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SYPHILIS 
 
 NERVOUS SYSTEM. 
 
 OOWER.S. 
 
BY THE SAME AUTHOR. 
 
 Diseases of The Nervous System. 
 
 Second Edition. 2 Vols. Illustrated. 
 
 Volume I. Diseases of the Neeves and 
 Spinal Cobd.— 624 pages. 180 Illustrations, 
 including Three Hundred and Sixty-seven Fig- 
 ures. Octavo: " Just Beady'. 
 
 Volume II. Diseases of the Beain and 
 Ceanial Neeves ; Geneeal and Func- 
 tional Diseases. — With a large number of 
 Illustrations. Octavo. Nearly Ready. 
 
 The whole work has been very thoroughly re- 
 vised and much new material has been added. 
 
SYPHILIS 
 
 NERVOUS SYSTEM 
 
 REVISED REPRINT OF THE LETTSOMIAX LECTURES FOR 1890 
 
 DELIVERED BEFORE THE MEDICAL 
 
 SOCIETY OF LONDON. 
 
 BY 
 
 W. R. COWERS, M.D., F.R.C.P., F.R.S., 
 
 CONSULTING PHYSICIAN TO UNIVERSITY COLLEGE HOSPITAL, PHYSICIAN TO THE 
 NATIONAL HOSPITAL FOR THE PARALYZED AND EPILEPTIC, ETC. 
 
 LONDON: 
 J. & A. CHURCHILL, 
 
 11 NEW BUELINGTON STREET. 
 1892. 
 

 Copyright, 1892, by P. Blakiston, Son & Co. 
 
 PRESS OF WM. F FELL &. CO.. 
 
 1220-21 SANSOM STREET. 
 
 PHILADELPHIA. PA., 
 
PREFACE. 
 
 These lectures, delivered three years ago, are now 
 reprinted on account of the frequency with which I 
 find it necessary to refer to statements made in them, 
 and the inconvenience of being obliged to. refer a 
 reader to the Medical Journals in which the lectures 
 originally appeared. Two translated reprints have 
 been published, and this renders their reproduction in 
 the English language the" more desirable. Moreover, I 
 have taken the opportunity of carefully revising them, 
 and have made a large number of additions. These, 
 although not obtrusive or extensive, will, I hope, be 
 found to increase the practical value of what is said, 
 and may serve to bring the lectures up to the level 
 of our present knowledge if they are below this in their 
 original form. At the same time, their scope and char- 
 acter make the need for such additions insignificant. 
 Their chief object is to enable those who read them 
 to grasp more firmly the cases they meet with, and to 
 understand better the methods of dealing with the 
 disease in practical thought and actual work. 
 
 My thanks are due Dr. D. D. Stewart, of Philadel- 
 phia, for assistance in reading proof, and for preparing 
 the index. 
 
 Queen Anne St., London, 
 October, 1892. 
 
 V 
 
 348429 
 
Digitized by the Internet Archive 
 
 in 2010 with funding from 
 
 Open Knowledge Commons 
 
 http://www.archive.org/details/syphilisnervoussOOgowe 
 
TABLE OF CONTEiNTS. 
 
 LECTURE I. 
 
 The Ultimate Pathology of Syphilis. 
 The Actual Pathological Position and Macroscopic (non-histo- 
 logic) Character of Sj'philitic Tissue-formations ; Their Divi- 
 sion into Classes, — Sjyeeific and Non-special. — General Con- 
 sideration of These, Their Situation and Effects, Direct and 
 Eemote ; the Specific or Xeoplastic, Consisting of Gummata 
 and Growths in the Arterial Walls, and the Pathologically 
 Non-special or Inflammatorj^ Lesions. — The Question of Evi- 
 dence as an Aid to the Diagnosis of Inflammatory or Patho- 
 logically Non-specific Lesions. — Evidence of Sequence and 
 that of Therapeutics as an Aid to the Proof of Causation. — 
 The Relations of Nerve-degenerations to S^"philis. — Analogy 
 Between the Effect of Certain Poisons, Chemical and Organ- 
 ized, and that of Syphilis. — Strlimpell's Hypothesis, . . . . 9-54 
 
 LECTURE II. 
 
 The Oeigix of Functional Neevous Disoedeks Atteibuted 
 TO Syphilis on Impeefect Evidence. 
 
 Considerations in Outline of the Possible and Probable Diag- 
 nosis of Syphilis of the Nervous System Determined by the 
 Situation and Nature of the Lesions, and the Character and 
 Course of the Symptoms. — Symptomatologj^ and Diagnosis of 
 Some Syphilitic Processes Affecting the Nervous System, 
 such as Gummata, Chronic Local Cerebral Meningitis, and 
 Arterial Disease with its Sequences, Thrombosis with Ne- 
 crotic Softening of the Brain. — Ocular Palsies. — The Import- 
 ance of Accuracy of Diagnosis in Syphilitic Disease of the 
 
 Nervous System, .5.5-90 
 
 vii 
 
Vlll CONTENTS. 
 
 LECTURE III. 
 
 The Essential Peinciples Underlying the Prognosis of 
 
 Syphilitic Disease of the Nervous System, and 
 
 Their Effect upon the Special Prognosis 
 
 OF the Chief Lesions. 
 
 The Prognosis a Matter of Special Consideration of Individual 
 Cases, as is also Diagnosis. — Symptoms of Syphilitic Disease 
 of the Nervous System Depend not on the Specific Process, 
 but on the Simple Alterations this Produces in Nerve-tissue. 
 — As Treatment E.xerts a Direct Effect on the Specific Process 
 Only, the Persistence of Symptoms Despite Treatment Indi- 
 cates the Persistence of Damage to the Nerve Elements, and 
 not of the Luetic Lesion Producing the Damage. — Special 
 Prognosis of the Chief Luetic Affections. — ilodifications of 
 Prognosis Entailed by Symptoms of Irritation Caused by 
 Certain Lesions. — Syphilis an Incurable Disea.se — this State- 
 ment Consistent with the Recognition of the Fact that the 
 Lesions of Syphilis are Readily Removed by Treatment. — 
 Respective Power of Mercury and of Potassium Iodide in the 
 Treatment of Syphilitic Diseases of the Nervous System. — 
 How these Drugs are best Employed. — Efficient Measures of 
 Prevention and of Arrest of Syphilis not j^et at Hand. — Un- 
 broken Chastity the only Certain Prevention, 91-127 
 
 Index, 128 
 

 SYPHILIS 
 
 NERVOUS SYSTEM, 
 
 LECTURE I. 
 
 Mr. President and Gentlemen, — Permit me first 
 to tender to you, Sir, and the Council, my thanks for 
 selection to the post of Lettsomian Lecturer to this 
 Society, a post around which cluster so many honor- 
 able associations. The duty which that selection lays 
 upon me, and which I have now to attempt to dis- 
 charge, has difficulties of its own. This Society consti- 
 tutes an audience with the widest professional interests, 
 but above all with an interest in the practical aspects 
 of medical science. This characteristic has been handed 
 down through successive generations of its Fellows, 
 from the time when theory bore a much smaller pro- 
 portion to practice than it does now. It is not one that 
 should be lightly esteemed or hastily discarded, espec- 
 ially in these days, when the " scientific imagination " 
 is apt to wander far and free. The subject to which I 
 2 9 
 
10 LETTSOMIAN LECTURES ON SYPHILIS 
 
 propose to ask your attention is one in which, more 
 perhaps than in any other, the two great branches of 
 the profession join hands in mutual supplement of 
 work. This co-operation is the more important because 
 the disease we are to consider turns to each a differ- 
 ent face. To the surgeon the processes of syphilis 
 are for the most part open and manifest ; to the physi- 
 cian they are secret ; its ways are obscure, its language 
 is seldom unequivocal. 
 
 This subject has, indeed, once already been made 
 that of the Lettsomian Lectures. Those of my distin- 
 guished predecessor, Dr. Broadbent, together with the 
 almost simultaneous work of Dr. Buzzard, were the 
 means of first diffusing widely, in this countr}^, a knowl- 
 edge of the extensive influence of syphilis on the nervous 
 system. But the fifteen years that have since passed 
 have been prolific in additions to our knowledge, and 
 the time seems ripe for a fresh review of at least some 
 aspects of the subject. Not only are there many new 
 facts that deserve notice, but tliere are msnaj doubtful 
 points that need consideration. If it is desirable to re- 
 view our positive knowledge, it is not less important 
 clearly to define or even to discern its limits. There is 
 perhaps no subject on which there is so much of what 
 may be termed (if the convenient contradiction is per- 
 mitted) uncertain knowledge — in which there are so 
 man}^ opinions that rest on no secure foundation, and 
 yet are accepted as true — so many mere hyjDotheses that 
 are put forward and received as more than hypothetical ; 
 so much that is possibly true, and yet is still unsupported 
 by any real evidence. Hence it seems especially desir- 
 
AND THE NERVOUS SYSTEM. 11 
 
 able to consider the evidence that has been or may be 
 obtained as to the relation to syphilis of many of the 
 diseases of the nervous system. In doing so, we shall 
 learn something of them, and see how we may learn 
 more. There are also practical questions in diagnosis 
 and prognosis that need consideration. Lastly, there 
 are questions in treatment on which current opinion is 
 divided, in some cases widely divided ; a discussion of 
 these, even if partial, may be of service by drawing to 
 them the attention of the many, which they at present 
 receive only from a few. These, then, are the topics to 
 which I propose to ask your attention. 
 
 I dare not depart from the time-honored custom of a 
 preliminary apology, especially as I feel that an apology 
 is not unneeded. Indeed, that I may be quite on the 
 safe side -alike of custom and of conscience, I will be 
 bold in my humility, and offer you two apologies. First, 
 you have a right to expect from a Lettsomian lecturer 
 something new, some definite addition to our knowl- 
 edge. This reasonable expectation I fear I must dis- 
 appoint. It is scarcely compatible with the chief object 
 that I desire to attempt. My second apology arises 
 from the fact that we cannot separate one part of a dis- 
 ease from the rest. In considering syphilis as it affects 
 the nervous system, and especially the question of evi- 
 dence, I cannot avoid alluding to points in its history 
 that I am not competent to discuss. In this also I 
 must ask your indulgence, and it may save time and 
 words if, once for all, I beg you to impute to me all due 
 diffidence and hesitation wherever they are seemly, even 
 
12 LETTSOMIAN LECTURES ON SYPHILIS 
 
 though; in the exigence of the moment, they may not 
 be manifest. 
 
 Among the visceral effects of syphilis those on the 
 nervous system stand first in extent, variety, frequency, 
 and gravity. Considering this fact, it may seem strange 
 that our knowledge of these lesions should have been 
 of such slow growth and late development, and that so 
 vast a range of syphilitic influence was scarcely sus- 
 pected thirty years ago. But we must not forget that 
 thirty years hence some future Lettsomian lecturer, now 
 playing with his toys, may make the same remark of 
 the knowledge of the present day. The cause that has 
 hindered our acquaintance with these diseases is not 
 far to seek. It is a cause that we cannot and must not 
 hope to be lessened in the future — the old and inevit- 
 able antagonism between pathology and therapeutics. 
 Each flourishes at the expense of the other. The ends 
 for which we gain our knowledge are the chief obstacle to 
 its acquisition. We know most about the pathology of 
 the diseases that we fail to cure. In proportion as we 
 are successful in treatment we are dependent on the 
 " chapter of accidents " for information as to the real 
 nature of the disease. This influence has affected 
 syphilis more than most other maladies. 
 
 The " ultimate pathology " of syphilis, even in its 
 special relations, is beyond the limit I have set to the sub- 
 ject of these lectures. That the cause of syphilis is a mi- 
 cro-organism can scarcely be doubted by any one who has 
 followed, even at a distance, those discoveries that have 
 transformed so much of our pathology, although it may 
 
AND THE NEEVOUS SYSTEM. 13 
 
 reasonably be doubted whether the organism itself has 
 yet been detected. It is also highly probable that the 
 organism is the immediate cause of most lesions, which 
 can be promptly influenced by the treatment known as 
 " anti-syphilitic." But beyond this I must not attempt 
 to discuss the pathology of the disease. It was part of 
 my original intention to endeavor to confer some sem- 
 blance of vitality on the dry bones I have to offer you, 
 by indicating the form in which some of the pathologi- 
 cal problems of syphilis present themselves at the 
 present day, and the kind of answer we may reasonably 
 expect from the knowledge that we hope the near future 
 has in store. But for a profitable discussion of such 
 questions, however brief, the time is not yet ripe. At 
 present we have no guide but analogy, certainly not 
 close, and possibly misleading, and I desire to avoid 
 the region of mere analogy and of pure speculation. 
 
 Permit me, however, at the outset, to remind you of 
 certain general considerations regarding the effects of 
 syphilis, — considerations that are not speculative, but 
 are merely abstract and familiar to you, certainly in 
 fact, and probably in form. If we compare the various 
 syphilitic lesions, not limiting our view to any single 
 organ, we may discern in them two elements — a process 
 of inflammation, and a process of tissue-formation. It 
 might seem more accurate to call the former the '' con- 
 gestive " element, since tissue-formation is so often a 
 part of the process of inflammation, but the term 
 " congestion " involves a limitation, and is scarcely 
 wide enough for the purpose. We can mentally distin- 
 guish these two elements, and the distinction is aided 
 
14 LETTSOMIAN LECTURES ONT SYPHILIS 
 
 by the fact that they are combined in various degrees 
 in the different lesions. The process of tissue-forma- 
 tion is seen, in ahnost a pure form, in syphilomata, — 
 " gummata," as they are called from their gluey aspect. 
 In these no more of the congestive element is to be 
 discerned than in most other tumors. On the other 
 hand, the inflammatory or congestive element is almost 
 or quite pure in many of the early skin eruptions, in 
 some cases of iritis, and in man}'- other lesions. Gen- 
 erall}'^ the two elements are combined, and the most 
 common condition is that often termed " hyperplastic 
 inflammation." Sometimes the combination is such 
 that it is not easy to decide in which class a lesion 
 should be placed, whether it should be regarded as a 
 hyperplastic inflammation or as a diff'use gumma. 
 
 If we survey the course of active syphilis, there 
 seems to be a tendency for the congestive or inflamma- 
 tory element to preponderate in the early lesions, and 
 the tissue-formation in the later. At the same time, the 
 earliest lesions, the primary induration and the enlarge- 
 ment of the nearer glands, are apparent exceptions to 
 this law — exceptions that will have to be considered 
 whenever wider and deeper knowledge brings with it 
 the possibility of framing an adequate hypothesis as to 
 the real pathology of the disease, and the relation of 
 the virus to the several lesions. 
 
 It has, indeed, been suggested that there is no real 
 difference between these two elements. The tissue 
 formed in syphilitic processes differs but little from 
 that formed in ordinary inflammation, and inasmuch 
 as it is combined in varying quantity with the signs of 
 
AND THE NERVOUS SYSTEM. 15 
 
 inflammation, it is urged that even the gumma has 
 closer affinities with inflammatory products than with 
 the true new growths. But the admission of this 
 opinion (if it is justified) does not preckide the dis- 
 tinction of the two conditions, for it is often well to 
 distinguish when we have no right to divide. The 
 distinction seems to be justified if each condition may 
 exist so far alone that we cannot clearly discern the 
 other. 
 
 Whatever be the real pathological position of the 
 tissue formed, it presents certain characters not found 
 in the same degree in ordinary inflammatory products, 
 and it is very important to keep these in mind. First, 
 the peculiarity of aspect when of recent formation, to 
 which the name " gumma " is due. Secondly, the ten- 
 dency to undergo certain changes — for the tissue-ele- 
 ments to perish in caseation, or else to undergo a change 
 into a dense contracting fibrous tissue. The gluey 
 aspect and the caseation constitute the most important 
 characters by which this tissue can be identified. The 
 tendency to degeneration is so widely but unequally 
 diffused through a mass, that the cheesy change usually 
 begins at many places. This tendency to multiple 
 caseation, and the irregular areas thus produced, con- 
 stitute the most important criterion of the nature of 
 the tissue, when the " gummy " aspect has ceased to be 
 distinctive. Lastly, the tendency to change to a con- 
 tracting fibrous tissue is of extreme importance in rela- 
 tion to the effects produced — by which the lesion is 
 manifested. This fibrous change often takes place in 
 the tissue at the surface of a gumma, as part of its 
 
16 LETTSOMIAN LECTURES ON SYPHILIS 
 
 degenerative or cicatricial changes, and it is probably 
 this that has given rise to the erroneous statement 
 sometimes made, that a capsule is characteristic of these 
 growths. It may also occur throughout the new for- 
 mation, as in the inflammation of the dura mater which 
 surrounds the spinal cord wdth a sheath of this dense 
 tissue. 
 
 We may divide syphilitic lesions into certain classes, 
 according to our knowledge of their pathological char- 
 acters, and we may expect to find these classes repre- 
 sented in the nervous system. First, there are morbid 
 processes with characters that are peculiar, processes 
 due to no other cause. Secondly, there are processes 
 that are not peculiar ; so far as Ave can see, they resem- 
 ble those that are due to other causes, although they 
 are produced by syphilis. Some of this second class, 
 however, although not special in pathological charac- 
 ters, are yet, when due to syphilis, peculiar in their seat 
 and distribution. Other's have not even this peculiarity, 
 but may be described as lesions due to many causes, 
 one of which is syphilis. I do not say they are not 
 really special and peculiar ; I only say that we cannot 
 discern the peculiarity. Outside the nervous system 
 we see many examples of these varieties. They are 
 conspicuous, for instance, in the skin. A gumma, 
 ulcerating in a serpiginous manner, is an example of a 
 truly special lesion. Many other cutaneous syphilides, 
 such as roseola and psoriasis, however, have no patho- 
 logical peculiarity, although most of them, when syph- 
 ilitic, are peculiar in distribution. Many cases of syph- 
 ilitic iritis are special in aspect, but others present no 
 
AND THE NERVOUS SYSTEM. 17 
 
 peculiarity to distinguish tliem from inflammation of 
 the iris due to other causes. Thus simple iritis, simple 
 so far as we can see, has several causes, of which syph- 
 ilis is one. Speaking generally, the more the conges- 
 tive or inflammatory element preponderates in a lesion, 
 the less special are its pathological features. These 
 depend chiefly on the element of tissue-formation. 
 Necessarily also, as the latter needs time for its produc- 
 tion, the more acute a syphilitic inflammation is, the 
 less are its features distinctive. This is, I think, a very 
 important consideration. 
 
 It is desirable to keep this classification in mind in 
 considering the lesions of the nervous system, because 
 the evidence as to the syphilitic nature of a lesion nec- 
 essarily diff'ers in the various classes, and it will be 
 desirable to adopt this classification in reviewing the 
 several lesions and the evidence regarding their nature. 
 I must pass unnoticed those that are caused by bone- 
 disease. 
 
 We begin, then, with the lesions of which syphilis is 
 the only cause. They possess distinctive characters, 
 and it is found that syphilis is their invariable antece- 
 dent. It can be traced in a large proportion of the 
 cases, and the more thorough our knowledge of the 
 individuals, the smaller is the proportion in which the 
 evidence of syphilis is not clear. On the other hand, 
 those lesions are never met in cases in which syphilis 
 can be excluded with certainty. From their special 
 characters they may be termed "specific" lesions. We 
 need this term for them, and it is a misfortune that the 
 word has come to be used in a wider sense, as a euphem- 
 
18 LETTSOMIAN LECTURES ON SYPHILIS 
 
 ism for " syphilitic." For this, moreover, there is a 
 word which might with advantage become as current 
 here as it is in Germany — "luetic." I propose, there- 
 fore, to use the term " specific " in the sense of a lesion 
 that is special, not only in its causation, but also in its 
 characters. 
 
 These truly " specific " lesions I must pass over with 
 merely a brief mention, because they are the best known 
 of the effects of syphilis, regarding which there is least 
 room for question. It will be remembered that I am 
 now dealing only with pathology ; we shall have again 
 to consider these lesions in regard to practical diagnosis, 
 in which they furnish many important problems. 
 
 First, there are the syphilitic growths, gummata, cir- 
 cumscribed masses of new tissue having the charac- 
 teristics I just mentioned. They grow commonly from 
 the pia mater, and both compress and invade the sub- 
 stance of the brain and spinal cord. The}^ are rare 
 within the substance of the brain, and they are rare 
 also, although sometimes symmetricalj on the cranial 
 nerves. Occasionally there is a more diffuse formation 
 of similar tissue in connection with the dura mater, 
 cerebral or spinal. 
 
 Secondlj^, there are the growths in the walls of the 
 arteries, which constitute one of the most important 
 of these specific lesions ; but they also are well known 
 and need not detain us. One point, however, should 
 be mentioned. As generally met with the disease is 
 recent and consists in a thickening of the wall which 
 is more limited than in atheroma and less opaque. 
 But when such a disease has been treated, as by a 
 
AND THE NERVOUS SYSTEM. 19 
 
 course of iodide of potassium, the thickening is less 
 and the opacity greater, so that the condition re- 
 sembles more closely ordinary atheroma, for which 
 it may usually be mistaken. I have seen such dis- 
 ease in one arter^^ associated with recent and character- 
 istic changes in another. I would ask you to note, 
 also, in passing, the remarkable correspondence in seat 
 between this arterial disease and ordinary atheroma. 
 Except in the arteries of the brain and in the aorta, 
 syphilitic disease is scarcely known. We ascribe the 
 proclivity of those arteries to atheroma to the influ- 
 ence of strain ; is this also the cause that determines 
 their affection in syphilis ? I can think of no other, 
 but the fact must be borne in mind in connection 
 with certain theories of the origin of the lesions. 
 
 Many facts regarding this arterial disease will have 
 to be considered when we come to the diagnostic 
 problems they furnish, but certain of its pathological 
 consequences must not be passed over. The first is 
 the necrotic softening that follows occlusion of the 
 diseased artery, or more often that of a branch 
 coming off from the diseased spot. It is by this 
 necrotic softening that the disease most frequently 
 causes symptoms. Occlusion, however, does not always 
 lead to softening. Induration may result, especially 
 in the cortex, and more often in children than in 
 adults. It is no doubt due to the arterial anas- 
 tomoses being sufficient to prevent actual necrosis, 
 although insufficient to maintain the integrity of the 
 tissue. 
 
 A second effect is the production of aneurism of the 
 
20 LETTSOMIAN LECTURES ON SYPHILIS 
 
 larger arteries, those that are the special seats of the 
 disease. Such aneurisms seem to be always due to 
 inflammation of the wall, by which extensible fibroid 
 tissue is substituted for the normal elastic elements. 
 We know two other causes of such intracranial aneur- 
 isms. One, very rare, is traumatic arteritis. The 
 other is embolism, imperfectly occluding the vessel ; 
 this is probably the cause of two-thirds of such 
 aneurisms before the degenerative period of life. In 
 the remainder, in which there is no history of injury 
 and no evidence of embolism, there is a history of 
 syphilis in so many cases as to justify the opinion 
 that most of them are due to this influence. Often the 
 history is imperfect, because the aneurism has been 
 unsuspected until the final rupture and syphilis has 
 not been enquired for. When we consider how great 
 is the amount of new growth in the wall of a diseased 
 artery, and how prone are the new elements to change 
 into extensible fibroid tissue, the wonder is that aneur- 
 ism is not a more frequent occurrence. Probably the 
 explanation is to be found in the common persistence 
 of the elastic layers, which afford the chief safeguard 
 against permanent dilatation. I am only able to offer 
 one additional instance of an aneurism due to syphilis. 
 A girl, aged about twenty -five, who had suffered from 
 syphilis, was admitted to University College Hospital 
 with the symptoms of a small tumor near the crus. 
 Soon after admission, she suddenly became uncon- 
 scious, and died in a few hours. A large amount of 
 blood was found at the base of the brain; it had 
 come from a small aneurism, the size of a large pea, 
 
AND THE NERVOUS SYSTEM. . 21 
 
 on the posterior cerebral artery, near its origin. No 
 source or evidence of embolism could be found. 
 
 A third, but very rare, effect of syphilitic vascular 
 disease is hemorrhage within the substance of the 
 brain. Doubtless, the reason why it is so seldom 
 met with is because the arteries within the substance 
 of the brain are so seldom the seat of syphilitic 
 disease. A few cases have been met with, and I have 
 seen one remarkable instance of it in the inherited 
 malady. The patient was a boy, aged tw^elve, with 
 clear evidence of congenital syphilis. He had suf- 
 fered from some transient cerebral symptoQis at the 
 ago of eight. The hemorrhage was a large one; it 
 had destroyed the greater part of one cerebral hemi- 
 sphere and had burst into the ventricles. Although 
 its source was not discovered, there was such disease 
 as to leave no doubt of its cause. Extensive and 
 characteristic syphilitic disease existed in the right 
 vertebral artery, and some smaller spots were seen on 
 the posterior cerebrals. Moreover, the aorta presented 
 some patches of similar disease, which was conspicuous 
 also on both coronary arteries, near their origin and 
 along their course, while several raised yellowish spots 
 existed on the flaps of the mitral valve. There were 
 no vegetations, and it should be added that the boy 
 had not had rheumatic fever. The case is thus re- 
 markable for more than one reason, not the least 
 being the late stage of the inherited disease at which 
 the lesion occured. 
 
 Inflammation that is specific in its pathological fea- 
 tures is chiefly meningeal. The special feature in this 
 
22 LETTSOMIAX LECTURES ON SYPHILIS 
 
 also is its hyperplastic character, much new tissue being 
 produced, which may undergo the caseous or the fibroid 
 degenerative change. Either of the two membranes 
 may be inflamed. In the dura mater the inflammation 
 is usually diffuse, and the tissue formed undergoes 
 chiefly the fibroid change. Such cerebral pachymen- 
 ingitis is more common in the inherited than in the 
 acquired disease. In the pia mater the inflammation 
 is usually local. The new tissue may undergo the 
 characteristic caseation, or fibroid change in it may 
 result in the formation of a layer of dense cicatricial 
 tissue, in which nerve roots at the part are in- 
 separably involved. 
 
 In the spinal cord the most frer|uent chronic inflam- 
 mation is that of the dura mater, the important and 
 well-known " spinal pachymeningitis." This may dam- 
 age greatly not only the spinal and bulbar nerve roots, 
 but the cord itself, from the great amount of fibrous 
 tissue produced. The pia mater is seldom inflamed 
 locally, and its diffuse inflammation is usuall}^ com- 
 bined with that of the dura mater. 
 
 Inflammation of the substance of the brain or cord 
 that can be regarded as pathologically speciflc is very 
 rare. Primary focal softening and induration have 
 been met with, but most of the cases are open to the 
 question whether the lesion was not due to arterial dis- 
 ease. When these changes do result from inflamma- 
 tion, they are seldom specific in their characters. A case 
 of chronic disseminated inflammation has been described 
 by Charcot and Gombault, which may, however, be re- 
 garded as a typical example of such a specific inflam- 
 
AND THE NERVOUS SYSTEM. 23 
 
 mation. Foci of chronic inflammation existed in the 
 brain, pons, and optic nerves, and in many of these foci 
 the new tissue presented muhiple points of caseation, 
 although in others it had undergone only the fibroid 
 change. 
 
 Very little is definitely known of inflammation of the 
 cranial nerves which is pathologically specific. These 
 nerves are often damaged by gummata and by chronic 
 meningitis, but there is also reason to believe that they 
 are sometimes the seat of hyperplastic inflammation, 
 involving the sheath and interstitial tissue. The distri- 
 bution is usually irregular, and it is seldom bilateral. It 
 is remarkable that the peripheral parts of the spinal 
 nerves are very seldom affected. The discovery of the 
 susceptibility of these nerves to various toxic influences 
 has revealed no liability for them to suffer in syphilis. 
 
 It will be observed that in speaking of specific path- 
 ological characters I have alluded only to those that 
 can be recognized by the naked eye. I do not think 
 that, at present, any confidence can be placed on his- 
 tological characters only. Even the structure of the 
 gumma is not distinctive ; all that the microscope enables 
 us to say is that the tumor may be syphilitic. In the 
 case of inflammations, it is very doubtful whether the 
 microscopical characters have anything like the signi- 
 ficance sometimes ascribed to them ; all the characters 
 need to be considered. 
 
 Are there any lesions of the nervous system that can 
 be said to belong to the second class — lesions that pre- 
 sent no pathological peculiarity — lesions that are due 
 to other causes besides syphilis, but which when syphi- 
 
24 LETTSOMIAN LECTURES ON SYPHILIS 
 
 litic in origin have peculiarities of distribution not 
 present when they are due to other causes ? Tliere are 
 a few that may possibly be of this character. One is a 
 form of disseminated subacute myelitis, in which de- 
 fined islets of inflammation occupy the white substance 
 of the cord, chiefly near the surface, and are perhaps 
 sometimes met with in the brain. This form has been 
 described, as related to syphilis, by Julliard and Pierret, 
 and I have met with one instance. Although syphilis 
 seems to have been its antecedent in the cases hitherto 
 published, more observations are needed before it can 
 be regarded as a specific lesion, even when its peculiar 
 insular character is taken into consideration, and the 
 facts at present do not prove specificity apart from its 
 distribution. The same may be said of a form of multi- 
 ple inflammation of the spinal roots, regarded as a 
 specific by Kahler, and of certain forms of sclerosis of 
 the cortex of the brain (without arterial disease) met 
 with by Barlow in infantile syphilis. 
 
 It is not likely that this completes the series of ob- 
 viously specific lesions. Many other morbid processes 
 may yet be added, by reason of their characters or seat, 
 when our knowledge of them is rendered adequate by 
 a sufiicient number of observations. For the present, 
 however, they must be placed in the class we have now 
 to consider, the lesions of which syphilis is one of 
 several possible causes — lesions analogous to the appar- 
 ently simple iritis. The chief morbid processes wdiich 
 seem to fall into this class are two : first, certain acute 
 and subacute inflammations ; and secondly, certain 
 forms of chronic inflammation or focal sclerosis of the 
 
AND THE NERVOUS SYSTEM. 25 
 
 nerve-centres. In the same category, moreover, we 
 must also place the important class of primary nerve 
 degenerations. These we shall notice later, but the 
 methods we are about to consider are applicable to 
 them also. 
 
 The question of evidence is of the greater importance 
 in regard to this class because we have to proceed to 
 some extent without the aid of pathological observa- 
 tion. We can make the diagnosis during life with con- 
 siderable confidence in some of these cases, especially 
 in the acute inflammations. In them, opportunities 
 for pathological observation come seldom, and it is very 
 doubtful whether, when they do come, they afford any 
 real help. We have already seen that it is the new 
 tissue which gives to the specific lesions their distinctive 
 peculiarity. For the formation of this tissue, time is 
 essential. In proportion as syphilitic inflammations 
 are acute, the inflammatory or congestive element pre- 
 ponderates, and the lesion assumes an apparently sim- 
 ple character. Obviously, therefore, if an acute inflam- 
 mation is produced by syphilis, we cannot expect it to 
 present such specific features as would declare the 
 nature. We cannot expect, therefore, that a post-mor- 
 tem examination would decide the question ; and yet 
 we need, and urgently need, to know whether such 
 lesions are or are not among the results of syphilis. 
 But in the case of these apparently simple lesions, only 
 two kinds of evidence seem at present within our 
 reach : the first is such sequence as proves causation ; 
 the second is the evidence of therapeutics. It is desira- 
 ble to examine these two kinds of evidence, to inquire 
 
 3 
 
26 LETTSOMIAN LECTURES ON SYPHILIS 
 
 how they can be obtained, and to what limitations they 
 are subject. This inquiry is important, because cur- 
 rent ideas on the subject seem ill-defined, and yet we 
 have no other evidence. I ought, indeed, to recognize 
 a possible future source of definite knowledge most 
 part vague (at least if we may judge by their applica- 
 tion), and also because, with one exception, I do not 
 see where else we are to look for evidence. 
 
 The progress of bacteriology may supply us with a 
 conclusive criterion. Such a criterion would be avail- 
 able also for the specific lesions, but for them it would 
 be merely confirmatory ; for the lesions now under 
 consideration it would be essential. Unfortunately, 
 such a criterion is still in the dim, if not in the distant, 
 future. We cannot assume that it will certainly follow 
 the discovery of the specific organism, or that its appli- 
 cation would be unlimited. It is not likely that the 
 test would be of negative as well as positive signifi- 
 cance, — that the absence of the organism would be as 
 conclusive as its presence. Thus even this criterion 
 may not relieve us from the need for other proof. 
 
 The evidence of sequence is thus of great import- 
 ance. Regarding it, the first important consideration is 
 that isolated instances are no proof of causation. 
 (Let me again remind you that T am now speaking of 
 scientific proof, not of practical diagnosis.) Individual 
 sequence would be proof if we could exclude all other 
 causes of a disease, but this is, as a rule, beyond our 
 power. The diseases in question have many causes, 
 and those causes are imperfectly known, so that their 
 exclusion in a given case is impossible. The fact that 
 
AND THE NERVOUS SYSTEM. 27 
 
 we cannot trace them does not prove that they do not 
 exist. We are often unable to trace the cause when 
 there is no question of syphihs, although some ade- 
 quate cause there must be. Hence, when there is 
 syphilis, the fact that we cannot trace any other cause 
 does not justify us in concluding that the disease in 
 question is due to syphilis. To do so is to treat the 
 unknown as non-existent, and to base our induction 
 not on knowledge, but on ignorance. Consider how 
 many diseases coincide with, or succeed, constitutional 
 syphilis, which no one dreams of attributing to it. We 
 do not ascribe acute rheumatism or acute sthenic pneu- 
 monia to preceding syphilis, and yet, because a morbid 
 process occurs in an organ, as the spinal cord, which is 
 sometimes the seat of syphilitic processes, it is assumed 
 that the process is due to syphilis, merely because the 
 patient is or has been syphilitic. It is perfectly certain 
 that such a combination must often occur when there 
 is no causation. It is certain, from the mere law of 
 chance; but such a coincident, without direct causation, 
 may well be more frequent than mere chance will ex- 
 plain. A general disease like syphilis may so influence 
 the general health as to predispose to many diseases for 
 which other causes may exist. Therefore, while indi- 
 vidual instances of sequence may justly direct atten- 
 tention to the possibility of causation — while they may 
 suggest a search for other evidence — they do not prove 
 causation. Indeed, I should not venture to call your 
 attention thus specially to a rule that is so obvious, 
 were it not that medical literature abounds with cases 
 
28 LETTSOMIAN LECTURES ON SYPHILIS 
 
 in which causation by syphilis is assumed to be proven 
 by a single sequence. 
 
 How, then, can sequence prove causation ? How 
 can the fact that a disease follows syphilis be evidence 
 that it is due to syphilis ? Only by the strength of 
 numbers. The sequence that is without significance 
 when isolated, has the highest significance when trace- 
 able in a series of cases. This fact is so well known, 
 and the method has been employed so frequently in 
 the case of tabes and other maladies of the same class, 
 that it may seem needless to consider it in detail. But 
 its use must be widely extended if we are to ascertain 
 whether or not many other diseases are related to 
 syphilis, and its value depends largely on the manner 
 in which it is used. The number of cases necessary will 
 vary according to the field of observation, the frequency 
 of the disease, its incidence on age and sex, and the 
 nature of the proof required. A small number of co- 
 incidences, in a fair field of observation, might be suffi- 
 cient to prove the mere fact of causation, although a 
 much larger number would be necessary to enable its 
 extent to be estimated. Used with care the method is 
 of the utmost value ; carelessly employed it is worth- 
 less and merits the sneers that have been so freely 
 bestowed upon it. 
 
 It is only practicable to approach the question from 
 the side of the disease to be tested, because even those 
 diseases that are certainly consequences of syphilis are 
 rare consequences, so that, from the side of s^qjhilis, it 
 is not easy to get an adequate view of them. It will 
 
AND THE NERVOUS SYSTEM. 29 
 
 also be convenient, in the case of many diseases, to 
 restrict the inquiry to the age at which syphilis is com- 
 mon and the sex in which it is most readily ascertained. 
 If the restriction is the same in each series compared, 
 the validity of the result is not affected. It is, there- 
 fore, wise to let the cases compared be those of males 
 only, and over twenty-five years of age. In some cases 
 it may be well to narrow the limit to cases between 
 twentj^-five and fifty. 
 
 The first task is to ascertain what is the average pro- 
 portion of males over twenty-five who have suffered 
 from syphilis. This term of the comparison (which 
 we may term " the standard ") will be the same for 
 all diseases. It is of great importance that it should 
 be ascertained, once for all, from a field sufficiently ex- 
 tensive to place the conclusion beyond the reach of 
 doubt. Although one standard will be sufficient for 
 all diseases, it will probably not be sufficient for all 
 classes or for all places, since it is probable that in both 
 class and place the frequency of syphilis varies. It is 
 probably greater in the lower than in the middle and 
 upper classes, greater in urban than in rural districts, 
 greater in seaports than in inland towns. Attempts 
 have been made abroad on a small scale to ascertain 
 the proportion, but not, I think, in this countr}^ I 
 regret that I am able to offer only a very small contri- 
 bution to it. I venture, however, to hope that the need, 
 once pointed out, may not be long unsupplied. Messrs. 
 Raymond-.Johnson and Marriott have kindly ascer- 
 tained the venereal history, positive and negative, of 
 112 cases at University College Hospital, and Mr. Little- 
 
30 LETTSOMIAN LECTURES ON SYPHILIS 
 
 wood that of 200 patients at the Leeds Infirmary. The 
 result is that in London there is a history of syphilis 
 (including in a few cases a certainly infecting sore 
 only) in 10.5 per cent., and of a chancre of uncertain 
 nature in another 10 per cent. At Leeds the percent- 
 age of sy23hilis, or hard chancre, is only 6.4, and of a 
 chancre of uncertain nature only 6 per cent. This 
 shows very clearly the need for more than one stand- 
 ard, but the want might be supplied without much 
 difficulty. A few months' observation by the registrars 
 of all the London hospitals would supply us with a 
 London standard, drawn from at least five thousand 
 cases, which would be available for all similar inquiries 
 for many years to come. 
 
 But the figures I have just mentioned place before 
 us at once one of the difficulties of the process of com- 
 parison. It is certain that some of the patients, who 
 give a history only of a chancre, have had an in- 
 fecting sore — but how many? What proportion of 
 the chancre-percentage should we add to the syphilis- 
 percentage to obtain the nearest approximation to the 
 truth ? Mr. Berkeley Hill and others, in this country 
 and abroad, have published analyses which show that 
 at least two-thirds of all venereal sores are infecting. 
 We have, however, already taken count of the cases of 
 certain syphilis, and of the remaining sores probabl}^ 
 the majority are not infecting. If we add to the per- 
 centage of syphilis one-quarter of the cases of chancre, 
 it will give us about 13 per cent, of syphilis in London, 
 and 8 j^er cent, at Leeds. 
 
 The proportion among the middle and upper classes 
 
AND THE NERVOUS SYSTEM. 31 
 
 is probably less than among the poor, and I doubt 
 whether it exceeds 10 per cent., even in London. The 
 difficulty of ascertaining it will be much greater than 
 among the poor. 
 
 In the other terms of comparison we ascertain in a 
 similar manner the percentage of syphilis among the 
 sufferers from the disease in question corresponding to 
 the standard in sex and age. If the proportion ex- 
 ceeds that of the standard, the excess must be due 
 either to the one disease being a cause of the other, 
 or to the fact that both are due to a common cause. 
 Obviously, however, the only conceivable relation is 
 that syphilis is in some way the cause of the disease 
 in question. If the excess is slight, and if the interval 
 is short, indirect causation is possible ; that is, syphilis 
 may have predisposed merely as any other depressing 
 disease may predispose. If the excess is considerable, 
 we must assume direct causation. 
 
 But the comparison itself is not quite a simple 
 matter. The significant fact is the excess of the 
 syphilitics among those who suffer from the disease, 
 and we have to ascertain this excess. It may seem 
 sufficient to deduct the percentage in the standard 
 from the percentage in the disease, and to consider 
 the difference as the percentage of causation. But 
 this would be erroneous, as an example will show. 
 Let us assume, taking simple numbers for con- 
 venience, that the percentage of syphilis in the 
 standard is 10, and in the disease 50. It is not right 
 simply to deduct 10 from 50, and assume 40 per 
 cent, causation. We start with 100 cases, and if we 
 
32 LETTSOMIAN LECTURES ON SYPHILIS 
 
 thus assume 40 to be the proportion of causation, we 
 have left 10 cases of accidental coincidence and 50 
 without syphilis. Thus we assume that in 10 cases 
 out of 60 there is mere coincidence, whereas our 
 assumed standard shows that in 60 persons there will 
 be only 6 with merely coincident syphilis. The true 
 method, I take it, maj be expressed in the following 
 rule: Deduct from the syphilitics the number that 
 bears the same proportion to the non-syphilitics as is 
 found in the standard ; the residue will represent the 
 causation. Thus in our example we must deduct 
 from the 50 syphilitics not 10, but 5.5, because not 
 10 but 5.5 bears the same proportion to 50 as 10 
 does to 90 (10 in 100), and the proportion in which 
 there is causation will not be 40, but 44.5. It is 
 certain that such a deduction for mere coincidence 
 is necessary in the case of diseases that are often due 
 to other causes, although it is open to consideration 
 whether this deduction is justified in the case of dis- 
 eases of which syphilis is the chief cause. But its 
 amount lessens in inverse ratio to the proportion in 
 which syphilis can be traced, and when this propor- 
 tion is high, the deduction becomes so small as to 
 be unimportant. If, for instance, syphilis can be 
 traced in 80 per cent, of the cases, the deduction for 
 coincidence would be less than 3 per cent. The error 
 from neglecting it will then be scarcel}^ appreciable, 
 especially in the face of the graver source of un- 
 certainty we have next to consider. 
 
 Whatever proportion of syphilis is found will fall 
 short of the truth. This is certain from the fact that 
 
AND THE NERVOUS SYSTEM. 33 
 
 persons occasionally suffer from syphilis and do not 
 know it, or know it only with a knowledge which 
 soon passes from their memory. Many persons who pre- 
 sent unequivocal signs of old syjDhilis can give^a history 
 only of a chancre, and others not even of this. We 
 meet with persons who know of no sore, who give 
 no history of syphilis, and yet have had the disease. 
 This fact is well known, but it is so important that I 
 venture to emphasize it with a few instances. A gen- 
 tleman had once, and only once, a slight sore. He 
 showed it to a doctor, who said it was of no importance, 
 and touched it with caustic. In a few days it was well, 
 and was soon almost forgotten, for no after-symptoms 
 occurred to keep it in mind. In a year or so he married 
 a lady in his own station. She bore him two dead chil- 
 dren, and then a living one. The latter soon showed 
 signs of syphilis, and became paralyzed and imbecile. 
 Then the wife herself died from the effects of the same 
 disease. Similar cases, we may hoj^e less tragic, must 
 be known to all of you — cases in which the transmis- 
 sion of the disease to others is the first proof of its 
 existence. A striking instance is the first case of pro- 
 gressive ophthalmoplegia in which the nature of the 
 lesion was proved. I suppose there is no one more 
 skilled in tracing syphilis than Mr. Jonathan Hutchin- 
 son, and yet in this case the search, many times renewed, 
 failed to reveal any indication of the disease ; there was 
 not even a venereal sore to suggest it ; but after the 
 man's death a child of his was brought to Mr. Hut- 
 chinson with interstitial keratitis and notched teeth. I 
 have met with many patients who had signs of the past 
 4 
 
34 LETTSOMIAN LECTURES ON SYPHILIS 
 
 disease, in some indubitable lesion of eye, tongue, throat, 
 or skin, who could give no history of a chancre. But 
 I am able to offer you more definite facts, for which I 
 am indebted to my friend Dr. Radcliffe Croker. He 
 has been kind enough to ascertain from his case-records 
 at University College Hospital the proportion of cases 
 of tertiary syphilitic skin eruptions in which there was 
 no history of a chancre. He has found 56 cases of such 
 eruptions, cases that are consecutive and unselected, 
 and in no less than 11 of these the occurrence of any 
 chancre was unknown. This is a proportion of 20 per 
 cent. It cannot be doubted, moreover, that besides 
 such cases there must be many more who have no late 
 symptoms whatever to reveal the disease. 
 
 These facts suggest a question most important in 
 regard to the problem we are considering, the actual 
 frequency of what may be termed latent syphilis, in 
 which the manifestations of the disease are insignifi- 
 cant, and are either unnoticed or untreated, so that, 
 years afterward, the memory of them is reduced to a 
 vanishing-point in the vista of the past. May not such 
 cases be far more frequent than is generally thought — 
 more frequent, indeed, than we can ascertain ? Besides 
 the facts I have mentioned there are others which, if 
 they do not suggest this conclusion, at least harmonize 
 with it and are explained by it. Many observers have 
 noticed how often severe late lesions have followed an 
 early stage that was slight or unnoticed. It has, indeed, 
 more than once been suggested that there is an actual 
 alternation in severity between the early and the late 
 effects. Such an alternation would explain the facts, 
 
AND THE NERVOUS SYSTEM. 35 
 
 but cases are frequent enough in which both stages are 
 alike severe. May not the frequent apparent alternation 
 be simply due to the great frequency of mild or latent 
 syphilis ? Take, again, the fact epitomized in what is 
 termed (abroad more often than in England) Colles'sLaw 
 — the fact that a woman who bears a syphilitic child, 
 although apjDarently free, is proof against infection, and 
 must therefore have suffered. It is supposed that preg- 
 nancy is in some way antagonistic to the activity of the 
 disease, but such antagonism is certainly often not 
 evident, and the anomaly may be equally explained 
 by the frequency of latent syphilis. 
 
 It is therefore certain that the facts we can ascertain 
 will fall short of the real facts, and will fall short of 
 them by a quantity which, because it is unknown, must 
 not therefore be neglected. Whatever the actual amount 
 of the discrepancy, its influence will be the greater the 
 larger the number of cases in which syphilis can be 
 traced. For instance, to take what may or may not be 
 an extreme proportion, let us suppose that S3'philis can- 
 not be ascertained in one quarter of the patients who 
 have suffered from it — that, besides the cases in which 
 there is clear evidence of the disease, there are one- 
 third more, on an average, in whom we cannot ascertain 
 it after the lapse of years. This would raise the pro- 
 portion of syphilitics among adult males to about 18 per 
 cent., but it would raise a proportion of 50 per cent, to 
 70, and of 60 per cent, to 80. To ascertain the mere 
 fact of causation we may indeed neglect the discrepancy, 
 but we must recognize, at least its existence, when we 
 endeavor to estimate the extent of causation. 
 
3G LETTSOMIAN LECTURES ON SYPHILIS 
 
 One last general remark. For the comparisons to be 
 significant the facts must, as a rule, be specially ob- 
 served. It is one of the many lessons of scientific 
 history, in no part more conspicuous than in medicine, 
 that facts observed without special reference to the 
 question at issue are of very little value for its decision. 
 
 On the second kind of evidence, that of therapeutics 
 — the influence of drugs on the disease — I must, and 
 can, be more brief. The considerations are not less im- 
 portant, but they are familiar, at any rate in the 
 abstract, and we shall have occasion to return to them 
 in discussing the problems of diagnosis. Unfortunately 
 the limitations to the use of this method are such as 
 to reduce very much its scientific value. 
 
 The chief conditions that must be secured may be 
 thus enumerated : (1) The effect of the drug must be 
 decided and unequivocal. (2) Its influence must not 
 be obscured by any other change in the measures em- 
 ployed, which might cause the improvement observed. 
 (3) The lesion must not be one of which the symptoms 
 tend to spontaneous subsidence. (4) The lesion must 
 not be one that can be influenced by the drug, when it 
 is not due to syphilis. (5) Before a negative result can 
 be admitted as evidence that the lesion is not due to 
 syphilis, we must be satisfied that the damage produced 
 is not so great that its manifestations cannot speedily 
 subside. These conditions render the process almost 
 useless for our present object. The method is applica- 
 ble chiefly to chronic lesions, in which the influence of 
 treatment can be clear and decided. Acute lesions, if 
 
AND THE NERVOUS SYSTEM. 37 
 
 they are slight, have too great tendency to subside, and, 
 if they are severe, have effects of too prolonged dura- 
 tion. 
 
 We may briefly glance at the lesions to which these 
 methods of proof apply. First, there are two import- 
 ant acute inflammations — those of the membranes of 
 the brain and of the substance of the spinal cord. 
 Are these ever due to syphilis ? Unfortunately, I can 
 only ask the question, and try to show how to obtain 
 the answer, which I am not able to give. That 
 syphilis causes chronic meningitis is one of the surest 
 facts of medicine. It causes chronic inflammation of 
 the membranes of the brain and of the spinal cord, 
 and either may be diffuse or focal. The latter is usually 
 in the pia mater, and is associated with the formation 
 of caseating new tissue. In the cord it usually begins 
 at the surface and involves the nerve roots, so as to give 
 rise to obtrusive radiating pains, or muscular wasting. 
 The diffuse inflammation more often involves the dura 
 mater and is attended with the production of fibrous 
 tissue constituting in the cord what has been called 
 " hypertrophic pachymeningitis," which compresses 
 the cord itself and gives rise to grave symptoms. 
 Within the skull bilateral headache and general con- 
 vulsions may be its expression, whereas the focal 
 inflammation gives rise to fits that begin locally. 
 These facts are very important in respect to diagnosis. 
 Whether syphilis also causes acute meningitis, such as 
 reaches a considerable degree of intensity in a few days, 
 is still uncertain. Analogy suggests that an acute 
 meningitis, like an acute iritis, may be due to it, 
 
38 LETTSOMIAN LECTURES ON SYPHILIS 
 
 but this is enough only to make us search for evidence. 
 Morbid anatomy, as we have seen, is not Hkely to sup- 
 ply an answer. The therapeutic test is of little value, 
 on account of its essential limitations, for we dare not 
 secure the absence of other influences ; we are bound to 
 do all we can for the safety of the patient, and there is 
 reason to believe that mercury may determine the sub- 
 sidence of an inflammation that is not syphilitic. I 
 have once known the symptoms of a general menin- 
 gitis to develop most acutely in a man who had suffered 
 from syphilis, and then to slowly pass away under the 
 influence of mercury ; but such a case can alone do no 
 more than raise or strengthen a suspicion ; it cannot 
 supply the needed proof. Acute meningitis is very 
 rare in adult men, but it does occur when we can 
 exclude syphilis, and hence the question of causa- 
 tion can be decided only by a series of cases. The 
 readiness with which acute meningitis is ascribed to 
 syphilis by some writers is astonishing, or would be 
 astonishing had not the capacity for wonder been 
 already diminished by the process of the diagnosis of 
 the disease. To quote one instance : A patient 
 suffered, for a few days only, from pain in one temple, 
 an elevation of temperature of half a degree Fahrenheit, 
 and diminished frequency of the pulse. This was con- 
 sidered to justif}^ the diagnosis, not indeed of menin- 
 gitis, but of a lesion safe in the region of hypothesis, 
 local congestion of the membranes. This assumed 
 lesion was further ascribed to syphilis, because the 
 symptoms occurred twenty-five days after — not definite 
 constitutional symptoms, not even after enlargement of 
 
AND THE NERVOUS SYSTEM. 39 
 
 the glands, not even after the primary induration was 
 discovered, but twenty -five days after the exposure to 
 infection ! We scarcely marvel after this to find that the 
 case is regarded as affording strong support to a theory 
 — indeed, as part of its proof — that the early symp- 
 toms of syphilis frequently include congestive lesions of 
 internal organs, especially of the nerve centres, which 
 are analogous to the early eruptions on the skin. I 
 think our time may be better occupied than by dis- 
 cussing this theory in detail. 
 
 The possible relation of myelitis to syphilis is one of 
 the most difficult problems connected with this subject, 
 and it is one on which definite evidence is speciall}'^ 
 needed. The term " myelitis," even in its narrower 
 sense, includes diseases widely different in their nature 
 and pathological relations, and these relations are still 
 imperfectly known. We can, however, distinguish 
 acute transverse myelitis, sub-acute disseminated my- 
 elitis, and acute poliomyelitis, as fairly well-defined 
 forms, which have distinctly different causation, and 
 the relation of each to syj)hilis must be separately 
 ascertained. In each form this investigation has still 
 to be made. The fact that special observations are 
 necessary renders it difficult for the evidence to be ob- 
 tained by any one person. It is certain that not one 
 of these forms is exclusively related to syphilis, and 
 it is not probable that the relation is, in any one of them, 
 so preponderant that the fact could be decided by a 
 small number of observations, for we must depend 
 almost entirely on the evidence of sequence. The 
 limitations to the method of therapeutics are here j^ro- 
 
40 LETTSOMIAN LECTURES ON SYPHILIS 
 
 hibitory. The course of the symptoms is no more guide 
 to that of the inflammatory process than is the course 
 of a cardiac murmur evidence of the course of the en- 
 docarditis to which it was due. If the inflammation 
 of the spinal cord is trifling, the tendency to sponta- 
 neous improvement deprives the subsidence of the 
 symptoms of any significance. Moreover, there are 
 some facts that suggest that the less acute forms may 
 be due to syphilis, and yet may not yield to its treat- 
 ment. In the case of an inflammation such a state- 
 ment seems self-contradictory, but in dealing with facts 
 we must lay aside all our preconceptions. I mentioned 
 just now a form of insular myelitis, possibly always 
 syphilitic in origin and specific in its distribution. 
 (To avoid confusion I may point out that in this form 
 the inflammation is in small islets ; in the common 
 form of disseminated inflammation larger scattered 
 tracts or areas are aff'ected.) If the insular mj^elitis is 
 syphilitic, it does not seem to be distinctly amenable to 
 treatment. In the cases hitherto observed the patients 
 have died. In some of them, as in my own, anti- 
 syphilitic treatment had no influence on the disease. 
 
 I have seen several other cases of sub-acute and sub- 
 chronic myelitis in syphilitic subjects, in which neither 
 iodide in large doses, nor mercury pushed to salivation 
 had any appreciable influence on the lesion, either on 
 its extension in the cord or its intensification in the 
 parts first aff'ected. This seems also to have been true 
 of the remarkable case of chronic caseating inflamma- 
 tion described by Charcot and Gombault, to which I 
 have already alluded as a lesion pathologically specific. 
 
AND THE NERVOUS SYSTEM. 41 
 
 Here, then, we are driven back on sequence for our 
 evidence of causation, and the needful observations, 
 serial and unselected, have yet to be made. The same 
 statement must be made regarding transverse myelitis, 
 the most common variety, recognizable during life 
 without much difficulty. My own experience is sug- 
 gestive only. I have seen several cases in which the 
 disease followed syphilis, more, I think, than mere 
 coincidence will explain. On the other hand, I have 
 met with no cases of acute poliomyelitis suggesting a 
 syphilitic causation, and the significance of a few cases 
 that have been published as evidence of such causation 
 seems to me open to doubt. We must remember that 
 the sub-acute form has only lately been distinguished 
 from peripheral neuritis, and the most common cause 
 of peripheral neuritis, alcoholism, is sometimes associ- 
 ated with syphilis as a consequence of mode of life. 
 
 Another acute affection of the sj^inal cord, the 
 mysterious acute ascending paralysis, has also been 
 supposed to be a result of syphilis, partly on the 
 ground of sequence, partly on that of recovery under 
 the influence of mercury. The proportion of pub- 
 lished cases in syphilitic subjects is certainly large, and 
 justifies careful investigation. In considering the in- 
 fluence of mercury we must remember that there is 
 some evidence that other acute toxic states besides that 
 of syphilis are modified by mercury. In the course of 
 some investigations made in 1885, at the Brown Insti- 
 tution, Dr. Cash discovered that animals, brought 
 under the influence of mercur}^, resist otherwise fatal 
 inoculation with the anthrax bacilli — a remarkable 
 
42 LETTSOMIAN LECTURES ON SYPHILIS 
 
 fact, which does not seem to have attracted the atten- 
 tion it deserves. We must also remember that the 
 syphilitic organisms may leave behind them a product 
 of a different nature which may not be amenable to 
 the influences which affect the organisms themselves. 
 
 Regarding the focal sclerosis of the nerve centres, 
 including what may be termed " chronic sclerotic in- 
 flammation," I have little to say. The evidence seems 
 to be against an}^ relation to S3''philis of true insular 
 sclerosis. Only future observations, for which we may 
 have long to wait, can determine the question as 
 regards certain other extremely rare forms of diffuse 
 sclerosis. A remarkable case of miliary degeneration 
 of the gray matter of the brain, published by me some 
 years ago, occurred in a syphilitic subject. Many years 
 ago I examined for Dr. Hughlings Jackson a brain of 
 an old syphilitic, which presented a remarkable indura- 
 tion of a large part of the white substance of one hemi- 
 sphere, without change in tint. (The history of this 
 case, unfortunately, we have been unable to trace.) 
 Lastly, sclerosis of the cortex in infantile sj'philis, as 
 we have already seen, may possibly be sometimes prim- 
 ary, although generally it is the result of inflammation 
 in infarcted areas. 
 
 The processes we have hitherto considered originate 
 either outside the nerve centres themselves, or, when 
 within the nerve tissue, are essentially interstitial. Of 
 all, therefore, it seems to be true that the primary mor- 
 bid process is independent of the nerve elements 
 themselves. These elements suffer just as they would 
 from any similar process, not syphilitic in nature. It 
 
AND THE NERVOUS SYSTEM. 43 
 
 is on these simple processes in the nerve elements, and 
 on these only, that most of the symptoms depend — a 
 fact of the utmost practical importance. 
 
 The spinal nerves seem to escape the influence of 
 syphilis, and the cranial nerves suffer chiefly at the 
 base of the brain, where several are involved in a focus 
 of inflammation. To this some of the nerves to the 
 eyeball seem to offer an exception ; they may suffer 
 alone. The facial nerves present a remarkable free- 
 dom. The nerves that arise from the side of the 
 medulla are often involved, especially the hypoglossal 
 and spinal accessory, causing palsy of the tongue, 
 palate, and vocal cord, on one side. These palsies are 
 seldom due to any other cause, so tliat their occurrence 
 should suggest syphilis at once to your mind. 
 
 Paralysis in the arm, due to deep cellulitis in the 
 neck, chronic and indurating, is another occasional 
 result. Note, however, that, as a rule, the spinal nerves, 
 if they suffer, do so only on one side and in conse- 
 quence of damage to their roots. 
 
 Until lately it was believed that the influence of 
 syphilis was limited to the production of such lesions 
 as we have hitherto considered. But modern observa- 
 tions, led by those of Fournier, have resulted in a con- 
 siderable amount of evidence that the effects of syphilis 
 are not thus limited — that the disease is followed by 
 lesions of a totally different nature, and is followed by 
 them in a way that admits of no other explanation 
 than that it causes them. These lesions are degenera- 
 tions of the nerve structures, with such a distribution 
 according to function as can be explained only by 
 
44 LETTSOMIAN LECTUKES ON SYPHIIIS 
 
 assuming that the process begins in the nerve elements 
 themselves. The relation of these " system degenera- 
 tions " to syphilis was first asserted in the case of tabes, 
 locomotor ataxy, and this disease is still the most con- 
 spicuous example, around which most of the contro- 
 versy has turned. The assertion that syphilis causes 
 lesions so totally unlike the known effects of the dis- 
 ease was sufficiently startling to be received with sur- 
 prise and suspicion, a suspicion not lessened by the fact 
 that the only evidence of the relation was, and still is, 
 that which depends on numbers for its weight. Various 
 objections were urged. It was said that syphilis could 
 not cause such disease ; that cases of true syphilitic 
 lesions had been mistaken for degenerations ; and that 
 if tabes were due to syphilis the lesion must be pri- 
 marily interstitial, and not a primary nerve-degenera- 
 tion. The common absence of benefit from anti-luetic 
 treatment was urged in support of the objection, and 
 the statistical evidence was met by other figures of 
 different significance, obtained from existing records. 
 Some of these arguments, however, were seen to be 
 untenable as soon as they were clearly stated. The 
 assertion that syphilis could not cause a lesion different 
 in nature from the effects previously known, was too 
 obviously a transfer to medicine of the method em- 
 ployed by Canute upon the sea-shore. The absence of 
 evidence of one kind, that of therapeutics, was mani- 
 festly no refutation of a totally different species of 
 proof. The comparison of statistics, moreover, resulted 
 in a curious and instructive episode in the history of 
 medicine. When those observers who had gathered 
 
AND THE NERVOUS SYSTEM. 45 
 
 their cases from old records came to make fresh obser- 
 vations on the subject, they found that the two sets did 
 not corresjDond. They found that the proportion of 
 syphiUs yielded by the special observations was much 
 higher, and in more than one instance the special in- 
 quiry transformed an opponent into a supporter of the 
 new opinion. It was one more instance of the fact I 
 just now mentioned — the uselessness of figures based 
 on observations not made with the special question in 
 view^ 
 
 The proportion of cases of tabes in which syphilis 
 has been traced by different investigators has varied 
 much — from 90 per cent, down to a proportion that has 
 been held to be not far above the range of accidental 
 association. Instead of detailing to you the various 
 statements that have been made, it may be more in- 
 structive to give the figures supplied by a consecutive 
 and unselected series of cases that has come under my 
 own observation. Of 170 cases of characteristic tabes 
 in males there was evidence of syphilis (in a few con- 
 fined to a chancre certainly hard) in 55 per cent. In 
 another 14 per cent, there was a history of a sore only, 
 of unknown nature. In only 31 per cent, could neither 
 be ascertained. Of the 170, 92 w^ere seen in private, 
 and 78 were hospital patients. The percentage of 
 syphilis in private cases was 57, in the hospital patients 
 52. Probably the difference is due to the more accu- 
 rate information to be obtained from those who are 
 most likely to notice and remember such diseases. It 
 is remarkable, however, that the proportion between 
 the cases of syphilis and the cases wdthout even a 
 
46 LETTSOMIAN LECTURES ON SYPHILIS 
 
 chancre is exactly the same in the two sets, as 11 to 6. 
 The difference in the percentage arises from the fact 
 that a history of a sore of unknown nature was ahnost 
 twice as frequent among the hospital as among the 
 private patients. In either series the addition to the 
 syphilitics of one quarter of the cases of chancre will 
 give about 60 per cent., and a deduction for mere acci- 
 dental coincidence would have at least 55 per cent, of 
 unquestionable causation. But it is certain that to this 
 a large addition must be made for untraceable syphilis. 
 These figures are obtained by placing all doubtful cases 
 on the negative side, including many with a strong 
 presumption of syphilis. If it is true that latent syphi- 
 lis is common, and if the disease can be proved to be a 
 cause of tabes in more than half the cases, is it not 
 almost certain that a large proportion of the remainder 
 are really due to it? In most of them no other cause 
 could be traced, and in not more than 5 per cent, of 
 the whole had there been no exposure to the risk of 
 infection. Although the method which discloses syphi- 
 lis in an exceedingly large proportion of the cases may 
 be open to question, I cannot but think that the ob- 
 servers who describe it in 75 or 80 per cent, are not far 
 from the real truth. 
 
 Not only is the relation of syphilis to tabes beyond 
 reasonable doubt, but we are beginning to discern that 
 there are other diseases that stand in a similar, 
 although unequal, relation to the disease. One other 
 group of degenerations we can, indeed, connect with 
 syphilis as surely and as extensively as tabes — the de- 
 generative ocular palsies, which, often associated with 
 
AND THE NERVOUS SYSTEM. 47 
 
 tabes, occur also alone. There is strong evidence of a 
 similar relation in simple atrophy of the optic nerve. 
 Among the motor palsies, one of the most important to 
 the physician, although the least important to the pa- 
 tient, is the isolated loss of the light-reflex of the iris, 
 with which the name of Argyll-Robertson is connected. 
 I have notes of only twenty-two cases in which this 
 symptom existed apart from other degenerative affec- 
 tions of the nervous system, but I believe that it is 
 much less rare than this number might suggest. It is 
 seldom looked for, unless other symptoms suggest de- 
 generative disease. Of these twenty-two cases, syphilis 
 was certain in twelve, and highly probable in three 
 others, while two more had a history of a venereal sore. 
 In six cases there was no history or evidence of either 
 syphilis or a chancre ; nevertheless, two of them had 
 had an attack of sudden hemiplegia in early adult life, 
 without any indication of a cause of embolism — an 
 event that always affords ground for suspecting syphilis. 
 From these facts we may feel confident that syphilis 
 existed in two-thirds of the cases, and we may susjDect 
 that it existed in three-cjuarters. One of the cases was 
 a young girl, the subject of inherited syphilis, and 
 another case was this girl's mother. 
 
 The relation of this symptom to syphilis makes it 
 one of great practical value. It proves that a degener- 
 ative process is at work in the nervous system, and it 
 raises a strong presumption that this process is the re- 
 sult of syphilis. It is true, the dependence on central 
 degeneration has not been proved by observation, but 
 the indirect evidence of it is very strong. 
 
48 LETTSOMIAN LECTURES ON SYPHILIS 
 
 The more extensive palsies, external and internal, to 
 which the term " ophthalmoplegia " has been applied are 
 much more rare. They occur in syphilitic subjects in as- 
 sociation with tabes, and also alone, as was clearly proved 
 by Mr. Jonathan Hutchinson. In the case of external 
 ophthalmoplegia, in which I made an examination of 
 the nerve centres, preceding syphilis was certain (the 
 evidence I have already mentioned), and the lesion was 
 as pure a nerve-degeneration as can be conceived. But 
 these diseases, like tabes, are not exclusively related to 
 syphilis ; they certainly occur, now and then, in persons 
 in whom syphilis can be excluded. 
 
 This evidence seems to leave no room for doubt. It 
 receives, moreover, a strong emphasis from the remark- 
 able fact that nerve-degenerations such as succeed ac- 
 quired syphilis in the adult, are met with also in young 
 persons who are the subjects of the inherited disease. 
 Such cases, it is true, are rare, but their rarity may be 
 due, less to any difference in the influence of the disease, 
 than to the greater vital stability possessed by younger 
 tissues. I have met with several examples, and their 
 interest may justify a brief mention of some. One case 
 was a lad who, in infancy and early childhood, suffered 
 much from various manifestations of syphilis, includ- 
 ing slight hemiplegia and choroiditis. At the age of 
 seventeen the symptoms of locomotor ataxy were dis- 
 tinct. There was unsteadiness in standing and walking, 
 there had been lightning-pains, and no trace of the 
 knee-jerk could be obtained. It was difficult to ascer- 
 tain when the symptoms commenced ; the unsteadiness 
 had onl}^ attracted attention during a year or so. A 
 
AND THE NERVOUS SYSTEM. 49 
 
 second case was that of a girl aged fifteen (seen through 
 the courtesy of Mr. Nettleship). She had typical teeth, 
 and traces of characteristic inflammation in cornea and 
 choroid. The left knee-jerk was absolutely lost, and 
 only a very slight movement could be obtained on the 
 right side. There was no ataxy or aneesthesia. In 
 each iris the light reflex was quite absent, although 
 there was full action to accommodation, and vision in 
 one eye was normal. In another case the disease was 
 thought to be pseudo-hypertrophic paralysis because 
 there was no knee-jerk and the child rose from the 
 floor with difiiculty. 
 
 Another malady of great importance in regard to 
 which this question has arisen is general paralysis of 
 the insane. The disease is probably to be classed with 
 primary nerve-degenerations, but in many cases, it 
 would seem, the secondary changes attain a very con- 
 siderable independence of degree. Its close alliance 
 with tabes is shown by the conditions of age and sex in 
 which it occurs, by the degenerative ocular palsies 
 common to the two, and by their actual combination 
 in many instances. This would lead us to expect a 
 similar relation to syphilis. The scientific proof, how- 
 ever, is beset with many difficulties. The statistics ob- 
 tained have varied greatly, but no less than 75 per cent. 
 of certain syphilis is described by Mendel in 146 cases. 
 A proportion almost as large has been met with by 
 others. One serious difficulty arises from the great va- 
 riations presented by the disease. Typical cases form 
 a minority of those that may be classed under the gen- 
 eral name, and both the typical and untypical forms 
 5 
 
50 LETTSOMIAN LECTURES ON SYPHILIS 
 
 certainly may occur independently of syphilis. I believe, 
 however, that syphilis can be traced in a large propor- 
 tion of each distinguishable variety, although I am not 
 able to offer you any definite figures. Fournier has 
 pointed out how often symptoms resembling more or 
 less closely those of general paralysis seem to result 
 from organic syphilitic lesions of the brain, and I believe 
 that the explanation of this is to be found, less in the 
 fact that the organic diseases cause these symptoms, 
 than in the profound degenerative tendency which so 
 often results from syphilis. This tendency may accom- 
 pany the organic lesion, and is perhaps sometimes 
 actuall}^ excited by it. I have occasionally observed 
 that degenerative symptoms, mental and articulatory, 
 may distinctly come on soon after a sudden organic 
 syphilitic lesion, and may subsequently lessen, and 
 even pass away. 
 
 Another central degeneration that is probably an 
 occasional consequence of syphilis is chronic muscular 
 atrophy, due to degeneration of the motor cells, with or 
 without the signs of lateral sclerosis. Great care is 
 necessary to avoid the error of mistaking for this the 
 atrophy that results from syphilitic pachymeningitis. 
 In several cases that I have seen, the true degenerative 
 afi"ection has been an early sequel of syphilis, and no 
 other cause could be traced. Similar cases have been 
 published by others, but they do no more than suggest 
 the relation, although they suggest it strongly, and my 
 own notes do not enable me to offer any statistical evi- 
 dence on the question. The difficulty of the investiga- 
 tion is increased by the large number of cases of senile 
 
AND THE NERVOUS SYSTEM. 51 
 
 character. The exclusion of these would simplify, 
 without hindering, the search for evidence. The inves- 
 tigation should thus be restricted to cases commencing 
 between twenty-five and fifty, the standard being 
 limited to the same age. 
 
 The other common degenerative diseases of the 
 spinal cord are associated with syphilis only, in a pro- 
 portion so small as to raise a doubt whether there is 
 any causal relation between the two. Nevertheless, 
 they occasionally follow syphilis when no other cause 
 can be traced. 
 
 This is especially true of primary lateral sclerosis, 
 that probably often underlies spastic paralysis. Ataxic 
 paraplegia, the combined effect of lateral and posterior 
 sclerosis, seems to be very seldom preceded by syphilis. 
 
 It must be admitted that the relation of these degener- 
 ative diseases to syphilis is a startling extension of our 
 knowledge of its influence. And yet, jDerhaps, our 
 surprise is not altogether justified. Other facts exist 
 which, if they do not lessen the marvel, at least may 
 prepare us for it. "We are familiar with the influence 
 of chemical poisons on certain parts of the nervous 
 system, — with the way in which atropine, curara, digi- 
 talis, and strychnia select for isolated derangement 
 certain nerve elements, leaving adjacent structures 
 unaffected. This must be the result, not only of the 
 nature of the poison, but also of the nature of the 
 nerve elements influenced, through which they, and 
 they only, have a responsive susceptibility. That an 
 organized virus may exert a similar elective influence, 
 
52 LETTSOMIAN LECTURES ON SYPHILIS 
 
 the symptoms of hydrophobia clearly show, and those 
 of whooping cough at least suggest. Further, it is, I 
 think, most important to note that the phenomena and 
 pathology of diphtheritic paralysis demonstrate that an 
 acute degeneration of certain nerve elements may also 
 be the effect of an organic virus. We may note, also, 
 that the effects of the poison of diphtheria sometimes 
 so closely resemble those of the poison of syphilis, that 
 cases of diphtheritic paralysis have been repeatedly 
 mistaken for tabes, and we have seen that syphilis has, 
 like diphtheria, a special tendency to derange an intra- 
 ocular muscle. Still further, in the circumstance that 
 the palsy is a sequel rather than a concomitant of 
 diphtheria, we have a fact that is most significant, and a 
 fact whose significance is not destroyed by the differ- 
 ence of interval in the two cases, since the difference of 
 interval is not proportionately greater than is the differ- 
 ence in duration of the primary maladies. Diphtheria 
 runs its course in a few days, and its effects on the 
 nervous system are developed in weeks or months. 
 Syphilis lasts, in the stage of a blood disease, at least 
 for months, and perhaps for much longer, and its effects 
 on the nervous system are developed only in the course 
 of years. But there is possibly even more than an anal- 
 ogy between the effects of the two diseases. I have 
 seen a few cases in which there was evidence of a per- 
 sistent, and even a progressive, lesion of the spinal cord 
 after diphtheria, and I have seen three cases in whom 
 true primary atrophy of the optic nerves, with partial 
 external ophthalmoplegia, was a distinct degenerative 
 sequel to diphtheria. 
 
AND THE NERVOUS SYSTEM. 53 
 
 It may, I believe, be regarded as a general law, and 
 a law of much importance in practical diagnosis, that 
 the isolated impairment of nerve structures that have a 
 certain function, when acute, indicates a toxic influence 
 — when chronic, a degenerative process. It is instruc- 
 tive to note that these two mechanisms are not entirely 
 dissociated — that the degenerative process may be the 
 late result of a toxic agent. * 
 
 The problems we have last considered have an 
 interest which is at present, alas, purely scientific. It 
 is a strange anomaly, this scourge of the sinister side 
 of civilized life. Its direct effects we can control more 
 than those of any other malady of like nature, and yet 
 both the essential element of the disease, and its remote 
 
 *It has, indeed, become highly probable that they are due to a toxic 
 agent that is produced by the syphilitic organisms, and is left by them 
 in the system — an agent that may be a chemical material and not an 
 " organized virus. " This was suggested by Strlimpell. (Neur. Cent., 
 1889, p. 547. ) The theory agrees with the fact that other acute specific 
 diseases, more acute in course, seem to have a like effect, since they may 
 be followed, even after some months, by degenerative multiple neuritis. 
 (See ' ' Manual of Diseases of the Nervous System, ' ' vol. i. ) This 
 theory enables us to understand why the treatment that is so powerful 
 over the true syphilitic has no influence on their degenerative states 
 — a point to which we shall return. We can also understand the 
 bilateral symmetry of the symptoms, so different from the irregular 
 distribution of the true syphilitic lesions. It is assumed that the 
 latter are due to the^fixation of germs and their development in the 
 tissues, while the degenerations result from the influence on the nerve 
 elements of the toxic agent circulating in the blood reaching all parts 
 and affecting those that possess a similar susceiitibility, which, of 
 course, corresponds on the two sides. 
 
 The hypothesis was suggested by Strlimpell before the delivery of 
 these lectures, but had not then come to my knowledge. 
 
54 LETTSOMIAN LECTURES ON SYPHILIS. 
 
 effects, seem alike beyond our reach. But the knowl- 
 edge that is not power now may be power in the future. 
 When the specific organism has been identified and 
 isolated — when it has yielded the secret of its life his- 
 tory — then we may look for means, if not of destroying 
 it, at least of modifying its processes and effects, and of 
 modifying them not only in the experimenter's flask, 
 but within the human body. Until this can be accom- 
 plished, the light of research does but reveal, in vaster 
 range and more complete detail, the grim features of 
 the malady. Still, the light is welcome. We see how 
 far the grasp of the disease extends into regions believed 
 to be beyond its reach. We see how long its conse- 
 quences endure, and that they live on after the disease 
 itself has ceased to be a power for evil, but we see also 
 how much more vast than was formerly conceived 
 will be the saving influence of prevention or of cure, 
 when the knowledge that is power is in our hand. 
 
LECTURE II. 
 
 Mr. President and Gentlemen, — From the ques- 
 tions of pathology and causal evidence that occupied 
 us in the last lecture we pass to-night to subjects 
 of more immediate practical interest — those of symp- 
 toms and diagnosis. The transition may perhaps 
 bring with it a sense of relief, but, unfortunately, it 
 brings with it no escape from the difficulties in which 
 the subject is involved, and which surround, not less 
 closely and scarcely less consciously, its practical 
 aspects. 
 
 First, however, I should supply one omission in the 
 last lecture. To the long list of maladies, the certain 
 or supposed consequences of syphilis, should be added 
 some of the functional diseases of the nervous system. 
 By some authorities it is thought that such diseases 
 as epilepsy, hysteria, insanity, and neuralgia, in their 
 purely functional form, are frequent consequences of 
 the influence of the virus on the nerve elements 
 during the period of its greatest activity. Time fails 
 me for any discussion of the subject, but there are 
 two points that are especially important in any 
 examination of the subject. The first is that if any 
 special forms of functional disease seem to be ex- 
 clusively related to syphilis, it is essential that the 
 positive evidence from the side of syphilis should 
 
 55 
 
56 LETTSOMIAN LECTURES ON SYPHILIS 
 
 be supplemented and confirmed by negative evidence 
 that these s^Decial and peculiar forms do not occur 
 apart from syphilis. Secondly, if the forms asso- 
 ciated with syphilis are not special, it is needful to 
 consider most carefully the question of indirect causa- 
 tion. The causes of these diseases are many and 
 various, and they are widely prevalent. Some of the 
 most potent are involved in the conditions and influ- 
 ences inseparable from constitutional syphilis and its 
 treatment, in which physical depression and mental 
 annoyance are sometimes combined with a reaction 
 from a life of intense excitement of body and mind. 
 It is also necessary to ascertain and allow for every 
 traceable predisposition, and likewise to see that the 
 therapeutic evidence is secured from fallacy b}^ a rigid 
 observance of the conditions that were mentioned in 
 the last lecture as being essential. I cannot help 
 thinkiug that these measures would alter consider- 
 ably the aspect of much of the evidence on which 
 the opinions rest, and would remove the uncertain 
 to an extent that would reduce the certain to its 
 vanishing point. 
 
 In the diagnostic study of symptoms we still feel 
 the pressure of the antagonism I mentioned at the 
 outset. The success, incomplete though it be, with 
 which we are able to treat syphilitic diseases of the 
 nervous sj'stem, renders it impossible to obtain a 
 knowledge of their s3anptoms as extensive or as 
 certain as we have gained in the case of most other 
 maladies. We can attain certainty, or at least the 
 
AND THE NERVOUS SYSTEM. 57 
 
 high probability, which in medicine has generally 
 to do duty for certainty, onl}^ by confining our atten- 
 tion to cases in which post-mortem evidence places 
 the nature of the disease beyond doubt. But if we 
 thus restrict oul' attention to these certain facts, 
 and our inferences to the sure conclusions we can 
 draw from those facts, our knowledge will be at once 
 small in extent and imperfect in character. It will be 
 based only or chiefly on cases of great severity, and 
 the effects of slighter forms and degrees of disease 
 will, to a large extent, escape us. If we include the 
 latter in our investigation, we are upon ground which 
 is always insecure, and often treacherous ; for an un- 
 certainty, varying with the knowledge and care of the 
 observer, will attach to a large number of our conclu- 
 sions. This uncertainty ought to be frankly admitted. 
 If we recognize its existence, if we employ the prob- 
 able conclusions as such, and do not impute to 
 them the certainty they lack, we may use them, or 
 many of them, without much risk of being misled. 
 To obtain the greatest practical power, we must, on 
 the one hand, be often content with probabilities 
 that are not high, but, on the other hand, we must 
 use these probabilities as such, and trust them only so 
 far as their nature Avarrants. Thus we may obtain 
 knowledge of the highest value, in which we can place 
 implicit confidence. 
 
 In the practical diagnosis of these diseases, just as 
 in their scientific investigation, it is necessary to weigh 
 carefully each step in the reasoning, and to do so far 
 more carefully than in the case of many other 
 
 6 
 
58 LETTSOMIAN LECTURES ON SYPHILIS 
 
 maladies. Remember that the amount of conscious 
 and deliberate attention to the process of inference, 
 which it is desirable to give, varies much in different 
 kinds of disease. It should always be reduced to 
 the least amount that is consistent with safet}^ but 
 no further. So far, however, we must go. Did 
 we weigh with care each step in every diagnostic 
 act, the limits of patience and of life would be 
 reached before a quarter of the work had been 
 done that might otherwise be accomplished. Here, 
 as so often, our proceeding has to be based on a com- 
 promise between the ideal and the adequate. Uncon- 
 scious inference enters, of course, largely into the 
 simplest so-called " observations," and into such diag- 
 nosis as seems to consist of pure observation. Still 
 larger is the share it takes in the recognition of 
 diseases that are inaccessible to direct observation, 
 and yet yield " physical signs " of their presence. 
 But, in the latter case, we can allow it to remain 
 unconscious without much risk of error, and we 
 habitually do so, and even speak of " finding " a 
 pneumonia or a pleurisy without a suspicion of error 
 in our language, although we really infer the existence 
 of the lesion by a series of mental processes that would 
 be of considerable length if the steps were distinguished. 
 Our short cuts, in such cases, involve little danger to an 
 observer who has been properly trained. But the lesions 
 in the nervous system are wholly beyond the range of 
 observation, however aided, and with all our looseness 
 in the use of words, we do not speak of " finding " a 
 cerebral hemorrhage, or even a cerebral tumor, during 
 
AND THE NERVOUS SYSTEM. 59 
 
 life. Ill purely inferential diagnosis, in which the 
 disease manifests itself only by effects that are not 
 only indirect, and, indeed, often doubly indirect — 
 the effects of effects of the lesion — we cannot dis- 
 pense with the careful consideration of each step we 
 take. This statement is eminently true of the dis- 
 eases we are now considering, because in them we 
 have to deal not only with the character of the 
 lesion, but also with its nature. 
 
 The fact indicated in the last words is the first im- 
 portant consideration in regard to the nature of the 
 diagnostic process. The process is, and must be, always 
 a double one. Of the two parts, one should always be 
 taken before the other. We should always ask what is 
 the seat and what is the nature of the morbid process, 
 before we attempt to decide whether or not it is specific 
 and due to syphilis. In greater detail, the essential 
 steps are these : (1) What is the seat of the lesion, as 
 indicated by the symptoms, and what is its nature as 
 shown by their course? (■^) Is the process thus indicated 
 one of those that may be syphilitic? (3) Has the patient 
 had syphilis ? (4) Can any other cause of such a morbid 
 process be traced? (5) Lastly, and subsequently, we 
 have to see whether the result of treatment confirms 
 our conclusion. The last element is different from the 
 rest in character and separate in time. Its considera- 
 tion involves questions that will come under our notice 
 in the next lecture, and, moreover, are those we exam- 
 ined in considering the scientific use of the therapeutic 
 test. They need not, therefore, detain us to-day. But the 
 other steps we must consider in the abstract, because 
 
60 LETTSOMIAN LECTURES ON SYPHILIS 
 
 the only mode of avoiding error in these cases, and of 
 reaching as sure a conclusion as the conditions permit, 
 is to treat each case as a new problem, irrespective of 
 other cases or generic types, and to work it out by tak- 
 ing each stei3 separately — com^^aring the steps only at 
 the end of the process. 
 
 One of these questions — whether any other cause can 
 be traced — may seem superfluous, when we are dealing 
 with processes that have no other cause than syphilis. 
 But this statement of " no other cause " is true only of 
 the pathological lesion. Most syphilitic ]3rocesses have 
 their analogues in processes that are not syphilitic. 
 The effects of the two on the nerve elements may be 
 the same, and the symptoms due to those effects may 
 be the same. A gumma of the cortex, and a glioma in 
 the same part, may produce identical symptoms. The 
 consequences of the occlusion of an artery by syphilitic 
 disease and by embolism may absolutely correspond. 
 The element of specificity, therefore, is absent during 
 life. There are no symptoms of which we can say, as 
 we can of post-mortem aspect, " this proves a specific 
 lesion," There are no symptoms, and no combinations 
 of symptoms, produced by syphilis, that are not also 
 produced by other causes. 
 
 While all specific processes have their simple ana- 
 logues, there are many simple processes that have no 
 specific analogues, and many of these are manifested 
 by characteristic symptoms. Some of these simple 
 processes may be due to syphilis, as we have seen, but 
 even then they are not specific ; so far as we can dis- 
 cern, they are simple. If they are due to syphilis, they 
 
AND THE NERVOUS SYSTEM, 61 
 
 are certainly not influenced by treatment as the specific 
 lesions are. Thus, while there are no symptoms that 
 prove a specific lesion, there are many symptoms that 
 prove that a lesion is not pathologically specific. 
 
 Hence arises the paramount importance of consider- 
 ing, in the first instance, what kind of lesion the symp- 
 toms indicate. To neglect this question, to conclude 
 that because a patient has a disease of the nervous 
 system, and has had syphilis, the disease is syphilitic, 
 is a proceeding precisely the same as if we assume that 
 a sore throat is syphilitic without looking at it. If a 
 syphilitic person has an attack of hst-matemesis, it 
 would not be considered quite logical to assume at once 
 that the hcematemesis was of syphilitic origin, and yet 
 observed facts actually afford more justification for this 
 opinion than for the conclusion that paraplegia of 
 absolutely sudden onset is due to syphilis. We know 
 that syphilis has caused hemorrhage into the stomach, 
 but we are not certain that it has caused hemorrhage 
 into the spinal cord. 
 
 Thus a consideration of the kind of lesion that must 
 exist to cause the symjDtoms may enable us to say one 
 of two things — either that the process is one that may 
 be specific, or that it is one that cannot be specific. To 
 deal with these indications in detail would be to enter 
 into the whole region of the diagnosis of diseases of the 
 nervous system. There are, however, two conditions 
 to which almost all specific lesions conform, one of 
 time, the other of place. First, true specific lesions are 
 generally either sudden, or sub-acute, or sub-chronic. 
 An acute onset — acute, not actually sudden — practically 
 
62 ■ LETTSOMIAX LECTURES ON SYPHILIS 
 
 means acute inflammation, and we saw in the first lec- 
 ture that the occurrence of acute syphilitic inflamma- 
 tion must be considered as still sub jud ice. As a matter 
 of fact, the symptoms of certainly specific lesions very 
 seldom develop to a considerable degree in less than a 
 week. Tliey are also very seldom actually chronic — 
 seldom occupy more than three months in develop- 
 ment. An actually sudden onset, however, is not at 
 all rare ; it is the common onset of the symptoms due 
 to vascular occlusion. With these exceptions, when 
 symptoms develoj) in a few days or many months, they 
 are not likely to be due to a true specific lesion. The 
 degenerative sequelte are, of course, chronic in onset, 
 but they are not truly specific. Moreover, the chronic 
 interstitial inflammations, doubtfully specific, are also 
 chronic. 
 
 Secondly, as to place. The specific processes are, as 
 we have seen, outside the nerve-elements, and they 
 have therefore no special relation to the nerve-functions. 
 Hence their effects are random in distribution. They 
 are related to a special function only when that func- 
 tion is subserved by one region, and this is so rare 
 as to be of little practical importance. As a general 
 rule, if we find certain structures of common function 
 selected, for isolated impairment from among others of 
 difterent function, we may be sure that we have not to 
 deal with a true specific process. It maj'' be a post- 
 syphilitic degeneration, but it is not a really specific 
 lesion. These two indications are thus chiefly of im- 
 portance as enabling us to exclude processes that are 
 not syphilitic. 
 
AND THE NERVOUS SYSTEM. 63 
 
 Assuming that we have evidence of a process that 
 may be specific, we can often go a step further, and say 
 that, from the symptoms, it is likely to be specific. But 
 before doing this, it is desirable to ascertain whetlier, 
 in the case before us, this possible cause can be traced 
 The lesion may be due to syphilis — is this particular 
 cause an actual antecedent in the case before us? In 
 every department of diagnosis, the fact that a certain 
 cause can be traced may always justly be allowed 
 weight. It must never take precedence of more direct 
 evidence of the nature of the lesion; but in due sub- 
 ordination, it is an indication of great value. Hence 
 the next question is, has the patient had syphilis? 
 At least, this is the form in which the question is com- 
 monly put; and in many cases this form is sufficient. 
 But we must not be content with a negative answer. 
 We have already seen that some of those who have 
 had syphilis do not know it. We cannot absolutely 
 exclude syphilis unless we can exclude infection. The 
 disease is so seldom contracted excej)t in one way, that 
 we need not take other possibilities into consideration. 
 Hence, if there has been an}^ possibility of exposure to 
 infection, the disease cannot be considered to be out of 
 the question. The truth and importance of this will 
 be doubted by no one who has seen much of the late 
 effects of syphilis, but to those under whose notice the 
 disease seldom comes, it may seem scarcely credible. 
 Indeed, as a matter of fact, few statements are more 
 often doubted. 
 
 In connection with this point, the question arises, — 
 presuming the disease to be possible, what influence 
 
64 LETTSOMIAN LECTURES ON SYPHILIS 
 
 should uncertainty as to the fact of S3^philis have on 
 the diagnosis? How far should probability of the 
 syphilitic nature of the lesion be diminished by the 
 improbability of past syphilis, and vice versa f I think 
 that the common error is to allow too much weight to 
 this element of uncertainty, but it is an error that is 
 not easily avoided. The symptoms, in a given case, 
 are of such a character that their cause may be a 
 syphilitic process ; if the patient is known to have had 
 syphilis, the syphilitic nature of the process seems 
 more probable than if his syphilis is doubtful. It is 
 right to attach som.e weight to the point, but the weight 
 should be attached to the element in the diagnosis to 
 which it properly belongs — the element of probabilit3^ 
 It must not be allowed to influence any distinct indi- 
 cations of either a positive or negative character. If, 
 for instance, the symptoms are such as distinctly indi- 
 cate a syphilitic lesion, a lesion scarcely ever due to 
 any other cause, it is evident that this indication is not 
 really influenced by the fact that the evidence of syph- 
 ilis is inconclusive, provided the disease is possible. 
 On the other hand, if the symptoms are such as to 
 make it most unlikely that the process is syphilitic, 
 this improbability is not materially lessened, even by a 
 certainty that the patient has had the disease. 
 
 If the lesion is one that may be syphilitic — if pre- 
 vious syphilis is certain or possible — the question arises, 
 Can any other cause of such a morbid process be 
 traced? If any other cause exists, the difficulty is 
 greatly increased. The diagnosis then depends on a 
 comparison of the precise character, first, of the lesions 
 
AND THE NERVOUS SYSTEM. 65 
 
 produced by the two causes with that indicated by the 
 symptoms, secondlj^, of the symptoms by which the 
 lesions are manifested with those presented by the 
 patient. 
 
 This abstract outHne of the process of diagnosis may 
 seem to you needlessly complex. You may think that 
 these considerations are purely theoretical, but they 
 actually represent, in the simplest form, the essential 
 processes adopted in actual diagnosis. I give them in 
 the abstract, because their application varies in each 
 case, and for their effective use familiarity with their 
 princijDles is essential. 
 
 It must, however, be frankly admitted that exact 
 diagnosis of the nature of these specific lesions is some- 
 times imjDOSsible. The symptoms may be equivocal, 
 such as may be produced by more than one syphilitic 
 process, but we can generally narrow the probabilities 
 to two lesions. 
 
 We may now consider the symptoms of a few of 
 these specific processes. A S3q3hilitic gumma causes, 
 for the most part, symptoms like those of any other in- 
 tracranial tumor of rapid growth — general cerebral 
 symptoms, and focal symptoms due to the local influ- 
 ence of the growth. The special features are never more 
 than suggestive. They depend on the course, and also 
 on the fact that gummata are rather more frequent in 
 certain parts than in others. The course, like that of 
 other specific lesions, is sub-acute or sub-chronic ; the 
 seat is generally suj)erficial, in the cortex or at the 
 base, sometimes within the pons, seldom in the cere- 
 bellum, occasionally in the thalamic region, growing 
 
66 LETTSOMIAN LECTURES ON SYPHILIS 
 
 in from the side of the crus. Hence symptoms of 
 cortical irritation are relatively more frequent than in 
 other tumors, and convulsions are common. They 
 give most important information from their local dis- 
 tribution or commencement, or from the aura that 
 equally indicates the spot at which the discharge 
 begins. But all these indications, even when com- 
 bined, furnish no absolute or even approximate 
 ground of distinction. They may be, and, indeed, 
 often are, produced by growths of other nature, espe- 
 cially by gliomata of rapid growth. 
 
 The indication of the course of the lesion afforded 
 by the symptoms is chiefly useful for its negative 
 significance ; a very chronic growth is not likely to be 
 syphilitic. On this point we may gain instructive 
 information from the ojDtic neuritis that is so often 
 present, the course of which generally shows the course 
 of the disease of the brain. Syphilomata always cause 
 an acute form of optic neuritis, becoming intense. A 
 rapid growth never causes a chronic form of neuritis, 
 although now and then a slow growth may cause an 
 acute form. Hence, while acuteness of the neuritis is 
 of little diagnostic value, chronicity — a neuritis that 
 remains for a long time moderate or slight in degree- — 
 is distinctly opposed to the diagnosis of a syphilitic 
 growth, and adds considerable weight to the similar 
 indication afforded by great chronicity of other symp- 
 toms. This indication is especially valuable when the 
 early symptoms are equivocal, and we find it difficult 
 to say how long the tumor has existed. 
 
 These growths are among the specific lesions in 
 
AND THE NERVOUS SYSTEM. 67 
 
 which the effect of treatment is of most diagnostic 
 vakie. It usually causes a prompt diminution in the 
 symptoms, but, to be of significance, this diminution 
 should be considerable, and should involve both sets of 
 S3anptoms, the local and general. It is a remarkable 
 but certain fact, that now and then a considerable 
 diminution in symptoms of other kinds of tumors, and 
 especially in the general symptoms, sometimes follows 
 the administration of potassium iodide. The effect is 
 most frequent in gliomata, and these are the growths 
 that give rise to most difficulty. Sometimes even the 
 optic neuritis may lessen, but more often it is un- 
 changed, and this should put us on our guard. In 
 estimating the significance of the subsidence of the 
 neuritis, we must remember that every intense inflam- 
 mation, after it has reached its height, slowly subsides, 
 although the tumor that has caused it continues to 
 grow. We must not mistake this natural subsidence 
 for the result of our treatment. This therapeutic diffi- 
 culty can only be met by waiting and watching. If any 
 of the symptoms return or increase, if any symptoms 
 persist that would be readily influenced were the 
 growth syphilitic, we must assume that it is not likely 
 to be of this nature. The 'delay cannot be avoided, 
 but it is a grave disadvantage, because the progress 
 of surgery has so greatly increased the need, not only 
 for exact, but for prompt diagnosis. 
 
 The chronic local meningitis of syphilis causes dis- 
 tinctive symptoms chiefly when it affects the base of 
 the brain and damages the cranial nerves, or when, at 
 the convexity, it implicates the motor region. The 
 
68 LETTSOMIAN LECTURES ON SYPHILIS 
 
 symptoms are such as indicate a surface lesion, and the 
 absence of the signs of any considerable loss of func- 
 tion of the subjacent tissue is the chief distinction 
 from a gumma in the same situation. Especially when 
 the symptoms indicate a wide area of irritation with 
 merely superficial damage, the diagnosis can be made 
 with considerable probability. This focal meningitis 
 is probably less frequent at the convexity than are 
 gummata, and it is certainly less frequent there than at 
 the base of the brain. In the latter situation the most 
 important symptoms are due to the damage to the 
 cranial nerves, and the most important diagnostic 
 points are well known. The therapeutic test is avail- 
 able only in recent cases of meningitis. When the 
 develojiment of the new tissue into fibres has set in, 
 this seems to go on in spite of treatment, and the inev- 
 itable cicatricial contraction may perpetuate the damage 
 produced in the more active stage. In a case of focal 
 meningitis that has lasted for some months, although 
 it may afterward be proved to be syphilitic in nature, 
 the symptoms are generally influenced but little, and 
 occasionally not at all, by anti-syphilitic treatment, 
 however energetic. The other forms of meningitis, 
 cerebral and spinal, interesting and important as they 
 are, I am compelled to pass over. 
 
 ~ The inadequacy of the clinical history of a syphilitic 
 lesion, when that history is based only on certain 
 evidence, is conspicuous in the case of the disease of 
 the walls of the arteries. The classical researches of 
 Heubner, who first placed our knowledge on this sub- 
 ject on a secure footing, were based, of necessity to a 
 
AND THE NERVOUS SYSTEM. 69 
 
 large extent, on fatal cases. The clinical picture, delin- 
 eated from those facts, faithful as it is so far as regards 
 the effects of extensive and severe disease, is yet imper- 
 fect as a representation of the slighter and much more 
 common consequences of the morbid process. Passing 
 over the former, because it is well known by description, 
 although now seldom met with, I would ask your 
 attention to some facts regarding the slight forms. The 
 importance of the early diagnosis of this condition is 
 unequaled even among syphilitic lesions. There is no 
 luetic process that is so likely to cause grave and last- 
 ing damage, no process the effects of which, when once 
 produced, are so entirely beyond our power, and yet 
 can be so surely averted by prompt treatment. For 
 this reason, I think it is wise to devote more time to 
 this than to the other special questions, and also because 
 it is a disease in which the diagnosis during life can 
 generally be made with sufficient confidence to give a 
 high value to clinical facts. 
 
 The chief mechanism by which this process is effect- 
 ive in causing symptoms is, as we have seen, by the 
 sudden closure of an artery or of a l^ranch going off 
 from the diseased spot. The suddenness of the closure 
 is no doubt due to the fact that the final occlusion is 
 effected by thrombosis, and in this respect the syphilitic 
 disease does not differ from the other common form of 
 arterial disease, atheroma. The closure has the usual 
 consequence, sudden ana3mia and necrosis of the brain 
 tissue, unless there be sufficient anastomoses to permit 
 a collateral circulation. This may be either complete, 
 restoring function, or incomplete, so that the continuity 
 
70 LETTSOMIAN LECTURES ON SYPHILIS 
 
 of the tissue is preserved only by a process which results 
 in sclerotic induration. 
 
 The characteristic symptoms are those of a sudden 
 focal lesion of the brain. Until the degenerative 
 period of life is reached, such a sudden lesion is ex- 
 cessively rare except from embolism. Embolism can 
 usually be excluded if there is no valvular heart 
 disease or other source of embolism, and if the patient 
 has not recently suffered from a disease known to cause 
 endocarditis. Hence it follows that the occurrence of 
 such symptoms in an adult under forty-five, who has 
 had syphilis, and has not heart disease, may generally be 
 held to indicate syphilitic disease of a cerebral artery, 
 and this diagnosis may be made with a confidence 
 possible in few other syjDhilitic lesions. This confidence 
 is confirmed by the occasional opportunities for a veri- 
 fication. When, under such conditions, the diagnosis 
 has been made, and the patient has subsequently died, 
 the arterial disease has been found, invariably so far as 
 my own experience and reading have gone. It is true 
 that, in rare cases, certain other causes of arterial 
 closure must also be excluded. I will mention these 
 presently ; they do not realh^ lessen the validity of the 
 statement just made, since the need for considering 
 them is rare, and is generally obvious. But this confi- 
 dence can exist only before the degenerative period of 
 life. When this period arrives, other causes of arterial 
 closure come into operation, causes which we cannot 
 exclude with the readiness and confidence with which 
 we can exclude embolism. This introduces an element 
 of doubt into the diagnosis of cases over fortj^-five or 
 
AND THE NERVOUS SYSTEM. 71 
 
 fifty years of age. Hence, in endeavoring to ascertain 
 the history of these cases from merely clinical observa- 
 tion, it is desirable to confine our attention to those in 
 which the diagnosis can be made with most confidence. 
 The disease does occur during the later period of life ; 
 we have to recognize the fact in our practical diagnosis. 
 It may be that this renders some of our conclusions 
 from the earlier cases imperfect, but we must accept 
 this imperfection in order to obtain as much certainty 
 as possible. 
 
 The following conclusions are based on a series of 
 cases that have come under my own observation, ex- 
 cluding those over forty-five years of age. The cases 
 are fifty in number, but on some points, owing to omis- 
 sions, the precise number available for comparison is 
 somewhat less.* The patients were over twenty-five, 
 with the exception of one, aged twenty-one. Males 
 were to females as three to one, a proportion that may 
 not be far from the incidence of syphilis itself. 
 
 Many observers have noted how various is the inter- 
 val between the primary disease and the cerebral 
 lesion, and the variation is conspicuous in this series. 
 In one quarter, the lesion occurred during the first two 
 years after infection, and the remainder were distributed 
 during the next twelve years (two, nine cases ; three to 
 five, seven cases ; six to ten, nine cases ; eleven to 
 fifteen, eleven cases ; sixteen to twenty, four cases). 
 There was an interval of nineteen years in a man who 
 had well-marked syphilis at eighteen, and at the age of 
 
 * I have seen many other oases since, but I have not had time to 
 analyze them. 
 
72 LETTSOMIAN LECTURES ON SYPHILIS 
 
 thirty-seven an attack of right liemiplegia, while a 
 year later paraplegia came on in a sub-acute manner. 
 Eighteen years intervened in a woman who, at sixteen, 
 married a man of unsteady habits ; her first two chil- 
 dren were born dead ; hemiplegia came at thirty -five, 
 with an onset characteristic of arterial thrombosis. 
 The shortest interval was apparently only three 
 months, but the case does not seem otherwise open to 
 doubt. A man, at the age of twenty-one, had for the 
 first time a chancre — a distinct hard sore, followed by 
 indolent enlargement of the glands. Three months 
 after the appearance of the sore he had sudden hemi- 
 plegia, which slowly passed away, but was followed six 
 months later by a second attack on the same side. In 
 these cases, as, indeed, in all those compared, a careful 
 search revealed no other cause. In the only other case 
 in which the interval was less than a year the attack 
 occurred six months after infection. 
 
 By far the most common effect of tlie lesion was hemi- 
 plegia, indicating disease of the middle cerebral artery, 
 and probably the closure of a branch to the central 
 ganglia. In only one case did convulsions at the onset 
 suggest that the damage was limited to the cortex. 
 (Simultaneous central softening necessarily prevents 
 such special indication of a cortical lesion.) In three 
 cases hemianopia suggested that the arterial disease 
 was in the posterior cerebral. It is evident, however, 
 that these cases present onl}'- some of the eff'ects of 
 vascular disease, and do not present at all its gravest 
 consequences. Lesions may occur in parts of the brain 
 where they cause no focal symj)toms, and, on the other 
 
AND THE NERVOUS SYSTEM. 73 
 
 hand, disease of the basilar and vertebral arteries suffi- 
 cient to cause definite symptoms is seldom survived. 
 These grave effects, however, are well known, and I 
 therefore pass them over. In probably nineteen cases 
 out of twenty the Sylvian artery is that by which 
 arterial disease causes symptoms, a fact easily ex- 
 plained, and of such disease this series presents a fair 
 example. 
 
 The degree of the paralysis and its course present 
 variations as great as, and similar to, those met with in 
 embolism. It may be slight and transient, or severe 
 and then often lasting, with only such recovery as 
 occurs from compensation — a slow return of power in 
 the leg, and some in the upper arm, the hand remain- 
 ing powerless, or almost powerless, with late rigidity. 
 I have a few times known two attacks of hemiplegia to 
 occur, at intervals of months. Very rarely symptoms 
 of some other syphilitic process coincide with the onset. 
 It is only in such a case, in which there is reason to 
 suspect a gumma, that I have seen optic neuritis. In 
 several cases the patients have at some other time 
 suffered from paraplegia, such as might be caused by 
 a gumma pressing on the cord. 
 
 The onset occurred during sleep in a third of the 
 cases, a proj)ortion nearly corresponding to the time 
 spent in the sleeping state. During the waking state 
 the onset is seldom attended by loss of consciousness ; 
 it was so attended in only one-tenth of the cases — a 
 fact of much importance. Giddiness and vomiting 
 were occasional accompaniments. Of great signifi- 
 cance also is the fact that the onset, in more than half 
 
 7 
 
74 LETTSOMIAN LECTURES ON SYPHILIS 
 
 the cases, was preceded by headache. The pain was 
 usually great, and was either general or chiefly on the 
 side of the subsequent lesion. It preceded the onset 
 sometimes for only a few days or a week, often for 
 several weeks, rarely for two or three months. It is 
 apparently in some way due to the arterial disease 
 itself. Occasionally, for a day or two before the onset, 
 there was a slight tingling or other sensation in the 
 side afterward paralyzed. Thus, one patient, after ten 
 days of severe headache, had repeated attacks of ting- 
 ling down the side during two days before onset. 
 The attack itself was often quite sudden, but in some 
 cases it was deliberate, or occurred in two stages. The 
 following are instances of these modes of onset : — 
 
 1. The arm and leg became weak for a few minutes, 
 then recovered, and half an hour later became suddenly 
 powerless. 
 
 2. Slight weakness came on, and continued for six 
 days before the sudden hemiplegia. 
 
 3. The leg became weak in the evening, and during 
 the night the arm became powerless. 
 
 4. The patient woke up one morning with loss of 
 power in the leg, and during the next two days the 
 palsy spread gradually to the arm and face. 
 
 5. The arm became suddenly paralyzed, and six days 
 later aphasia came on, with a convulsion, doubtless 
 from the occlusion of a cortical branch. 
 
 The diagnosis of this disease chiefly depends on the 
 causal indications, negative and positive, the absence of 
 other causes, and the presence of syphilis. The evi- 
 dence of therapeutics here fails us. The syphilitic 
 
AND THE NERVOUS SYSTEM. 75 
 
 process in the artery, and the secondary thrombus that 
 resuUs, are wholly separate from the simple process in 
 the brain — the necrotic softening on udiich the symp- 
 toms directly depend. Treat the patient as you will ; 
 remove as speedily and as com23letely as possible the 
 disease of the arterial wall ; you cannot restore the cir- 
 culation, nor can you avert the resulting necrosis of the 
 brain tissue when once the blood has clotted in the ves- 
 sel. Compare two series of cases of hemiplegia, one 
 due to embolism, and the other to this disease, and you 
 will find that their general course corresponds, however 
 wise and thorough may have been the treatment adopted 
 in the syphilitic series. In each series we meet with 
 cases in which the palsy is slight or transient, but these 
 are cases in which the motor structures haA^e not Ijeen 
 involved in the softening, and have only been interfered 
 with for a time because the lesion was adjacent to them. 
 In each series we find cases of severe paralysis, because 
 the motor path was interrupted or the centres were 
 destroyed. Hence, by your treatment you may save 
 the patient from a fresh attack, or from an extension 
 of the old mischief, but you cannot save him from de- 
 struction of tissue or avert its effects. Recognize any 
 warning there may be — the attack may perhaps be 
 prevented, but once the vessel is occluded, your treat- 
 ment is powerless over the accomplished injury. Thus 
 these are cases in which the result of treatment has no 
 diagnostic significance, and if a positive result seems 
 traceable we may be sure that the improvement is a 
 coincidence and not a consequence. An illustration 
 may make this important fact more definite. If the 
 
76 LETTSOMIAN LECTURES ON SYPHILIS 
 
 illustration is hypothetical it will nevertheless be felt, 
 I think, to be within the bounds, not only of the possi- 
 ble, but of the probable. A man is seized with sudden 
 hemiplegia due to some embolism, which has caused a 
 small spot of softening near, but not involving the mo- 
 tor structures. The function of these is temporarily 
 impaired, as we know commonly happens in such a 
 case. He has undetected mitral obstruction, a short 
 presystolic murmur having escaped recognition, also 
 not beyond the limits of experience. His medical at- 
 tendant, who know^s that the patient has had constitu- 
 tional syphilis, believes that the hemiplegia is syphilitic, 
 and at once gives him iodide of potassium. In two or 
 three days there is a distinct return of power in the 
 limbs ; the improvement goes on, and in a month the 
 patient is practically well. What will be the strength 
 of the conviction on the part of the practitioner that the 
 hemiplegia was due to syphilis ? Will it not be almost 
 impregnable? And yet it would be wholly wrong. 
 Note, moreover, that had the same lesion of the brain 
 been due to syphilis, his reasoning from the effect of 
 the treatment would have been equally wrong, and yet 
 his conclusion would have been right. A great deal of 
 error in medical science (and not in medical science 
 alone) is due to the fact that correctness of a conclusion 
 is transferred to the reasoning by which it has been 
 reached. 
 
 The frequence of premonitory symptoms, and of a 
 more or less deliberate onset, without loss of conscious- 
 ness, furnish diagnostic indications that are often of 
 great importance. They are especially important when 
 
AND THE NERVOUS SYSTEM. 77 
 
 some other cause of arterial occlusion co-exists, and 
 especially when a source of embolism can be found. 
 Sometimes heart disease is left by rheumatic fever ; the 
 individual contracts syphilis, and afterward has an 
 attack of sudden hemiplegia. We are then unable to 
 avail ourselves of the causal indication, unless we find 
 evidence that one influence or the other has recently 
 been active in the sj'^stem, as by recent embolism or 
 recent syphilitic processes elsewhere. A deliberate 
 onset is strongly in favor of thrombosis, and therefore 
 of syphilitic disease, rather than of embolism. Most 
 important of all, however, are the premonitory symp- 
 toms, and especially headache. This, if severe, shows 
 that a morbid process within the skull preceded the 
 onset, whereas in embolism the intracranial condition is 
 normal until the obstructing particle is suddenly trans- 
 ferred from the heart to the cerebral artery. The prac- 
 tical value of this indication is increased by the fact 
 that it is not only a common, but a prominent symptom. 
 At the same time its absence is far less significant than 
 its presence. This is true, remember, of all symptoms 
 commonly regarded as " characteristic." Their absence 
 proves little when their presence proves much. 
 
 Apart from embolism and injury, sudden hemiplegia, 
 coming on between twenty-five and forty -five, is, I 
 believe, very seldom due to any other cause than 
 syphilis, and its occurrence may justly raise a strong 
 suspicion of this disease, even in a case in which there 
 is no positive evidence. But this suspicion is stronger 
 in the case of men than in women, because in women, 
 less rarely than in men, sudden hemiplegia, clearly due 
 
78 LETTSOMIAN LECTURES ON SYPHILIS 
 
 to an organic lesion, sometimes comes on when we can 
 trace no source of embolism, and can exclude syphilis. 
 Now and then the onset is accompanied by that form 
 of pyrexia which suggests septicaemia, and actual proof 
 of this may be furnished by the characteristic retinal 
 hemorrhages. A softened clot, in some situation, is 
 the most probable cause of the symptoms, and the 
 hemiplegia may be regarded as embolic. But there are 
 other cases, in which the onset is unaccompanied by 
 any symptom to suggest embolism. I have seen 
 several such cases in girls between eighteen and thirty, 
 in whom, from history, character, and life, inherited or 
 acquired syphilis could be absolutely excluded. The 
 hypothesis of thrombosis in a healthy artery, due to 
 some general condition, seems perhaps the least im- 
 probable explanation of such cases. But if the sub- 
 ject of such a palsy happens to be a girl of the lower 
 classes the diagnosis of probable syphilis is not unlikely 
 to be made, and the more readily because we cannot 
 exclude the risk of infection in the case of unmarried 
 women as we can in unmarried men. 
 
 With the advent of the degenerative period of life 
 comes an enormous accession of difficulty in diagnosis. 
 After the age of forty -five or fifty is passed, we can never 
 feel sure that we are not in the presence of the changes 
 in the arteries which cause cerebral hemorrhage or cere- 
 bral softening. The difficulty is further increased by the 
 fact that syphilitic disease becomes not only relatively 
 but absolutely less frequent, so that the likelihood of it 
 does not help the observer, as at an earlier period of life. 
 Hence, w^hen it does occur it is more likely to be unsus- 
 
AND THE NERVOUS SYSTEM. 79 
 
 pected and unrecognized. This is indeed one of the 
 chief practical risks of error, for the diagnosis can still 
 be made in most cases, although less surely. The 
 diagnostic indications that are often distinct and im- 
 portant in the earlier period of life are equally common 
 and equally significant in the later period. The sig- 
 nificance of some of them is indeed not so strong as in 
 early adult life, but their relative importance is greater, 
 since on them, and especially on those that are still 
 unequivocal, the diagnosis chiefly depends. Their sig- 
 nificance is strengthened by a history of syphilis, but 
 this history alone has far less value than at an earlier 
 age. Further, as we cannot exclude syj^hilis merely 
 because there is no history of it, so we cannot ex- 
 clude the degenerative lesions merely because degen- 
 eration is not manifest. Hence arises the extreme 
 importance of the diagnostic indications afforded by 
 the mode of onset and premonitory symptoms, taken, 
 of course, in combination with the general diagnostic 
 indications that apply to all sudden lesions in late 
 life. The absence of coma, the frequent occurrence of 
 prodromata, or a deliberate development of the palsy, 
 together with the state of the heart, may render hemor- 
 rhage unlikely, and the chief difficulty is the distinction 
 from atheromatous softening. In this, as in syphilitic 
 disease, a morbid state of the arteries exists before the 
 sudden onset, and these may cause slight premonitory 
 symptoms analogous to those we have been considering. 
 But headache is not very common, and is never so con- 
 siderable as it very often is in syphilitic disease. Athe- 
 romatous softening, moreover, is essentially a senile 
 
80 LETTSOMIAX LECTURES OX SYPHILIS 
 
 malady. Apart from kidney disease or an early degen- 
 erative tendency, usuall}^ conspicuous, it is not often 
 met with under sixty, and it becomes more frequent as 
 life advances and the syphilitic lesion becomes more 
 and more rare, till at last it is only to be thought of 
 when special circumstances suggest its possibility. 
 
 The application of these principles, varying as it does 
 in detail, I must leave ; but I may mention to you a 
 case which shows very well their use and value. By a 
 curious and convenient coincidence, this case, one of 
 the best unverified illustrations of this particular diag- 
 nostic difficulty that I have ever met with, came under 
 my notice as I was finishing this part of mj lecture. 
 Dr. Barnes, of Ewell, asked me to see with him a woman, 
 forty -two years of age, in whom, two days before, right 
 hemiplegia had come on in the course of a few hours, 
 without loss of consciousness. The face was not 
 affected on the right side, and this fact, with distinct 
 weakness of the left side of the face, diplopia, tingling 
 of the left hand, and frequent hiccough, made it almost 
 certain that the lesion was in the pons. The urine had 
 for some years contained albumin and granular casts. 
 In the left e^^e were the remains of syphilitic choroiditis, 
 and one child had been born dead without traceable 
 cause. For several months she had suffered much 
 from headache, of increasing severity, and had become 
 much stouter. 
 
 Here, then, we had evidence of a lesion which was 
 probably softening and not hemorrhage, on account of 
 its position, and of the deliberate onset, without loss of 
 consciousness ; hemorrhage into the pons causing more 
 
AND THE NERVOUS SYSTEM. 81 
 
 severe initial symptoms, which are, moreover, seldom 
 survived for more than a few hours. Hence, the most 
 probable lesion was disease of the basilar artery, with 
 thrombosis in some of its branches. For such arterial 
 disease we had two adequate causes — renal mischief 
 sufficient to render atheroma probable at her age, and 
 syphilis. There was no evidence of recent active syph- 
 ilis, and the balance of probability was strongly in 
 favor of atheroma, by reason of the greater average 
 frequency of this affection under these circumstances 
 and causal conditions. But there was one symptom of 
 a positive character, the significance of which no mere 
 probability or improbability could be allowed to influ- 
 ence — tlie severe and' persistent headache. Kidney 
 disease will cause headache, but not such headache as 
 this patient had suffered from, which had kept her 
 awake at night repeatedly, and was often more severe 
 on the left side of the head than on the right. It was 
 a symptom that suggested more than mere atheroma, 
 and distinctly turned the balance of evidence in favor 
 of syphilitic disease. The case was clearly one of 
 urgent danger, as every case is in which there is an 
 active morbid process in the pons, and I confess I had 
 little hope that any treatment would be of avail. But 
 we decided to treat the patient, for a time, on the 
 assumption tliat the disease was syphilitic, and to 
 increase the iodide, which she was already taking in 
 small doses, to forty-five grains a day, adding a little 
 digitalis to steady the circulation. If no improvement 
 could be observed at the end of a few days, the dose of 
 
82 LETTSOMIAN LECTURES ON SYPHILIS 
 
 iodide should be reduced again, lest, if no good could 
 be done to the wall of the vessel, the drug might do 
 harm by increasing the tendency of the blood to clot. 
 But on the third day the patient was distinctly better ; 
 the improvement steadily went on, and I hear now 
 from Dr. Barnes that she has fair power in the arm and 
 leg, is free from headache, and has no symptoms to 
 suggest anxiety. Of course, it is possible that the diag- 
 nosis was wrong, but its method may not be uninstruct- 
 ive, and the result appears to afford some confirmation 
 both to the principles and to their application. At least 
 we may see in this case how essential it is to arrive at 
 a precise diagnosis of the character of the lesion before 
 the causal indications are considered, and that this 
 need, always present, is especially obvious in those 
 whose age or state of health involves a liability to 
 several lesions. A hasty diagnosis of cerebral hemor- 
 rhage in this patient would probably have prevented 
 any significance being attached to the indications of 
 previous syphilis. 
 
 We may see also how necessary it is to give its due 
 weight to each indication, how the significance of one 
 may be strengthened by the concurrence of others, and 
 how paramount is the necessit}'' of limiting the influ- 
 ence of mere probability, and not permitting this to 
 counterbalance any distinct and positive indication. 
 Although, as I said, recovery does not prove that a 
 diagnosis is correct, this reservation must be made 
 whenever a patient happily survives. The reservation 
 applies only, moreover, to solitary cases. The test of 
 
AND THE NERVOUS SYSTEM. 83 
 
 the reasoning, afforded by the resuh, may not be valid 
 in the individual case, but in a number of cases com- 
 bined it will not mislead. 
 
 Another point in the differential diagnosis of vascu- 
 lar disease should, however, be specially mentioned, 
 because its peculiar and unusual difficulty occasionally 
 leads astray even those who have had much experience. 
 It is the distinction of the slighter forms of hemiplegia, 
 or other local symptom, from the unilateral symptoms 
 that are common in general paralysis of the insane, 
 even in the early stage of the disorder. Whatever be 
 their immediate cause, they do not seem to depend on 
 an organic lesion, but the symptoms of an organic 
 lesion are sometimes simulated by them in a puzzling- 
 manner. The difficulty is increased, and, indeed, is 
 largely due, to the fact that so many of the subjects of 
 general paralysis have had syphilis. 
 
 Cases are not rare in which this formidable disease 
 comes on while syphilis is manifestly active ; it ma}' 
 even supervene on some actual syphilitic lesion of the 
 brain. Thus the effects of syphilitic vascular disease 
 are occasionally followed by degenerative symptoms 
 of various kind and degree. After recovery, complete 
 or incomplete, fresh symptoms may come on, such as 
 failure of memory or other mental change, or failure in 
 articulation. These symptoms may also commence 
 during recovery from the hemiplegia. Moreover, an 
 attack of hemiplegia, which seems at the time to be 
 due to the common vascular disease, is occasionall}^ 
 followed, in the course of a few months, by symptoms 
 of general paralysis of the insane quite typical in char- 
 
84 LETTSOMTAN LECTURES ON SYPHILIS 
 
 acter and course. For instance, a man about eight 
 years after primary sj'^philis had an attack of sudden 
 hemiplegia, severe, and preceded by headache. In 
 the course of a month he recovered ahnost completely, 
 and those who knew him observed very little difference 
 from his state before the attack. A little later, however, 
 a slight change in articulation attracted their notice, 
 coupled with some scarcely definable alteration in liis 
 mental characteristics. A few weeks later optimistic 
 delusions suddenl}^ burst out ; he was about to make 
 his own fortune and the fortune of his friends ; the 
 thousands and hundreds of thousands poured from his 
 lips in the flow of magniloquence we know so well, a 
 flow that was soon rendered almost unintelligible by 
 the usual characteristic failure of articulation, and 
 typical general })aralysis ran a rapid course to its 
 common termination. In such a case, if the initial 
 hemiplegia is slight and transient, it may be difficult 
 to say whether the attack is due to an organic lesion, 
 or is one of those inorganic attacks that occur in the 
 course of this disease. Indeed, the diagnosis may be 
 impossible except by waiting and watching the case. 
 
 Another difficulty is due to the fact that, in general 
 paralysis, attacks occur in which, instead of the sudden 
 weakness of hemiplegic character, there are unilateral 
 symptoms characteristic of a local " discharge " in the 
 brain. When such discharge is so great and so situ- 
 ated as to cause actual convulsion, there is less risk 
 of this particular error, but sometimes there are other 
 sudden symptoms, more equivocal in character, such 
 as tingling, beginning in some part and spreading 
 
AND THE NERVOUS SYSTEM. 85 
 
 through the side, and accompanied, it may be, by in- 
 hibitory weakness or temporary aphasia. Such attacks 
 have often been ascribed to syphilitic vascular disease. 
 The latter, however, does not cause such definite limited 
 " discharges " as a first symptom. These alwaj's sug- 
 gest a chronic process and not a sudden lesion, and, 
 therefore, in the absence of signs of tumor or of 
 meningitis, the degenerative malady should always 
 be thought of. This is true also if there have been 
 similar attacks, or any change in mind or speech, 
 however slight. 
 
 Among the innumerable other diagnostic problems 
 that invite, and almost demand consideration, I can 
 notice only one group, those that relate to the palsies 
 of the ocular muscles. These are among the most fre- 
 quent manifestations of the influence of syphilis on 
 the nervous system. The long course of the ocular 
 nerves exposes them to many kinds of specific damage. 
 Arterial disease seldom interferes with their functions, 
 and when it does so, it is only by causing a sudden 
 vascular lesion, separable from all others by the com- 
 plex associated derangement produced, and by the 
 actually sudden onset. Gummata and local menin- 
 gitis may damage the nerves at the base of the brain, 
 and the locality of the lesion is then indicated by the 
 grouping of the nerves affected ; the two processes are 
 sometimes distinguishable by the greater interference 
 with the central organs, or with the motor tract in the 
 crus and pons, and also by the greater frequency of 
 optic neuritis in gummata than in meningitis of the 
 posterior part of the base. Optic neuritis may be 
 
86 LETTSOMIAN LECTURES ON SYPHILIS 
 
 readily caused by meningitis when this is in the 
 front part of the base, so that this distinction must 
 depend on the evidence of the position of the dis- 
 ease. Gummata on the nerve trunks themselves can 
 scarcely be distinguished from inflammation. In any 
 part of their course they may be the seat of a syphilitic 
 neuritis, and this is probably the most common cause 
 of an isolated affection of a single nerve or of a single 
 branch. 
 
 Thus each diagnosis of this kind involves the care- 
 ful consideration of the symptoms and their combi- 
 nations, as well as of their mode of onset and asso- 
 ciations. The subject is too large for me to do more 
 than indicate the lines on which it must be ap- 
 proached. It needs, indeed, to receive a thorough 
 investigation in the light of pathological facts that are 
 scattered through medical literature, and which need 
 to be greatly increased in number before our diagnosis 
 can be exact. The greatest difficulties in these cases 
 arise from the fact that ocular palsies are caused by 
 some of the effects of syphilis that are not specific in 
 their nature. For instance, an isolated palsy of one 
 third nerve, in a young man known to have suffered 
 from the constitutional disease, was naturally sup- 
 posed to be truly specific. But treatment, although 
 prompt and thorough, had no influence on it. One day 
 he suddenly became unconscious, and died in a few 
 hours. We can scarcely doubt that an aneurism, 
 due to syphilis, caused the palsy and his death. But 
 the most frequent non-specific causes of these symptoms 
 are the degenerations. These may set in before the 
 
AND THE NERVOUS SYSTEM. 8/ 
 
 period of true specific lesions has passed, and the 
 ocular nerves constitute one of the regions in which 
 the symptoms of the two kinds most often coincide. 
 More frequent than actual coincidence is the doubt 
 produced by it. Is this palsy due to a true specific 
 lesion, or is it part of nerve degeneration that is a non- 
 specific sequel to syphilis ? The question is of great 
 importance in regard both to prognosis and to treat- 
 ment. In cases of locomotor ataxy that occur com- 
 paratively early, this diflSculty is especially frequent. 
 The distribution of the symptoms may furnish an 
 answer, as we shall see in a moment. Sometimes the 
 suddenness of the onset raises a strong presumption 
 that the pals}^ is tabetic and not specific. The same 
 conclusion is indicated when symptoms quickly lessen 
 without treatment and soon afterward return. 
 
 The nature of many of these tabetic palsies is doubt- 
 ful, but some are certainly due to nuclear degeneration. 
 These, as we saw in the first lecture, are often sequelee 
 of syphilis. Their distinction from a true sj^ecific 
 lesion is another problem of much difiiculty — a diffi- 
 culty further increased by the fact that nuclear affec- 
 tion seems sometimes to follow a peripheral palsy so 
 directly that the symptoms of one pass into those of the 
 other. 
 
 The most important characteristics of the nuclear 
 palsy are the association of muscles according to func- 
 tion, its bilateral distribution, and its persistence in spite 
 of treatment. In most true specific lesions prompt treat- 
 ment has an influence which is absent in the degenera- 
 
hh LETTSOMIAN LECTURES ON SYPHILIS 
 
 tive maladies. I need not trouble you with instances 
 of these features. They are important distinctions 
 both in the isolated degeneration and in that associated 
 with tabes. I may add to them the therapeutic test, 
 which is often of great use in diagnosis, but is of nega- 
 tive significance only when the proper treatment has 
 been employed early. 
 
 I have said that the nuclear degeneration sometimes 
 seems to follow a specific palsy, but it also occurs, as 
 we have seen, when there has been no paralysis, so 
 that we are perhaps not justified in connecting the 
 two. 
 
 A tendency is often to be observed in the present 
 day to underrate diagnosis, or at least the elaborate 
 diagnosis of which the diseases of the nervous system 
 furnish so many examples. In the face of the urgent 
 needs of suffering humanity, with its mute appeal or 
 uttered cr}^ for the relief we cannot always give, our pre- 
 cise distinctions and elaborate processes may seem like 
 an ingenious device for interesting us while the patient 
 suffers. That such an impression is wholly wrong I 
 need not say to those who hear me now. But the ten- 
 denc}'' is real, and is reflected beyond our own ranks ; 
 and I may give one w^arning, a warning to myself as 
 well as to others, that we should be always on our guard 
 lest we do anything, by word or manner, that may 
 excite or foster the feeling to which I refer. Diagnosis 
 must come before treatment, and this should make us 
 careful lest we produce an impression that we regard 
 the order of the two in time as also that of their im- 
 
AND THE NERVOUS SYSTEM. 89 
 
 portance — an impression easily produced when the 
 treatment is plain and its methods familiar, while the 
 diagnosis is complex and its processes strange. But 
 surely the diseases we are now considering supply a 
 strong reproof to those who consider that, " to say the 
 least, diagnosis is somewhat overdone." A diagnosis 
 that can be described as " rough and ready "• may 
 serve to make our treatment effective in the majority 
 of cases, but there are many in which only a most 
 careful and even elaborate diagnosis will enable us to 
 do all that can be done, and there are not a few in 
 which the utmost degree of care and elaboration is 
 needed to save us from being wrong in our treatment 
 — often wholly wrong, and sometimes disastrously 
 wrong. I could give many instances of this, striking 
 and sad, but it is needless to do so, and it may be 
 unwise. My own conviction is that diagnosis in itself 
 cannot be overdone. To permit diagnosis to be studied 
 and employed, at the expense of treatment, is a pro- 
 ceeding for which no words of condemnation are too 
 strong. To cultivate, at the expense of its application, 
 that which has no other end, should, in medicine, be a 
 sin beyond the reach of pardon. But, as a guide to 
 treatment and prognosis, we cannot well know too 
 minutely the seat of the maladies we are treating, and 
 we assuredly cannot know too certainly their nature. ' 
 Our art may be all-powerful to save : but without 
 guidance it is useless — a hand to use without an eye to 
 see. When the disease is beyond our present means 
 the same guidance may still be needed to save the 
 patient from that which, without power of good, may 
 
90 LETTSOMIAN LECTURES ON SYPHILIS 
 
 not be without capacity of harm, and I believe that 
 there is no point in diagnosis, however elaborate it may- 
 be, or however superfluous it may seem, which is not 
 or will not be, in some case or at some time, of definite 
 use and perhaps essential service in enabling life to be 
 saved or health restored. 
 
LECTURE III. 
 
 Mr. President and Gentlemen, — To-night we jjass 
 to the final ends for which we gain our knowledge — 
 the ability to foretell and to control the future course 
 of the malady. The attemjjt to define our knowledge, 
 which I proposed at the outset as a chief object of these 
 lectures, will here have results not, I fear, wholly satis- 
 factory. The progress of science involves loss as well 
 as gain. Where the ground seemed firm beneath our 
 feet, and the path before us appeared smooth, w^e may 
 suddenly find our footsteps insecure, and that the 
 smoothness was apparent only — an illusion due to a 
 too sweeping generalization. When we come to know 
 thoroughly this part of the region of medical science 
 we are now" traversing, we find the ground is broken 
 by exceptions, which we cannot ignore except at the 
 risk of certain error and equally certain discredit. It 
 is not long since the diagnosis of syphilis as a cause, 
 and the prospect of adequate treatment, were held to 
 warrant a prognosis absolutely favorable in almost 
 every form of disease so produced. Indeed, I am not 
 sure that it is correct to allude to this opinion only in 
 the past, tense, if we may judge from the measures 
 some hopeless sufferers are induced to undergo. We 
 see them subjected to course after course of similar 
 treatment, each to supplement some supposed defect in 
 
 91 
 
92 LETTSOMIAN LECTURES ON SYPHILIS 
 
 the previous courses ; we see methods employed from 
 which it would seem to be supposed that a drug, 
 administered thoroughly in one way, is still capable of 
 doing more if only it is introduced into the system by 
 some other channel ; and we see advice given which 
 suggests a belief that treatment powerless in England 
 will be effective abroad. If we are so bold as to 
 recognize the nature of the opinions that must underlie 
 such measures and such advice, we can scarcely believe 
 that the old view does not still dominate many minds, 
 and that, although it may not often make its appear- 
 ance on the surface as a definite assertion, it must still 
 exist as an undercurrent of thought, adequate to guide 
 the practitioner's advice, although perhaps not always 
 consciously admitted. Yet the facts that are within 
 the reach of simple observation suggest a very different 
 conclusion. The scars upon the skin or brow tell us 
 more than the mere fact of syphilis: they tell us 
 unmistakably of the imperfect character of tissue-res- 
 toration, and that, too often, when the proper elements 
 of a part have perished, their place is and can be sup- 
 plied only by cicatricial tissue. The internal organs 
 teach us the same lesson. The fibrous nodule in the 
 liver means a loss of liver-tissue perhaps many times 
 the area of the scar, and so with other organs. When 
 such a result occurs in the central nervous system, how 
 can perfect restoration of function be expected or how 
 can it occur ? In the liver the effect on loss of function 
 may be inappreciable, but in the nervous system each 
 cell and fibre has its special use, and the loss of a few 
 may have effects on function not only appreciable but 
 
AND THE NERVOUS SYSTEM. - 93 
 
 conspicuous. In truth, in a very large number of the 
 cases of such lesions, complete recovery of function 
 does not and cannot take place. 
 
 Yet also in a large number of cases the symptoms 
 pass away. Between entire recovery on the one hand, 
 and entire persistence of the symptoms on the other, 
 we have every degree of partial recovery. The 
 course of the disease in any given case may be any- 
 where between these two extremes, and if we are to 
 foretell it aright we must recognize this fact, and we 
 must learn where to seek and how to find the indica- 
 tions that will guide us. Every prognosis, therefore, 
 must be a matter of special and individual considera- 
 tion, just as diagnosis must be. No rule can be laid 
 down applicable to all cases, and the rules that can be 
 made for any groups of cases are limited and partial. 
 In each group, indeed, the general prognosis varies, but 
 in each group also the individual case must be dealt 
 with as a separate problem. So stated, the task of 
 acquiring any adequate prognostic power may seem 
 both difficult and long; but, happily, the power is 
 easily acquired, and its use is simple. I said that "as 
 much individual consideration is needed as in the 
 process of diagnosis," but I should have been nearer 
 the truth had I said that the same individual consider- 
 ation will almost suffice. Did the statements regarding 
 the process of diagnosis I made in the last lecture 
 appear to you exaggerated ? Surely they will seem 
 within the truth when we realize that a full and correct 
 diagnosis is not only essential for, but actually almost 
 involves, the most complete and correct prognosis it is 
 
94 LETTSOMIAX LECTURES OX SYPHILIS 
 
 possible for us, under the circumstances, to give. 
 Realize the nature of the lesion ; realize that the 
 symptoms depend not on the specific process, but on the 
 simple eflfects that are thereby j)roduced in the nerve- 
 tissue ; picture to yourself the changes that have taken 
 place, consider how long they have existed, and you 
 have only to ask yourselves how far it is likely that 
 the mechanism of damage can be removed, and how 
 far the nerve elements can recover from the damage 
 they have sustained. 
 
 Let me repeat the injunction, "picture to yourselves 
 the changes that have taken place," for its imj)ortance 
 is profound. Accjuire the habit of forming a mental 
 picture of the morbid process and the way in which the 
 lesion is doing its work. You will find it of unspeak- 
 able service to you in giving you a firm grasp of the 
 nature of pathological process, a grasp that will help 
 you to a prognosis as adequate and a treatment as wise 
 and full as the nature of the case permits. This is true 
 not only of this, but of all diseases. To pass to the 
 special prognosis of these diseases, only that of the true 
 specific lesions can be now considered. It is onl}'- in 
 these that the fact that disease is due to syj^hilis has an 
 extensive and considerable influence. The lesions that 
 are doubtfully specific, and those that are not specific 
 in their characters, do not often respond to the special 
 drugs, and their forecast is not influenced by their 
 causation. The specific processes alone will more than 
 suffice to occuj^y us. But here, again, we meet at every 
 turn the importance of precision in diagnosis. We 
 must decide the probable nature of any lesion, decide 
 
AND THE NERVOUS SYSTEM. 95 
 
 whether it is specific or non-specific, before the ques- 
 tions of prognosis can be even raised; and we must 
 further decide, as far as we can, the precise form of 
 lesion that exists, before any attempt at prognosis is 
 possible. This done, the . prognosis becomes at once 
 comparatively simple. The fact that a separate answer 
 must be given in each case does not involve, therefore, 
 a mental process essentially different from that of diag- 
 nosis. The special prognostic element, the process by 
 which we read the future in the present and the past, 
 is much the same in all lesions. In brief, we have a 
 varying diagnostic process, but a prognostic i^rocess 
 that only differs in so far as its color and outline, and 
 not its real form, vary with the diagnosis. This, as. 
 indeed, most of the statements I have made in these 
 lectures, are merely familiar facts in perhaps a fresh 
 form. It is strange how far certain principles, when 
 they are definitely grasped, will carry us, and how 
 much they will effect in their various applications. 
 Not seldom a change in the form in which a truth is 
 presented makes it almost equivalent to a new truth. 
 Hence I venture to be so persistent in my reiterations, 
 for repeat I must, again and again. 
 
 Prominent above all the others in prognosis, there- 
 fore, we must remember the two leading princi];)les, by 
 this time, I hope, familiar to you : first, the dependence 
 of symptoms on the simple processes in the nerve tis- 
 sue, and not on the specific element ; secondly, the fact 
 that it is the specific process only on which our treat- 
 ment exerts a direct influence. So the first conclusion 
 that we must seize and hold fast is that treatment can 
 
96. LETTSOMIAN LECTURES ON SYPHILIS 
 
 never influence the symptoms directly. The simple 
 processes that cause the symptoms are scarcely at all 
 amenable to direct treatment, and not at all to the 
 specific treatment. The utmost we can do is to try and 
 remove the specific process, and so allow the nerve ele- 
 ments to recover, if they can. Here, then, we see the 
 essential principles that must guide every prognosis. 
 Is the specific process such, and in such a stage, that 
 we cannot remove it wholly or partially? Is it to be 
 expected that such removal of it as we can ef!ect will 
 be followed by such recovery of the damaged nerve 
 tissues as will permit a return of function ? This is 
 the method by which, and by which alone, in every 
 form and degree of lesion, our prognosis must be ob- 
 tained. The process, thus, is simple. Its application is 
 not difficult, but it needs the same exactness, the same 
 attention to every step, that we have seen to be requisite 
 in every practical proceeding in connection with these 
 diseases. No short road can be found here, any more 
 than in diagnosis. We may make each step sure with- 
 out any extensive special experience, but we can only 
 do so by patient care. Any senior student who has 
 been properly trained may, in the majority of the 
 cases of syphilitic disease of the nervous system, give a 
 prognosis that shall be nearly as correct as could be 
 given by a physician of large and special experience, 
 and each must employ the same process. 
 
 The first question then is, how far can the specific 
 process be influenced by treatment? We caught a 
 glimpse in the first lecture of the variations that exist 
 "in the susceptibility of the different processes to treat- 
 
AND THE NERVOUS SYSTEM. 97 
 
 ment. We saw that hyperplasia is the great character- 
 istic of visible specificity, and that it is this element in 
 the process over which treatment has most influence. 
 Inflammation, even when it is due solely to syphilis, 
 seems to vary much in its susceptibility. Here, how- 
 ever, our vision is limited by the fact that we cannot 
 discern, during life, how much of this apparent in- 
 utility of treatment is due to the lack of influence over 
 the specific element, and how far it is due to the fact 
 that the nerve elements cannot recover. In chronic 
 inflammation it sometimes seems as if we cannot arrest 
 the true specific process, but in acute and subacute 
 inflammations the facts we can perceive and the anal- 
 ogy of similar processes elsewhere make it probable 
 that the second explanation is the true one ; that it is 
 the persistence of the damage to the nerve elements, 
 and not of the lesion producing the damage, which 
 causes the persistence of the symptoms. 
 
 The first important consideration, however, is cer- 
 tainly the fact that the tissue-formation of syphilis is 
 the element that can be influenced with most fre- 
 quency, with most certainty, and in greatest degree. 
 But it is only in the early period of the process, when 
 the tissue is still soft, that it can actuall}^ be made to 
 disappear. When it caseates it may also disappear, 
 although the removal of the degenerated particles 
 is perhaps not due directly to our treatment. When 
 and where the process of fibroid transformation has 
 set in, it is doubtful whether our treatment does more 
 than aid this j)rocess, which is really cicatricial in 
 nature. The tissue that is produced lessens in 
 
 9 
 
98 LETTSOMIAN LECTURES ON SYPHILIS 
 
 amount whether we treat the patient or not, but ap- 
 parently only as the shrinkage takes place which all 
 scar tissue undergoes, a shrinkage by which the 
 elements occupy less and less space as they change 
 from the original cells, or their original form, into 
 inert fibres. 
 
 In the process of sub-acute and chronic inflamma- 
 tion, moreover, the effect of treatment through the 
 specific element is largely dependent upon the 
 amount of new tissue formed, and the stage of de- 
 velopment which this has reached. Inflammation, 
 however, causes also direct damage to the nerve ele- 
 ments, proportioned to the acuteness of the process. 
 In acute inflammation it is great, and seems to con- 
 stitute the most effective element of this process. We 
 saw that in such acute inflammation there are com- 
 monly no true specific features. Our treatment has 
 only to bring the acute inflammatory process to an 
 end, and if this can be effected speedily enough there 
 is nothing further for the special treatment to do : 
 there is no new tissue for it to remove. When we 
 have arrested the process of inflammation all we can 
 do in our treatment is to wait while the nerve struc- 
 tures recover, and all that we can do in our prognosis is 
 to endeavor to form an opinion as to whether they can 
 recover or not. But when the inflammation is chronic, 
 or, if acute in onset, has lasted for a long time, we have 
 to consider also the tissue that may have been formed, 
 the extent to which its removal is possible, and the 
 effects which it has produced on the nerve elements, as 
 well as the degree to which they can recover. 
 
AND THE NERVOUS SYSTE:^!. 99 
 
 These, then, are the chief elements that liave to 
 be taken into consideration in forming a prognosis. 
 But, in addition, there is a Cjuestion, subordinate to 
 the others in actual position, but at least ec^ual to 
 them in importance. This question is the state of 
 the new tissue in connection with its relation to the 
 nerve elements. You will see what I mean in a 
 moment. As I have just said, when the fibroid 
 transformation has set in, treatment does not seem 
 capable of removing the new tissue, or doing more 
 than hastening this cicatricial process. But this pro- 
 cess involves, as we have seen, contraction of the 
 fibres. If the new tissue merely compresses the ner- 
 vous structures from one side this contraction is as ef- 
 fective as absorption in relieving these structures from 
 the damaging pressure. But whenever the new tissue 
 encircles the nerve elements and encloses them, the 
 compression is actually increased by it. Thus the 
 healing of the syphilitic process, the recovery of the 
 essential syphilitic lesion, may mean that the damage 
 to the nerve structures is maintained, and so also are 
 the symptoms produced by that damage. After a 
 time, it is true, there is often a further improvement 
 in the symptoms. When the process of contraction is 
 at an end, perhaps even before it comes to an end, 
 nerve fibres, at any rate, seem to be able, in some 
 degree, to accommodate themselves to the new con- 
 ditions, and although greatly narrowed, may yet re- 
 gain some capacity of conduction, which is sometimes 
 considerable in amount and goes on increasing for a 
 long time. 
 
100 LETTSOMIAN LECTURES ON SYPHILIS 
 
 We see a very pertinent illustration of these import- 
 ant facts in the eye, in the case of common optic neu- 
 ritis. It is common for sight to fail more during the 
 process of subsidence of the neuritis than when the 
 inflammation is at its height. The inflammation 
 produces a large amount of new tissue in the sub- 
 sidence of the optic nerve at the papilla. This in- 
 filtrates the nerve extending between the fibres, and 
 the contraction of this tissue necessarily involves 
 great compression of the fibres. But when the sub- 
 sidence has become considerable, when most of the 
 swelling has passed away, some improvement in sight 
 commences, and often it goes on slowly for many 
 months, and ultimately reaches a very considerable 
 degree. But it is also common, when the compres- 
 sion of the optic fibres is great, for the ultimate re- 
 covery to be incomplete, and occasionally the amount 
 of vision that is regained is even at last very small. 
 In many of the syphilitic lesions of the nervous 
 system the processes which we can see so clearly 
 in the eye, and estimate so accurately by our tests 
 of vision, certainly go on in like manner, and with 
 corresponding effects upon the function of the parts. 
 
 Hence it follows that whenever there is reason to 
 suppose that there is new tissue which has begun to 
 undergo, or which has already undergone, the process 
 of fibroid transformation, and that this new tissue is so 
 placed as to surround either the spinal cord, the nerve 
 roots, or nerve fibres, our prognosis must be influenced 
 by the considerations I have just mentioned. In all in- 
 flammations that are not actually acute or are not brief 
 
AND THE NERVOUS SYSTEM. 101 
 
 there is this new tissue. If the inflammation has lasted 
 for a few weeks before treatment has been effective we 
 cannot assume that the new tissue will be removed. 
 The amount of new tissue will be proportionate to the 
 intensity, extent, and duration of the inflammation, of 
 which other indications enable us to judge, and we 
 must consider how far the position of the tissue is 
 likely to entail this encircling compression. Hence, 
 until we can see what influence treatment has upon 
 the symptoms, our prognosis must be deferred, at least 
 so far as details are concerned. If improvement is 
 absent or slight, or when improvement begins to flag, 
 we must expect that the degree of disturbance of func- 
 tion which then remains will, for a time, lessen only 
 in slight degree or at a slow rate; that a little further 
 improvement may take place in the course of time by 
 the functional adaptation of the nerve elements to 
 their new condition ; but that some amount of the 
 impairment of function is not unlikely to remain. We 
 must recognize also the important fact that when once 
 the early and distinct improvement that follows our 
 treatment is at an end, or even when it has distinctly 
 begun to slacken, it is not likely that any further 
 improvement the case will show will be in any degree 
 the result of anti-syphilitic treatment. I believe that 
 these general principles are absolutely true, and I am 
 sure that their recognition in practical work is of the 
 utmost importance. Their application to any indi- 
 vidual case will furnish an accurate and adequate 
 prognosis, and as I said, this application requires 
 
102 LETTSOMIAN LECTURES ON SYPHILIS 
 
 rather care than practice, patience than special knowl- 
 edge. 
 
 Thus three points in every morbid process have to 
 be considered — the nature of the tissue in the sj^ecific 
 lesion, the mechanism by which the nerve elements 
 are damaged, and the character of this damage. We 
 must consider the nature of the tissue to determine the 
 effect our treatment is likely -to have upon it; we must 
 consider the mechanism by which the nerve elements 
 are damaged to determine how far the changes we are 
 able to produce in the specific tissue can relieve the 
 nerve elements ; and we have to consider the nature of 
 the changes in these nerve elements to determine 
 whether it is or is not likely that they can recover 
 function if completely relieved from the morbid influ- 
 ence. We have seen that it is by the removal of new 
 tissue, which is still in the early stage, by reducing the 
 bulk of such tissue when it is exerting compression, 
 and by checking the process of pure inflammation, that 
 our treatment is effective. We have seen that it is 
 when the compression is from one direction that the 
 reduction in bulk of the syphilitic tissue has the 
 greatest effect in releasing the nerve tissue from the 
 influence of the syphilitic process, and that when the 
 new tissue presses on them from all sides the diminu- 
 tion in its bulk is more than compensated by the con- 
 stricting contraction of the tissue. 
 
 A word or two more seems needed regarding the 
 third element, the changes in the nerve elements them- 
 selves. In jDure acute inflammation, even when due to 
 
AND THE NERVOUS SYSTEM. 103 
 
 syphilis, this is the only point to be attended to. In 
 the subacute and chronic inflammation it is secondary 
 to the considerations regarding the new tissue which 
 have just been mentioned. 
 
 ISTote, once more, that these changes are simple and 
 not specific, and that it is on them that the symptoms 
 depend. They may be the simple breaking up of the 
 tissue elements, seen in simple inflammation and also 
 in necrotic softening of the brain from syphilitic 
 disease of the arteries. The prognosis of this we con- 
 sidered so fully last time that I need not speak of it 
 further. Except in this process of necrosis, and in the 
 very rare pure acute inflammation, I do not think you 
 will find any certain instances of change in the nerve 
 elements in specific j)rocesses without a production of 
 new tissue. Secondly, we have the effects of compres- 
 sion already mentioned. Simple lateral compression 
 readily arrests function, but it seems to do so by 
 producing alterations in the nerve elements that can 
 be recovered from to a larger extent than is jjossible in 
 any other form of damage. Whether the axis-cylinders 
 persist or not, the fibres seem to be able to regenerate 
 even after they have been exposed to such pressure for 
 months. Lastly, in the damage produced by so-called 
 " hyperplastic inflammation " there seems to be both 
 compression by new tissue and also the alterations that 
 result from the inflammation itself, which we have 
 alread}^ considered. The contraction of tissue that 
 encircles the elements keeps up the comj^ression 
 originally caused by its bulk ; hence this, and also the 
 persistence of the inflammatory changes in the nerve 
 
104 LETTSOMIAN LECTURES ON SYPHILIS 
 
 tissue, cause the efifects of such hyperplastic inflamina- 
 tiou to persist long after the activity of the inflamma- 
 tory process itself is at an end, and even long after 
 the treatment has ceased to exert any influence over 
 the morbid process. 
 
 Except for another point, I might content myself 
 with this outline of the general principles of prognosis. 
 Time fails me to illustrate its use, but I may briefly 
 enumerate the general character of the effect which 
 these considerations have upon the special prognosis of 
 the chief kinds of lesion. Afterward I will mention 
 the one remaining point that has to be considered — the 
 modification of prognosis entailed by the irritation which 
 some lesions cause. 
 
 The practical influence of these facts upon the chief 
 lesions is as follows : syphilitic growths— gummata — 
 can be removed more completely than any other lesion, 
 and when their influence is exerted by simple lateral 
 pressure the resulting damage to the nerve structure is 
 recovered from in the greatest degree. Hence, in such 
 cases, the prognosis is good, unless the duration of the 
 damage is ver}^ long, and its degree is very great. 
 When the growth infiltrates, however, the problem be- 
 comes similar to those met with in some inflammations. 
 
 In all forms of meningitis the prognosis is good ex- 
 cept in so far as relates to the damage to nerves and 
 nerve-roots which are surrounded by the newly-formed 
 tissue, and also the damage to the spinal cord when the 
 dura mater is greatly thickened. In all these cases the 
 effects and the symptoms commonly lessen up to the 
 point when the contraction of the tissue comes into 
 
AND THE NERVOUS SYSTEM. 105 
 
 operation. The effects of the inflammatory damage, 
 and of the early compression, lessen, but a residuum re- 
 mains in most cases, and is increased in some of them. 
 Although further improvement is not uncommon after 
 a time, some permanent effects may remain. When 
 there is reason to suspect inflammation of the cranial 
 nerves — syphilitic neuritis — the prognosis is chiefly in- 
 fluenced by the duration of the morbid process. If the 
 inflammatory products are in such a stage that they 
 can be removed the prognosis is good ; they will recover 
 conducting power. If, however, there is reason to sus- 
 pect cicatricial transformation of the new formation 
 into fibroid tissue it is improbable that the degree of 
 improvement will be sufficient to permit severe symp- 
 toms to pass away entirely. The same general prognosis 
 is true also of infiltrating growths. In true acute in- 
 flammation that is treated early and arrested early, the 
 prognosis is the same as in similar inflammations that 
 are not specific. The recovery or persistence of the 
 symptoms depends on the recovery or persistence of the 
 changes in the nerve elements which are produced by 
 an intense inflammation. Such changes are simple, 
 and not specific. 
 
 The point which I have left to the last is the prognosis 
 of the symptoms of irritation, which forms so large a 
 part of the manifestations of many lesions. The irrita- 
 tion may be that of nerve fibres, causing pain, or that 
 of motor structures in the cortex of the brain, causing 
 convulsions. The irritation of nerve fibres is due to 
 the influence of inflammation in the first instance, and 
 secondly to the influence of the residual compression I 
 
 10 
 
106 LETTSOMIAN LECTURES ON SYPHILIS 
 
 have spoken of, and it has a course analogous to the 
 other effects of this compression. It therefore need not 
 detain us. But the irritation of the cortex which is 
 manifested by convulsions is of great import in relation 
 to the problem of prognosis, and needs special consider- 
 ation in every case in which its action can be traced. 
 Convulsions are often produced by a syphilitic lesion 
 on the surface of the brain ; they may persist after 
 treatment has done all that is possible in removing that 
 lesion. Such convulsions are usually ascribed to a cica- 
 trix on the surface of the brain. They are commonly 
 of local commencement or distribution, and a cicatrix 
 does commonly exist at the spot to which the local 
 commencement points as that in which the " discharge " 
 commences. But general convulsions — always general 
 in commencement — may be the sequel to what seemed, 
 from the symptoms, to be diffuse general meningitis. 
 The theory which is commonly held, that a cicatrix 
 causes such symptoms by persistent irritation, may be 
 correct, but it is not easy to understand perpetual irri- 
 tation by a stationary cicatricial process, unless there 
 are such adhesions to the bone as involves repeated and 
 perpetual mechanical disturbance. The facts are equally 
 explicable on the assumption, which seems to me much 
 more probable, that the " discharges " originate from 
 slightly damaged nerve cells, and that the discharging 
 tendency is perpetuated by the residual influence of the 
 discharges themselves. This view is quite consistent 
 with the effect of the excision of a cicatrix in arresting 
 the attacks, since the removal of the scar entails that of 
 the nearest and most unstable cells. Be the cause what 
 
AND THE NERVOUS SYSTEM. 107 
 
 it may, the effect is certain and important, though 
 the symptoms may persist long after all other symp- 
 toms of a cortical lesion, and may even constitute in 
 effect, although not in origin, a variety of epilepsy. 
 These persistent fits, especially when general, are not 
 influenced by anti-syphilitic treatment. Hence their 
 occurrence must always cause a special concern, and 
 should tinge your prognosis with a special caution. 
 
 A general survey of the treatment of sj^philis, as 
 well as the observation of individual cases, can scarcely 
 fail to impress one important conclusion on the impar- 
 tial observer. It is difficult to express this conclusion 
 in language not open to misconstruction. Stated in its 
 baldest form, the conclusion is that syphilis is an incur- 
 able disease.* Stated in the form least liable to misin- 
 terpretation, and with the limits of exactness, it is this : 
 There is no real evidence that the disease ever is or ever 
 has been cured, the word " disease " being here used to 
 designate that which causes the various manifestations 
 of the malady. The short statement that " syphilis is 
 an incurable disease," is legitimate if we recognize that 
 " incurable" means that there is no proof of cure. I 
 do not put this opinion forward as in any way novel ; 
 indeed, I feel that on this and on many other points in 
 these lectures I express opinions that are held by many 
 others, some of which have been well stated by others, 
 
 *This statement has been widely objected to. It should be noted, 
 however, that it is perfectly consistent with the recognition of the fact 
 that the lesions of syphilis have been and are readily removed by 
 treatment. 
 
108 LETTSOMIAN LECTURES ON SYPHILIS 
 
 and all of which, I cannot doubt, have been expressed 
 more than once.* In current works on syphilis the 
 fact of incurability is clearly admitted, although even 
 in these it is not Cjuite compatible with the language 
 here and there employed. But the fact is certainly not 
 accepted by the profession at large in the manner that 
 seems to me to be indicated by the facts. It is, I think, 
 most important, for practical reasons, that it should be 
 understood by all that, as far as evidence at present 
 goes — whatever power we may hope and anticipate 
 that the future will bring — no treatment, however 
 thorough, will bring syphilis, as a disease, to an end, so 
 that the patient does not suffer again from an}^ of its 
 direct effects. In this sense (and it is the only proper 
 sense of the words) the assertion seems to me to be 
 open to no question. Yet the fact is very remarkable. 
 It is strange that this should be true of a disease the 
 effects of which are so largely under control. We can, 
 under favorable circumstances, remove most true spec- 
 ific lesions, we can bring to an end most true specific 
 processes, but the arrest or removal of the manifesta- 
 tions of a disease is a very different thing from its cure. 
 We can, indeed, do a little more than remove the 
 manifestations and effects of the disease ; we can restrain 
 
 * I regret that it has not been possible for me to ascertain the extent to 
 which these and other opinions have been before expressed. Hence I feel 
 that the only course at once just to others and safe for myself is to ask 
 you to regard nothing in these lectures as having any claim to original- 
 ity. As I said at the outset, my desire is to render more definite the 
 knowledge that already exists, and not to bring new knowledge into 
 existence. 
 
AND THE NERVOUS SYSTEM. 109 
 
 the activity of the virus, wliatever it be, that causes the 
 manifestation and effect. But when we speak of the 
 cure of a disease we mean that its essential element, the 
 virus that lies behind all its symptoms and conse- 
 quences, that which is the persistent cause beneath the 
 transient effects — we mean that this is made to cease, is 
 ended once and for all as a morbific agent, so that tt 
 never again disturbs the system. In this sense I 
 believe that it is literally correct to say that we have 
 no evidence that syjDhilis ever is, or ever has been, 
 cured. 
 
 I can scarcely doubt that so absolute a statement 
 will seem, even to some here to-night, unjustified and 
 even mistaken. Some of you may call to mind cases 
 that seem to contradict it, cases in which a patient was 
 suffering from symptoms of the disease, and is known 
 to have been afterward free from any indication of the 
 malady. Such cases do occur ; they may be numerous. 
 Far more frequent, however, in the experience of most 
 observers, are cases in which the immunitj' that follows 
 a course of treatment is not permanent, in which other 
 symptoms reappear at a later period. In very few of 
 the cases regarded as " cured " has the patient been 
 kept under observation long enough to justify the 
 positive conclusion that the disease was at an end. 
 Nowhere has this fact been recognized more clearly 
 than in the admirable work of Hill and Cooper. 
 Cases are common enough in which the hope of cure 
 produced by several years of jDerfect freedom was 
 ultimately disappointed. Of the patients with late 
 syphilitic lesions that come under the observation of 
 
110 LETTSOMIAX LECTURES ON SYPHILIS 
 
 the physician, many, very many, have undergone 
 thorough treatment for the early symptoms. It is 
 difficult, I may say that to me it is impossible, to com- 
 pare the history of the various sufferers from syphilitic 
 lesions, to compare the course of the disease in cases 
 in which treatment was early and thorough with those 
 in which no treatment was employed, and not to ques- 
 tion whether early treatment has yet been shown to have 
 an}^ appreciable influence in preventing the late symp- 
 toms of the disease. But if this be so, how are we to 
 explain the cases in which the malady has seemed to 
 cease after a course of treatment, or those in which it 
 has ceased so long as observation has continued ? I 
 have already hinted at the explanation which I believe 
 to be the true one. We saw in the first lecture that if 
 we compare a series of cases, we meet with manj'- in 
 which the primary affection received no treatment at 
 all, and yet the later symptoms were of a trifling 
 character. There is the strongest reason to believe 
 that many other cases occur in which late symptoms 
 are altogether absent. Some facts that have an instruc- 
 tive bearing on this subject come to light in the his- 
 tories of patients in the medical wards of a hospital or 
 in the out-patient room, suffering often from diseases 
 that have no relation to syphilis. It is not uncommon 
 to meet with those who have unquestionably suffered 
 from primary syphilis and from slight secondary sj^mp- 
 toms, but who took little or no notice of them, and who 
 have never been treated, have had no later manifesta- 
 tions. I have mentioned the series supplied to me by 
 Dr. Radcliffe Crocker, and which I hope he will extend 
 
AND THE NERVOUS SYSTEM. Ill 
 
 and publish, for their importance is very great. In this 
 series there are many cases in which notable late syph- 
 ilitic skin eruptions occurred without any recognized 
 previous manifestations of the disease, and even many 
 in which the primary lesion had been unnoticed by the 
 patient, and was certainly never treated. As I have 
 said, there must be many more with a similar latency 
 of the early stages, with a similar absence of treatment, 
 who passed, not merely six or ten years without any- 
 thing to call the malady to notice, but who never 
 observed, through life, any manifestation of the disease 
 to tell them that they were or had been its subject. 
 Take, again, the other class of cases I referred to — the 
 immunity of mothers of syphilitic children. They are 
 certainly syphilitic, and yet many of them have never 
 been treated and never suffer. I believe that the 
 variations in the general course of the disease, in those 
 who have been treated, find parallels in the course of 
 cases that have not been treated. I suspect that if a 
 large number of each class could be compared the dis- 
 crepancy between the two series would be found to be 
 surprisingly small, and that it would not be difficult to 
 find in each series a corresponding proportion of cases, 
 on the one hand, in which the disease without treat- 
 ment was brief and trifling, and, on the other hand, in 
 which the disease with treatment was prolonged and 
 severe. All the facts, impartially examined, seem to 
 me to have one meaning, clear and unmistakable to 
 those who choose to read it. The extreme variations 
 in the natural character and course of the disease have 
 not been sufficiently considered and allowed for by 
 
112 LETTSOMIAN LECTURES ON SYPHILIS 
 
 those who are under the impression tliat the cure of 
 sj^philis is certainly within our power. This impres- 
 sion is an illusion produced by variations in the course 
 of the disease. In some patients the disease is brief; 
 the symptoms that bring the patient under treatment 
 may be the expiring eflfort of the virus, and the spon- 
 taneous cessation of the disease is ascribed to the treat- 
 ment which was adopted. In other cases the tendency 
 to further manifestations, at some future time, near or 
 distant, may be so strong that in spite of the most 
 energetic treatment, long continued, many times 
 repeated, wave after w^ave of activity brings to the 
 unhappy subject year after year of varied suffering, 
 and sometimes his life ends before the disease. 
 
 I have put the matter strongly in order to empha- 
 size the essential truth. But certain qualifications are 
 desirable, although they do not touch the fact itself. 
 One qualification is that while we have no proof that 
 we ever can or ever have cured syphilis, it is possible 
 that we do come very near the achievement, and even 
 sometimes attain it. I said that some manifestations 
 are probably — indeed, I might say certainly — the ex- 
 piring efforts of the malady. It may be that in some 
 others the symptoms that bring the patient under 
 treatment are only the penultimate manifestations, and 
 that some further consequences, which would occur 
 were it not for the treatment, may be averted. Then 
 we do arrest the symptoms altogether. In such a case 
 the malady may be said to be cured ; but the cure is at 
 best limited, and cannot be regarded as more than 
 hypothetical. The second reservation is one rather of 
 
AND THE NERVOUS SYSTEM. 113 
 
 words and theory than of fact. There are some who 
 hold that the duration of the disease is much more 
 brief than that of its manifestations, that these later 
 symj)toms are indirect consequences, either in their 
 mode of production or in the mechanism by which 
 they are caused. The statement I have made is one 
 that is independent alike of pathology that is known 
 or any theory that may be held. Whatever be the in- 
 timate and ultimate pathology of the later symptoms 
 from the point of view of practical medicine, they are 
 part of the disease, and no question as to their origin 
 or their relation to the virus can alter the fact that the 
 disease, as a disease to be dealt with, and not merely to 
 be thought about, is not, in the proper sense of the 
 word, a disease that can be cured. Speculations as to 
 the origin of the lesions, and the essential nature of the 
 malady at different periods, have no influence, it seems 
 to me, on the practical problems to which we must now 
 confine our attention, although it may be that these 
 practical questions have an important bearing on these 
 speculations. Although the course of the disease in 
 its relation to treatment justifies the doubt whether it is 
 ever cured, except in this narrow and partial sense, the 
 question arises whether the removal of the lesions, and 
 the repres'sion of the activity of the essential elements 
 of the disease, have an influence on the course of the 
 affection. It is difficult here to resist the seductive 
 attractions of theory and of analogy. But the ques- 
 tion can be answered only by facts, and we ought not 
 to try to obtain the semblance of an answer in any 
 other way. 
 
114 LETTSOMIAN LECTURES ON SYPHILIS 
 
 The conclusion that the essential element in the dis- 
 ease resists treatment, and runs its course uninfluenced 
 by our efforts, is in harmony with what we know of 
 other specific diseases due to a poison introduced from 
 ■without and communicable from one person to another. 
 There is not any fact whatever to show that a single 
 disease of this kind can be cut short. The course of 
 the acute exanthemata cannot be arrested by any 
 means at our disposal at any stage of their course, and 
 the same seems true of this chronic exanthematous 
 disease. This is eminently true also of the disease that 
 stands perhaps nearer to syphilis than any other known 
 malady — leprosy. 
 
 Here we catch another glimpse of the strange duality 
 of the disease. And yet the word " strange " is scarcel}'' 
 accurate. In syphilis we probably only see that which 
 exists in all maladies of like nature, but in most others, 
 to a large extent, escapes our notice. What is it that 
 treatment influences in so remarkable a manner? 
 What is it that remains in spite of the treatment — 
 remains, to assume from time to time a fresh activity, 
 and to cause renewed manifestations ? We say, in 
 general terms, that treatment removes the effects of the 
 disease, the local lesions it produces. Besides this, 
 treatment seems to be capable of repressing, 'and even 
 suppressing, the activity of the materies morbi. Take 
 this one fact, evidence of which you will find presented 
 with care in the work of Hill and Cooper : A syphilitic 
 woman who would bear a child certainly diseased, and 
 probably dead, can by treatment be made to bear a 
 child that at the time of birth shows no trace of the 
 
AND THE NERVOUS SYSTEM. 115 
 
 disease ; yet even such an influence on the morbid pro- 
 cess in the mother does not prevent her from again 
 suffering. If we are able to hold securel}'' the outline 
 of a general truth only by means of the point of an 
 hypothesis, we may consider that our drugs destroy the 
 developed and developing organisms, and fail to influ- 
 ence the germs of these. But much remains obscure, 
 when this or any other hypothesis that we can frame 
 has done the utmost that it can to clear our view, and 
 we must wait, perhaps for long, before we can under- 
 stand the real reason why we are able to do so much, 
 and yet can do no more. 
 
 The general treatment of syphilitic lesions does not 
 come within the limits that I have set to these lectures, 
 and even if time permitted me to make an exception on 
 account of the importance of the subject, I should still 
 hesitate to take up your time with that which every 
 student is taught. The few minutes that remain I 
 may best spend in pointing out certain points on which 
 we need to have a far firmer foundation of observed 
 facts than has at present been supplied. 
 
 One question on which there is some difference of 
 opinion is regarding the respective power of mercury 
 and of iodide of potassium, which is represented in its 
 extreme forms by the custom of some physicians to 
 give only iodide for the late lesions, and the opinion of 
 others that mercury alone is effective, and that iodide 
 has only the power of bringing into an efficient activity 
 the mercury that may have been deposited and held 
 inert in the various tissues. The only point chiefly at 
 issue, then, is the influence of iodide. I have on this 
 
116 LETTSOMIAN LECTURES ON SYPHILIS 
 
 subject to range myself with the majority. It seems to 
 me impossible to see much of the true specific lesions 
 of the nervous system, and not to believe that over 
 most of them iodide has a powerful influence. The 
 symptoms of a gumma, for instance, lessen and pass 
 awa}^ under the influence of iodide of potassium as 
 speedily and as completely as would seem, a priori, to 
 be possible with any agent. I am inclined to think 
 that when a lesion is distinctly influenced by either 
 drug, if this is given freely, the eff'ect of one is as great 
 as that of the other ; and in most circumstances I doubt 
 whether it is necessary to follow the iodide with a course 
 of mercury. But this is only an impression. The 
 physician cannot gain from his cases any really trust- 
 worthy conviction. We need more detailed observations 
 by those under whose observation the treatment of 
 lesions in the skin and other parts can be seen; we 
 need observations, superfluous for them but most 
 important for us, as to the relative eff'ect of different 
 kinds of treatment, and the time needed for the com- 
 plete removal of specific processes. And we need, in 
 such observations, careful discrimination, as far as is 
 possible, between the actual effect of the drug and the 
 changes which result from that effect, but need time for 
 their full completion. It is \qyj easy for physicians to 
 mistake the remote effect of the treatment, the slow 
 improvement in symptoms that goes on for a consider- 
 able time after the syphilitic lesion has been removed, 
 for the slow removal of this lesion. 
 
 At the same time the question needs asking, and needs 
 an answer : Are there late syphilitic lesions over which 
 
AND THE NERVOUS SYSTEM. 117 
 
 iodide of potassium has no influence, and which 
 yield to mercury ? Some years ago this question was 
 impressed upon me by the case of a woman who had a 
 firm mass deeply seated in the posterior triangle of the 
 neck, compressing the lower nerve roots entering the 
 brachial plexus, and causing paralysis of the muscles 
 of the forearm and hand. She presented unmistakable 
 signs of constitutional syphilis, including the loss of 
 almost the whole of the soft palate, which had been 
 destroyed by ulceration several years before. Iodide of 
 potassium was given in large doses for about six weeks, 
 but without the slightest effect on the mass. Perhaps 
 during the following two months it did not get larger, 
 but it certainly did not get less, nor did the pain which 
 was caused by the compression of the nerve roots. 
 Mercury was then given, and as soon as its influence 
 was established the mass began to lessen and the pain 
 ceased, and in a few weeks the neck had resumed a 
 normal state. The lesion was no doubt the chronic 
 syphilitic periadenitis not uncommon in this region. 
 Except for one possible source of fallacy (to be men- 
 tioned later), this case seems to be conclusive evidence 
 of the possibility of this difference. 
 
 I have not met with any case of intra-cranial disease 
 in which there was reason to believe that mercury was 
 successful while iodide failed. In the case of gummata 
 I have found, as a rule, the effect of iodide perfectly sat- 
 isfactory, as great as seemed possible, and with entire 
 removal of the symptoms, except in cases in which 
 such complete removal could not be expected. Syphilitic 
 inflammation is, I think, better treated with mercury, 
 
118 LETTSOMIAN LECTURES ON SYPHILIS 
 
 since this has far more influence than iodide over the 
 process of inflammation, irrespective of its nature and 
 cause, but I cannot say that this opinion is based on 
 observations free from sources of fallacy. 
 
 With regard to the methods of administration of 
 mercury I have nothing to say. The old method of 
 inunction seems to me to bring the patient under the 
 influence of the drug as speedily as it can be done with 
 safety, and with a certainty incomparably greater than 
 the administration by the mouth. I have been deterred 
 from a trial of the hypodermic method because the 
 published evidence seemed to me not to aff'ord any 
 satisfactory proof of superiority, being destitute of the 
 elemept of comparison essential to such proof, and 
 because this method seems to afford an opportunity for 
 psychical influence not free from risk of that which is 
 undesirable. But I would not for one moment suggest 
 that such an influence has entered into the motives of 
 those who have used this method. 
 
 There are two points in the treatment of syphilitic 
 diseases of the nervous system on which I think a 
 word of caution is urgently needed. The first is re- 
 garding the prolonged administration of anti-syphilitic 
 drugs, especially of iodide of potassium. By "pro- 
 longed " I mean exceeding from six to ten weeks. 
 I believe that full doses in this time will eflect all 
 that can be thus achieved in the removal of the 
 syphilitic process. But here, as I have just said, 
 we want facts that are visible — numerous and care- 
 fully observed — to guide us in our conclusion. I 
 do not say that the symptoms will have disappeared. 
 
AND THE NERVOUS SYSTEM. 119 
 
 It cannot be too firmly remembered that symptoms 
 are due to changes that are not syphilitic — changes 
 in the nerve elements secondary to the syphilitic dis- 
 ease, but so far independent in course that they may 
 persist long after the specific lesion is at an end. 
 Hence, the fact that the symptoms have not yet 
 ceased is no indication that the specific lesion is not 
 entirely removed. Here, then, I would range myself 
 with the minority — a minority fast growing in size, 
 especially in Germany — with those who hold that 
 the long-continued treatment by small doses of mer- 
 cury or iodide is a mistake, great and dangerous; 
 who hold that treatment of any true specific lesion 
 should be energetic, but should continue only a little 
 longer than is necessary to remove the lesion, repeated, 
 it may be, after an interval occupied either by tonic 
 treatment or by the other of the two chief drugs. 
 If iodide is continued, as it often is, during many 
 months (and much more, as it sometimes is, during 
 years), there is a danger that the system and tissues 
 of the patient may become so accustomed to its pres- 
 ence that the drug will no longer hold in check the 
 syphilitic processes. Probably we may still influence 
 the lesions by increasing the dose, but this process 
 must have limits, in practice if not in theory. Such 
 prolonged and augmented treatment may do definite 
 injury to the patient's health, and even then may 
 fail to effect the desired object. If the poison is an 
 organized virus we might a priori expect this result. 
 By long-continued gradual alteration in the condi- 
 tions, low organisms, as Dallinger has shown in his 
 
120 LETTSOMIAN LECTURES ON SYPHILIS 
 
 remarkable experiments, can be made to endure influ- 
 ences that would at first be fatal to them. By slowly 
 raising the temperature, they will not only live, but 
 will flourish, at a degree of heat which, had it not 
 been for their acclimatization, would kill them in 
 a few minutes. Still, the question is not one in 
 which we can be guided by theory, far less by an 
 analogy possibly remote. There is, however, a posi- 
 tive danger in this method, and it is especially great 
 in the practice to which I referred at the beginning of 
 the lecture, that of repeated courses of energetic treat- 
 ment to remove residual symptoms that cannot be 
 thus removed, because they do not depend on any 
 residual specific process. The test of experience alone 
 can show the extent of this danger, but, at the same 
 time, the fact does not need for its proof the evidence 
 of accumulated experience or numerous observations. 
 A single clear instance will suffice to establish it, 
 and no number of negative instances would dis- 
 prove it. We know how erratic the course of syphi- 
 lis is, and how great must be the variations in the 
 state and tendency of the virus in the system. In 
 one case, if the energy of the disease is subdued, 
 it is for a long time tranquil, while in another the 
 tendency to fresh development soon reasserts itself. 
 Hence it may readily happen that a series of cases 
 leads to a delusive confidence in the safety of a 
 course of treatment, which is, nevertheless, now and 
 then fraught with danger. 
 
 The following instance clearl}^ proves that the 
 danger is not imaginary. Many years ago a man 
 
AND THE NERVOUS SYSTEM. 121 
 
 came under my treatment with symptoms of local 
 chronic meningitis about the pons. Ten grains of 
 iodide of potassium were given, and the symptoms 
 rapidly lessened. Slight residual symptoms, however, 
 remained, for which iodide was continued, and he took 
 it regularly for about four months. At the end of that 
 time some obscure cerebral symptoms developed, the 
 syphilitic nature of which was doubted because they 
 had developed in spite of the iodide. He was ad- 
 mitted to the hospital, and the iodide was continued 
 and slightly increased, but the symptoms rapidly de- 
 veloped, spinal symptoms were superadded, and in a 
 few weeks he died. Post-mortem we found the remains 
 of local syphilitic meningitis at the base, as had been 
 suspected, and also a second syphilitic gumma in 
 the cerebral hemisphere, and another in the spinal 
 cord. Here, then, we had clearly a new development 
 of that syphilitic lesion over which iodide has most 
 influence, although the patient was at the time, and 
 had been for long before, continuously taking the drug. 
 I have seen similar instances, both with iodide and 
 mercury, but this case impressed me so as to preclude 
 the occurrence of fresh illustrations in my own practice, 
 and I do not care to adduce evidence not observed by 
 myself throughout. Especially in early syphilis, how- 
 ever, I have been satisfied that the virus may resume 
 activity during the continuation of mild mercurial 
 treatment. Here there is a source of a possible fallacy 
 in the case I mentioned just now, in which iodide had 
 no influence on the syphilitic process in the neck. It 
 is possible that the patient had been taking iodide for 
 11 
 
122 LETTSOMIAN LECTURES ON SYPHILIS 
 
 a long time before she came under my care. There is 
 no evidence of it, but the point was not investigated, 
 and must remain doubtful. 
 
 I would add only one other remark. If it is true 
 that we cannot cure syphilis, it is most important to 
 consider how it can best be kept in check. This is 
 why the fact of incurability, if true, is so important. 
 A mistaken belief in curabilit}^ may dangerously hin- 
 der attempts at prevention. If no present treatment 
 can prevent future development, then it is wise, whether 
 they come or not, to anticipate them. I think the cus- 
 tom sometimes recommended is good — that every 
 syphilitic subject, for at least five years after the date 
 of his last symptoms, should have a three weeks' course 
 of treatment twice every year, taking for that time 
 twenty or thirty grains of iodide a day. If this practice 
 were adopted generally, is it not reasonable to antici- 
 pate that grave lesions would be much more rare ? 
 
 The idea that residual symptoms are necessarily 
 proof of residual specific lesions, which can be removed 
 by a renewal of treatment that has already been ener- 
 getic, is not only destitute of proof, but is, as I have 
 said, dangerous. I have alluded already to the ease 
 with which a mistaken conclusion can be reached. 
 The danger depends on the tendency which I have 
 more than once mentioned, and must again advert to 
 in its therapeutical aspect — the tendency to degenera- 
 tive changes in the nervous system, presented so fre- 
 quently by those who have had syphilis. The danger 
 is considerable both in those who have had true syphi- 
 litic lesions and in those who have not. These degen- 
 
AND THE NERVOUS SYSTEM. 123 
 
 erations, as we have seen, are not checked by specific 
 treatment, and there is some reason to think that they 
 are not rarely accelerated by such treatment, especially 
 when it exerts a depressing influence on the general 
 health. I have seen many instances of this, especially 
 from energetic mercurial treatment. In most cases of 
 the kind, the evil has been done by the repetition of 
 mercurial treatment, in the hope of removing symp- 
 toms which were not, and could not be, removed by 
 such treatment. 
 
 There is one other important element in the treatment 
 of luetic lesions in the nervous system that is often for- 
 gotten. We have to do with a syphilitic process, and 
 with the damage to the nerve tissues which the process 
 causes. Thus there are three elements in the affection 
 — the specific process, the damage to the nerve tissues 
 caused by that process, and the symptoms that are 
 due to this. It is important to recognize each of 
 these elements, and to consider, in arranging our 
 treatment, how far the two pathological elements need 
 special measures. In arranging the treatment of syphi- 
 litic lesions we must never forget, any more than 
 in diagnosis and prognosis, the simple changes in the 
 nerve tissues on which alone the symptoms depend. To 
 confine our attention to the syphilitic element in treat- 
 ment is to neglect measures that may make an appre- 
 ciable difference in the ultimate result. The cases are, 
 it is true, rare in which we are able to appreciate the 
 effect of neglect on the one hand, or of recognition on 
 the other. In the improvement that follows the re- 
 moval of the syphilitic process, we are commonly unable 
 
124 LETTSOMIAX LECTURES ON SYPHILIS 
 
 to discern, that which may be due to collateral measures. 
 A chief bane of modern therapeutics is, it seems to me, 
 the demand for proof where proof cannot be forthcom- 
 ing, and the tendency to reject that of which the 
 evidence is not clear, when the absence of such evi- 
 dence is often no ground for inferring the absence of 
 benefit. In every case, all measures should be em- 
 ployed that are suggested b}" what we can learn of the 
 nature of the morbid process and of the known ten- 
 dency of therapeutic agents, in confidence that they 
 cannot be altogether without influence in bringing 
 about the ultimate result, and satisfied if now and then 
 we can distinctly trace their beneficial action. 
 
 Here I must end. To me, and if I have been in 
 any measure successful in achieving the result that 
 has been my aim, to you also, the subject cannot but 
 grow in importance the more it is studied ; its vast pro- 
 portions seem to loom still vaster through the mists 
 that obscure its features and prevent clear vision of its 
 outline — still to us unlimited. To those who have 
 attempted to explore the range of its influence on the 
 nervous system, or to those who look on and note the 
 efi"orts of others — who see, from time to time, some 
 fresh discovery extend our knowledge in directions 
 altogether unsuspected, and see region after region of 
 disease opened out before the mental eye as part of this 
 affection — the malady may seem like some " dark con- 
 tinent," not yet half traversed, in which the known 
 may even now be less than the unknown. But the 
 nervous system is only one out of many parts of the 
 
AND THE NERVOUS SYSTEM. 125 
 
 human frame in which this terrible disease plays 
 havoc, and it may be that the greater frequency and 
 extent of its influence here is merely apparent, due to 
 the readiness with which these delicate structures are 
 deranged in their structure and function, and of the 
 distinctness with which such derangement is revealed. 
 Strange indeed it is to think that all this train of mor- 
 bid processes — so long, so varied, often so disastrous — is 
 the consequence of the entrance into the system of a 
 few organisms, scarcely to be seen even with the utmost 
 increase in the power of vision that human ingenuity 
 has yet contrived. And strange is it to think that this 
 malady, rivaled in its total capacity for wrecking 
 human happiness, and health, and life, by no other, 
 and exceeded in apparent dreadfulness only by those 
 whose effects are more sudden, is equally formidable 
 by reason of our limited power over it. Make what 
 deductions you can for the mild or latent forms of the 
 disease, and for our power of repression, the fact remains 
 that we have yet to find the means of arresting it; and, 
 I may add, we have yet to find effective means for its 
 prevention. That philanthropy, the vision of which is 
 so narrowed by misplaced feeling that only one imper- 
 fect aspect of the means employed can be perceived, 
 has decreed that the chief method hitherto suggested 
 shall not have even a trial under fair conditions, and, 
 despite the manifold benefit from its partial use, has 
 decreed that the malady shall continue to work its ruin 
 on the innocent and the guilty alike. One means 
 alone remains, old as the malady itself, by which it 
 can be prevented. One method, and one alone, is 
 
126 LETTSOMIAN LECTURES ON SYPHILIS 
 
 possible, is sure, and that one is open to all. It is the 
 certain prevention secured by unbroken chastity. Is 
 this potentiality increasing? As we look back through 
 the long centuries, we see the sensual more and more 
 dominant as we recede, and clearly lessening as we 
 return toward the present. But when we look around, 
 we can trace small ground for hope that the disease 
 will thus be materially reduced, unless or until there 
 is some change in men more potent and effective 
 than the slow " live upward, working out the beast " 
 of moral evolution. But that which, perhaps, may not 
 be for the mass may yet be for the individual. And, 
 in ending, I must ask a question that I would fain had 
 left unasked, unthought. Do we do all we can — and 
 our profession gives us power that no other has — do we 
 do all we can to promote that perfect chastity which 
 alone can save from this and from that which is worse ? 
 The opinions that, on pseudo-physiological grounds, 
 suggest or permit unchastity are absolutely false. 
 Trace them to their ultimate basis, and they are 
 groundless. They rest only on sensory illusions, one 
 of the many illustrations of a maxim I have often to 
 impress on various sufferers, " There are no liars like 
 our own sensations." Rather, I should say, they rest 
 on misinterpretations of these, always biased, and 
 often deliberate. With all the force that any knowl- 
 edge I possess, and any authority I have, can give, 
 I assert that no man ever yet was in the slightest 
 degree or way the worse for continence or better for 
 incontinence. From the latter all are worse morally ; 
 a clear majority are worse physically ; and in no small 
 
AND THE NERVOUS SYSTEM. 127 
 
 number the result is, and ever will be, utter physical 
 shipwreck on one of the many rocks, sharp, jagged- 
 edged, which beset the wa}^, or on one of the many 
 banks of festering slime which no care can possibly 
 avoid. Let us, then, with our power for good or evil, 
 beware lest we ever give even a silent sanction to that 
 against which, I am sure, on even the lowest grounds 
 that we can take, we should resolutely set our face and 
 raise our voice. 
 
INDEX. 
 
 A. 
 
 Analysis of fifty cases of syphi- 
 litic disease of the cerebral 
 arteries, 71, et seq. 
 
 Aneurism, intracranial, syphilitic 
 and non-syphilitic, 19, 20. 
 
 Arterial disease, syphilitic, seat 
 of, 18-21. 
 
 Atheroma, difference between it, 
 and correspondence in seat with 
 it, and syphilitic arterial dis- 
 ease, 18, 19. 
 
 Atrophy, chronic muscular, rela- 
 tion of, to syphilis, 50. 
 
 Barlow, reference to, 24. 
 Broadbent, reference to, 10. 
 Buzzard, reference to, 10. 
 
 Cerebral embolism, 70, 77-78. 
 hemorrhage, due to syphilitic 
 
 vascular disease, 21. 
 meningitis, chronic, local, of 
 luetic origin, symptomat- 
 ology and diagnosis of, 67- 
 68. 
 thrombosis, results of, 69, 70, 
 and 78. 
 premonitory symptoms 
 in, 76-77. 
 Cerebritis, pathologically specific, 
 rare, 22. 
 
 Charcot and Gombault, reference 
 to, 22, 40. 
 
 Chastit}^ unbroken, a certain pre- 
 vention against syjihilis, 126. 
 
 Convulsions, significance of 
 absence of, attending onset of 
 hemiplegia due to a cortical 
 lesion, 72. 
 
 Cranial neuritis, syphilitic, prog- 
 nosis of, 105. 
 
 D. 
 
 Dal linger, reference to, 109. 
 Diagnosis of syphilitic disease of 
 
 the nervous system, outline of 
 
 process, 56-65. 
 Diphtheria and syphilis, analogy 
 
 between the effects of, 52. 
 
 E. 
 
 Evidence, question of, as an aid 
 to the diagnosis .of non- 
 pathologically s p e c i f i c 
 luetic lesions, 25. 
 
 of sequence as proof of causa- 
 tion, 25-32 
 
 of treatment as proof of causa- 
 tion, 25, 36. 
 
 Functional nervous disorders, the 
 origin of improperly attributed 
 to syphilis, 55-56. 
 
 129 
 
130 
 
 INDEX. 
 
 Gummata, common situation of 
 growth of, 18. 
 
 general and special symptom- 
 atology and diagnosis of 
 65. 
 
 special prognosis of, 104. 
 
 H. 
 
 Heubner, reference to, 68. 
 
 Hemiplegia, sudden, not due to 
 embolism or injury, occurring 
 between 25 and 45 years, prob- 
 ably luetic, 77-78. 
 
 Hill, Berkley, reference to, 30. 
 and Cooper, reference to, 109, 
 114. 
 
 Hutchinson, Jonathan, reference 
 to, 33, 48. 
 
 I. 
 
 Infiltrating growths, prognosis of, 
 
 105. 
 Iodides and mercury, respective 
 
 power of, in the treatment of 
 
 syphilis, 115-117. 
 Irritation, prognosis of symptoms 
 
 of, 105-106. 
 
 Julliard and Pierrot, reference to, 
 24. 
 
 K. 
 
 Kahler, reference to, 24. 
 
 L. 
 
 Latent syphilis, frequency of, 34- 
 
 35. 
 Law, Colles's, 35. 
 Luetic lesions, division of into 
 
 specific and non-special, 16-17. 
 
 "Luetic," the term pi-eferable 
 to "specific,'' when used as a 
 synonym for " syphilitic," 18. 
 
 M. 
 
 Meningitis, chronic syphilitic, 37. 
 prognosis of all forms of, 104. 
 Mercury and the iodides, pro- 
 longed treatment by, 
 dangerous, 118, 119. 
 respective power of, in 
 the treatment of syphi- 
 lis, 115-117. 
 Myelitis, disseminated, subacute, 
 24. 
 pathologically specific rare, 
 
 22. 
 relation of, to syphilis, 39- 
 41. 
 
 N. 
 
 Narcotic cerebral softening from 
 
 syphilitic arterial disease, 69, 
 
 103. 
 Neuritis, cranial, pathologically 
 
 specific, 23. 
 Nuclear palsy, characteristics of, 
 
 87. 
 
 O. 
 
 Ocular palsies, relation of, to syph- 
 ilis, 46-48. 
 Optic neuritis, due to syphilo- 
 mata, 66-67. 
 in the diagnosis of syphi- 
 litic lesions, 56. 
 
 Pachymeningitis, cerebral, 22. 
 
 spinal, 22. 
 Paralysis, acute ascending, rela- 
 tion of, to syphilis, 41. 
 cerebral, syphilitic, symp- 
 toms attending onset 
 of, 73-74. 
 
INDEX. 
 
 131 
 
 Paralysis, due to specific cerebral 
 arterial disease, variation 
 in degree of, 73-74. 
 general, of the insane, hemi- 
 plegia in, 83-84. 
 relation of, to syphilis, 
 49-50, 83-84. 
 Pathology, ultimate, of syphilis, 
 
 12, 51-54. 
 Percentage of males who have 
 
 had syphilis, 29-32, 35. 
 Prognosis of luetic disease of the 
 nervous system, essential prin- 
 ciples underlying it, 95-104. 
 
 R. 
 
 Reason for lack of diagnostic sig- 
 nificance of result of treatment 
 in syphilitic cerebral throm- 
 bosis, 75. 
 
 S. 
 
 Sclerosis, focal, of nerve-centres, 
 
 relation to syphilis, 42. 
 Sequence, isolated instances of, 
 
 no proof of causation, 26-27. 
 ' ' Specific ' ' lesions, character, 
 situations and effects, 18- 
 19. 
 wrongly used as euphemism 
 for "syphilitic," 17-18. 
 
 Strlimpell's hypothesis, 53. 
 
 Sylvian artery, that by which 
 arterial disease causes symp- 
 toms, 73. 
 
 Syphilis an incurable disease, 107- 
 109. 
 ultimate pathology of, 1^, 51- 
 54. 
 
 Syhilitic processes affecting the 
 nervous system, symptomat- 
 ology and diagnosis of, 65 et seq. 
 
 Syphilbmata, diagnostic value of, 
 effects of treatment on, 67. 
 
 System degenerations, relation of, 
 to syphilis, 44-46. 
 
 Tabes dorsalis, relation of, to 
 syphilis, 44-46. 
 
 Tabetic palsies, nature of, 87. 
 
 Therapeutic test, limitations of, 
 availability of, in syphilitic 
 chronic cerebral meningitis, 68. 
 
 Tissue formations due to syphilis, 
 pathology, position and char- 
 acter of, 13-16. 
 
 Treatment of syphilitic inflam- 
 mations, better by mercury 
 than by iodides, 117. 
 
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