-motor changes, nausea, in- creased salivation, yawning, deep, sighing respirations, and other symptoms, all of which point to disturbed func- tion in the medullary centres. On May 30, 1909, further observations were made on the steamship Angler. The trip lasted about eight and a half hours, during which observations on the pulse-rate and blood-pressure were made almost constantly. The results are recorded in protocol 8. The weather was mild. There was rather more motion to the boat than on the previous occasions. An early start was made for the boat, so as to avoid the effects of rush and hurry upon the cir- culation. No food had been taken since the previous night, so that a test meal could be given, and observations made on the functions of digestion, etc. The figures re- corded down to 10.24 a.m. show but little effect upon the circulation, and yet the subject experienced most of the symptoms of seasickness of mild grade, e.g. , "lump-sensa- tion" in the stomach, increased secretion of saliva, head- ache, fulness in the head, dizziness, pain in the eyes, dis- inclination for work or effort of any kind. The figures from 10. 24 to 12.38 p.m. show practically the same thing, although there was considerable rolling of the boat during this period. The subjective sjmiptoms were increased. Food was taken with the result that it subsequently caused pain in the stomach. Occipital headache and pain in the back of the neck upon the right side were features of this period. The blood-pressure showed a slight downward tendency. a42 SEASICKNESS From 12.38 until 2, vaso-motor fatigue was in evidence, with a steady decline in blood-pressure. The pulse-rate was increased to meet the failure of the vaso-motor system. The subjective symptoms of this period included nausea, headache, par8esthesio3 of the scalp, irritability of temper, muscular weakness and tremors. Eructations were fre- quent. Between 2 and 3.85 there was general fatigue, and especially fatigue of the vaso-motor mechanism with the pulse-rate moderately increased. The subjective symp- toms persisted, causing general wretchedness. About 8.50, there was a tendency to recovery on the part of the vaso-motor mechanism, with a drop in the pulse-rate. The general condition of the circulation was fair, and yet the subject's condition was far from good. The symptoms were : pain in the muscles of the back of the neck, upon the right side, extending up into the occiput, general weakness, and sweating, "lump-sensation," eructations, dull ache in the eyeballs. All through the trip the arteries were alternately contracting and dilating. The general effect upon the circulation was to induce fatigue, with a consequent fall in the blood-pressure. An Ewald break- fast was given subject "B," and allowed to remain in the stomach 1 hour and 54 minutes. The K I absorption test showed iodin in the saliva in 54 minutes. The motility test showed salol in the intestine in 2 hours and 2 min- utes. The amount of chyme recovered was about ^vi. This had to be computed, as the subject vomited on in- troduction of the stomach-tube. Analysis of the filtered gastric juice showed total acidity, .13% by weight; free HCl, .05%; combined HCl, .06%. A trace of blood was found in the chyme, as the result of straining and con- gestion during the vomiting. There was no other abnor- mality. Analysis after a test meal given to subject "S" on the same trip and retained 1 hour and 12 minutes showed: total acidity, .86%; free HCl, .26; combined HCl, .09, with the K 1 test positive in 12 minutes, and the salol test positive in 1 hour and 7 minutes. This subject, however, has little susceptibility — at least he is not affected in weather such as that which prevailed on this occasion. Moreover, he is by times a boatman and "follows the water" as a business. SEASICKNESS 343 Analysis of specimen taken May 30, 1909, from subject "B" aboard the Angler. Ewald meal taken on fasting stomach at 8.30 a.m. and withdrawn at 10.24. Amount of chyme, §vi. Resorcin test for free HCl positive, but feeble reac- tion: Tot. acidity, 38, or .13% by wt. Other enzymes, normal Free HCl, 14, or .05% by wt. Starch, absent. Comb'd HCl, 18, or .06% by wt. Amylodextrin, absent. Total HCl, 32, or .11% by wt. Erythrodextrin, trace. Acid salts, 6, or .02% by wt. Maltose, present. Lactic acid, absent. Bile, absent. Peptonizing enzymes, dimin- Blood, present in small amt. ished. Mucus, very small amount. Analysis of specimen taken May 30, 1909, from subject "S" aboard the Angler, Ewald meal ingested at 8.30 a.m. on fasting stomach; withdrawn at 9.42. Amount of chyme §iii. Resorcin test for free HCl positive. Tot. acidity, 100, or .36% by Enzymes, normal. wt. Starch, absent. Free HCl, 72, or .26% by wt. Amylodextrin, present. Comb'd HCl, 26, or .09% by Erythrodextrin, present. wt. Maltose, present. Total HCl, 98, or .35% by wt. Bile, absent. Acid salts, 2, or .007% by wt. Blood, absent. Lactic acid (direct and ether), Mucus, very little. absent. On May 31, 1909, a trip lasting one hour was made in the motor launch Maggie. Observations on the pulse and blood-pressure were made almost continuously through- out the trip. Protocol 4 shows the results. The subject "B" was somewhat fatigued before the start. There was little in the way of a swell upon the water, and yet the boat pitched and rolled somewhat. The circulation all through the trip showed slight fluctuations, but the arteries nevertheless were constantly contracting and dilating. At times the blood-pressure was rather low, but this was in part due to previous fatigue. Even in the fresh breeze, there were some subjective symptoms, such as "lump-sensation" in the stomach, and a "queer sick feeling" in the head, as well as deep, long drawn breaths and eructations. These symptoms were present in spite of the fact that the sub- ject was not feeling badly. In the second half of the trip, the pulse-rate showed a tendency to slowing, in spite of 344 SEASICKNESS the low blood-pressure. Note at the commencement of the protocol, the effect of recumbency upon the circulation, when vaso-motor fatigue has supervened. The conclusions are: 1. That in the beginning of seasickness, the blood- pressure may show slight changes, the effects in general being a slight rise. 2. That the arteries are constantly contracting and dilating, the tendency in general being toward a state of contraction. 3. That the pulse-rate varies somewhat with the con- traction and dilatation of the arteries, the chief feature being a tendency to slowing, with some rhythmic irregu- larity. 4. That cerebral, gastric and other "dolors" occur simultaneously with unimpaired or even with enhanced circulation. 5. That digestive disturbances even in the milder phases of seasickness set in early, and form an important and constant feature in the train of phenomena. 6. That the phenomena of seasickness seem identical with those of rotation-and aural-irrigation-sickness. 7. That disturbed circulation is not the prime cause of seasickness. 8. That gastric and circulatory disturbances, however much they may contribute as secondary causes to the phe- nomena of seasickness, are not the prime cause, but are themselves, together with the psychic and motor depression and the other phenomena, the result of irritation of the medullary, cerebellar and cerebral centres. CHAPTER XXV FURTHER STUDIES IN SEASICKNESS DURING A TRANSATLANTIC TRIP On June 26, 1909, a trip was commenced from New York to Glasgow, on board the steamship Caledonia of the Anchor Line. Observations of the circulation were made at frequent intervals during each day. The passage was not rough, there being just enough motion to afford an ideal opportunity of testing the prolonged effects of mild irritation upon the nervous, circulatory and digestive mechanisms. Protocol 5 shows the effects of the first day's sailing upon the blood-pressure and pulse. Almost im- mediately after the start, typical symptoms of mild sea- sickness set in. The boat started at 2.22 p.m., and by 3 o'clock the subject experienced the familiar "lump- sensation" in the stomach, increased salivary flow, per- verted sense of smell (the odour of tobacco-smoke being offensive), occipital headache, especially in the region of the right mastoid and parsesthesiae of the scalp (e.g., ' ' cap' ' sensation) . With these there were eructations and a considerable decline in blood-pressure, with increased pulse-rate. These phenomena are undoubtedly character- istic of seasickness, but there was practically no motion to the boat which could produce such symptoms, for w^e were scarcely out of the harbour and the sea was as calm as a lake. An explanation of the symptoms therefore has to be sought elsewhere. The subject was an old victim of the sea, having crossed the ocean about fifty times, and never once without suffering from seasickness in one form or another. On one occasion he had an experience which throws considerable light on the phenomena just detailed. He had been in the habit of crossing in the smaller boats of the Anchor Line, and had come to the conclusion that the equino:^e§ were not the most favourable times for go- 345 846 SEASICKNESS ing to sea. On this occasion, however, circumstances compelled him to cross in the beginning of April, and a cabin was secured in the steamship Astoria^ which was a comparatively small boat. The date of sailing was fixed for Sunday, and on Saturday afternoon a visit was made to inspect the boat. It was a dismal, dreary day. Every- thing was hurry and bustle with the crew. Things were in a state of chaos on board, as might be expected. The stewards were scurrying about without uniforms, the decks were in disorder, and everything was so differ- ent from the conditions that obtain on the open sea, where orderliness, discipline, and white, spotless decks are the rule. The appearance of things was distinctly discourag- ing. This, coupled with the thought, that at that par- ticular time of the year, a rough passage was to be ex- pected, greatly depressed the prospective traveller. In such a frame of mind he went below, to inspect his cabin. The odour and gloom between decks overpowered him to such an extent that he became dizzy and nauseated, and experienced much of the distress that is associated with genuine seasickness. In fact at each step on the deck, the latter seemed to sink beneath his feet, as with a gentle rolling motion, and with all the tantalizing, sickening effects that such a motion can have upon the seasick brain. The subject left the boat. His seasickness persisted, how- ever, for quite some time as he travelled homeward by street-car. It should be mentioned that although the sub- ject is very susceptible to seasickness, he is not at all affected by the motions of trains or street-cars. The out- look for the journey was dismal. From past experience he knew that but little food would pass his lips during the coming eight days. However, he grimly determined to make the most of it, and so set about eating as much as he could conveniently digest, with the hope of storing his organs with an available supply of energy for the days of privation to come. Heavy meals were the order of the day even to the minute the boat sailed. Finally the journey was commenced, and now all the feasting was over, and nothing remained but to wait. The passage was a very rough one. Most of the passengers were dread- fully ill for days, but not this one, who, although slightly affected, never missed making an appearance ^t me^l-time, SEASICKNESS 847 In fact it was the least disagreeable passage he had ever had. It should be stated, however, that the weather was very cold, and the subject's cabin well ventilated during the whole journey. This experience opens up the ques- tion of the influence of the imagination in the etiology of seasickness. Unquestionably the imagination plays an important part. Coupled with subconscious memories of past experiences, it may be a powerful factor, and is al- ways an important secondary source of discomfort. It must not be considered, however, as the primary cause of seasickness. The phenomena of the early part of this first day's sailing on the Caledonia may, therefore, be attrib- uted to fatigue and excitement backed by strong subcon- scious memories and by present impressions and associa- tions. And here once and for all, impressionability is to be distinguished from fear, for in spite of his experiences of the sea, the subject was never afraid of seasickness and never "gave in" to it, as the expression goes. After dinner, at 7 p.m., the absorption and motility tests were tried. A positive reaction for iodin in the saliva was found in 2 hours and 17 minutes, whilst salol was found to be present in the intestine in 2 hours and 22 minutes. Absorption evidently occurred only after food has passed into the intestine, for all through the tests, the salivary flow was free. Toward night there were still present: headache, and "lump-sensation" in the stomach and throat. The cir- culation was very much depressed, on account of vaso- motor fatigue induced in part by heat and exhaustion, and in part by the motions of the ship. The behaviour of the circulation upon lying down as shown in protocol 5, where the pulse-rate suddenly makes an extensive downward excursion, whilst the blood-pressure makes a correspondingly sudden and extensive upward excursion, indicates exhaustion of the vaso-motor apparatus, the dynamics of the circulation, especially the return flow to the heart, being favoured mechanically in recumbency. Such variations of pulse-rate and blood-pressure when represented in charts, show divergent and overlapping curve loops which are common features of seasickness and of circulatory fatigue in general and which afford an important clue as to the method of treatment. 348 SEASICKNESS The urine during this day was rather heavy, the speci- fic gravity at different times being 1.086, and 1.038, with a marked reaction for glycuronic acid. The amount passed was low, considering the liberal amount of fluid taken during the day. The warm weather and free sweating were factors in the diminished amount of urine, though the disturbed circulation undoubtedly played a part. On the day previous to sailing, the urine showed a specific gravity of 1.080 with no glycuronic acid or merely a trace. During the first night at sea the subject slept fairly well but was disturbed by dreams. June 27th. — The subjective symptoms were very mild on this day, and were perhaps to be attributed to the hot weather, and to general fatigue as much as to the motions of the boat. The digestive symptoms were those of the "lump-sensation" in the stomach and throat, which was present at various times during the day, and eructations. The absorption test showed iodin in the saliva in 21 minutes after the midday meal. The motility test was not tried, because there were still traces of salicyluric acid in the urine since the test of the previous day. Occipital headache was present, with a tired feeling about the eyes. Protocol 6 shows the effects upon the circulation. The blood-pressure was rather low, even after a fair night's rest and the morning cold tub. The pulse-rate and blood- pressure indicate vaso-motor exhaustion, whilst the steady drop in the pulse-rate indicates, in the presence of low blood-pressure, irritation of the vagus centre. The urine on this day was somewhat increased, the specific gravity at different times being 1.034, 1.080, and 1.028, with a less marked reaction for glycuronic' acid. June 28th. — On this day the notes make no mention of subjective symptoms. The urine had increased in amount, and was about the normal for this particular subject. The specific gravity at various times was 1.028, 1.024, and 1.020. A mere trace of glycuronic acid was present. Regular meals were eaten and caused no trouble. The bowels were constipated from the beginning of the journey, so that cascara sagrada was taken on retiring. Protocol 7 shows a decided improvement in vaso-motor tonus due, in part perhaps, to the effects of the cold plunge, and the general tendency of the vaso-motor system to recover under the influence of cooler weather. The fig- SEASICKNESS 849 ures indicating the pulse-rates and blood-pressures, when represented in chart form, showed less divergence of the curve loops upon lying down. The blood-pressure was well maintained under the influence of improved vaso- motor tonus. The pulse-rate was uniformly low. The ef- fect of sound, refreshing sleep is well shown, the pulse and pressure curves running along uniform and parallel lines. June 29th. — This was a cold, foggy day. The ship commenced rolling during the night, and continued to roll all through the day. The result was a return of the sub- jective symptoms, viz., "lump-sensation" in stomach, fulness and lightness in the head, occipital headache, flush- ing of the face, aching and heaviness about the eyes, ful- ness in the ears, parsesthesise of the scalp, psychic and motor depression, and irritability of temper with a ten- dency to worry about trifles. Protocol 8 shows the effects upon the circulation. There was a return of the vaso-motor exhaustion, which the cold plunge did not appreciably benefit. There was a return also of the diverging and converging curve loops, representing the pulse-rates and blood-pressures, notwith- standing the coldness of the weather, and a thorough evacuation of the bowels. The porthole was closed all day, but in spite of this fact the temperature of the air in the cabin was rather low. After the midday meal, the absorption and motility tests were made. The salol and K I reactions appeared simultaneously in 2 hours and 16 minutes. The urine was normal in amount and specific gravity, the latter being at various times 1.020, 1.022, etc. June 30th. — On this day the ship rolled and pitched considerably, especially from the early afternoon on into the night. The subject felt very well in the forenoon, but as time went on, the symptoms of mild seasickness re- turned, with slight headache, and a feeling of dulness and heaviness. The "lump-sensation" was present in the stomach and throat, and with it a feeling of fulness and lightness in the head. At times there was a feeling as if "the top was being raised off the head. " The saliva was increased, and the eyes ached. There was fulness in the ears, and a burning sensation in the stomach. The ab- sorption test was tried after the midday meal, and iodin found in the saliva in B hours and 24 minutes. 350 SEASICKNESS At 6.80 p.m., dinner was over. There was consider- able rolling and pitching during the whole evening. The motions, however, were slow and regular. The subject experienced no bad feeling, but gradually all the phenom- ena of disturbed digestion appeared, with increased secre- tion of saliva, "lump-sensation" in the throat and stom- ach, ringing in the ears, fulness in the head, etc. At 11 p.m., the contents of the stomach were removed, and that organ irrigated. A burning sensation, present before irrigation, persisted in spite of the latter. Analy- sis showed the presence of a moderate excess of mucus and of lactic acid with total acidity, .18% by weight, free HCl .18, and combined HCl .05. Analysis of specimen taken June 30th from subject "B." In- gested at 6 p.m. a meal consisting- of macaroni, brown bread with butter, 1 cup of tea, and some marmalade. With- drawn at 11 p.m. Amount of chyme §iv, but a large amount was lost by vomiting. Resorcin test showed the presence of free HCl. Tot. acidity, 52, or .18% by Starch, absent. wt. Amylodextrin, absent. Free HCl, 38, or .13% by wt. Erythrodextrin, present. Comb'd HCl, 14, or .05% by Achroodextrin, present. wt. Maltose, present. Tot. HCl, 52, or .18% by wt. Peptones, present. Acid salts, . Bile, absent. Blood, absent. Lactic acid (direct), present. Mucus, moderate excess. Absorption and motility tests not made. The condition of the circulation during the day is shown in protocol 9. In the early part of the day the vaso-motor tone was fair, the response to the cold plunge being fairly good. As the day wore on, however, and es- pecially with the onset of the subjective symptoms and of disturbed digestion, the vaso-motor mechanism showed evidence of fatigue, with lowered blood-pressure and in- creased pulse-rate. The urine on this day was normal in amount. The specific gravity at various times was 1.018, 1.016, and 1.018. The subject was taking fluids freely. The weather was no longer very warm, consequently there was less sweating. July 1st. — The boat rolled and pitched considerably 5 ^ CO o ^ o g g . c 1 a sU ^(^ > [^ s. It u ■< 4-* §- ^ s \ 1 H ti 7»ior«>i< ? 5 r^ / II II *. k u u r A i^ \ } J/ d ^a ,k( , -Si C Lsi ng \n J) ■ed . /. I'fi V A s 7 u II r- H V > /< II Ju). 1'^ S:5i am fi r ri ll M If m • ^ I& i Sic n^ lr\C It /I S:i] "V ^ ^ > T r ) ll o- >i >«-> < \ If u «< ? < BU ndt] i y ll u II k u F^ / r ■1 •1 M •• u ^ ^ 1 Sfa wdx ^?) «/ II l> r •A» > ^ «' 5 o 1 pas \, c* ^ "S? z aft / ^ 1/ 1/ ft ^ ''i s V^ i< ■^ P 3 2 ) / i c n k. ■i I) ^ & ^ ^ •• /< < V ? t; MV.j^ r » / < (1 << /r -2 ** — . \ 11 <• ' 1 ■ 1- 09 \ ^ C-« /lY 'S m ^ -1 ic-. ) r^ ^ H 5 c .1 i £ k ■^ « u < ST rS tn C / k ^ H U II J< * < 5l ^flyi <^n to 1 / ^ l< 1. It o ? n > >l it ( P* 1- L [ > « t| ^ ^ — ■^ t'< i »> • ■ ^ O ISO c « rj . .. ^ 3 — N 11 II l< ^ P ''•■ V s.-^- -— ^' s-< AVI It o r* — SEASICKNESS 869 Manclie was living up to its reputation. On this occasion subject "B" experienced all the horrors of seasickness in its most aggravated form. The odour of the cabin, not too wholesome at any time, became intolerable. When the time came for evacuating the stomach contents, all that the subject had to do when the basin was in place, was simply to turn on the side, and with one sudden act of vomiting, everything left the stomach. Water was subse- quently taken, in order to clean out the stomach as much as possible. This was also immediately rejected, bringing with it nothing but mucus. The amount of chyme re- covered was 3xi. It was now 10.18 a.m. The boat had been out since 8.53 a.m., and was not expected to return before 6 or 7 p.m. On this account it was decided not to try the effect of drugs until the afternoon. Subject "B" felt much relieved for having his stomach emptied and irrigated. After a time, however, his wretchedness returned, and he was obliged t» take to the floor again and wedge himself in an angle as best he could to keep from being tossed about. By this time he was very irritable, and the swirl of the water rushing past the side of the boat was extremely annoying. However, there was nothing left for him but passive resistance, which, in the sick and helpless, often represents the very acme of courage. He had made up his mind that the struggle was to be a long one, and bowed to the inevitable. At 12 m., however, it was an agreeable surprise to find that the boat was " alongside the wharf" and everything ready to go ashore. On inquiry it was learned from the skipper, that owing to the rough weather, the fishing nets had been swept away, and it was considered too risky to remain out longer. The condition of the circulation was studied with great difficulty on this trip, and only at irregular intervals. The results are shown in protocol 18. There was a good deal of muscular activity at all times when the blood- pressure was taken. When the subject was lying quietly, if that were possible at any time, there were manifest signs of profound circulatory depression. In the after- noon subject "B" felt exceedingly nervous and irritable. It was only after several hours in bed that the effects of his rough tilt with the sea wore off. He had a slight 870 SEASICKNESS headache, and every fibre in his limbs and body was in a tremour. Even a two hours' sleep did not relieve his ner- vousness. The "lump-sensation" in the stomach, which made its appearance upon the boat, remained with him as late as 5 p.m. The blood-pressure was well maintained, however, but the vaso-motor system was evidently still demoralized. Analysis after the test meal showed absence of HCl, both free and combined, and a total acidity of .021% by wt. Tests were made for the presence of the gastric enzymes, but an unfortunate accident destroyed the specimens before the customary time had elapsed. It was ascertained, however, that in the case of chymosin (rennet) coagulation was retarded considerably. It may, therefore, be assumed that the ferments were diminished. Both the K I and salol tests were negative, not only dur- ing the trip, but all through the afternoon. It was evi- dent that no absorption had taken place, and that nothing had escaped into the intestines. Analysis after the test meal given subject "S" and re- tained 26 minutes, showed total acidity .048% by wt., with HCl both free and combined absent. The K I and salol tests were negative during the trip and all through the afternoon. The first urine passed by subject "B" after leaving the boat, was in amount 3V, and slightly turbid, due to the presence of an excessive amount of mucus. The spe- cific gravity was 1.028. There was no evidence of albu- min or of sugar. Glycuronic acid was present. Analysis of specimen taken July 22d on the Quatre Freres, from subject "B." Ing-ested at 9.10 a.m. an Ewald breakfast. Withdrawn (vomited) at 10.10 a.m. Amount of chyme, |xi. Reaction faintly acid (litmus). Free HCl (resorcin), absent. Tot. acidity, 6, or .021% by Erythrodextrin, present, wt, Achroodextrin, present. Free HCl, absent. Maltose, present. Comb'd HCl, absent. Coagnlating enzymes, dimin- Tot. HCl, . ished. Acid salts, . Peptones, faint trace. Lactic acid (direct), trace. Bile, absent. Starch, absent. Mucus, abundant. Amylodextrin, trace. Blood, absent. SEASICKNESS 371 Analysis of specimen taken July 22d on the Quatre Freres, from subject "S. " Ingested at 9.10 a.m. an Ewald breakfast. Withdrawn (vomited) at 9.36 a.m. Amount of chyme, ^viii. Reaction faintly acid (litmus). Free HCl absent (resorcin). Tot. acidity, 12, or .043% by Amylodextrin, present. wt. Erythrodextrin, present. Free HCl, absent. Achroodextrin, present. Comb'd HCl, absent. Maltose, present. Tot. HCl, . Peptones, trace. Acid salts, . Bile, absent. Lactic acid (direct), trace. Mucus, considerable amount. Starch, absent. Blood, absent. Jiily 23d.. — At Cherbourg the steamship Sotdhtvestern, bound for Southampton, was boarded at 10.12 p.m. At 11.47 p.m. subjects "B" and "S" received each, hypo- dermatically, gr 1/75 of atropin sulphate, and gr 1/40 of strychnin nitrate. Jaly 24th. — At 12.05 a.m. the boat started, and at 12.34 a.m. an Ewald test-meal w^as given to each subject. The weather was very rough. The boat pitched, twisted, and rolled badly. On this occasion the party travelled in the second cabin, as the sleeping compartment was situated in the bow where the motion was certain to be at its worst, and where one would be most liable to be made seasick. The berths were ranged around the sides of the ship as in a dormitory. The boat had scarcely started, when the passengers began to climb into their beds, and in a very few minutes no one was astir but the members of our party. Here an amusing incident occurred which those who practise psychic therapeutics will appreciate. The boat had been behaving badly, and there was every indi- cation that there were rough times ahead. Suddenly the steward, a good-natured fellow, appeared with an armful of large white basins made of agate or papier mache. One of these was placed beside the head, you might say under the nose of each passenger in a smart, businesslike way, as much as to say, "There! now it's up to you." The steward made the round of the compartment in quick time, but he had scarcely placed the last basin, when almost every one in the place commenced vomiting. He even had the temerity to place basins in front of subjects "B" and "S" and as he did so, he leered at them out of the corner of his eye, tg ^ee how they were standing the pace. It was 872 SEASICKNESS easily understood why, for sanitary and economic reasons, vessels should be placed convenient to the passengers, but it was not at the time so apparent why the steward should so jauntily rattle his basins as he placed them around. His conduct seemed more intelligible the next morning when it was learned from stickers placed conspicuously in various parts of the boat that a certain remedy was a sure cure for seasickness and that it could be had at any time from the steward, price two shillings and nine pence. The test meals were eaten with relish, and although the boat pitched and rolled very badly, no ill effects were felt. In the stomach there was a cool, agreeable sensation, as though one had just eaten ice-cream. No perversion of the sense of smell was experienced. There was a peculiar sour taste in the mouth as though one were eating unripe apples. The saliva was not free, and yet the mouth was not dry. Both subjects felt an inclination for work. The balancing movements necessitated by the rolling of the ship were effectually and easily executed, without the usual anxiety and awkwardness. The subjects sat, stood, and walked about at various times during the hour that the test meals were retained. They felt exceedingly well during all the tossing and tumbling of the boat. At times subject "B," who is extremely susceptible to seasickness, felt a slight transitory fulness in the head. There were no symptoms referable to the stomach, in fact an agreeable feeling was associated with that organ. There was no psychic depres- sion or distress. At 1.07 a.m., subject "B" still felt well, but on standing up was almost thrown by the rolling of the boat. Although feeling well he was disinclined to stand up or walk about. At this time there was a slight inti- mation of the "lump-sensation" in the stomach, though no disagreeable feeling was associated with it. When the boat gave an unusually heavy lurch, lioth subjects felt it affect their heads momfsntarily, but no worry or distress was induced. At 1.83 a.m., subject ^^R" experienced a pronounced "lump-sensation" with a slight sense of nervousness or tremour in the muscles. Subject "S" felt no lump-sensation in the stomach at any time. At 1.50 a.m., the stomach contents of subject "B" were removed. The amount of chyme obtained we^s ^iy, SEASICKNESS 373 A little blood also came with the chyme. Analysis showed : total acidity, .075% by wt. ; combined HCl, .051, and free HCl absent. The tests for enzymes showed diminution or absence of these bodies. The K I absorption test showed the presence of iodin in the saliva in 11 minutes. The salol test was negative A faint reaction occurred in 50 minutes, but was of too doubtful a nature to afford basis for a conclusion as to stomach motility. Analysis of specimen taken at 1.50 a.m., July 24th, on the steamship Southwestern from subject "B" after hypoder- mic injection of strychnin nitrate, gr 140, and atropin sulphate, gr 175. Ingested at 12.34 a.m. an Ewald test meal. Withdrawn at 1.50 a.m. Amount of chyme, siv. Reaction to litmus, acid. Free HCl absent (resorcin). Tot. acidity, 20, or .073% by Erythrodextrin, present. wt. Achroodextrin, present. Free HCl. absent. Maltose, present. Comb'd HCl, 14, or .051% by Peptones, trace. wt. Bile, absent. Tot. HCl, 14, or .051% by wt. Mucus, moderate amount. Acid salts, . Blood, trace. Chymosin, deficient. Lactic acid (direct), trace. Peptonizing enzymes, absent. Starch, absent. Peptonizing zymogens, defi- Amylodextrin, trace. cient. At 2 a.m., the stomach contents were withdrawn from subject "S." The amount of chyme was |iv. Analysis showed: total acidity, .21% by wt. ; free HCl, .11; combined HCl, .08. The K I absorption test showed the presence of iodin in the saliva in 16 minutes. The salol test was negative at all times. Analysis of specimen taken at 2 a.m., July 24th, from subject "S," on the steamship Southivestern, after hypodermic in- jection of strychnin nitrate, gr 1 40, and atropin sulphate, gr 1 75. Ingested at 12.34 a.m. an Ewald test meal. With- drawn at 2 a.m. Amount of chyme, siv. Resorcin test showed the presence of free HCl. Tot. acidity, 58, or .211% by Tot. HCl, 56, or .19% by wt. wt. Acid salts, 2, or .007% by wt, Free HCl, 32, or .11% by wt. Comb'd HCl, 24, or .08% by Lactic acid (direct), trace. wt. Starch, absent. 874 SEASICKNESS Amylodextrin, absent. Coagulating enzymes, normal. Erythrodextrin, present. Peptonizing enzymes, normal. Achroodextrin, present. Bile, absent. Maltose, present. Mucus, moderate amount. Peptones, present. Blood, absent. The circulation was well maintained, as shown in pro- tocol 19. The vaso-motor apparatus was evidently in a keen, steady state of activity and did its part in main- taining the blood-pressure without increase of the pulse- rate. Muscular activity was in part responsible for the high blood-pressure. From the foregoing experience there can be no question of the beneficial effects of strychnin combined with atropin. The conditions of this journey were such that without these drugs both subjects would have been very seasick. Each subject after irrigation of the stomach went to bed and slept well. Both had a free action of the bowels on arising, and both felt well in every way. July 24th. — At 11.22 p.m., the steamship Southioest- em was boarded at Southampton, bound for Cherbourg. At 11.23 p.m., subject "S" received gr Ix of potassium bromid, and at 11.50 subject "B" received, hypodermic- ally, atropin sulphate, gr 1/80. July 25th.— At 12.08 a.m. , the boat started. At 12.36 subject "B" was given an Ewald test-meal. At 12.40 subject "S" was given a similar meal. The weather was not rough during this i3art of the night, but the boat rolled and pitched considerably. Both subjects experienced the "lump-sensation" in the stomach for a time. Neither subject at any time experienced more than a passing "feeling in the head," i.e., dizziness when the boat gave an unusual lurch. In subject "B" the sense of smell was slightly perverted, tobacco-smoke smelling like burnt rags. The test was a fair one in so far as subject "B" w^s concerned, for owing to his sensitiveness to seasickness, the trip would undoubtedly have sufficed to sicken him thoroughly. Subject " S, " however, is less susceptible, and would probably have been fairly well through such weather as was encountered. In subject "B" the atropin again caused a peculiar sour taste in the mouth. At 1.40 a.m., SEASICKNESS 875 the test meal was withdrawn from subject '*B's" stomach. The amount of chyme obtained was 3iiss. When its con- tents had been evacuated, the stomach was irrigated and a good deal of mucus with a little blood was removed. Analysis showed: total acidity, .073% by wt. ; free HCl, absent; combined HCl, .058. The K I absorption test showed a positive reaction in 14 minutes. The salol test did not react at any time. Analysis of specimen taken July 25th, on steamship South- western from subject "B," after atropin sulphate, gr 1/80 hypodermically. Ingested at 12.36 a.m. an Ewald test- meal. Withdrawn at 1.40 a.m. Amount of chyme, |iiss. Reaction (litmus), acid. Free HCl absent (resorcin). Tot. acidity, 20, or .073% by Starch, absent. wt. Amylodextrin, absent. Free HCl, absent. Erythrodextrin, present. Comb'd HCl, 16, or .058% by Achroodextrin, present. wt. Maltose, present. Tot. HCl, 16, or .058% by wt. Bile, absent. Acid salts . Mucus, considerable amount. Blood, trace. Lactic acid (direct), trace. Enzymes, diminished. At 1.50 a.m., the contents of subject "S's" stomach were withdrawn. The amount of chyme recovered was |v. Analysis showed: total acidity, .277% by wt. ; free HCl, .189; combined HCl, .08. The K I absorption test showed a positive raection in 10 minutes. The salol test showed no reaction at any time. After evacuation of its contents, the stomach was irrigated. Analysis of specimen taken July 25th on steamship South- western from subject "S" after KBr. gr Ix. Ingested at 12.40 a.m. an Ewald meal. Withdrawn at 1.50 a.m. Amount of chyme, sv. Resorcin test showed the presence of free HCl. Tot. acidity, 76, or .277% by Amylodextrin, trace. wt. Erythrodextrin, present. Free HCl, 52, or .189% by wt. Achroodextrin, present. Comb'd HCl, 22, or .080%, by Maltose, present. wt. Peptones, present. Tot. HCl, 74, or .269% by wt. Bile, absent. Acid salts, 2, or .007% by wt. Mucus, moderate amount. Lactic acid (direct), absent. Blood, absent. Starch, absent, Enzymes, normal. 376 SEASICKNESS Whilst the test-meals were in the stomach, subject *'B" felt somewhat drowsy, but subject "S" was wakeful. When the work with the test meals was finished, the weather became rather rough, but both subjects went to bed and slept soundly without suffering any ill effects. Cherbourg was reached about 7 a.m. There can be little question that on this occasion atro- pin served subject "B" well in warding off the disagree- able effects which would certainly have been experienced without its use. It is to be noted here, as in rotations and aural irrigations, that atropin is of no benefit what- ever in tending to relax the pylorus in the presence of irri- tation of the medullary centres. The bromid of potassium had an effect similar to that exhibited by it in rotations. It lessened psychic distress, and the fear of what was to come. On this occasion, however, it must be said that the conditions were not quite such as would properly test the efficiency of the drug. July 26th. — At 9.50 p.m. , the steamship SoutMcester^i, bound for Southampton from Cherbourg, was boarded. At 9.55 p.m., subject "B" was given, ^er 05, gr Ix of potas- sium bromid. At 10.89 subject "S" received atropin sulphate, gr 1/50, 2^er os. July 27th. — At 12.06 a.m., each subject was given an Ewald meal. At 12.17 subject "B" was given orthoform, gr v. On this occasion the weather was fairly rough. The boat pitched and rolled considerably. Subject "B" ex- perienced all the symptoms of the severe form of seasick- ness. The "lump-sensation" was present in the stom- ach and throat. There were also present nausea, increased salivary flow, pain in the left region of the epigastrium, nervousness and irritability of temper; general muscular weakness with tremulousness; a full, sickening feeling about the ears ; occipital headache, worse toward the right side, a sense of fulness and liglitness in the head, especi- ally in the mastoid regions and behind the eyeballs. At times there was pain in the right as well as in the left f^pigastric region. The subject also felt chilly and drowsy. The face was flushed, the pupils normal, the conjunctivae congested, and the skin cold. He was very anxious to lie SEASICKNESS 877 down, which indeed he had to do in order to retain the test meal for the customary hour. At 1.07 a.m. , the stom- ach contents of subject ' • B " were withdrawn. The amount of ch}Tne recovered was $vi. Analysis showed: total acid- ity, .080 by wt. ; free HCl, absent, and combined HCl, .058. The K I absorption test showed a positive reaction in 19 minutes. The salol test did not react at any time, the stomach having been irrigated after its contents had been withdrawn. The irrigation of the stomach gave the sub- ject great relief from his S}Tnptoms, nevertheless each roll of the ship caused that indescribable sickening feeling which elsewhere has been called dolor cerebri. The sub- ject was very glad to get back to bed. Analysis of specimen taken July 27th on the steamship South- western, from subject "B" after receiving, per os, K Br., gr Ix, and orthoform, gv v. Ingested at 12.06 a.m. an Ewald meal. Withdrawn at 1.97 a.m. Amount of chyme, §vi. Reaction (litmus), acid. Free HCl, absent (resorcin). Tot. acidity, 22, or .080% by Amylodextrin, absent. wt. Erythrodextrin, present. Free HCl, absent. Achroodextrin, present. Comb'd HCl, 16, or .058% by Maltose, present. wt. Peptones, trace. Tot. HCl, 16, or .058% by wt. Bile, absent. Acid salts, . Mucus, moderate amount. Lactic acid (direct), trace. Blood, absent. Starch, absent. Enzymes, deficient or absent. With the exception of a sense of fulness in the head, and a slight pain in the right, and also at times in the left epigastric region, subject "S" felt fairly comfortable. At 1.20 a.m. his stomach contents were withdrawn. The amount of chyme recovered was 3xii. The stomach was irrigated, and the symptoms previously mentioned disappeared, i.e., the pain in the epigastrium and the sensation of fulness in the head. Analysis showed: total acidity, .255%bywt. ; free HCl, .183; combined HCl, .109. The K I absorption test showed a positive reaction in 24 minutes. The salol test did not react at any time, the stomach having been irrigated after its contents had been removed. The subject stood up all through the period during which the test meal was retained. 378 SEASICKNESS Analysis of specimen taken July 27th on steamship Southwest- ern, from subject "S," after atropin, gr 1/50, per os. In- gested at 12.06 a.m. an Ewald test meal. Withdrawn at 1.20 a.m. Amount of chyme, Ixii. Tot. acidity, 70, or .255% by Amylodextrin, trace. wt. Erythrodextrin, present. Free HCl, 34, or. 133% by wt. Achroodextrin, present. Comb'd HCl, 30, or .109% by Maltose, present. wt. Peptones, present. Tot. HCl, 64, or .242% by wt. Bile, absent. Acid salts, 6, or .021% by wt. Mucus, moderate amount. Lactic acid (direct), absent. Blood, absent. Starch, absent. Enzymes, normal. The experiences of this trip show that neither bromid of potassium nor orthoform has any potent action in counteracting the effects of seasickness. They also show that atropin jjer os may be used in seasickness to advan- tage, but not with such good effect as when used hypoder- matically and in combination with strychnin. It was observed that the effect upon the bowels was not so happy after bromid as after atropin and strychnin. The subject experienced a sour taste after the bromid, similar to that experienced with atropin. July 27th. — A trip was made on the steamship Lorna Doone from Southampton to Southsea. The boat started at 9.15 a.m. The morning was fine and the water calm. No ill effects were experienced, but on the return trip in the evening the weather was wet and dismal, and the boat rolled and pitched somewhat. Subject "B" felt many of the milder symptoms of seasickness, but the journey was too short to cause much trouble under the conditions pre- vailing. CHAPTER XXVII STUDIES IN SEASICKNESS (Continued) July 28th. — After a good night's rest in a cool room on shore at 7.18 a.m. each subject was given an Ewald test breakfast. At 8.25 the stomach contents of subject "B" were withdrawn. The amount of chyme recovered was 5ii- It was mixed with much mucus. Free HCl was absent. Unfortunately the specimen was thrown away by accident before the quantitative examination was made. The K I test showed a positive reaction in 21 minutes. The salol test did not react at any time, the stomach hav- ing been irrigated when its contents had been removed. At 8.80 the stomach contents of subject "S" were re- moved. The amount of chyme recovered was |ss. This specimen was also thrown away by mistake, but not until it had been ascertained that it contained free HCl. The amount of mucus was very moderate. The K I test showed a positive reaction in 16 minutes. The salol test reacted strongly in 1 hour 12 minutes. The condition of sub- ject "B's" circulation after a restful night in a cool room is shown in protocol 19. The cardiac and neuro-vascular mechanisms were in good working order. The subject felt well in every way, except for an occasional feeling of indigestion. At 11.52 a.m., the steamship Teutonic, bound for New York from Southampton, was boarded. As shown in pro- tocol 20, the subject's circulation, before the boat started, manifested some depression incidental to the fatigue of making preparations to go on board. At 12.15 p.m. the boat started. The weather was mild and clear. The boat was very steady, but some slight vibration was felt from the machinery. Subject "B" felt well in every way. He took his meals and enjoyed them. After the evening meal, however, he had a slight feeling of indigestion. The cir- culation as shown in protocol 20 was efficiently maintained. 379 880 SEASICKNESS July 29th. — After lying all the morning in ^ueenstowH Harbour, the pilot was put off at 1.15 p.m., and the boat got away under full steam. During the afternoon the boat pitched somewhat. This, with the jolting of the machinery, caused subject " B" to have occipital headache, worse upon the right side, with an occasional sick feeling in the head, as the ship made an unusually bad lurch. Toward 9 o'clock the ship was pitching considerably and subject "B" had the "lump-sensation" in the stomach to a marked degree. This was temporarily relieved by 10 drops of dilute HCl, in water, but it returned later and was as bad as ever. The effects of the pitching of the ship began to tell upon the circulation as seen in protocol 21. The vaso-motor tone was not as efficient in the late afternoon and evening as it had been earlier in the day. July 30th. — At 7.40 a.m. both subjects felt very well after a good night. Each was given an Ewald breakfast. At 8.47 the stomach contents of subject "B" were evacu- ated. The amount of chyme recovered was |iii. Analysis showed absence of free HCl. Quantitative determinations were not made, owing to an accident. A considerable amount of mucus was present. The K I absorption test showed a positive reaction in 31 minutes. The salol test reacted in 55 minutes. At 8.59 the stomach contents of subject "S" were removed. The amount of chyme recov- ered was 5 iii- Analysis showed: total acidity, .262% by wt., free HCl, .175, combined HCl, .080. The KI test showed a positive reaction in 32 minutes. The salol test did not react at any time, the stomach having been irrigated after its contents had been removed. Analysis of specimen taken July 30th on the steamship Teutonic, from subject "S. " Ingested at 7.40 a.m. an Ewald break- fast. Removed at 8.59. Amount of chyme, §iii. Resorcin test showed the presence of free HCl. Tot. acidity, 72, or .262% by Amylodextrin, trace. wt. Erythodextrin, present. Free HCl, 48, or .175% by wt. Achroodextrin, present. Comb'd HCl, 22, or .080% by Maltose, present. wt. Peptones, present. Tot. HCl, 70, or .255% by wt. Bile, absent. Acid salts, 2, or .007% by wt. Mucus, moderate amount. Lactic acid (direct), absent. Blood, absent. Starch, absent. Enzymes, normal. SEASICKNESS 881 In the afternoon the sea became very rough and many people were made seasick. Subject "B" experienced no disagreeable symptoms except a ' ' slight lump-sensation' ' in the stomach. At 5. 11 p.m. the stomach-tube was in- troduced and siss. of chyme removed. This was the re- mains of a meal taken at 1.10 p.m., and consisting of pea-soup, boiled codfish, mashed potatoes, boiled rice and water, 3viii. Analysis showed free HCl, .073%. This subject "B" felt exceedingly well in spite of the very rough weather. Whatever slight trouble he experienced should be attributed, perhaps, to his indigestion. The condition of the circulation as represented in protocol 22 ;shows the vaso-motor mechanism to be thoroughly effective toward the latter part of the day. July 81st. — On this day the weather was fair and the boat steady. After breakfast at 9.05 a.m. the K I absorp- tion test showed a positive reaction in 1 hour and 5 min- utes in subject "B. " The salol motility test reacted in 2 hours and 22 minutes. This subject "B" felt very well all day. At times during the day he had slight intima- tions of indigestion. The condition of the circulation is shown in protocol 28. The blood-pressure was well main- tained in the normal manner, excepting at times when the effects of the hot stuffy cabin manifested themselves by impaired vaso-motor tonus. August 1st. — On this day the weather was warm, but on account of rain and mist the port-holes were kept closed. Subject " B" felt well in every way except for an occasional feeling of indigestion. He had no symptoms that could be attributed to the motion of the boat. The circulation as sho-sATi in protocol 24 was not properly maintained in the normal manner. There is evidence of vaso-motor in- efficiency which is perhaps to be attributed to the effects of the warm stuffy cabin. The effects of hot and cold air upon the circulation are of importance not only in seasick- ness, but in any condition where the vaso-motor tone needs watching. As we have seen, time and again, seasickness is not due primarily to disturbance of the circulation and yet the latter is such a usual and constant phenomenon in the malady that whatever hinders or helps the efficiency of the circulatory mechanisms becomes a matter of mo- ment to the sufferer. The good effect of cool fresh air 382 SEASICKNESS upon the circulation is well shown in protocol 24, at 4. 04 p.m., where there is every indication of keen vaso-motor efficiency. The difference between the torpid neuro-vas- cular mechanism and the neuro-vascular mechanism that is exhausted from overstimulation should constantly be remembered. In the former condition the mechanism is intact and measures to rouse it to activity may be em- ployed, such as mild exercise, friction, thermic stimulation by cold bathing, and even drugs. In the latter condition, which is the characteristic one of true seasickness, the neuro-vascular mechanism is exhausted from overwork. For all practical purposes of therapy intended to directly enhance vaso-motor efficiency, there is no neuro-vascular mechanism, and it is irrational and harmful to try to stimulate the medullary centres or the sympathetic nervous system under these conditions. Here the problem has to be approached from the other side. If nothing may be done directly to enhance lessened vaso-motor efficiency the most should be made of what remains by conserving the circulatory mechanisms and diminishing to the utmost the demands put upon them. The principle of adaptation of the functional activities to the capacity of any organ or set of organs, or to the capacity of the organism as a whole, finds application in seasickness as in every other condition that faces the medical strategist. Any kind of treatment that offers hope must not be employed. A thorough understanding of the underlying causes and con- ditions is imperative in order that the best method of treatment in the individual case may be discovered and applied. August 2d. — The effects of a hot, stuffy cabin upon the circulation are shown in parts of protocols 24 and 25. The contrast between the condition of the circulation after a night in a close cabin and when the port-holes were open later in the morning, challenges attention. See protocol 25. The vaso-motor efficiency from 11.86 a.m. until 9.53 p.m. was perfect. During all this time the port- holes were open, the temperature of the cabin being about 68° F. After breakfast at 9.36 a.m. the K I absorption test showed in subject "B" a positive reaction in 27 minutes. At 9.55 a.m. subject "B" took ten drops of dilute HCl, SEASICKNESS 383 to ascertain whether it would hasten the progress of food through the pylorus. It was noted that the salol test showed a positive reaction in exactly the same time that it took upon July 31st, viz., 2 hours and 23 minutes. Observations on subject "S" showed that the cool cabin had little effect in restoring vaso-motor efficiency. This subject's vaso-motor mechanism, as we have before re- marked, is of an altogether different type from that of subject " B. " Subject " S " seldom perspires freely. Cold bathing, if continued for any length of time, makes him blue all over and sets up actual rigours which last for some time. With subject "B" cold bathing causes the usual reaction, i.e., tonic hypersemia with the glowing skin and general sense of well-being that accompanies it. Here is another indication of the necessity of closely study- ing the circulatory mechanism in every individual be- fore recommending cold procedures in hydrotherapy. August 3d. — In the early part of the day the weather was somewhat warmer, the temperature in the cabin being 74° F. at 7.47 a.m. The port-holes were open, but the cabin was on the leeward side and there was no fresh breeze blowing in. The effect upon the circulation is shown in protocol 26. The effects of the cool night are well shown. Subject "B" felt very well all day. August 4th. — On this day the weather was cool, but wet and windy. There was little motion to the l3oat. The port-holes were closed all night on account of rain. The effect upon the circulation is shown in protocol 26. The subject felt well all day. August 5th. — On awakening the ship was lying in New York Harbour. Subject "B" felt well in every way. The temperature in the cabin was 71 ° F., but the air was "stuffy." The effect upon the circulation is shown in protocol 26. At 8 a.m. the passengers were landed in New York. CHAPTER XXVIII STUDIES IN SEASICKNESS (Continued) So far the experiments had shown that atropin in eombination with strychnin is very effective in overcom- ing the chief disagreeable symptoms of seasickness. It was, however, apparent, notwithstanding the subjective sense of well-being, that the gastric functions were any- thing but normal. An effort was therefore made to find some means w^hereby the good effects of atroj^in and strychnin might be supplemented, the special object in view being improvement in gastric secretion, absorption and motility. A series of experiments was undertaken in which decoctions of the mucous membrane of the duodenum, and of the pylorus and other regions of the stomach, made after the manner described by Bayliss and Starling ^^ and by Edkins,^^ ^ere thoroughly tested by means of rotations. These experiments belong to a separate series and are detailed elsewhere. The results, however, warranted a trial of the decoctions in seasick- ness. Accordingly several sea-trips were undertaken with this object in view. Each of the three subjects used for the purpose of this study had been a long time under observation. Numerous test meals had been given to each on various occasions, so that the condition of the stomach in each as regards secretion, absorption and motility was thoroughly understood. During these tests observations of the pulse-rate and blood-pressure were also made as well as a study of the changes occurring in the retinal vfjssels during the milder fonns of seasickness. On November 8, 1910, a trip lasting about nine hours was made upon the steamship Angler. The weather was fair, but on the outward leg of the trip the boat pitched and rolled just enough to excite in all three subjects some of the milder symptoms of seasickness. During a period 384 SEASICKNESS 385 when the boat was at anchor the rolling was so bad that one of the subjects, "B," became very sick and succeeded in retaining his test meal for the accustomed hour only by remaining absolutely quiet and exercising all the self- control at his command. Subject "C" had an instillation of homatropin in the right eye and the retinal vessels were studied with the ophthalmoscope at the commencement of, and several times during, the trip. As the boat started at 8.20 a.m. the retinal veins and arteries were somewhat constricted, the veins being slightly larger than the arteries. The blood- pressure at this time was 145 and the pulse-rate 92. At 8.52 the retinal vessels appeared to be slightly smaller, the white line of the arteries being more marked, although the retina as a whole was not very pale. The pupil was well dilated and yet some difficulty was experienced in studying the fundus at this period, because of the boat's motion and the unsteadiness of the candle-flame, an added factor being perhaps some slight changes in the refractive mechanisms. The blood-pressure at this time was 120 and the pulse-rate 76. At 11.52 the retinal veins were dilated as compared with the arteries which were very small. The retina looked paler than previously. The subject felt "a little queer in the head," i.e., heavy and groggy. At 11.21 the blood-pressure was 185 and the pulse-rate 84. This subject "C" has, in the receptors or afferent arcs related to his horizontal semicircular canals a certain degree of insensitiveness to aural irriga- tions, rotations and galvanism. This was manifested on numerous occasions in experimental tests. It was there- fore a matter of interest to find that, on this trip as he sat with the coronal plane parallel to the long axis of the boat, the rolling motion (through his superior and pos- terior canals) so weakened him during the period that the boat lay at anchor that he could scarcely stand. This weakness was accompanied by nausea, vertigo and nystagmus, the latter being vertical toward the feet and accompanied by an apj^arent movement of external objects "away from him in front." At 8.32 an Ewald meal was given upon the fasting stomach and removed at 9.82. The chyme returned was siv and contained a little fresh blood. At 10.16 a decoction of pig's pyloric mucous membrane, 386 SEASICKNESS representing J of the yield of four stomachs, was given in its purity j^er os and followed by a few sips of water. At 10.25 an Ewald meal was given in which allowance was made for the fluid taken as pyloric decoction and as the mouth rinser that followed it. At 11.28 the stomach contents were withdrawn, the amount of chyme being siv^. With this meal the K I absorption test reacted for iodin in the mouth at 10.44, i.e. , in nineteen minutes. The salol test showed no reaction within the hour and only a feeble reaction at 11.43. Analysis showed for the fii'st meal: total acidity, .343% by wt., free HCl, .211, combined HCl, .102; and for the second meal: total acidity, .284, free HCl, .226, combined HCl, .036. The amount of free HCl after these two meals was unusual for the subject, who under somewhat similar cir- cumstances, i.e., in rotations generally showed free HCl diminished or absent. As the subject had been up early and had had no food before 8.32 a.m., it is presumed that the resting state of the gastric glands coupled with normal hunger had something to do with the production of so much free HCl in the first meal, whilst in the second meal the high percentage of free HCl might perhaps be attributed in part to the pyloric decoction. The latter assumption, however, gains no support from the results of the test meals given to the other subjects *'B and S" in whom there was no distinct increase of free HCl in the test meals following the administration of pyloric extract. It is possible that in this test some of the gastric contents from the previous meal remained in the stomach, as there is no mention in the notes of the stomach having been irrigated after removal of the first Ewald meal. Analysis of specimen taken Nov. 8th on the Angler from sub- ject "C." Ingested at 8.30 a.m. an Ewald breakfast. Re- moved at 9.32. Amount of chyme, siv. Resorcin test showed the presence of free HCl. Tot. acidity, 94, or. 343% by Tot. HCl, 86, or .313% by wt. wt. Acid salts, 8, or .029% by wt. Free HCl, 58, or .211% by wt. Comb'd HCl, 28, or .102% by Lactic acid, trace. wt. Starch J absent. SEASICKNESS 387 Amylodextrin, trace. Peptones, present. Erythrodextrin, present. Enzymes, normal. Achroodextrin, present. Bile, absent. Maltose, present. Mucus, small amount. Albumin, trace. Blood, present. Note. A small amount of fresh blood came with the last of the stomach contents. Analysis of specimen taken Nov. 8th on board the Angler from subject "C. " Ingested at 10.25 a.m. an Ewald test meal fol- lowing- the administration pe?- os of pyloric extract at 10.16. Withdrawn at 11.28. Amount of chyme, §iv. The chyme contained a few old blood-stained shreds but no free blood. Resorcin test showed the presence of free HCl. Tot. acidity, 78, or .284% by Achroodextrin, present. wt. Maltose, present. Free HCl, 62, or. 226% by wt. Albumin, trace. Comb'd HCl, 10, or .036% by Peptones, present. wt. Bile, absent. Tot. HCl, 72, or .262% by wt. Mucus, very little. Acid salts, 6, or .021% by wt. Blood, absent. Coagulating enzymes, normal. Lactic acid, trace. Peptonizing enzymes (pepsin). Starch, absent. subnormal. Amylodextrin, trace. Peptonizing zymogens (pep- Erythrodextrin, present. sinogen), subnormal. Note. The test for pepsin and pepsinogen showed a poor degree of digestion as compared with the controls. The tests made with subject "B" on board the Angler November 8th were as follows: The subject arose at 5 a.m. and had breakfast at 5.80, consisting of 6 oz. of bread with butter, 2 boiled eggs with butter 4 oz. , and two cups of weak tea with milk and sugar. At 7.56 whilst the boat was still at the wharf the blood-pressure was 140 and the pulse-rate 96. This condition of the circulation was due to the heavy choppy motion of the boat, which caused marked dizziness in this susceptible subject. A few mo- ments later the subject was sweating and the face and ears were flushed. At this time the blood-pressure and pulse-rate were 90 and 96 respectively. The cabin was warm and stuffy and the odour of bilge water extremely offensive. At 8.20 the boat started. During the first part of the journey the boat was fairly steady, but the air in the cabin was bad and affected the subject considerably. The vibration of the machinery was also annoying. The 388 SEASICKNESS subject had a slight occipital ache with a sense of fulness in the head. The face was flushed and hot. The sight of the water rushing past the boat caused distress. There was nausea accompanied by chilly sensations along the spine. The subject sat with the coronal plane parallel to the long axis of the boat. At 9.08 the blood-pressure was 140 and the pulse-rate 96. The subject at this time was sitting in his shirt-sleeves in the path of a cool breeze from an open door. He felt weak and nervous all over. There was some nausea coupled with a slight "lump- sensation" in the stomach and a sickening heavy ache all through the head {dolor cerebri). Light was annoying to the eyes whilst noise of any sort was distinctly unpleas- ant. Psychic depression was marked. The boat rolled constantly, the movements being short and abrupt. At 10.01 the blood-pressure was 140 and the pulse-rate 84. At 10.50, after removal of its contents, the stomach was irrigated. The chyme amounted to | iii and contained much mucus and a few old blood-stained shreds. At this time (11.07) the boat, lying at anchor, rolled very much. At 11.11 pyloric extract equivalent to \ of the yield of four stomachs was given per os. This was followed by an Ewald test meal at 11. 16 as in the case of subject " C. " At 11.22 the subject felt heavy and wretched, the head ached, the face was flushed and warm, and the feet were cold. At 11.35 the blood-pressure was 140 and the pulse-rate 76. At 11.42 the subject felt a slight "lump-sensation" in the stomach toward the left of the epigastrium and with this a "groggy, drunken heaviness" in the head. The boat was still at anchor but rocking in a distressing manner. At 11.53 the subject felt nauseated and sick. The lump-sensation was present in the stomach, and the face was flushed. A moment later the subject was on the verge of vomiting; the skin became pale and broke out in sweat. At 12. 05 the blood-pressure was 145 and the pulse- rate 76. The subject was still sweating, and very sick. Long deep breaths were frequently taken, the subject's weakness was extreme and he experienced a sense of suffo- cation as if "smoke were in the lungs preventing the entrance of the air. " There were signs of marked irrita- bility of temper which was, however, to a great extent controlled, After a few minutes the attack passed off. The SEASICKNESS 889 subject's face assumed a better color; the feet became warm, but the muscles were still very tremulous and weak. The respirations just after the attack were from twelve to fourteen to the minute. It will be noted that all through the above attack there was marked physical and psychic depression and yet the blood-pressure was high for this subject, i.e., 145 as com- pared with the normal, which for him is about 110. The pulse-rate was also remarkable in being rather slow, 76 as compared with the normal which averages for this subject 88 to 92. More remarkable still was the fact that at no time was there any gagging or contraction of the abdominal muscles. These observations show that lowered blood- pressure is not necessarily associated with the extreme sense of weakness that precedes vomiting. This fact, how- ever, must not be interpreted as meaning that everything goes well with the circulation in the pre-vomiting stage. On the contrary; for whilst the peripheral vascular con- striction with slowed heart-rate (both being the direct result of medullaiy irritation) may suffice to maintain a high blood-pressure yet the volume of the heart's output is so small in any given period that medullary anemia ensues. This latter condition may, to a great extent, be relieved by recumbency but nature has a most effective way of meeting it by vomiting which rids the subject of one of the powerful (secondary) causes of medullary irri- tation, viz., the gastric contents, and at the same time pro- motes the flow of abdominal blood toward the heart, i.e., raises the blood-pressure by mechanical means thereby obviating, to some extent, the necessity for extreme pe- ripheral arterial constriction. Without entering into a dis- cussion as to the mechanism of shock, i.e., as to whether shock is due to arterial relaxation (Crile) or to arterial constriction (Porter), or to venous relaxation (Hender- son), it can be safely said that the end result of the vom- iting is the same, viz., the supply of a greater volume of blood to the medullary centres with less effort on the part of the cardiovascular system. At 12. 18 the stomach contents were removed by vomit- ing. The amount of chyme recovered was sixss. It con- tained a moderate amount of mucus, and a few old blood- stained scales. The salol, which had been administered 390 SEASICKNESS in a gelatine capsule at the end of the meal, was vomited as a moist mass but intact, just as it had been swallowed, only minus the capsule. Owing to this fact in all subse- quent experiments the salol was administered at the be- ginning of the test meals instead of at the end as in pre- vious tests. Immediately after'vomiting, the subject felt ver}'- much better. At 12. 37 the blood-pressure was 140 and the pulse- rate 76. The subject at this time was feeling fairly well but he had a slight headache and was very weak. As soon, however, as the boat weighed anchor and got under steam the cool air benefited him very much. At 6 p.m. the urine was normal. There was no evidence of albu- min, sugar, or glycuronic acid. Analysis of specimen taken Nov. 8th on board the Angler from subject "B." Ingested at 5.30 a.m. — breakfast consisting of 2 soft-boiled eggs with 4 oz. of butter ; 2 cups of weak tea with milk and sugar and 6 oz. of bread with 2 oz. of butter. Removed at 10.50. The chyme was 3 iii in amount and contained much thick mucus with a few tiny, old, blood- stained scales. Resorcin test showed absent or very great- ly diminished free HCl. Tot. acidity, 32, or .116% by Maltose, present. wt. Albumin, present. Free HCl, 6, or. 021% by wt. Peptones, faint trace. Comb'd HCl, 20, or .073% by Coagulating enzymes (chymo- wt. sin), present. Tot. HCl, 26, or .094% by wt. Peptonizing enzymes (pepsin). Acid salts, 6, or .021% by wt. diminished or absent. Lactic acid, present. Peptonizing zymogen (pepsin- Starch, absent. ogen), present. Amylodextrin, absent. Bile, absent. Erythrodextrin, absent. Mucus, considerable amount. Achroodextrin, absent. Blood, absent. Note. There was no evidence of gross fat in the chyme. Ab- sorption and motility tests not made. Analysis of specimen taken Nov. 8th on board the Angler from subject "B." Ingested at 11.16 a.m. an Ewald breakfast, preceded at 11.11 by pyloric extract given per os and representing J of the yield of 4 stomachs. Removed by vomiting at 12.16. The chyme amounted to ?ixss and con- tained a moderate amount of mucus with a few old, blood- stained scales. Resorcin test showed absent or considerably diminished free HCl. SEASICKNESS 391 Tot. acidity, 26, or .094% by Achroodextrin, present. wt. Maltose, present. Free HCl, 6, or .021% by wt. Albumin, present. Comb'd HCl, 14, or .051% by Peptones, faint trace. wt. Peptonizing enzymes (pepsin) ^ Tot. free HCl, 20, or .073% by diminished or absent. wt. Peptonizing zymogens (pep- Acid salts, 6, or .021% by wt. sinogen), present. Coagulating enzymes (chymo- Lactic acid, trace. sin), present. Starch, absent. Bile, absent. Amylodextrin, absent. Mucus, moderate amount. Erythrodextrin, trace. Blood, absent. The K I absorption test showed iodin in the saliva in 17 minutes. The salol (motility) test did not react within the hour. Experiments made November 8th on board the Angler upon subject "S." At 8.09 a.m. the blood-pressure was 135 and the pulse-rate 76. At this time the boat was be- side the pier, and rocking very nuich. At 8.20 the boat started, and at 8.42 an Ewald meal was given upon the fasting stomach. At 8.54 the boat was fairly steady. The blood-pressure at this time was 140, and the i3ulse-rate 72. At 9.25 the blood-pressure was 130 and the pulse-rate 72. At 9.42 the stomach contents were removed. The ch}Tne amounted to siiif, and contained nothing abnormal. During the journey so far, the boat had behaved fairly well. It pitched and rolled a little, however, just enough to cause disagreeable symptoms in subjects "B" and "C." At 9.55 atropin sulphate, gr 1/50, was administered h}^odermically. At 10.28 the blood-pressure was 130 and the pulse-rate 104. The rapid pulse, a very unusual thing in this subject, represents the atropin effect upon the vagus terminals in the heart. The boat was rolling somewhat at this period. At 10. 33 pyloric extract, equiva- lent to ^ of the yield of 4 stomachs, was given per os. At 10.44 an Ewald test meal was given. At 11.30 the blood-pressure was 135, and the pulse-rate 92. At 11.42 the stomach contents were removed. The chyme amounted to 3VSS and contained nothing abnormal. During the time that the test meal was retained the subject complained of no disagreeable feelings although the boat rocked con- 392 SEASICKNESS siderably as she lay at anchor. At 11.53 there was heavi- ness over the eyes. Otherwise the subject felt well. At 11.48 the blood-pressure was 125 and the pulse-rate 80. Analysis of specimen taken Nov. 8th on board the Angler from subject "S." Ingested at 8.42 a.m. an Ewald breakfast. Removed at 9.42. The chyme was § iii^ in amount and con- tained nothing abnormal macroscopically. Resorcin test showed the presence of free HCl. Tot. acidity, 80, or .292% by Amylodextrin, present. wt Erythrodextrin, present. Free HCl, 54, or .197% by wt. Maltose, no marked reaction. Comb'd HCl, 16, or .058% by Albumin, faint trace. wt. Peptones, present. Tot. HCl, 70, or .255% by wt. Enzymes, normal. Acid salts, 10, or . 036% by wt. Bile, absent. Lactic acid, trace. Mucus, no excess. Starch, absent. Blood, absent. Absorption and motility tests not made. Analysis of specimen taken Nov. 8th on board the Angler from subject "S." Ingested at 10.44 a.m. an Ewald test meal, preceded by atropin sulphate, gr 1/50 hypodermically, at 9.55, and pyloric extract per os equivalent to J of the yield of 4 stomachs at 10.33. Removed at 11.44. The chyme amounted to §vss and contained nothing abnormal macro- scopically. Resorcin test showed the presence of free HCl. Tot. acidity, 54, or .197% by Achroodextrin, present. wt. Maltose, present. Free HCl, 26, or .094% by wt. Albumin, faint trace. Comb'd HCl, 22, or .080% by Peptones, present. wt. Peptonizing enzymes (pepsin), Tot. HCl, 48, or .174% by wt. diminished. Acid salts, 6, or .021% by wt. Peptonizing zymogens (pep- sinogen), diminished. Lactic acid, trace. Coagulating enzymes, normal. Starch, absent. Bile, absent. Amylodextrin, present. Mucus, no excess. Erythrodextrin, present. Blood, absent. The K I absorption test showed iodin in the saliva in 19 minutes. The salol test showed no reaction within the hour. The pyloric extract used in the tests made on November 8th had been made some weeks and might therefore have undergone oxidation which seems to render it inert. On November 20th another trip, lasting about eight hours, was made on the Angler. On this occasion tests SEASICKNESS 393 were made upon the same subjects as in the previous ex- periments. As Edkins ^^ has shown on animals that atropin does not affect the action of pyloric secretogogues, the action of this drug in conjunction with extracts of gastric mucous membrane was studied in subjects " B" and " C, " whilst in subject "S" the effect of the extracts alone, i.e., without atropin was observed. The blood-pressure and pulse-rate and the general symptoms were also studied. In subject "C" the condition of the retinal vessels was studied. Observations made November 20th on subject "C." At 3.30 a.m. two glasses of diluted(half and half) milk were taken. At 6.30 one cup of water was taken and another at 7. The bowels moved rather freely at 6.30, 6.35 and 7. These movements were the result of cathartics taken on the previous day. At 8 a.m., after boarding the Angler^ the blood-i)ressure was 140 and the pulse-rate 100. The boat started at 8.07. At 8.27 an instillation of homatropin was given in the right eye. At 8.42 the retinal arteries were about normal in size and of a slightly greyish color. The veins were somewhat larger than the arteries and of a dull red hue. The fundus as a whole was of a rich red colour. The boat was going steadily — no motion being manifested beyond the vibra- tion from the engines. At 8.53 an Ewald meal was given. At 9.07 the blood-pressures were 140, 145, 140, 140, with corresponding pulse-rates of 100, 96, 100, 100. The boat was pitching and rolling somewhat at this period. At 9.35 the blood-pressure and pulse-rate were 135 and 100 respectively. At 9.40 the retinal vessels were about the same as when observed at 8.42. Just after the ophthal- moscopic examination of the eye the blood-pressure and pulse-rate were 135 and 96. At 9.53 the stomach con- tents were removed. Thech^^me was siiij in amount and contained a moderate amount of mucus and a few old blood-stained scales. After removal of its contents the stomach was irrigated. At 10.25 atropin sulphate, gr 1/50, was given hypodermically. At this time the boat was rolling and pitching somewhat, and the subject, who was sitting with the coronal plane parallel to the long axis of the boat, felt a little distress in the head. At 10.47 the subject received, per os, extracts from the gastric mucous 394 . SEASICKNESS membrane of the pig (fundic and intermediate portions), each portion representing J of the yield of four stomachs. The bulk of the extracts was i^Y. At 11.04 the boat was rolling considerably. The blood-pressiire and pulse-rate were 140 and 116 respectively. The pulse-rate evidently indicated the atropin effect upon the cardiac vagus termi- nals. At 11.19 the boat, lying at anchor, rolled considerably and made the subject feel heavy and sleepy. At 11.20 the retinal arteries were distinctly smaller, whilst the veins were comparatively larger and darker. The fundus as a whole seemed paler than in previous observations. At 11.82 an Ewald test meal was given and removed at 12.82 p.m. The ch}Txie was Jiii in amount with no abnormal macroscopic contents. The K I absorption test showed iodin in the saliva in 15 minutes. The salol test showed a feeble, unreliable reaction at 12.80 but was distinctly positive at 1. From 12.89 to 12.42 the blood-pressures were 145, 145, 145, 145, with corresponding pulse-rates of 88, 88, 96, 92. At 2 p.m. the retinal arteries were not so small as in the previous observations; the veins were a trifle larger than the arteries. Analysis of specimen taken Nov. 20th on board the Angler from subject "C." Ingested at 8.53 a.m. an Ewald meal. Re- moved at 9.53. Amount of chyme, siiij. No abnormal mac- roscopic contents. Resorcin test showed the presence of free HCl Tot. acidity, 70, or .255% by Amylodextrin, present. wt. Erythrodextrin, present. Free HCl, 50, or .182% by wt. Achroodextrin, present. Comb'd HCl, 14, or .051% by Maltose, present. wt. Albumin, absent. Tot. HCl, 64, or .233% by wt. Peptones, present. Acid salts, 6, or .021% by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, no excess. Starch, absent. Blood, absent. Note. The high percentage of free HCl in this meal, a very unusual thing for this subject, may be in part the result of the milk taken in the early morning, the products of digestion which lingered in the stomach acting as gastric secretogogues. SEASICKNESS 395 Analysis of specimen taken Nov. 20th on board the Angler from subject "C." Ingested at 11.32 a.m. an Ewald meal, after atropin sulphate, gr 150 hypodermically, at 10.25, and intermediate and fundic extracts representing for each por- tion J of the yield of 4 stomachs given per os at 10,47. Withdrawn at 12.32 p.m. Amount of chyme, ^iii. No ab- normal macroscopic contents. Resorcin test showed the presence of free HCl. Tot. acidity, 54, or .197% by Amylodextrin, trace, wt. Erythrodextrin, present. Free HCl, 40, or .146% by wt. Achroodextrin, present. Comb'd HCl, 10, or .036% by Maltose, present, wt. Albumin, absent. Tot. HCl, 50, or .182% by wt. Peptones, present. Acid salts, 4, or .014%by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, no excess. Starch, absent. Blood, absent. Such a percentage of free HCl as shown in the above analy- sis never occurred in this subject before under similar circum- stances, except in the tests of November 8th, when it resulted probably from secretogogues retained in the stomach from the previous meal. This, coupled with the fact that in the tests made upon subjects "B" and "S" there was unusual and marked increase of the free HCl, led to the supposition that the in- creased production of free HCl may have been the direct result of the gastric extracts. The tests made on subject "S," November 20th, were as follows : The air was rather cold and sharp as the A ngJer was boarded. At 8.07 a.m. the boat started. The blood- pressure and pulse-rate at 8.10 were 115 and 80 respec- tively and at 8.13, 125 and SS. The boat had rocked rather freely at the pier but was fairly steady after the start. At 8.58 an Ewald breakfast was given. The weather was fine and ever}i;hing looked merry in the bright sunlight. At 9.08 the blood-pressure and pulse-rate were 115 and 72 respectively. At 9.58 the stomach contents were removed and the stomach irrigated. The amount of chyme recovered w^as 3ii with nothing abnormal macro- scopically. At 10.44 the subject received, j^er os, extract of fundic and intermediate mucous membrane each por- tion representing ^ of the yield of four stomachs. The bulk of the extract was £3 v. At 11 the boat was rolling a little and the blood-pressure and pulse-rate were 110 and 72 respectively. At 11.19 an Ewald test meal was given. At this time the boat was lying at anchor and rolling with 896 SEASICKNESS sickening effect. At 11.20 the stomach contents were removed. The chyme, which was 3 iii in amount, con- tained nothing abnormal macroscopically. At 12.46 the blood-pressure and pulse-rate were 115 and QS respectively. The subject experienced no marked disagreeable effects from the trip. After going home he had several loose movements from the bowels. Analysis of specimen taken Nov. 20th on board the Angler from subject "S." Ingested at 8.58 a.m. an Ewald breakfast. Withdrawn at 9.58. Chyme amount 3 ii. Nothing abnormal macroscopically. Resorcin test showed the presence of free HCl. Tot. acidity, 88, or .321% by Amyioaextrin, trace. wt. Erythrodextrin, present. Free HCl, 64, or .233% by wt. Achroodextrin, present. Comb'd HCl, 16, or .058% by Maltose, trace. wt. Albumin, absent. Tot. HCl, 80, or .292% by wt. Peptones, present. Acid salts, 8, or .029% by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, no excess. Starch, absent. Blood, absent. Absorption and motility tests not made. Note. The high percentage of free HCl shown above, is un- usual for this subject and may, perhaps, be explained by the resting state of the glands and the long fast. Ordinarily the subject eats breakfast at 5.30 a.m., whereas in this test the first food was taken at 8.58 a.m. Analysis of specimen taken Nov. 20th on board the Angler from subject "S." Ingested at 11.19 a.m. an Ewald meal. The subject had received, per os, at 10.44 extract of fundic and intermediate mucous membrane, each part representing J of the yield of 4 stomachs. Withdrawn at 12.20 p.m. Amount of chyme, ^iii. Nothing abnormal macroscopically. Resorcin test showed the presence of free HCl. Tot. acidity, 94, or .343% by Amylodextrin, trace. wt. Erythrodextrin, present. Free HCl, 72, or .262% by wt. Achroodextrin, present. Comb'd HCl, 20, or .073% by Maltose, present, wt. Albumin, absent. Tot. HCl. 92, or. 335% by wt. Peptones, present. Acid salts, 2, or .007% by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, no excess. Starch, absent. Blood, absent. The K I absorption test showed the presence of iodin in the saliva in 15 minutes. The salol did not react within the hour SEASICKNESS 897 but reacted positively in 1 hour and 45 minutes. The high per- centage of free HCl seems to have been due in part to the effect of the gastric extracts. The tests made on subject "B" November 20th, on ooard the Angler^ were as follows: The subject was de- tained unexpectedly and had to run 650 yards at a good pace, so as not to miss the boat. After going on board he experienced some tightness in the chest as if smoke were in the bronchial tubes, preventing the free ingress of air. At times he coughed like an asthmatic. Undoubtedly the subject's symptoms were due to spasm of the bronchial muscles. A moment after entering the cabin the subject began to perspire but the tightness in the chest still per- sisted. At this time the subject's anger was aroused by the obstinacy of a disagreeable individual who would not move his chair a couple of inches, so as to afford room for the blood-pressures to be taken with comfort to all con- cerned. Words were exchanged and for a moment it looked as though the members of the party might have to defend themselves against the disagreeable individual and his friends. Good sense and sober judgment prevailed however, which was a good thing for the instruments and perhaps for a certain burly bully. The blood-pressures which were observed all through the period of possible impending struggle, i.e., from 8. 16 to 8.20 were 155, 150, 150, 140, 140, with corresponding pulse-rates of 104, 100, 104, 100, 100. At 8. 30 the subject felt well and was perspir- ing slightly. The blood-pressure and pulse-rate were 180 and 100 respectively. At this period the subject felt a slight ache and sense of fulness in the head. There were also some eructations. The boat was rocking slightly, and the room was filled with tobacco-smoke. From 9.12 to 9.22 the blood-pressures were 135, 130, 125, 115, 120, 120, 115, 120, 115, and 115, with corresponding pulse-rates of 96, 96, 100, 100, 96, 96, 92, 92, 92, and 96. At 9.34 the blood-pressure and pulse-rate were 115 and 96 respectively. At this period the subject had a slight headache, and his face was flushed and hot. Air blew into the room fresh and cool from an open door. At 8.48 the boat was rolling and pitchmg to some extent. The subject had a slight occipital headache on the right side, extend- 398 SEASICKNESS ing to the ear. The face was still flushed and warm. At 9.58 the skin was moist from perspiration, and the subject felt a little sick with a slight "lump-sensation" in the stomach. At 10.87 atropin sulphate, gr 1/50, was given hypodermically. At 10.55 the face was flushed, and the head felt heavy. At 1 1 the boat was still rolling somewhat. The subject experienced fulness in the head, and had a tendency to sleep. The face was still flushed. From 11.08 to 11.15 the blood-pressures were 120, 125, 125, 125, with corresponding pulse-rates of 88, 92, 92, 92. At this period the boat lay at anchor, and rolled with sick- ening effect. The subject's mouth was dry from the atro- pin. The rolling of the boat caused a little distress in the head. At 11.40 the stomach contents were removed. The chyme, which amounted to ^iif, contained much mu- cus, a few old blood-stained scales and, toward the end, a very small amount of gross fat with a little fresh blood. After removal of its contents the stomach was irrigated. At 11.57 the subject was given, per os, extract of fundic and intermediate mucous membrane of each an amount equivalent to ^ of the yield of 4 stomachs. At 12.05 p.m. there was a slight pain in the right epigastric region. At 12.28 flatus was passed, and there was pain in the region of the left iliac fossa. The subject felt well except for those pains low down in the abdomen. At 12.82, an Ewald test meal was given. The usual sour taste which so often follows the administration of atropin was experienced as the subject ate his test meal. At 12.88 there was a cool pleasant sensation in the stomach. There were no unpleasant symptoms of any kind, but the face was slightly flushed. At 12.48 there were intermit- tent sharp colicky pains in the lower abdomen. From 12.52 to 12.55 the blood-pressures were 125, 180, 180, 180, with corresponding pulse-rates of 76, 80, 80, 80. At 1.80 the stomach contents were removed. Owing to persistent gagging, it was unusually hard to introduce the stomach-tube. The chyme, which amounted to ?iii, con- tained a moderate amount of mucus, and a few old blood- stained scales, but no free blood. At 1.50 the blood- pressures were 185, 185, 180, 185, with corresponding pulse-rates of 68, 72, 72, 72. At 2.05, the subject felt well and enjoyed a hearty dinner, which was followed by SEASICKNESS 899 a large loose evacuation of the bowels. Evidently the atropin and perhaps the gastric extracts stimulated gastro- intestinal motility, for the other subjects were somewhat similarly affected, especially subject "S." It is noteworthy that the atropin in the dose given had no effect in releasing the heart from vagus control in this subject as in the others. This fact has been repeat- edly observed in subject "B" in whom atropin in fair dosage generally tends to slow the pulse-rate if anything. Analysis of specimen taken Nov. 20th on board the Angler from subject "B." Ingested at 6 a.m. 2 soft-boiled eggs with 4 oz. of butter ; 2 cups of weak tea, with milk and sugar, and 6 oz. of bread with 2 oz. of butter. Withdrawn at 11.40 a.m. Amount of chyme, siif. Macroscopically there was a considerable amount of mucus with a few old blood-stained scales, a trace of free fat and a small amount of fresh blood. Resorcin test showed the absence of free HCl. Tot. acidity, 44, or .160% by Maltose, trace. wt. Albumin, present. Free HCl, . Peptones, present. Comb 'd HCl, 26, or .095% by Peptonizing enzymes (pepsin), wt. diminished or absent. Tot. HCl, 26, or .095% by wt. Peptonizing zymogens (pep- Acid salts, . sinogen), present. Lactic, trace. Coagulating enzymes (chymo- Starch, absent. sin), present. Amylodextrin, absent. Bile, absent. Erythrodextrin, absent. Mucus, some excess. Achroodextrin, absent. Blood, present. Note. The old blood-stained scales so often alluded to repre- sent epithelium and exudate from the gastric mucous membrane. Evidently subject *'B" suffered from a mild grade of chronic gastritis. Analysis of specimen taken Nov. 20, 1910, on board the Angler from subject "B." Ingested at 12.32 p.m. an Ewald meal. Atropin sulphate, gr 1 50, had been given hypodermatically at 10.37 a.m. and gastric extract, fundic and intermediate, of each an amount equivalent to J of the yield of 4 stomachs at 11.57 per os. Withdrawn at 1.30 p.m. Amount of chyme, Siii. Macroscopically there was a moderate amount of mucus and a few old blood-stained scales. Resorcin test showed the presence of free HCl. Tot. acidity, 58, or .211% by Comb'd HCl, 22, or .080% by wt. wt. Free HCl, 36, or .131% by wt. Tot. HCl, 58, or .211% by wt 400 SEASICKNESS Acid salts, none. Albumin, absent. Lactic acid, absent. Peptones, present. Starch, absent. Enzymes, normal. Amylodextrin, absent. Bile, absent. Erythrodextrin, present. Mucus, moderate amount. Maltose, trace. Blood, absent. The K I absorption test showed the presence of iodin in the saliva in 12 minutes. The salol test reacted positively in 1 hour and 3 minutes. Note. The high percentage of free HCl shown in the above analysis is unique for this subject. In all analyses following Ewald test meals given this subject, even in the resting state upon shore, free HCl was very low or absent. It seems, there- fore, justifiable to attribute, in part at least, the enhanced pro- duction of free HCl in this and the other cases of this day's tests to the effects of the gastric extracts. On November 24th another trip lasting about eight hours was made on the Angler. The same subjects, viz., " B, " " C, " and " S, " were used as in the preceding tests. The details of the tests made on subject " B" are as follows : At 5.50 a. m. breakfast was taken, consisting of several slices of toast representing about 3vi of bread, with ^ii of butter and 2 cups of tea, to which were added milk and sugar. At 8.02 the blood-pressure was 185 and the pulse-rate 84. At this time the boat was still at the pier, but was rock- ing very much from the wash of passing craft. The sub- ject had arisen early, and had plenty of time to reach the boat, so that there was no hurry or rush as on the previous day. When the blood-pressure above recorded was taken, he was sitting in his shirt-sleeves in a cool atmosphere. At 8. 15 the boat started. The weather was fair and cool, but the skies were overcast. The boat rolled and pitched somewhat. At 8.30 the subject's face was flushed and hot, and there was a sense of pressure across the abdomen, about the level of the umbilicus. The cabin was filled with tobacco-smoke, the air being anything but fresh. At 8.40 the blood-pressures were 130, 130, 185, 135, with corresponding pulse-rates of 72, 76, 76, 76. At 8.48 the subject had slight headache with flushed face. At 8.59 there was still some slight headache, and a little nausea. The odour of t^jbacco-smoke was distinctly unpleasant. The gloom of the day seemed to attach itself to everything. The subject felt warm. At this period the boat was roll- SEASICKNESS 401 ing considerably, and the sound of the engines reverberated through the head in a distressing manner. At 9. 12 the blood-pressures were 125, 125, 125, 130 with correspond- ing pulse-rates of 76, 76, 80, 80. At this period there was dizziness and heaviness in the head with some head- ache, "lump-sensation" and a distinct tendency to sick- ness of the stomach. At 9.29 an Ewald test meal was given. The stomach had not been irrigated before this meal. The boat at this time was rolling considerably, and the subject felt some headache and doloi' cerebri. At 9.34 the boat was still rolling somewhat, and the subject felt "sick in the head" with pain in the occipital region, and heaviness about the eyes. The sense of tension in the muscles of the abdomen persisted. At 9.38 the boat was rolling and pitching badly. At 10. 14 the subject felt heavy, and there was a burning sensation in the stomach accompanied by eructations. At 10.30, the boat was still rolling and pitching. The subject felt heavy, and slightly sick. There was a distinct "lump-sensation" in the stomach. At 10.29 the gastric contents were removed and the stomach irrigated. The chyme amounted to |v and contained much mucus and a few old blood-stained scales. These latter were much less than after previous breakfasts in which eggs had been taken. At 10.46 the boat lay at anchor, but it rolled constantly with sickening effect. At 11.02 atropin sulphate, gr 1/50 was given hypodermically. At this time the subject felt somewhat distressed from the constant rolling. At 11.12 the subject received, yer os, pyloric extract representing | of the yield of four stomachs. The bulk of the extract was f^iv. At 11.30 the blood-pressures were 125, 125, 130, 130, with corresponding pulse-rates of 76, 76, 72, 72. The boat was still rolling and the subject had a slight headache. The mouth was dry from the atropin. The odour of tobacco-smoke seemed somewhat changed, al- though not as unpleasant as usual. The stomach mani- fested no disagreeable symptoms. At 11.40 the mouth was very dry and the subject felt much better and stronger. At 11.53 an Ewald meal was given. No sour taste was ex- perienced as on previous occasions after atropin. At 1 1. 57 strychnin sulphate, gr 1/30, was given hypodermically. The subject felt well in every way, and experienced a nice 402 SEASICKNESS cool sensation in the stomach. He noticed, however, that when he attempted to walk he was unable to balance very well, although the tossing about did not cause much dizzi- ness or distress. Similar incoordination following the use of atropin at sea was frequently observed in "B" and other subjects. At 12. 10 the subject still felt well in every way. There were some eructations. The knee-jerks were somewhat active. From 12. 16 to 12.21 the blood-pressures were 130, 125, 130, 125, 120, 115, 120, with corresponding pulse-rates of 88, 88, 88, 92, 92, 88, 92. The boat was still rolling very much, but the subject felt well in every way. There were some eructations, however. At 12.48 the boat was still rolling very much just off Sandy Hook. The subject's nose and mouth were very dry, but otherwise he felt quite well. At 12.53 the stomach contents were removed. The amount of chyme recovered was Iss. It contained nothing abnormal macroscopically. At 1.10 the blood-pressures were 130, 130, 135, 130 with corre- sponding pulse-rates of 80, 84, 80, 80. At this time the boat was rolling considerably. The air was chilly, but the subject experienced no effect beyond diyness of the mouth and nose, and a slight, not unpleasant sense of lightness in the head. Analysis of specimen taken Nov. 24th on board the Angler from subject "B." Ingested at 9.29 a.m. an Ewald test meal. The stomach had not been irrigated and the subject had taken breakfast at 5.50 a.m., consisting of toast, equivalent to §vi of bread with 2 oz. of butter and two cups of tea with milk and sugar. Removed at 10.29. Amount of chyme, ?v. Macroscopically there was much tenacious mucus and a few old blood-stained scales. Resorcin test showed the presence of free HCl. Tot. acidity, 42, or .153% by Amylodextrin, absent. wt. Erythrodextrin, trace. Free HCl, 24, or .087% by wt. Achroodextrin, present. Comb'd HCl, 14, or .051% by Maltose, present. wt. Albumin, trace. Tot. HCl, 38, or .138% by wt. Peptones, present. Acid salts, 4, or .014% by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, excessive amount. Starch, absent. Blood, absent. Note. The products of digestion left over in the stomach from the breakfast at 5.50, were undoubtedly the cause of the fair gastric secretion represented in the analysis above. In SEASICKNESS 403 similar test meals tried at various times upon the subject, on a fasting stomach or after irrigation the tests always showed diminished or absent free HCl. Absorption and motility tests not made. Analysis of specimen taken Nov. 24th on board the Angler from subject "B. " Ingested at 11.53 a.m. an Ewald meal. Atropin sulphate, gr 1,50, had been given hypodermically at 11.02 a.m. and pyloric extract § of the yield of 4 stomachs, per OS, at 11. 12. At 11. 57 strychnin sulphate, gr 1/30, was given hypodermically. Withdrawn at 12.53 p.m. Amount of chyme, §ss. Nothing abnormal macroscopically. Re- sorcin test showed a very feeble reaction for free HCl. Tot. acidity, 30, or. 109% by Achroodextrin, present, wt. Maltose, present. Free HCl, 10, or . 036% by wt. Albumin, trace. Comb'd HCl, 10, or .036% by Peptones, absent. wt. Peptonizing enzymes (pepsin), Tot. HCl, 20, or .072% by wt. absent. Acid salts, . Peptonizing zymogens (pep- sinogen) present. Lactic acid, absent. Coagulating enzymes, normal. Starch, absent. Bile, absent. Amylodextrin, absent. Mucus, moderate amount. Erythrodextrin, trace. Blood, absent. The K I absorption test showed the presence of iodin in the saliva in 11 minutes. The salol test showed a positive re- action in 1 hour and 42 minutes. The low percentage of free HCl may, perhaps, have been due in part, to fatigue of the gastric glands following the previous meal. Absorption and motility were evidently favoured by the pyloric extract as well as by the atropin and strych- nin. Owing to the small amount of chyme the quantitative analysis involved some difficulty, but the figures given are fairly reliable, especially when taken in conjunction with the result of the resorcin test. The details of the tests made November 24th on sub- ject "C" were as follows: At 7 a.m. the subject took a cup of sweetened lemonade. At 8 homatropin was instilled into the right eye. At 8.05 on board the Angler, which was still beside the pier, the blood-pressures were 145, 140, 140, with corresponding pulse-rates of 100, 104, 104. The boat was much disturbed by the wash from passing craft. At 8. 15 the boat started. At 8. 28 the sub- ject drank ^viii of water. At 8.38 an Ewald meal was given, but with only ^ii of water, as the subject had had fviii of water at 8.28. At 8.44 the blood-pressures were 130, 130, 135, 140, 140, with corresponding pulse-rates 404 SEASICKNESS of 96, 96, 96, 96, and 100. The slight rise in the last two pressures may have been due to a scolding given the sub- ject for taking water without permission and for failing to report having taken it. At 8.58 the retinal arteries were moderately constricted, the veins being somewhat larger. At this time the subject felt a heaviness in the head, due to the rolling and pitching which had been con- siderable. At 9.16 the blood-pressures were 145, 140, 140, with corresponding pulse-rates of 100, 100, 96. At 9.38 the stomach contents were removed. The chyme amounted to §iii, and was of a dark brown (chocolate) colour, with about half an ounce of gross fat floating on the surface. This was the result of chocolate-vanilla ice- cream taken at 10 p.m., on the preceding evening. At 9.57 atropin sulphate, gr 1/50, was given hypodermically. At 9.58 the subject was feeling badly, and had a frontal headache. There was no "lump-sensation" present. At 10 the blood-pressures were 140, 140, 140, 140, with corresponding pulse-rates of 88, 88, 92, 92. At 10. 15 the subject received, j'je?* os, extract of the fundic mucous membrane, equivalent to ^ of the yield of 4 stomachs and a similar amount of pyloric extract. The bulk of the ex- tract, in a watery diluent, was f$v. At 10.25 the retinal arteries were somewhat larger than they had been in the previous observation. The veins were relatively somewhat smaller, but were still a trifle larger than the arteries. At 10.50 strychnin sulphate, gr 1/30, was given hypodermically. At 10.55 an Ewald meal was given. At 10.51 the knee-jerks were ab- sent even with Jendrassik's reinforcement. At 11.05 the subject felt "bad in the head." There was frontal head- ache, as if a tight band were tied about the head. The stomach felt very well. There was no "lump-sensation" and no eructations. At this period there was no nystag- mus. At 11.88 the blood-pressure was 145, and the pulse- rate 100. The knee-jerks were still absent, even with reinforcement. At 11.55 the stomach contents were re- moved. The chyme was 1v in amount and was of a yel- lowish colour. There was no evidence of gross blood. At 12.10 p.m. the knee-jerks were still absent, even with reinforcement. At 12.28 the ])l()od-pressures were 140, 145, 145, 145, with corresponding j^ulse-rates of 84, 92, SEASICKNESS 405 92, 92. The boat at this time was rolling considerably. At 1.18 the blood-pressiires were 140, 145, 145, 145, with corresponding pulse-rates of 84, 84, 84, 88. At 1.30 there was a sour taste in the mouth, due probably to the atropin. About this time it was suggested that the party retire to the dining-room, but the subject had no desire for food. At 2. 15 he ate a fairly large dinner, consisting of clam chowder, turkey with dressing, a cup of coffee, plum- pudding, and mince-pie. This dinner was taken, al- though the subject knew from previous experience, that it would sicken him. At 8.20 he was compelled to empty the stomach, which he did in his accustomed way by tick- ling the i)harynx with his forefinger. At 3.30 the knee-- jerks were not only present without reinforcement, but were somewhat exaggerated. From 3 it was evident that the subject was beginning to have one of the typical gastric crises of tabetic origin of which he was a victim. Analysis of specimen taken Nov. 24th on board the Angler from subject "C. " Ingested at 8.38 a.m. an Ewald meal. The subject had taken one cup of sweetened lemonade at 7 a.m. Withdrawn at 9.38. Amount of chyme, ?iii. On macroscopic examination the chyme was found to be dark brown in colour with about half an ounce of free fat floating on the surface. Resorcin test showed the presence of free HCl. Tot. acidity, 68, or .248% by Amylodextrin, absent. wt. Erythrodextrin, trace. Free HCl, 44, or .160% by wt. Achroodextrin, present. Comb'd HCl, 14, or .051% by Maltose, present. wt. Albumin, absent. Tot. HCl, 58, or .211%, by wt. Peptones, present. Acid salts, 10, or . 036% by wt. Enzymes, normal. Bile, absent. Lactic acid, present. Mucus, moderate amount. Starch, absent. Blood, absent. Note. The stomach evidently contained normal gastric juice at the beginning of the meal, and the products of digestion acted as gastric secretogogues since the percentage of free HCl shown in the analysis is very unusual for this subject after similar test meals. The marked stasis of food taken on the previous evening is noteworthy as a precursor of the gastric crisis which was evidently hurried on by the atropin and strychnin and perhaps by the gastric extracts for which the subject has a positive dislike. The enhanced secretion of free HCl may have been due to the early mild irritation of the medullary centres incidental to the approach of a gastric crisis. 406 SEASICKNESS Analysis of specimen taken Nov. 24th on board the Angler from subject "C." Ingested at 10.55 a.m. an Ewald meal. Atropin sulphate, gr 1 50, had been given hypodermically at 9.57 and strychnin sulphate, gr 1 30, at 10.50, also hypo- dermically. The subject also had received, per os, at 10.15 fundic extract equivalent to J of the yield of 4 stomachs and a similar amount of pyloric extract. The bulk of the ex- tracts with their watery diluent was 3V. Withdrawn at , 11.55. Amount of chyme, svss. On macroscopic examina- tion the chyme was of yellowish colour with no evidence of blood. Resorcin test showed a very feeble reaction for free HCl. Tot. acidity, 26, or .095% by Maltose, present. wt. Albumin, trace. Free HCl, 10, or. 036% by wt. Peptones, faint trace. Comb'd HCl, 12, or .044% by Peptonizing enzymes, absent. wt. Peptonizing zymogens, dimin- Tot. HCl, 22, or .080% by wt. ished. Acid salts, 4, or .014% by wt. Coagulating enzymes, absent. Lactic acid, trace. Coagulating zymogens, pres- Starch, absent. ent. Amylodextrin, trace. Bile, absent. Erythrodextrin, present. Mucus, moderate amount. Achroodextrin, present. Blood, absent. The K I absorption test reacted in 12 minutes. The salol motility test reacted in 1 hour and 5 minutes. • The inefficiency of fundic and pyloric extract to induce secretion of a normal gastric juice in spite of the fact that absorption and motility were enhanced is noteworthy. The absence of symptoms referable to the stomach is to be attributed to the atropin, although this latter drug is quite inefficient in combating the distress referred to the stomach in gastric crises. The absence of skijiped beats in the pulse during the forenoon and their reappearance on the approach of the gastric crisis is also noteworthy. Whether the present test made on this particular subject is a fair one as to the efficiency of the combinations of pyloric and fundic extract is an open question. The failure of gastric secrf;tion can hardly be attributed to pronounced medullary irritation from the oncoming gastric crisis, because in that case we might expect marked gastric stasis and failure of absorption from the same cause, whereas the gastric motility and absorption were distinctly en- hanced after strychnin and atropin, etc. The failure of normal gastric secretion miglit possibly be attributed to SEASICKNESS" 407 fatigue of the gastric glands, but in a previous test where intermediate extract was used, no such fatigue effects were manifested. The fact that in subject "B" the gastric secretion was deficient, throws no light on the subject, since in his case only pyloric extract was used. In subject "S" to whom intermediate extract was given the gastric juice secreted was normal or enhanced for this subject. It remains therefore a question as to whether the failure of gastric secretion in the case of "B'^ and "C" was due to fatigue or other cause, or to the in- efficiency of fundic and pyloric extracts to stimulate the gastric glands to activity. Pending further investigation, the latter view seems the more probable. The details of the tests made November 24th upon subject "S" are as follows: At 8.10 a.m. on board the Angler which, though still at the pier, was rocking very much in the wash of passing craft, the blood-pressures were 130, 185, 180, 180, with corresponding pulse-rates of 72, 68, 76, 68. At 8.15 the boat started and at 8.20 the fasting stomach was irrigated. At 8.29 an Ewald breakfast was given. The boat at this period was rolling and pitching somewhat. At 8.48 the blood-pressures were 125, 125, 125, 125, 125, with corresponding pulse-rates of 76, 76, 76, 68, 64. At 9. 20 the blood-pressures were 125, 115, 115, 115, with corresponding pulse-rates of 68, 64, 68, 68. At 9.29 the stomach contents were removed. The chyme was jiii in amount, and was thin in consistency and of a yellowish colour. At 9.58 atropin sulphate, gr 1/50, was given hy}3odermically. At 10 the subject felt very well. At 10.05 the blood-pressures were 125, 125, 125, 125, with corresponding pulse-rates of 56, 60, 60, 56. The boat was still rolling a good deal. At 10.08 the subject received, ^;er os^ "intermediate extract" equivalent to | of the yield of 4 stomachs and a similar amount of fundic extract. The extracts with their watery diluent amounted to f^v. At 10.45 an Ewald meal was given, and at 10.57 strychnin sulphate, gr 1/80, was given hypodermically. At 11.06 the subject felt a band sensation around the head. At 11.17 there was slight dizziness, although the stomach felt very well. There was no nystagmus visible to the naked eye. At 11.40 the blood-pressures were 125, 120, 120, 115 with corresponding pulse-rates Qf 80, 80, 84, 80. 408 SEASICKNESS The increased pulse-rate was evidently the effect of the atropin on the cardiac vagus terminals. At 11.45 the stomach contents were removed. The chyme amounted to 3iiss and was of a yellowish colour with little or no mu- cus. At 12.10 the knee-jerks were active, but resembled movements of voluntary extension rather than the sharp response of the normal knee-jerk. At 12.80 the blood- pressures were 105, 110, 110, with corresponding pulse- rates of 64, 68, 68. Evidently the effects of the atropin upon the cardiac vagus terminals and upon the vaso-motor mechanisms had worn off. At 1.20 the blood-pressures were 105, 105, 110, 105, 105 with corresponding pulse- rates of 68, 60, 64, 60, 60. At 1.24 the subject felt very well. At 1.80 there was no great desire to eat. Analysis of specimen taken Nov. 24th on board the Angler from subject "S. " Ingested at 8.29 a.m. an Ewald breakfast. The fasting stomach had been irrigated at 8.20 a.m. Re- moved at 9.29. Amount of chyme, siii. Macroscopically the chyme was of yellowish colour, thin in consistency and contained no excess of mucus. Resorcin test showed the presence of free HCl. Tot. acidity, 64, or .233% by Amylodextrin, trace. wt. Erythrodextrin, present. Free HCl, 54, or .197% by wt. Achroodextrin, present. Comb'd HCl, 4, or .014% by Maltose, present. wt. Albumin, absent. Tot. HCl, 58, or .211% by wt. Peptones, present. Acid salts, 6, or 021% by wt. Enzymes, normal. Bile, absent. Lactic acid, absent. Mucus, no excess. Starch, absent. Blood, absent. Absorption and motility tests not made. Note. The free HCl content may here be fairly attributed to the activity of the well-rested gastric glands. Analysis of specimen taken Nov. 24th on board the Angler from subject "S. " Ingested at 10.45 a.m. an Ewald meal. At 9.53 the subject received hypodermically atropin sulphate, gr 150. At 10.08 he received, per os, fundic and interme- diate gastric extract of each an amount equivalent to J of the yield of 4 stomachs. At 10.57 strychnin sulphate, gr 1 30, was given hypodermically. Removed at 11.45. Amount of chyme liiss. Macroscopically the chyme was yellowish in colour and contained nothing abnormal Resorcin test phowed the presence of free HCl, SEASICKNESS 409 Tot. acidity, 56, or .204% by Amylodextrin, trace. wt. Erythrodextrin, present. Free HCl, 40, or . 146% by wt. Achroodextrin, present. Comb'd HCl, 14, or .051% by Maltose, present. wt. Albumin, absent. Tot. HCl, 54, or .197% by wt. Peptones, present. Acid salts, 2, or .007% by wt. Enzymes, normal. Bile, absent. Lactic acid, absent. Mucus, no excess. Starch, absent. Blood, absent. The K I absorption test reacted in 18 minutes. The salol test reacted in 1 hour and 20 minutes. The fairly normal gas- tric juice of the above analysis may fairly be attributed in part, at least, to the effects of the gastric extracts, as the percentage of free HCl is higher than that obtained in simi- lar test meals in the resting condition on shore. It was again observed that in subjects "B" and "S" the bowels moved rather freely, on the same afternoon in the case of "S, " and on the next morning in the case of "B. " The latter subject has a tendency to constipation. Subject "C's" bowels did not move that evening or the next day, but he received morphin sulphate, gr ss. , hypodermically about 5 p.m. as he had devel- oped one of his usual attacks of true gastric crises. On January 8th the effect of hypnotic suggestion was studied in subject "F." At 7 a.m. the subject drank ^iv of water. At 8.07, on board the Angler^ the ear drums were normal, there being no blood-vessels visible. At 8. 15 the blood-pressures were 125, 125, and 125 with corresponding pulse-rates of 92, 92, and 88. At 8.20 the boat started. On ophthalmoscopic examination under homatropin, the retinal arteries were moderately dilated the veins being somewhat larger. The fundus jerked to- ward the left about every three seconds, at times executing this movement toward the left in one sharp movement, and at other times in a series of small jerks. Later, the nystag- mic movements of the fundus toward the left (of the patient) were almost constant. During these observations the subject sat erect, the coronal plane of his body being parallel to the long axis of the boat, and his right side directed toward the bow. At this time the boat was rolling moderately. At 8.51 the blood-pressures were 130, 135, 135, and the corresponding pulse-rates 80, 84, and 84. At 9.09 an Ewald meal was given. At 9. 12 the blood-pressures were 185 and 185, the pulse-rates being 76 ^nd 76. At this 410 SEASICKNESS time there was slight horizontal nystagmus of the fundus toward the subject's left. The retinal arteries were slightly constricted. Both arteries and veins seemed smaller than at the previous examination. At times it was difficult to see the fundus properly. The boat continued to roll some- what. At 9.25 no vessels were visible in the ear drums. The subject felt well in every way. At 9.42 the blood-press- ures were 185, 180, 185, the pulse-rates being 80, 84 and 80. At 10.09 the retinal arteries were somewhat con- stricted, the veins appearing large, dark and full. Occa- sionally there were nystagmic jerks of the fundus toward the subject's left. At 10.12 the stomach contents were removed, and the stomach irrigated. The amount of chyme recovered was fiv. For the purpose of removing the stomach contents, the subject was hypnotized, as his pharynx could not tolerate the stomach-tube. On previous occasions this subject, even under hypnosis and with ap- propriate suggestions, could not tolerate the stomach-tube. On this occasion, however, it was suggested to him, both before and during hypnosis, that the operation would cause no discomfort and little difficulty was experienced in evac- uating and irrigating the stomach. When the stomach irrigation had been completed, the subject was allowed to remain in hypnosis, and at 10.80 an Ewald meal was given with the suggestion that it was cake and champagne. During the meal, and at frequent intervals afterward, it was suggested that the motions of the boat would not cause seasickness or the usual disagreeable phenomena. At 10.51 the boat was rolling considerably, and there was marked nystagmus of the fundus to the left. To the naked eye at this time there was nystagmus to the left, when the subject turned his eyes to the left, and to the right when he turned his eyes to the right. In an observation made on a subsequent occasion on shore, it was found that when the subject turned his eyes to the left the latter jerked slightly with the watch, whilst with the eyes turned to the riglit the eyes jerked tx) the right and with the watch. At 11.08 the retinal arteries were moderately dilated, the veins being full and dark. There was slight nystagmus of the fundus to the subject's left, but at times the oscilla- tions were simply back and forth movements of about SEASICKNESS 411 equal rate and range. At this time the boat was rolling eo much that subject "B" felt rather dizzy and heavy in the head. At 11.22 the retinal arteries were constricted, the veins being dark and full. There was horizontal nys- tagmus of the fundus to the left. The boat, lying at an- chor, was rolling with sickening effect. At 11.85 the stomach was evacuated and irrigated. The amount of chyme recovered was fivss. At 1.05 p.m. the retinal arteries were constricted. The retina looked pale, and there was nystagmus of the fundus to the subject's left. At this time the subject felt very dizzy. In fact he was dizzier and sicker under hypnosis than in the ordinary waking state. After irrigation of his stomach he slept considerably and could not be kept from lying down. At 1.09 the blood-pressures were 125, 125, the pulse-rates be- ing 68 and 68. The boat still continued to rock, and the subject felt dizzy and heavy. At 1.25 there was experi- enced heaviness in the left side of the head, and the sub- ject felt hungry, sleepy, and tired. No vessels were visi- ble in the membrana tympani. At 2 the subject, on being taken out of hypnosis, complained of hunger, but on being taken to the dining-room, a surprisingly small amount of food soon satisfied his appetite. During hypnosis, on attempting to walk, the subject almost fell down the companion-way. It seemed that his powers of equilibration had become considerably disor- dered. Analysis of specimen taken from subject "F, " Jan. 8th, on board the Angler. Ingested at 9.09 a.m. an Ewald breakfast. Removed at 10.12. Amount of chyme, jivss. Macroscopi- cally the chyme was normal in appearance. Reaction (lit- mus) acid. Resorcin test showed the presence of free HCl. Tot. acidity, 94, or .343% by Amylodextrin, present. wt. Erythrodextrin, present. Free HCI, 80, or .292% by wt. Achroodextrin, present. Comb'd HCl, 12, or .043%, by Maltose, present. wt. Albumin, absent. Tot. HCl, 92, or .335% by wt. Peptones, present. Acid salts, 2, or .007% by wt. Enzymes, normal. Bile, absent. Lactic acid, trace. Mucus, moderate amount. Starch, absent. Blood, absent. Absorption and motility tests not made. 41^ SEASICKNESS Analysis of specimen taken from subject "F,** Jan, 8th, on board the Angler. Ingested at 10.30 a.m. an Ewald meal. Removed at 11.35. Amount of chyme, sivss. Macroscopi- cally the chyme was normal in appearance. During the period that the meal was retained, the subject was in wak- ing hypnosis and under the suggestion that the movements of the boat would not cause seasickness or the usual diges- tive disturbances. Reaction (litmus), acid. Resorcin test showed the presence of free HCl. Tot. acidity, 66, or .240% by Amylodextrin, present. wt. Erythrodextrin, present. Free HCl, 48, or .175% by wt. Achroodextrin, present. Comb'd HCl, 16, or .058%, by Maltose, present. wt. Albumin, faint trace. Tot. HCl, 64, or .233%, by wt. Peptones, present. Acid salts, 2, or .007% by wt. Enzymes, normal. Bile, absent. Lactic acid, absent. Mucus, moderate amount. Starch, absent. Blood, absent. The K I absorption test reacted in 12 minutes. The salol motility test did not react within the hour. The details of the tests made on subject "S" aboard the Angler^ January 8th, were as follows: At 6 a.m. the subject had breakfast, consisting of bread and butter, with milk and coffee, "half and half," sweetened with sugar. At 8.08 a.m. the ear drums were normal, no blood-vessels being visible. The blood-pressures were 130 and 130, the pulse-rates being 76 and 76. At 8.20 the boat started. At 9 the stomach-tuVje was introduced, but nothing was recovered. At 9.38 an Ewald meal was given. At 10.38 the stomach contents were removed, and the stomach irri- gated. The amount of chyme recovered was ?iii. During the period that the meal was retained, the boat rolled moderately. At 10.48 the blood-pressures were 130, 130, the pulse-rates being 08 and 72. At this time the boat was rolling considerably, but the naked eye could discover no trace of nystagmus. At 10.55 the boat was still rolling ))adly, and when the subject turned his eyes to the right or hift, a trace of horizontal nystagmus was visible. At 11.07 the blood-pressures were 125, 125, the pulse-rate being 68 and 72. At this time the boat was rolling and pitching considerably. At 11.08 the subject was given, per OS, pyloric extract equivalent to the yield of 1\ stom- achs. This extract had been made on January 5th. At SEASICKNESS 413 11.52 the blood-pressures were 125, 125, 125, the pulse- rates being 64, 64 and 64. At this time the boat was lying at anchor, but rolling considerably. At 11.57 an Ewald meal was given. At 12.08 p.m. the boat, still at anchor, was rolling badly. The blood-pressures were 120, 115, 125, 130, the pulse-rates being 64, 64, 68 and 64. About this time the subject complained of cramps in the stomach, caused probably by the pyloric extract. At 12.57 the stomach contents were removed and the stom- ach irrigated. The amount of chyme recovered was 3iiiss. At 1.23, the blood-pressures were 120, 115, the pulse-rates being 68 and 68. The patient was but little affected by the motions of the boat during the trip, and felt fairly well. At 1.25, on looking to the right or left, a trace of horizontal nystagmus was visible. There was no vertigo or sense of dizziness Analysis of specimen taken from subject "S," J^n. 8th, on board the Angler. Ingested at 9. 38 a. m. an Ewald meal. Removed at 10.38. Amount of chyme, liii. Macroscopically the chyme was normal in appearance. Reaction (litmus), acid. Resorcin test showed the presence of free HCl. Tot. acidity, 56, or .204% by Amylodextrin, absent. wt. Erythrodextrin, present. Free HCl, 34, or . 124% by wt. Achroodextrin, present. Comb'd HCl, 16, or .058% by Maltose, present. wt. Albumin, faint trace. Tot. HCl., 50, or. 182% by wt. Peptones, present. Acid salts, 6, or .021% by wt. Enzymes, normal. Bile, absent. Lactic acid, absent. Mucus, moderate amount. Starch, absent. Blood, absent. Absorption and motility tests not made. Analysis of specimen taken from subject **S, " Jan. 8th, on board the Angler. Ingested at 11.57 a.m. an Ewald meal. Re- moved at 12.57 p.m. Amount of chyme, ?iiiss. Macroscopi- cally the chyme was normal in appearance. At 11.08 the subject had received, per os, pyloric extract equivalent to the yield of li stomachs. Reaction (litmus), acid. Resor- cin test showed the presence of free HCl. Tot. acidity, 66, or .240% by Tot. HCl, 64, or .232% by wt wt. Acid salts, 2, or .007% by wt. Free HCl, 50, or .182% by wt. Comb'd HCl, 14, or .051% by Lactic acid, absent. wt. Starch, absent. 414 SEASICKNESS Amylodextrin, present. Peptones, present. Erythrodextrin, present. Enzymes, normal. Achroodextrin, present. Bile, present. Maltose, present. Mucus, moderate amount. Albumin, faint trace. Blood, absent. Absorption and motility test not made. The details of the tests made on subject "B" aboard the Angler, January 8th, were as follows: At 4.45 a.m., the subject drank 3viii of water. At 6.15 he had break- fast, consisting of bread 5viii, butter jiv, and tea fxiv with milk and sugar. At 8.11 the blood-pressures were 185, 135, the pulse-rates being lOO and 104. At 8.20 the boat started. At this time the boat was rolling consider- ably, so that the subject felt a little dizziness and heavi- ness in the head. At 9.22 the subject complained of ful- ness and lightness in the head and of a band sensation about the lower portion of the thorax (hypochondriac region). At 9.80 the gastric contents were removed, and the stomach irrigated. The amount of chyme re- covered was ^viii. It contained much thick mucus, a few old blood-stained scales, and much fat. There was a distinct odour of lactic acid. At 9.58 an Ewald meal was given. At 10.88 the blood-pressures were 125, 125, the pulse-rates being 84 and 84, At 10,40 pyloric extract, equivalent to the yield of \\ stomachs, was given ^er os. At 10.42 the boat was rolling and pitching considerably. The subject felt heavy in the head, and his face was flushed and hot, though the rest of his body was cool. At 10.49 the boat was still rolling, and pitching badly. The subject, who was sitting upright with his coronal plane parallel to the long axis of the ])oat, exhibited no signs of nystagmus. At 10,58 the blood-pressures were 115, 115, the pulse-rates being 84 and 84. At 11,05 the boat was still rolling and pitching. The subject complained of heaviness in the head. The face was flushed and hot, whilst the stf)mach felt well . At 1 1 . 1 2 the blood-pressures were 125, 125, the pulse-rates being 88 and 84. The head still felt a little heavy, but the stomach felt well. At 11.15 an Ewald meal was given. At this time the boat, lying at anchor, rolled considerably and with sickening effect. At 11,80 the blood-pressures were 140, 145, 145, SEASICKNESS 415 the pulse-rates being 84, 84 and 84. At this time the boat lay very still at anchor, and the subject felt very well. At 11.47 the boat, still at anchor, rolled consider- ably. The subject felt a sensation of warmth in the stom- ach. There were some eructations. At 11.57 the blood- pressures were 130, 180, the pulse-rates being 80 and 80. At 12.11 p.m. the boat was rocking considerably, and the subject's head felt heavy. At 12.14 the boat was steady. At 12. 15 the gastric contents were removed, and the stomach irrigated. The amount of chyme recovered was fiii. It contained much mucus. At 12.41 the sub- ject complained of pains in the lower abdomen. At 12.50 the blood-pressures were 115, 115, the pulse-rates being 80 and 80. At this time the boat was still at anchor and rolling considerably. At 1.18 the blood-pressures were 120, 115, the pulse-rates being 80 and 80. The boat was rolling slightly at this time, and the subject had a burn- ing sensation referred to the epigastrium, and a slight ache in the top of the head, with a sense of fulness in the latter. At 1.25 on turning the eyes to the left, there was slight horizontal nystagmus to the left. On looking to the right there was no visible nystagmus. Analysis of specimen taken from subject "B," Jan. 8th, on board the Angler. Ingested at 6. 15 a. m. breakfast consisting of bread Iviii, butter ^iv, tea Ixiv, with milk and sugar. Removed at 9.30. Amount of chyme, oviii. The chyme contained much thick mucus, a few old blood-stained scales, and a quantity of fat. There was a distinct odour of lactic acid. Reaction (litmus), acid. Resorcin test showed a fee- ble reaction for free HCl. Tot. acidity, 38, or .138% by Maltose, trace. wt. Albumin, trace. Free HCl, 18, or . 065% by wt. Peptones, present. Comb'd HCl, 18, or .065% by Peptonizing enzymes, dimin- wt. ished. Tot. HCl, 36, or . 130% by wt. Peptonizing zymogens, nor- Acid salts, 2, or .007% by wt. mal. Lactic acid, present. Coagulating enzymes, normal. Starch, absent. Bile, absent. Amylodextrin, absent. Mucus, in excess. Erythrodextrin, absent. Blood, trace. Absorption and motility tests not made. 416 SEASICKNESS Analysis of specimen taken from subject "B," Jan. 8th, aboard the Angler. Ingested at 11.15 a.m. an Ewald meal. Re- moved at 12.15. Amount of chyme, ?iii. The chyme con- tained a considerable amount of thick mucus and a few blood-stained flakes. At 9.58 an Ewald meal had been taken and retained permanently. At 10.40 pyloric extract, equivalent to the yield of li stomachs, had been taken per os. Reaction (litmus), acid. Resorcin test showed the presence of free HCl. Tot acidity, 44, or .160% by Amylodextrin, present. wt. Erythrodextrin, present. Free HCl, 22, or . 080% by wt. Achroodextrin, present. Comb'd HCl, 20, or .073% by Maltose, present. wt. Albumin, trace. Tot. HCl, 42, or .153% by wt. Peptones, present. Acid salts, 2, or .007% by wt. Enzymes, normal. Bile, absent. Lactic acid, absent. Mucus, in excess. Starch, absent. Blood, trace. Absorption and motility tests not made. The urine after the tests had a specific gravity of 1018 and did not react for albumin, sugar, glycuronic acid or phosphates. CHAPTER XXIX GENERAL CONCLUSIONS FROM STUDIES IN SEA- SICKNESS. PROTOCOLS The general conclusions from the foregoing observa- tions are as follows : 1. The effects of seasickness upon the organism as a whole, and upon the mechanisms of the circulation and digestion are quite analogous to those of the sickness caused by rotation, aural irrigations, and by galvanism applied over the mastoid areas. 2. Disturbances of the circulation are not the primary cause of seasickness since the chief subjective phenomena of the malady are found present, simultaneously with both efficient and impaired states of the circulatory mechanisms. Disturbed circulation, however, especially vaso-motor exhaustion, is frequently associated with sea- sickness and is an important feature of the malady. 3. Digestive disturbances, similarly, are not the pri- mary cause of seasickness, though they are constant accom- paniments and frequently the most salient and distress- ing features of the condition. The firm and persistent closure of the pylorus and the lowered acidity, as seen in the analyses of the gastric contents, are identical with the phenomena observed in rotations and aural irrigations. In extreme conditions, such as those encountered on the Lady Wolseley and on the Quatre Freres, there was com- plete absence of acids and digestive enzymes. Prolonged exposure to conditions that cause seasickness are undoubt- edly injurious to the digestive organs, and more especially to the stomach which may become seriously impaired in its functions and even the seat of organic disease. Thus subject "B" undoubtedly developed during the various journeyings a mild grade of chronic gastritis. The irregu- 417 418 SEASICKNESS lar mode of life and the alcohol taken by him during the period extending from July 10th to July 27th, were prob- ably factors in the causation of his gastritis, but the con- tinually repeated perturbations of the nervous mechanisms controlling the general circulation as well as gastric secre- tion and motility were the chief cause. 4. Disordered states of the circulatory and digestive mechanisms when once initiated become powerful second- ary sources of irritation. Thus injudicious muscular ex- ertion, the retention of stagnant gastric contents or the introduction of improper food into the rebellious and highly irritable stomach tend greatly to over-irritation and exhaustion of the gastric vagal, vaso-constrictor and other centres. 5. The ventilation and temperature of the cabin are also important secondary factors in seasickness, the cool, well-ventilated room tending greatly to restore the individ- ual, whilst a hot stuffy cabin may cause disturbances of the circulatory and digestive mechanisms as distressing almost as those which occur in seasickness though caused primarily in another way. 6. Cold bathing and the employment of methods or drugs calculated to enhance directly vaso-motor efficiency by stimulation of the nervous centres are contraindicated where the circulatory depression is due to exhaustion from over- irritation. Muscular exertion in these condi- tions is therefore injurious. At a later stage, when there is evidence of restoration of function on the part of the nervous centres, and when there is reason to believe the stage of exhaustion is past, mild exercise, massage and hydrotherapy are of undoubted benefit. The last of these measures, however, has to be resorted to with the greatest caution and only after special study of the peculiarities of the individual's circulatory mechanisms. For even more imperative reasons drugs and procedures that tend to depress or over-stimulate the vaso-motor mechanisms, or indeed any of the medullary centres, are contraindi- cated. Drugs that depress the psychic and higher centres, such as bromides and alcohol, are on the whole of ques- tionable benefit and alcohol in excessive quantities is distinctly harmful to the circulation. The effects of mor- phin, cocain, hyoscin, and nitroglycerin in rotation SEASICKNESS 419 sickness were such as to offer little hope of usefulness in seasickness. They were, therefore, excluded from the list of possible safe and beneficial measures. 7. Psychic depression, and disagreeable sights and odours are also important secondary causes of distress. Hence sunshine and clear weather with pleasant surround- ings and agreeable companionship are of benefit. 8. Since exhaustion of the nervous centres is charac- teristic of seasickness at its height, mental effort, especial- ly when coupled with the use of the eyes as in reading, may be particularly harmful. Quite frequently during the progress of recovery from an acute spell of seasickness subject "B" has retarded his recovery by thinking too intently over his future plans or by emotional reading or by indulging in a train of emotional thought. 9. Recovery from seasickness means the adaptation of the individual's organism to the rhythm and extent of the movements of that particular boat upon which he has been travelling. Hence a traveller may have recovered from seasickness upon an ocean liner and later fall a victim to the motions of a Channel steamer. Even marked aggra- vation of the movements of the boat upon which an indi- vidual has recovered may cause a return of all the phe- nomena of seasickness. This frequently occurs under varying conditions of weather. Frequently individuals who were for the greater part of their lives victims of seasickness lose their suscepti- bility. On the other hand persons who have been im- mune may, at some time or other, develop a susceptibility for the malady. This is one of the mysteries which sailors and others hurl at the medical man who presumes to know anything about seasickness. However, bilateral degeneration of the eighth nerve which so frequently oc- curs in advancing years and earlier in certain families, accounts for the first class of cases. If the degeneration progresses irregularly so that the nerve on one side alone is affected or is affected to a greater or less extent than the nerve on the other side, we have a condition of rela- tive heightened irritability of the vestibular nerve endings in one labyrinth which, as we have seen under aural irriga- tions, is the great cause of disturbance of the vestibulo- cerebellar mechanisms involved in equilibration. Actual / 420 SEASICKNESS cases of this kind have been studied, but the details will be related in another chapter. 10. Atropin, more especially in combination with strychnin, is effective in combating the subjective symp- toms of seasickness, especially the nausea and the gastric and cerebral discomfort, but it has no direct effect in pro- moting gastric secretion and digestion, and does not pre- vent the incoordination or disturbances of equilibrium in- cidental to seasickness although it tends to eliminate the associated sense of vertigo. 11. Although the tests made on January 8th afford, in themselves, no satisfactory basis for conclusions as to the effect of hypnotic suggestion in seasickness, the results obtained, especially when taken into consideration with the results obtained from hypnotic suggestion in aural irrigations and rotations, indicate that hypnotic sugges- tion is not a very efficient means of offsetting or prevent- ing the effects of seasickness even during actual hypnosis, not to mention the rapidly waning influence of post- hypnotic suggestion. It is to be regretted that further opportunity has not so far presented itself for the study of this important phase of the subject. 12. The fact that extracts made from the various por- tions of the gastric mucous membrane were about equally efficient (in some instances the "intermediate extract" appearing to be the most efficient of the three) in stimu- lating the flow of normal gastric juice seems to indicate that the effects of the extracts were due to the contained substances with secretogogue action rather than to gastric secretin developed by decoction. This fact was more ap- parent in subsequent tests made on shore and reported else- where. In these tests it was found that ordinary broth was as efficient, and at times more so than decoctions of pyloric or fundic mucous membrane. Following the ad- ministration of these extracts no appreciable alterations in blood-pressure or pulse-rate were observed which could be safely attributed to the extracts. It seems reasonable, therefore, to conclude that gastric secretin is inert when administered ^er os (possibly, because of changes induced as the decoction reaches the stomach) and that the effect of decoctions of the gastric mucous membrane given ^jer OS in promoting the flow of normal gastric juice is due to SEASICKNESS 421 other substances (secretogogues) contained in the decoc- tions. In the matter of enhancing the flow of gastric juice, therefore, decoctions of gastric mucous membrane have, when administered j^^^r os no advantage over ordi- nary meat-extracts, such as beef tea, soup, etc. Decoc- tions of gastric mucous membrane seem however to aid absorption and to promote, to some extent, gastric and in- testinal motility. STUDIES IN SEASICKNESS Protocol 1. — Observations made on subject "B" aboard the steamship "Taurus" Dec. 27, 1908. Temperature of air 60° F. Time, a.ni. 8:25 8:37 8:45 9:30 10:00 10:30 11:05 12:30 Pulse- Blood- rate, press. 96 96 92 92 80 76 68 68 68 72 68 64 64 120 120 115 120 110 105 105 95 105 100 110 110 110 Remarks. On boat before starting. < < < < < < After start. Slight roll. Weather calm. Slight headache. < < Pulse slightly irregular. Headache. Face flushed. Conjunctivae slightly congested. At anchor. Protocol 2.— On "B " aboard steamer "Angler," April 4, 1909. 8:05 8:10 8:11 20 22 26 84 80 88 80 80 80 84 8 : 28 80 8 : 29 80 8 ; 32 88 105 110 115 125 125 120 120 125 125 120 125 On boat after slight injury of hand. Feels well in fresh, cool air. Boat started. Conjunctivae slightly congested. Feels well. Draught on right shoulder. Dizzy ; slight lump-sensation ; fulness in head. Well again, but some fulness in head still. << << << << << Feels well, but has fulness in head and is slightly dizzy. 422 SEASICKNESS Remarks. Taking deep breaths. Conscious of heart action after slight exertion, viz. : standing on seat. Frontal headache. Fulness in head. Con- junctivae congested. Face pale. Slight nausea ; stomach distress. Draught on shoulder. Feels as if about to sneeze. Dizzy and mentally depressed. < < < < < < Feels well. Sight of water rushing by dis- tresses. Cold on one side because of draughts. Face pale. Conjunctivae congested. Pupils normal. Face pale. Cheeks warm. Feels well. Eructations. Artery contracted. Feels depressed. Lump-sensation. Fulness in head. Eructa- tions. Nauseated. Sense of fulness in ears. Boat steady. Conscious of respiratory movements. Sense of tension in scalp over occiput. "Lump-sensation" in stomach. Abnormal sensation (fulness) in left ear. Head heavy and full. "Lump." Dizzy. Uninterested. 9 : 06 76 125 Taking deep breaths. Nauseated. Not so depressed now. 9 : 12 76 125 "Lump. " Sense of weight in frontal region. Conscious of stomach contractions. 9:13 72 25 Eructations. "Lump. " Nausea. 9 : 15 76 125 Moving head from side to side aggravates nausea. 9 : 17 72 125 Dizzy as boat lurched. 9:25 80 120 "Lump." Dizzy. Arteries contracted. 9 : 41 72 125 Sick feeling in head. Deep breaths. Noise of water distresses. 9:46 68 125 Fulness about ears as if head was in the grip of something. 9:52 68 125 "Lump." Eructations. Boat rolling. Sa- liva increased. 9 : 55 68 120 Conjunctivae congested. Face not so pale now. Yawning. 9:57 68 120 Boat rolling and pitching. Dizzy. Arteries contracted. Deep breaths. Yawning. Eructations. 10 : 00 68 120 Tobacco-smoke inoffensive to smell. Sub- ject has been out on bow. Time, '. a.m. 8:33 Pulse- Blood- rate, press. 76 125 8:35 76 72 120 120 8:37 8:38 80 76 120 125 8:39 8:40 8:41 76 72 80 120 120 125 8:43 8:44 72 76 120 120 8:49 72 120 8:51 8:56 76 72 125 125 8:58 76 120 9:00 9:01 76 72 125 125 9:03 9:04 76 76 125 125 SEASICKNESS 423 V^^' ^JiT^}^' Remarks. a.in. rate, press. 10 : 02 68 120 Photophobia. Sneezed. Muscular tremors. Dizzy. Difficulty in balancing. Mental effort causes distress in head. 10 : 03 68 120 Arteries contracted moderately. 10:11 68 130 Feels well. Slight "lump." Arteries con- tracted. 10 : 13 68 135 Arteries much contracted. 10:15 68 125 Feels well. 10 : 17 72 125 Arteries contracted. Conjunctivae con- gested. Pupils normal. 10 : 20 64 125 Sense of weight in head. Boat rolling and pitching. 10 : 22 64 130 Arteries contracted. Deep breaths. Fron- tal headache. 10 : 24 72 125 Lightness in head. Feels well. 10 : 37 64 125 Boat stopped. Feels well. Air cold. 10:38 68 135 Tobacco-smoke not disagreeable but not pleasant. 10 : 42 64 125 At anchor. Fulness in head. 10 : 10 64 125 Slight eructations. Deep breaths. 11:15 64 125 12 : 00 68 115 Feels well. Hands cold. Face flushed and warm. 12:04 '68 125 Feels well. 1 : 40 72 120 Ate an orange. Feels refreshed. Boat roll- ing. 1:43 68 125 Fulness in head. Arteries moderately con- 1:46 68 125 Strolled on deck. 2 : 22 68 120 Feels well. Pupils and conjunctivas normal. 2 : 25 68 125 Artery moderately large. Stomach and head feel well. 2 : 27 68 125 Feels well in every way. 2 : 28 64 125 Weighed anchor. Boat rolling some. 2 : 30 68 125 Fulness and lightness in head. Feels fairly well. 2 : 47 68 125 Before starting homeward feels well. 2 : 49 68 125 Not yet started. Artery normal. 2 : 52 72 125 Boat rolling. Fulness in head. 2:58 68 125 Artery contracted somewhat. Feels well. 3:01 64 125 3 : 03 68 125 3 : 04 64 120 Boat started homeward. Eructation. 3 : 05 64 120 Headache. Face flushed. Feels well. 3 : 06 64 120 Fulness in head. Face hot. 3 : 09 64 120 Sense of weight in head. Feels well. 3 : 12 68 120 Sight of passing water distresses. 3:30 68 125 Odour of tobacco-smoke slightly disagree- able. 424 SEASICKNESS Protocol 3.— On "B" aboard steamer "Angler," May 30, 1909. Time, Pulse- Blood- Remarks. a.m. rate, press. «"«.«. 7 : 46 80 120 On boat resting. 76 120 76 120 76 120 72 115 " 76 120 76 120 76 115 " 76 120 76 120 76 120 76 125 " 76 120 76 125 8 : 14 Boat starts. Weather fine. Boat steady. 8:15 72 120 72 130 80 125 76 115 72 120 72 120 8 : 21 Ewald breakfast 8:22 76 120 76 125 80 120 76 120 8:45 76 120 "Lump-sensation." Saliva increased. 72 120 Fulness in head. Eructations. 76 120 72 120 72 120 72 115 72 115 9 : 08 76 110 Dizzy. Fulness in head. Saliva increased. 72 110 72 110 72 105 9:14 72 110 Frontal headache. "Lump-sensation" in stomach. 72 110 72 110 72 105 9 : 19 76 110 General headache. Fulness in top of head. 72 105 68 115 76 115 76 HO Ache over eyes. Pain in eyeballs. SEASICKNESS 425 Time, Pulse- Blood- Remarks. a.m. rate. press. 76 115 "Lump-sensation. " 72 115 9:32 76 115 Boat rolling some. Headache. Eructations. 72 115 9:35 76 115 Eructations. Disinclined for work. 72 110 68 110 68 110 9:53 68 115 Frontal headache. 9:55 72 110 Dizzy. Lump-sensation. 76 115 72 115 . 68 115 9:59 72 110 Feels as if about to sneeze. General head- ache. 72 115 Disinclined for work. Would like to lie down. 10:14 Boat at anchor. 10:24 64 ii5 Stomach contents withdrawn. 76 120 76 120 80 120 10:32 76 120 Headache. 76 120 76 120 10:36 76 120 Boat rolling at anchor. 76 120 76 120 72 115 72 110 72 110 72. 110 68 110 10:47 72 110 Diffuse headache. Looks worried. 68 105 Boat still at anchor and rolling-. 76 105 72 110 68 110 76 115 10:54 72 110 Lunch of beef sandwiches and oranges. 72 110 11:21 80 110 Boat starts. Much rolling. 72 110 Dizzy. Fulness in head. 72 110 Headache. 76 110 76 110 72 115 72 110 72 105 76 115 72 115 426 SEASICKNESS Remarks. Time, Pulse- Blood- a.m. rate. press. 68 115 72 115 11:35 76 115 12:00 72 115 72 110 72 110 72 105 80 115 76 115 76 115 76 115 80 110 76 110 76 115 76 115 76 110 p.m. 76 115 12:22 76 115 76 120 76 115 72 110 76 115 76 120 80 120 76 120 76 125 12:31 76 120 84 125 80 125 80 120 80 120 80 120 12:38 80 120 12:39 76 120 80 120 76 115 80 115 80 115 76 110 76 110 12:46 76 115 12:59 80 110 76 110 76 110 80 110 80 110 80 105 80 115 Boat at anchor. Walked deck from 11:35 to 12 : 00. Boat rolling at anchor. Headache. Arteries contracted. Annoyed by intermeddler. Boat starts. Headache. Boat rolling much. Sight of moving water distresses the eyes. Dizzy. Headache. Pain in back of the neck on right side. Arteries contracted. Pain in left of epigastrium. Headache. Pain in eyeballs. Boat rolling and pitching badly. Boat at anchor again. Rolling at anchor. Pain in epigastrium. Sense of constriction about lower part of chest. Dizzy. Headache. After walking about. "Lump-sensation. " Headache occipital and frontal. SEASICKNESS 427 Time. Pulse- Blood- Remarks, p.m. rate, press. 76 110 80 95 1 : 10 80 100 Arteries dilated. 80 100 76 105 76 105 80 105 Fulness in head. Nausea. 80 105 80 95 Arteries dilated. 80 90 80 90 80 90 Pain in epigastrium. 80 90 Sense of band about lower part of chest. 80 100 1:22 80 90 80 90 80 95 80 105 Biparietal headache. Feels very tired. 80 105 80 95 80 95 76 85 1 : 31 80 95 80 95 76 95 76 95 Headache. Dizzy. 76 105 76 100 Rolling much. 76 110 Arteries contracted. 76 110 76 110 72 110 Headache. Dizzy. 1 : 44 76 115 Annoyed by intermeddler. 80 110 Angry and irritable. Muscles trembling all over. 76 115 80 100 80 95 80 95 Severe headache. 76 100 Eructations. Stomach feels well. 80 100 1:53 80 95 Headache. 80 95 80 100 80 100 80 90 Taking deep breaths. 80 100 Frontal headache. 2:00 84 90 Headache. Eructation. 76 90 Stomach feels well. 80 95 428 SEASICKNESS Time, Pulse- Blood- Remarks, p.m. rate, press. *vciiic«n.o. 2:05 80 95 Boat starts. 80 100 2 : 07 80 100 Boat stops. 84 100 Feels weak. Perspiring freely. 84 95 Eructation. Arteries dilated. 84 95 Tired and weak. 84 95 Would like to rest head on something. 2 : 27 76 100 Walked about from 2 : 14 to 2 : 27. 76 100 Felt weak and tremulous in muscles. 72 110 General wretchedness. 72 110 Boat steady and still at anchor. 76 110 80 110 2 : 35 84 115 Boat started for home. 76 105 80 95 80 100 80 100 76 90 80 100 Headache. 80 90 Taking deep breaths. 76 90 80 95 80 100 80 100 80 100 80 100 2:55 76 100 Headache. 76 100 Odour of tobacco-smoke offensive. 80 100 3 : 00 80 100 76 100 Boat moving smoothly. 80 105 Fresh cool breeze. Headache. 72 100 76 100 72 100 76 100 76 105 76 105 3 : 15 80 100 Cool breeze on occiput. 76 100 80 95 Headache persists. 80 95 80 95 80 90 76 110 80 110 Arteries contracted. 80 110 Feels better and brighter. 3 : 23 76 110 Boat going smoothly. 76 110 Headache almost gone. SEASICKNESS 429 Time, Pulse- Blood- Remarks, p.m. rate, press. xvcuic«n.o. 84 105 80 100 Headache bad again. 80 100 80 100 Pain through eyeballs. 76 100 3:30 80 110 72 110 Headache. 72 110 Not so tired now. 84 110 76 105 Occipital headache. 3:36 80 100 3 : 44 68 110 After walking in the open air. 76 100 80 110 Throbbing frontal headache. 76 100 72 110 76 110 72 100 3:50 76 95 Coronal headache. 76 110 76 110 3 : 55 76 105 Pain in back of neck, right side. 76 105 76 100 Arteries contracted. Face pale. 80 100 Deep breaths. 76 105 Pain in occiput and right side of neck. 4:00 76 105 Feeling wretched. 4 : 01 80 110 Right hemicrania, especially over right, su- perior curved line of occipital bone. 76 105 76 105 4 : 05 80 105 Taking deep breaths. 76 105 Dull ache in eyeballs. 76 100 Looking at things causes occipital ache. 76 100 76 95 4 : 10 80 100 Pain all over scalp, but worse on right side. 72 105 80 100 Sweating. Eructations. 76 100 Would like to lie down. 80 100 Would like to let eyelids droop. 4 : 15 80 100 Closing eyes causes distress. 76 100 76 100 76 100 80 100 Lump-sensation in stomach. 72 105 Eructations. 76 100 Headache in right parietal region. 4:21 76 100 4 : 26 76 110 After walking about. 480 SEASICKNESS Time, Pulse- Blood- p.m. rate. press. 72 110 4:28 72 110 76 110 4:30 76 100 72 105 4:32 76 105 76 105 76 105 76 110 4:35 76 105 76 115 76 105 4:38 76 110 76 100 76 100 . 76 100 80 100 4:42 72 115 80 110 4:44 80 100 80 100 80 110 4:46 76 110 4:47 , , • • • Remarks. Headache across top of head. Lump-sensation. Deep breaths. Occipital headache. Sweating. Feels weak. Lump-sensation marked. Coronal headache. Headache not so bad. Subject brighter and more cheerful. Lump-sensation persists. Taking deep breaths. Sinking feeling in stomach. Arteries contracted. Arteries dilated. Lump-sensation. Feels sick. Occipital headache in region of hat band. 6:36 Just before landing. Some congestion around the periphery of drum membranes and along the handle of the malleus. Occipital headache persists, i.e., nearly two hours after landing. Protocol 4. — On " B " aboard tlie motor launch " Maggie," May 31, 1909. Trip lasting 1 hour. 5:25 96 105 96 105 96 100 72 130 80 125 84 120 76 120 80 120 84 120 Standing after hard day's work. Feet heavy and tired. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. SEASICKNESS 431 Pulse- Blood- rate, press. Remarks. 84 120 Lying supine. Face flushed. Pupils moder- ately dilated. Room dark. 108 105 Standing. Pupils normal but illumn'n better. 88 105 92 105 96 105 Boarded launch and started. 88 105 Fresh cool breeze. Vibration in feet. Feels well. 76 100 84 105 84 110 Arteries small. Feels well. Water smooth. 88 110 84 110 Feels fresh and cool in breeze. 88 95 Taking deep breaths. 92 95 Slight feeling of distress in head. 92 95 Perspiring along spine. 88 95 Lump-sensation. Feels a little sick. 88 95 88 95 88 90 88 115 After turning north. Boat pitching much. 88 100 Lump-sensation. Taking deep breaths. 88 95 Head feels well. 88 105 Arteries contracted. Head feels cool. 88 105 Slight lump-sensation. Feels well. 88 110 Arteries contracted. 84 100 Lump-sensation. 84 95 Slight distress in head. 80 100 Lump-sensation. Eructations. 84 95 Arteries small. 84 95 80 95 80 95 Cool breeze. Feels well but has lump-sen- sation. 88 95 Vibration does not annoy now. 80 90 Arteries much contracted. 76 95 Taking deep breaths. 80 95 Feet tired, heavy and aching. 80 95 Lump-sensation. 80 100 " Taking deep breaths. 80 105 Just before landing. 80 105 Landed. 76 115 1 min. after landing. 92 115 2 " Feels well. 80 115 Drank ginger ale, Iviii. 84 120 1 min. later. 88 115 2 432 SEASICKNESS Protocol 5. — On "B" aboard steamship "Caledonia.'* Transatlantic trip commenced June 26, 1909. Time, Pulse- Blood- Remarks. p.m. rate. press. 2:07 84 130 Lying, after exertion, on board Caledonia. 84 125 4 < 76 125 << 72 125 ( ( 2:22 72 125 Boat starts. 84 120 < ( 88 115 Standing. 2:23 84 115 < < 88 115 < ( 2:55 68 115 Lump-sensation in stomach. 3:09 72 115 Lying. Odour of tobacco-smoke offensive. 72 110 Saliva increased. 72 110 " Occipital headache. Arteries small. 72 110 " Ache behind right mastoid. 3:20 76 95 Standing. Feels well. Fresh breeze from port-hole. 76 95 Standing. 84 100 < ( 80 100 (< Head feels well. 88 95 << Slightly hungry. 80 95 < ( Eructations, 3:30 80 90 Standing. Masklike feeling in scalp. 4:40 84 100 < ( Tobacco-smoke not offensive. 84 100 << Slightly dizzy. 4:44 80 100 <( 4:45 68 110 Lying. Arteries dilated. 72 110 << (< 68 110 «( «< 68 110 <( 68 105 (( 68 105 <( 68 105 << 68 105 ( ( 4:55 80 90 Standing, small. Pulse-rhythm irregular. Arteries 76 95 Standing. 84 95 < < 5:00 84 100 < < 5:19 88 90 < < Slightly dizzy and faint. 5:21 80 80 95 95 Standing. < < 7:00 , ^ • • • Dinner. K I aborption test reacted in 2 hours 17 min. Salol motility test reacted in 2 hours 22 min. 7:23 76 115 Lying. 72 115 Feels well . Lying. SEASICKNESS 4Be Time, Pulse- Blood- p.m. rate, press. 8:14 8:15 8:21 8:32 8:39 8:40 8:56 10:41 72 72 72 72 76 72 72 72 76 80 76 76 76 72 V2 72 76 68 76 72 72 76 72 84 84 88 88 88 84 68 68 76 68 72 88 92 84 84 76 115 115 125 125 125 120 115 115 115 115 120 115 115 115 115 115 115 115 115 115 110 115 115 115 95 100 90 100 100 120 115 115 115 115 95 85 85 95 95 Remarks. Lying. Conscious of stomach movements. Slight lump-sensation. Head feels well. Arteries larger. Slight lump-sensation. Saliva free all through K I tests. Lying. ach. Lying. Biparietal headache. Artery large. Marked "lump-sensation" in stom- Lump-sensation marked. Standing. Eructation. Flatus. " Momentary lightness in head. " Lump-sensation not so manifest. Lying. Lump-sensation in throat and stom- ach. Lying. Port-hole has just been closed. Standing. Sweating. Cabin warm. Went to bed. Slept well but dreamed much. Protocol 6. — On "B." Second day at sea on "Caledonia," June 27, 1909. a.m. 6 : 44 72 105 Lying in bed before arising. 72 105 6:46 68 110 484 SEASICKNESS Time, Pulse- Blood- Remarks. a.m. rate. press. 6:47 88 90 Standing. Feels well. 84 100 Cool breeze from port-hole. 6:49 84 105 7:05 88 95 " 3 min. after cold plunge. 84 95 7:07 88 95 7:40 68 115 Lying. Feels well. Face flushed. 72 115 Pupils moderately dilated. 72 120 " Conjunctivae normal. 68 130 68 125 72 125 7:47 68 125 7:55 84 105 Standing. 84 100 80 105 76 95 7:59 72 100 9:56 92 105 Feels well, but is a little tired. 88 100 92 95 10:04 92 95 10:05 76 120 Lying. Congestive headache. 80 120 " Pupils slightly dilated. 80 120 " Slight lump-sensation. 76 120 " Right frontal headache. 76 125 80 120 " Slight stomach distress. 10:11 80 120 10:18 76 115 Slight headache. Arteries dilated. 10:20 80 90 Standing. Eructation. Lump-sensation less. 10:22 92 95 < < p.m. 92 95 " Arteries moderately dilated. 12:21 76 110 ** After walking in cool breeze. 76 105 " Lump-sensation in stomach and throat. 76 105 Standing. 76 110 < < 12:25 72 105 12:57 72 95 " After making analysis in cabin. 72 95 " Arteries small. 1:00 72 95 " Lump-sensation. 1:01 68 110 Lying. Fulness in head. Artery moderately large. 68 105 Lying. 64 105 < < 68 115 < < 1:07 68 110 < < 1:08 72 85 Standing. Blood-pressure rose to 120 from effort, but instantly fell to 85. SEASICKNESS 435 Time, Pulse • Blood p. m. rate. press. 72 90 1 :10 76 95 2 :02 •• ... 4 .15 68 105 68 100 72 100 4 21 68 100 4 36 68 100 68 100 64 100 64 95 4 41 68 100 4 42 68 110 64 110 60 115 4 45 68 120 4 46 60 115 60 115 64 120 60 115 4 56 64 115 4 57 64 130 68 105 68 100 5 00 68 100 8 50 68 90 72 95 8 52 68 95 8 53 64 105 . 60 105 60 115 60 110 60 110 60 110 9 03 60 115 9 04 72 125 72 90 68 95 72 95 9 :08 72 90 9 :35 , , • • • Remarks. Standing. Dinner. K I absorption test reacted in 21 minutes. Standing after walking in cool breeze. Arteries small. Arteries small. Feels well. Lying. Feels well. Fulness in head. Slight headache. Lump-sensation in stomach. Right occipital pain. Feels sleepy. On standing up. Standing. Feels a little better standing. After walking in the air. Feels well, but is tired. Lying. Face flushed and hot. * * Conscious of respiratory movements. " Lump-sensation in stomach. " Pupils slightly dilated. " Conjunctivae normal. *' Feels sleepy. On standing up. Blood-pressure instantly fell to 90. Standing. Sleepy. " Arteries moderately large. " Lump-sensation occasionally. Went to bed. Was awakened by indigestion, which soon disappeared, 436 SEASICKNESS Protocol 7.— On "B." Third day on "Caledonia." 28, 1909. June Time, Pulse- Blood- Remarks. a.m. rate. press. 7:05 80 115 Lying in bed. 64 115 < < < i 7:07 64 115 < < <( 7:08 80 105 Standing. 80 110 " 7:11 80 105 < ( 7:12 80 95 < ( Before cold tub. 7:13 72 140 Lying after getting into cold tub. 7:13i 72 135 < < Still in cold tub. 8:00 72 105 Standing after dressing. 8:01 76 100 < < Feels well. Arteries small. 8:02 68 120 Lying. 64 125 < < 64 120 < < 8:05 64 120 < < 80 110 Standing. Arteries small. 76 105 < < 76 110 < ( p.m. 1:07 72 100 ( < after sitting in the air. 72 100 <( 1:10 72 100 t* 1:11 64 105 Lying. 1:14 64 110 < < 1:15 64 110 Standing. Feels well. 76 110 4 72 100 t 1:17 72 115 H 1:56 76 110 < after dinner. 76 115 ( 80 105 < 1:59 76 105 < 3:40 68 76 76 76 105 110 100 100 ( < ( < after being on deck. 80 120 < Sneezed. 80 120 < 80 120 < 30 UO f 76 105 ( 3:55 76 105 M 3:56 72 115 Lying. Face flushed and hot. 72 115 ( < Feels sleepy. 68 115 *t Conjunctivae slightly congeste(| 68 115 1 1 Pupils slightly dilated. 4;00 64 105 H After falling asleep, SEASICKNESS 437 Time, Pulse- Blood p.m. rate. press 4:01 64 100 64 105 4:10 64 105 60 110 60 105 60 105 64 105 64 110 64 110 64 110 60 105 60 110 64 105 64 105 64 110 64 110 64 105 64 105 4:26 64 105 4:27 60 110 60 110 64 110 60 105 60 105 60 105 60 105 60 105 60 105 60 105 60 105 60 105 60 105 60 105 4:49 64 110 4:50 60 100 60 105 60 105 4:54 60 110 60 110 4:58 72 110 68 105 68 105 5:03 68 110 68 110 68 110 68 110 68 110 ^:12 76 100 72 100 78 m Remarks. Lying. Partially roused. Asleep ; face flushed. Snoring. Face deeply flushed. Not snoring. Snoring. Face deeply flushed. Snoring, Face flushed. asleep. Face flushed. Snoring. Deep breaths. Awake. Skin warm on awaking. Half awake. Standing. Cool breeze on body. Arteries small, 438 SEASICKNESS Time, Pulse- Blood- p.m. rate, press. 5 : 15 72 100 10 : 23 76 105 76 100 10 : 25 72 100 10 : 26 68 115 64 115 64 115 10:28 64 115 Remarks. Standing. Lying. Face flushed and hot. " Pupils moderately dilated. " Conjunctivae normal. Protocol 8. -On "B," aboard the "Caledonia." June 29, 1909. Fourth day. a.m. 7:00 12 13 7:15 7:29 7:35 7:36 7:40 10:06 10:12 10:13 76 72 76 84 92 84 68 68 68 64 64 80 84 72 76 84 68 76 80 88 84 76 68 68 64 72 72 72 68 76 68 72 72 72 68 72 120 120 120 110 110 105 130 130 130 125 130 120 95 110 110 105 90 95 105 100 105 100 120 120 115 120 130 120 120 120 120 120 120 120 125 120 Lying in bed. Cold breeze on arms. " " Weather foggy and cold. " " Ship rolling much. Standing in cool breeze. Lying after cold tub. " Cool breeze from port-hole. Standing. in cool cabin. Breeze from port-hole. Lying. Fulness in head. Occipital headache. Weather cold. Dark day. Feels chilly. Sleepy. Disinclined to get up. SEASICKNESS 439 Time, Pulse- Blood- a.m. rate, press. Remarks. 10:45 10:46 10:52 p.m. 12:35 12:39 12:&1 12:53 72 72 76 76 72 72 80 84 80 84 80 84 80 76 76 80 80 80 72 76 68 64 64 60 60 60 64 68 68 68 72 76 76 76 1 : 09 72 6 : 48 76 84 84 84 88 6 : 56 84 6 : 57 80 80 76 76 7 : 04 76 7:05 88 84 01 02 04 05 120 120 120 125 125 120 110 110 100 100 105 100 100 90 90 90 95 95 95 100 125 125 125 125 125 125 120 120 125 120 115 90 90 90 90 105 105 105 105 110 110 130 130 130 125 125 120 100 Lying. Standing. Headache better. Some fulness in head still. Slight headache. Feels chilly. Occipital pain and tenderness. Eyes heavy, weak and aching. Paraesthesias of scalp. Fulness in mastoid areas. Forehead hot. Hands cold. Lying. Drowsy. Fulness in head. Face flushed. Feet cold. Headache. Face flushed. Standing. Headache better. Some fulness in head. Eyes ache and feel heavy. Absorption and motility tests re- acted in 2 hours 16 min. After dinner. Feels well. Lying. Fulness in head, especially at vertex. Face flushed. " Pupils normal. Standing. Fulness in ears. 440 SEASICKNESS Time, Pulse- Blood- Remarks. p.m. rate, press. 76 105 Standing. Frontal headache. 84 100 " Dizzy. Lump-sensation in stom 88 110 " [ach 84 110 88 110 7:17 84 110 10:10' 72 105 " After walking. 76 105 " Feels well. Skin in a glow. 10 : 13 76 105 10:14 76 125 Lying in bed. 72 130 < < 68 125 << 10:17 68 130 < < Slept well. Port-hole closed because of rough weather. Protocol 9.— On "B." Fifth day out on "Caledonia." June 30, 1909. 6: 50 64 125 68 120 68 120 68 125 7: 00 68 125 7: 01 80 120 72 100 76 110 76 110 7 '05 76 110 7 16 76 110 76 110 76 105 7 20 76 110 7 .21 68 125 68 125 64 125 7 :25 64 125 7 :26 76 125 76 115 76 110 80 120 72 120 7 :31 76 110 9 :48 80 105 88 100 84 100 80 100 9 :58 80 100 Lying in bed. Feels well. Slight coryza. ' ' Face and hands slightly eczematous. Standing. Arteries very small. 2 min. after cold tub. Lying. Slight fulness in head. Standing. Ship rolling considerably. Slight headache. SEASICKNESS 441 Time, Pulse- Blood- Remarks. a.m. rate. press. 9:59 72 120 Lying. Feels sleepy. 72 120 < < 72 120 < < 10:02 68 120 Ship rolling and pitching. 84 105 Standing. Slight headache. 84 115 Feels heavy and dull. 80 100 ' ' Lightness in head. 84 100 10:07 84 105 p.m. 1:14 76 95 " Before dinner. Arteries small. 80 105 1:16 72 95 2:06 80 100 After dinner. Feels well. 2:07 80 105 ' ' Absorption test reacted in 3 hours 24 minutes. 5:55 64 95 " Feels well, but has indigestion. 72 105 " Lump-sensation. 68 105 5:58 68 105 10:05 76 95 Slight headache. Lump-sensation. 72 105 " Fulness in ears made worse by moving head. 72 95 68 95 72 100 68 95 68 100 68 95 68 95 " Lightness and fulness in head. 68 90 72 100 " Feels as if top were being raised off head. 76 95 " Indigestion. 10:21 72 100 " Eyes aching. 10:22 64 120 Lying. Saliva increased. 56 115 " Lump-sensation in throat. 64 115 " Fulness in ears, especially in right. 60 115 10:26 60 115 " Ship rolling and pitching. 10:30 60 115 10:31 60 115 " Ship rolling mainly. 10:32 60 115 Standing. Lump-sensation comes and goes» 68 105 " Tinnitus aurium. 72 105 " Burning sensation in stomach. 72 105 68 95 72 95 " Lump-sensation in tbroat. 76 100 10:40 ^ 105 ** Stomach irrigated. 442 SEASICKNESS July 1, 1909. Time, Pulse- Blood- Remarks. a.m. rate. press. 12:15 72 110 Standing. Feels well. 72 100 " Burning sensation in stomach still 72 100 12:18 76 100 < < 12:19 64 120 Lying in bed. Lump-sensation in throat. 56 120 1 < << 60 120 ^^„,T,„ a.m. rate, press. Remarks. 64 120 Lying. 64 120 7:06 68 120 7:07 84 105 Standing. Feels well. 88 105 80 105 84 105 7:11 80 105 7 : 54 72 120 Lying. After packing suit-cases. 76 120 68 120 7:57 72 120 7 : 58 96 95 Standing. For a moment blood-pressure was at 115. 92 90 Standing. 92 90 92 95 8 * 02 92 95 * * 9:40 112 85 " Cabin very hot and close. 112 90 •* Sweating. 108 90 " Lightness in head. 108 90 108 80 '* Arteries variable, i.e., small at times and at others large. 9:49 104 85 9 : 50 76 135 Lying. Headache. Fulness in head. 80 125 " Respirations 24. 80 120 " Feels well. 76 115 80 120 " Pupils normal. 80 115 84 115 10:01 84 115 10 : 02 112 90 Standing. Arteries moderately large. 112 85 " Conscious of respiratory move- ments. 108 90 108 85 104 90 108 90 108 100 10:09 104 90 11:25 88 105 " After walking in cold air (57° F.). 84 95 •* Feels well. 88 95 88 85 11:29 88 90 11 : 30 84 105 Lying. Arteries larger than when standing. 76 105 11:32 72 105 "' Respirations 20, 22. 452 SEASICKNESS Time, Pulse- Blood a.m. rate. press 11:33 76 115 68 115 11:37 76 115 11:38 84 100 84 95 84 90 80 85 92 80 84 85 84 90 11:45 84 95 p.m. 12:15 100 85 92 85 92 85 12:19 96 85 12:20 92 125 80 120 80 115 80 110 76 115 12:'28 80 120 12:29 76 85 92 80 88 85 96 85 96 85 92 85 12:35 92 85 12:47 84 12:48 96 12:49 92 12:50 92 12:51 80 3:33 72 95 72 95 72 90 76 95 72 90 84 90 80 85 3:40 76 95 3:41 76 115 72 115 72 110 3:46 68 110 3:47 84 95 80 90 84 95 Remarks. Lying. standing. Feels well. Arteries moderately dilated. Feels well. Arteries moderately large. Lying. Arteries large. " Respirations 24. Arteries smaller. Fulness in head. Headache. Standing. Standing on deck in cold air. After standing on deck until feet grew tired. Standing. Artef ies small. Lying. Feels well. Arteries small. < < «« (< Standing. Just before landing. SEASICKNESS 453 Time, Pulse- Blood- p.m. rate, press. Remarks. 3:51 3:52 4:38 4:39 4:40 4:41 4:42 4:47 4:50 4:53 4:54 4:59 9:46 9:53 9:54 9:57 84 76 96 88 92 88 84 92 88 84 76 72 72 68 68 68 68 80 80 88 84 84 84 92 84 84 96 88 68 68 64 68 90 95 105 105 115 115 120 110 105 105 120 115 115 115 110 110 115 95 95 100 100 110 100 95 95 100 105 95 110 110 115 115 Standing. Landed at Stobcross Quay, Glasgow. Standing in hotel room, Glasgow. < < Lying. << It I Standing. < < Lying. Standing. Feels well. After stroll in botanical gardens. Arteries moderately contracted. Lying in bed. Protocol 14.— On "B." July 5th, on shore. 8 25 60 100 64 100 64 100 8 28 68 100 8 29 64 110 64 110 68 110 64 110 64 115 64 110 8 43 64 110 Lying in bed after awaking. " Arteries contracted. Room cool. After turning from head to foot of bed. 454 SEASICKNESS Time, Pulse- Blood- a.m. rate, press. 8:44 8:49 9:15 9:22 9:23 9:29 9:30 9:34 88 80 88 84 84 84 88 88 88 84 80 64 64 64 64 60 84 84 80 80 80 p.m. 5 : 55 92 92 96 5 : 58 92 5 : 59 80 76 72 72 6 : 07 72 6:08 80 88 6 : 10 92 92 6 : 12 88 105 110 110 110 110 110 100 110 110 100 105 105 110 115 115 115 115 105 105 105 105 105 120 125 125 125 125 125 125 125 120 125 125 120 115 110 Remarks. Standing. Feels well. Arteries contracted. After dressing. Arteries contracted. Lying. Feels well. Arteries contracted. < < " Respirations 20. < I Standing. Arteries contracted. Before leaving for train to catch Dublin boat. Lying. Respirations 24. Standing. Arteries moderately dilated. Protocol 14a. — On " B," aboard the steamship "Tiger" of Duke's line from Glasgow to Dublin. July 5, 1909. p.m. 7:58 8:02 8:03 108 108 104 108 108 95 90 95 100 95 108 95 Standing in cabin. Sweating after exertions. Cabin hot. " Temporary lump in stomach. Boat starts. Standing. i SEASICKNESS 455 Time, Pulse- Blood p.m. rate. press 8:05 108 95 8:06 92 120 84 120 84 115 84 120 84 115 88 115 84 115 84 110 80 105 80 105 80 105 76 105 80 105 80 105 84 115 80 110 8:32 80 115 8:33 96 85 104 90 96 95 96 90 96 95 96 90 92 95 96 90 100 95 100 90 100 85 100 85 96 85 96 90 100 85 100 85 100 85 100 85 96 85 96 85 100 85 92 90 96 85 96 85 96 90 100 90 100 90 9:05 100 90 Remarks. Standing. Lying. Slight lump-sensation in stomach. " Arteries smaller but still large. " Fulness in head. Respirations 26. " Slight pain and numbness in occiput on right side. ** Boat jolts and trembles. '* Jarring of body from head to foot. " No rolling or pitching. " Arteries large. " Respirations 24. " Worrying about trifles. " Deep respirations. " Lump-sensation in throat. " Respirations 24. " Arteries moderately contracted. Standing. Arteries small. " Slight lump-sensation in stom- ach. Biparietal headache. Sweating. Fulness in ears and mastoid areas. Headache occipital, right side. Lightness in head. Lump-sensation marked. Pupils slightly dilated. Muscles feel in fair condition. Numbness in occiput. Boat pitching somewhat. Much jolting from machinery. Slight pain near umbilicus. Occipital numbness and aching worse on right side. Arteries moderately contracted. 456 SEASICKNESS July 6, 1909. Time, Pulse- Blood- Remarks. a.m. rate. press. 12:10 76 95 Standing. After walking on deck. 72 95 <« Occipital headache worse on left side. 72 100 <( 76 95 i< 72 95 << 12:15 64 95 << Arteries moderately contracted. 12:16 64 120 Lying. Respirations 24. 68 125 Arteries moderately contracted. 68 125 Coronal headache. 68 125 Face flushed. 64 125 Pupils moderately dilated. 60 125 Frontal headache. 68 125 Respirations 21. Headache. Lump- sensation in stomach. 6:20 68 110 Lying in bed after awaking. 68 110 Arteries moderately large. 72 110 Respirations 19. 72 110 Yawning 72 115 68 115 6:30 68 115 6:31 88 105 Standing. Arteries moderately contracted. 84 95 84 95 88 100 Arteries moderately contracted. 80 95 84 100 88 100 84 95 Arteries small. 84 95 Feels well. 6:41 88 95 7:00 , , , , Landed at the North Wall, Dublin. Protocol 15a.— On "B," aboard the "Lady Wolseley" of the British and Irish Steam Packet Company from Dublin to Southampton. July 10, 1909. p.m. 4:54 .. Boat started. 4:55 104 95 Standing. Arteries large 100 95 108 90 108 90 104 95 5:03 104 95 Standing. SEASICKNESS 457 Time. Pulse- Blood- p.m. rate. press. 5;04 92 120 96 120 96 115 92 115 92 115 96 115 88 115 92 105 92 105 5:15 92 110 5:16 112 95 104 85 100 95 104 95 100 90 104 95 5:21 104 90 6:32 84 95 88 95 84 105 92 100 6:36 92 105 7:16 96 100 92 105 96 105 92 105 92 100 7:21 92 105 9:55 96 95 96 95 96 95 100 95 88 95 96 90 92 95 92 90 96 90 92 90 92 85 88 85 92 90 92 85 10:15 92 90 10:16 80 135 80 135 76 135 10:20 80 135 Remarks. Lying. Boat steady, but much vibration from machinery. << " Arteries large. ** Pupils moderately dilated. Lying. Asleep. Respirations 22. Standing. Arteries moderately large. Feels well. Standing. After being on deck. Arteries moderately contracted. Weather calm. After dinner. Standing. After walking on deck. " Fresh breeze. Boat pitching a little. Lump-sensation and burning in stomach. Boat rolling considerably. Feeling sick at stomach. Saliva increased. Lying. Great relief to lie down. " Arteries large. *' Lump-sensation in stomach. *' Respirations 24. Sleepy. Very nervous. 458 SEASICKNESS Time, Pulse- Blood. a.m. rate. press. 5:55 80 135 76 130 76 130 76 130 72 135 76 135 6:15 76 135 6:16 84 100 84 100 6:18 88 100 6:20 92 110 88 105 88 115 92 105 80 110 6:27 80 115 6:28 80 135 80 135 76 135 72 135 72 135 76 125 6:34 76 130 7:15 •• •• 8:05 80 125 80 125 80 125 80 130 80 135 80 135 80 135 80 135 80 135 80 135 80 135 80 135 76 135 8:24 80 130 8:25 86 125 92 110 88 115 88 115 8:29 88 110 11:00 88 125 Protocol 15b.— July 11, 1909. Remarks. Lying in bed. Awoke at 4 A.M. after a stormy night. ** Boat rolled and pitched furiously. ** Marked "lump-sensation" in stom- ach as boat rolls. '* Feels dizzy and sick, though lying in bed. ' ' right side out with head toward bow. " Pain in occiput right side. << Standing. Arteries contracted. Ship rolling badly. Marked balancing efforts. Lump-sensation in stomach. Saliva increased. Heaviness in head. Lying. Lump-sensation very marked. " Mind dull. Sick headache. " Saliva much increased. " Occipital headache. " Pain in neck. " Arteries moderately contracted. Stomach irrigated. Mucus and some fresh blood removed. Lying. After test meal. " Sick, heavy feeling in head. " Dull coronal headache. ** Saliva free. " Lump-sensation in stomach. " Respirations 22. " Arteries very small. " Sleepy. Face flushed. Occipital headache. Lying. Disinclined for work. " Irritable. Wants to be let alone. " Ship rolling badly. Standing. Marked efforts at balancing. Nervous. Sweating. Feels weak. Ship rolling badly. SEASICKNESS 459 Time, Pulse- Blood- a.m. rate, press. 92 120 96 110 92 110 11 : 04 84 105 p.m. 1 : 50 88 96 92 88 80 1 : 55 92 3 : 25 . . 4:40 100 92 4 : 43 92 9 : 43 76 80 80 80 80 9 : 50 80 9:51 76 72 68 72 68 10:05 72 105 105 105 115 105 105 105 105 105 110 110 110 105 105 110 125 125 125 125 125 125 Remarks. Standing. Much effort at balancing. " Arteries contracted. " Feels weak from balancing. After dinner. Boat steady now. Arteries moderately contracted. Whiskey and soda at dinner. Alongside pier at Falmouth. Standing after making analyses. " Boat at pier. <( '* After walking on deck. " Respirations 24. ** Arteries moderately contracted. (< Feels well. Lying in bed. Boat still by Falmouth pier. Arteries moderately large. Respirations 20. Feels well. Protocol 15 c.— July 12, 1909. 7:45 76 72 72 72 72 • 72 72 8 : 03 72 8:04 100 100 96 96 92 88 92 9 : 09 96 9:10 80 72 125 125 120 120 120 125 120 120 105 110 105 105 105 110 105 105 140 135 Lying in bed after awaking. Boat still at Falmouth pier. Arteries moderately contracted. Respirations 22. Standing. Arteries moderately dilated. Feels well. Lying after effort of getting into berth. Arteries moderately large. 460 SEASICKNESS Time, Pulse- Blood- a.in. rate. press. 72 125 76 125 9:18 80 125 9:19 104 95 ^00 95 96 105 96 105 96 100 92 105 9:25 96 100 10:49 92 105 88 105 92 105 88 105 92 105 10:55 92 105 10:56 72 140 72 140 72 140 76 140 76 135 76 135 76 135 76 135 11:11 80 135 11:12 100 105 88 105 88 105 84 105 88 110 88 105 92 105 88 105 84 105 11:21 88 105 p.m. 3:00 6:00 , , 7:14 92 lio 96 110 100 105 7:17 96 105 7:18 76 120 88 125 88 125 88 120 88 120 84 120 7:25 84 120 Bemarks. Lying. Boat started for Plymouth at 9:17 A.M. Standing. Arteries moderately large. Feels well. Boat moving smoothly. Feels well. Lying. Arteries moderately contracted. " Respirations 18, 20. " Pupils normal. Sleepy. ** Slight "lump-sensation." " Much jolting from machinery. ** Occipital headache. Standing. Arteries moderately contracted. Slight occipital headache. Arrived at Plymouth. Strolled about towa Boat started for Southampton. Standing after dinner. Ly ng. Arteries moderately large. Respirations 20. SEASICKNESS 461 Time. Pulse- Blood p.m. rate. press. 7:26 108 95 100 105 96 105 96 110 100 105 7:31 96 105 10:42 76 100 80 105 80 105 80 105 80 105 76 105 88 105 80 105 84 100 10 : 58 80 105 10:59 76 125 72 125 72 120 76 120 72 120 11:09 72 120 Remarks. Standing. Face flushed. Fulness in head. Feels stupid and heavy. After a bottle of ale. Slight dizziness. Fulness in head. Lying in bed. Fulness in head. Face flushed. Slept poorly. Protocol 15d.— July 13, 1909. 5 43 72 125 72 125 72 120 76 125 72 120 72 120 76 120 5 56 72 120 5 57 104 95 96 95 92 95 88 95 88 95 88 105 88 100 92 110 92 105 96 95 96 100 88 95 6 10 88 100 6. 12 , , , , Lying after awaking. Slight lump-sensation in stomach. Respirations 24. Standing. Gliding up' * Southampton Water. ' ' Arteries contracted. Feels sick at the stomach. Sweating. Feels weak. Landed at Southampton. i62 SEASICKNESS Protocol 16a.— On "B," aboard the "Southwestern" from Southampton to Cherbourg. July 13, 1909. Time, ] Pulse- Blood- Remarks. p.m. rate. press. 11:50 96 110 Standing. After walking from the Hippo- drome, i.e., about | of a mile. 92 110 << 88 120 Cabin stuffy. 88 115 ** Arteries moderately contracted. 92 105 tt 92 105 <( 96 105 July 14,1909. 88 105 Standing. 92 110 < < a.m. 12:01 88 105 (( 12:02 76 125 Lying. Respirations 24. 76 125 " Twitching of long flexors in right wrist. 76 130 <( 76 130 << 12:06 76 130 < < 12:11 76 130 <( 12:12 96 110 Standing. Arteries small. 92 115 Feels well. 92 115 (< 88 110 t( 92 105 tt 12:20 88 105 tt 12:24 Boat started. 1:37 92 95 Standing. Arteries moderately dilated. 88 105 Feels well. 88 105 < < 88 105 tt 88 105 1 1 1:43 88 105 < < 1:44 76 125 Lying in bed. 76 130 " Arteries moderately contracted. 72 125 •* Feels well. 72 125 68 125 1:51 72 125 6:33 76 125 Lying, after awaking. 76 125 Boat rolling and pitching. 76 120 Awoke with lump-sensation in stom- ach. 80 120 SEASICKNESS 463 Time, Pulse- Blood- Remarks. a.m. rate. press. 76 120 Lying. Saliva free. 80 120 80 120 6:50 80 120 (( Feels nervous. 6:51 80 115 Standing. Some balancing efforts. 92 120 < i Marked lump-sensation. 96 115 96 110 < ( Feels weak. 96 120 << 96 110 <( Saliva increased. 92 105 << < ( < < 96 115 96 105 <« Sweating. 92 110 92 105 (( Arteries much contracted 92 110 92 110 7:20 Landed at Cherbourg. Protocol 16b.— On "B," aboard a train. July, 1909. a.m. 9:22 92 96 125 125 Sitting • in train before starting. 9:25 88 125 9:26 88 88 92 120 95 120 On moving train. 9:29 88 110 9:30 88 115 At a stop. 9:31 88 105 On rapidly moving train. 9:32 88 105 9:33 88 88 115 120 At a stop. Arteries ver: 9:35 88 120 9:36 88 84 80 115 120 120 At a stop. 9:40 80 120 (< 9:41 80 125 Lying. At a stop. 9:42 68 125 Protocol 17.— On "B," after dressing ashore. July. 19, 1909, 6:07 84 105 Standing after dressing ashore 80 105 Feels well. 80 105 " Arteries small. 6:12 80 105 < < 6:13 68 125 Lying. Arteries larger. 464 SEASICKNESS Time, Pulse- Blood- a.m. rate, press. 68 68 6:16 64 6 : 17 76 80 80 6:20 84 125 125 125 115 115 120 115 Remarks. Lying. standing. 7:15 7:30 7:41 7:42 7:45 7:46 7:49 7:50 8:15 8:16 8:24 88 8:32 8:33 8:41 8:42 84 88 88 88 88 88 80 72 72 72 88 00 06 88 84 88 92 84 84 84 96 96 88 88 88 84 88 84 80 105 115 130 130 130 130 135 140 135 140 125 130 125 125 130 125 130 120 135 135 135 135 135 135 140 130 130 130 130 130 130 135 July 20, 1909. Cup of tea. Standing after dressing ashore. Arteries contracted. Lying. Arteries larger than when standing. Standing. Arteries contracted. Boarded steamship Cygne bound for Gorey, Island of Jersey, Channel Islands, from Carteret, Manche. Boat started. Ewald breakfast. Absorption test reacted in 15 minutes. Motility test reacted in 1 hour 20 minutes. Sitting. On deck in hot sun. Boat rolling and pitching. Lump-sensation in stomach. Arteries contracted. In the sun. Much balancing effort. Ship rolling and pitching. Feels well in spite of heat. Strong odour from cook's galley. On deck as before. Arteries moderately contracted. Slight lump-sensation in stomach. Eructations. On deck in sun. Slight headache. SEASICKNESS 465 Time, Pulse- Blood- a.m. rate, press. 9:10 84 9:38 84 9:43 92 9 : 45 . . Remarks. 80 140 Sitting. Otherwise feels well. 88 140 140 135 92 135 96 120 96 120 92 125 120 On deck. Arteries moderately contracted. Landed at Gorey. Protocol 18 — On "B," aboard the fishing smack "duatre Freres." July 22, 1909. A.in. 8:53 8:54 9:00 12:27 12:28 76 120 80 80 9:22 76 76 76 72 72 72 72 72 72 76 9:59 72 10:18 72 12:00 .. p.m. 12:24 80 84 84 80 76 84 76 80 76 72 76 12:33 76 125 115 105 105 115 115 125 125 115 115 90 115 115 120 130 120 120 115 115 120 130 135 135 135 135 135 Boat started, a fresh breeze filling her sails. Lying in cabin. Feels sick. Arteries small. Odour horrible. Boat pitching badly. Sweating. Rapidly getting sicker. Arteries not so small now. Sweating. Lump-sensation. Saliva free. Lump in throat. Wretched all over. Bathed in cold sweat. Marked lump-sensation in stomach. On verge of vomiting. Pain in epi- gastrium. Feels better now. Arteries small. Face pale. On verge of vomiting again. Feels better. Sweating. *' Arteries small. Feels thoroughly wretched. The rough weather compelled the crew to put back into the harbour. Put ashore. Sitting after leaving boat. Arteries contracted. Lying. Arteries moderately contracted. 466 SEASICKNESS Time, Pulse- Blood- Remarks. p.m. rate. press. 4:55 92 125 Standing. Muscles of forearm twitching. 92 120 Arteries moderately large. 96 120 Feels nervous and irritable. 92 120 Lump-sensation still in stomach. 96 120 5:02 92 120 5:03 76 125 Lying. S ize of arteries varies slightly from time to time. 68 135 " Pupils normal. 72 130 " No special fulness in head. 68 130 76 125 5:11 72 130 5:12 92 105 Standing. Arteries moderately contracted at times, and at other times small. 96 105 Standing. 92 135 92 135 Lump-sensation still in stomach. 92 130 92 120 92 135 92 125 5:20 88 130 The subject suffered the whole afternoon from the effects of the sea trip. Protocol 19.— On "B," aboard the " Southwestern," from Cherbourg to Southampton. July 23, 1909. Standing in cabin. " Arteries moderately contracted. 4 i ** Lying. Arteries moderately large. p m. 11 25 80 120 80 130 80 125 30 80 125 31 72 135 68 140 68 135 36 68 135 37 76 130 80 120 80 115 :40 84 115 .47 , , ^ , Standing. Arteries contracted. both hypoder- 12:04 1:43 76 125 Strychnin nitrate, gr 1/40. Atropin sulphate, gr 1/75, mically. July 24, 1909. Boat started. Lying. Arteries moderately contracted. SEASICKNESS 467. Time, Pulse- Blood- a.m. rate, press. 1:46 80 72 80 135 130 135 7:49 76 135 Remarke. Lying. Following an Ewald meal given at 12 : 34 A.M., the absorption test reacted in 11 minutes. The motility test did not react within the hour. The blood-pressures could not be taken with the subject standing on account of the ex- cessive incessant pitching and tossing of the boat. Standing as boat approaches pier at South- ampton. 7:50 84 120 St anc 88 125 84 125 84 125 88 125 88 125 84 120 84 120 84 125 84 125 8:11 84 120 8:12 72 135 Ly ini 76 130 76 130 72 125 72 130 8:18 72 130 8:19 80 130 St anc 84 130 < < 84 125 ( < 8:23 84 130 < < Jiily 28, 1909. Standing. After good night's rest in cool room. Arteries moderately contracted. Lying. Arteries moderately contracted. Standing. Arteries much contracted. In an Ewald breakfast given at 7: 18 a.m., the ab- sorption test reacted in 21 minutes. The motility test did not react within the hour. Protocol 20.— On " B," aboard the "Teutonic" from South- ampton to New York. First day out. July 28, 1909. a.m. U : 52 88 88 92 110 105 no Standing in cabin. 468 SEASICKNESS Time, Pulse- Blood- Remarks. a.m. rate. press. 92 110 Standing in cabin. 88 115 < < . 96 120 *i 88 110 << p.m. 12:04 88 110 <« 12:05 80 135 Lying. Arteries moderately large. 80 130 < « 76 125 (< 76 125 i( 76 125 < < 12:13 80 120 << 12:14 100 120 Standing. Arteries moderately contracted. 92 115 << 92 110 < ( 12:17 88 105 << Boat sailed from Southampton at 12:15 P.M. 5:05 80 140 Standing. Arteries small. 88 135 84 135 84 135 76 135 80 135 84 130 5:17 84 135 ( < 5:18 68 145 Lying. Arteries moderately contracted. 72 140 < < Fulness in ears. 72 145 < < 68 145 < ( 68 140 < < 5:25 68 145 < < 5:26 76 135 Standing. Arteries contracted. 80 130 < < Room cool. 80 135 < < 76 130