CORNELL UNIVERSITY LIBRARY FROM :Irs. A.T.Kerr Cornell University Library QH 207.G143 1892 The microscope and histology. 3 1924 003 059 270 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003059270 THE MICROSCOPE AND HISTOLOGY SIMON HENRY GAGE, Associate Professor of Physiology and Lecturer on Microscopical Technology in Cornell University, Ithaca, N. Y., U. S. A. Part I. THE MICROSCOPE AND MICROSCOPICAL METHODS. Illustrated with six plates and eight figures in the text. FOURTH EDITION, REVISED AND ENLARGED. PUBLISHED BY JAMES W. QUEEN & CO. , IOIO CHESTNUT STREET, PHILADELPHIA, PA. I892. Copyright, 1S92. t By Simon Henry Gage, All Rights Reserved . Printed by Andrtjs & Church Ithaca, N. Y. PREFACE TO THE FOURTH EDITION. In the use of the third edition of this work with large classes and advanced students, the absence of illustrations for the chapter on the micro-spectroscope and micro-polariscope was found to be a serious defect. To remedy the defect an addi- tional plate has been added to this edition ; and with the plate are given several spectra to elucidate the text on the one hand, and on the other to depict the ap- pearances actually seen in working with the micro-spectroscope more accurately than in Plate V. (See Plate VI and explanation opposite p. 54. ) It was found also that the plan and directions for arranging serial sections (p. 78) were not satisfactory in embryological work, they have, therefore, been replaced by those which are believed to be more logical and convenient, and of more general application. The author is greatly indebted to Professor Wilder, to Instructors Hopkins and Pish for suggestions in devising the plan now offered. Besides the changes indicated above, a few minor ones were found necessary as indicated in the table of corrections and additions on the reverse of this sheet. The author would feel grateful to any person who uses this book, if he would point out any errors of statement that may be discovered, and also suggest modi- fications which would tend to increase the intelligibility, especially to beginners. Finally, as indicated on the title page, the work is now published by Messrs. James W. Queen & Co. SIMON HENRY GAGE. May 20, 1892. ADDITIONS AND CORRECTIONS. Corrections : Table, p. 6. In the last catalog of Leitz, the tube-length is given as 160 mm., and this length is said to be measured between the points a-d of the djagram (Fig. 8 b .) P. 7, eighth line from the bottom : For N.A. =sin «onx sin u, etc., read N.A. =« or i x sin u. P. 14, last two lines : For "the eye-point is nearer the eye-lens in low than in high oculars," read, The eye-point. is usually nearer the eye-lens in high than in low oculars. P- 3°. § 77. second paragraph : Only part of the field will be lighted if a low power is used and a very small diaphragm is close to the object ; but if the small diaphragm is considerably below the object, the whole field will be lighted, al- though n6t very satisfactorily. P. 38, paragraphs 1 and 3 : For •' Wallaston " read Wollaston. P. 40, third paragraph : For ' ' presbyopic ' ' read hypermetropic. P. 48, I 121, first paragraph, next the last line : For "party " read partly. P. 54, I 128, first paragraph, second line from the end: For "emergent rays parallel " read emergent rays approximately parallel. Pp- 55> 62 and 94 : For " malazeit " read monazite. P. 85, last line, also in the Bibliography : For "Klement and Regnard" read Kl£ment et Renard. Additions : P. 26, $ 72. The Japanese paper for cleaning lenses was named by the author, "Lens-Paper," Feb. 27, 1892, and may be properly called by that name wherever mentioned in the book. P. 21, \ 59. In \ 59 reference is only made to the swaying of the image due to oblique light. It should be added that if the coarse or fine adjustment is imper- fect, the object may sway even when the light is axial. Swaying with central light would serve to indicate the defective mechanism. In Chapter IV, special attention should be called to the work of MacMunn on the Spectroscope in Medicine, and the Bibliography of works relating to the spec- troscope given in it. Add to the list of books on pp. 86-89 : Carpenter-Dallinger — The Microscope and its Revelations, by the late William B. Carpenter. Seventh edition, in which the first seven chapters have been en- tirely re-written, and the text throughout reconstructed, enlarged and revised by the Rev. W. H. Dallinger. London and Philadelphia, 1891. This work deals very satisfactorily with the higher problems relating to the mi- croscope, and is invaluable as a work of reference. Griffith and Henfrey — The Micrographic Dictionary ; a guide to the examination and investigation of the structure and nature of microscopic objects. Fourth edi- tion, by Griffith, assisted by Berkeley and Jones. London, 1883. Pelletan, J. — Manuel d'Histologie normale. Paris, 1878. Situation of the Plates : Plates I and II, opposite page 1. Plate III, p. 29. Plate IV, . . . . .p. 36. Plate V p. 66. Plate VI, P- 54- THE MICROSCOPE AND HISTOLOGY. CONTENTS OF PART I. CHAPTER I. PAGE. \\ 1-74. The Microscope and its Parts — Care and Use, . 1-28 CHAPTER II. ? \ 75 _ 96- Interpretation of Appearances, 2 9~35 CHAPTER III. $, 97-127. Magnification, Micrometry and Drawing, . 36-53 CHAPTER IV. 128-157. The Micro-Spectroscope and Micro-Polariscope, 54-65 . CHAPTER V. 158-200. Slides and Cover-Glasses, Mounting, Labeling, Cataloging and Storing Microscopical Preparations ; Experiments in Micro- Chemistry 66-85 Bibliography, ... 86-90 Index, 91-96 LIST OF ILLUSTRATIONS. All of the Figures, except when otherwise indicated, are original, and were drawn by Mrs. Gage. PLATES. PLATE I. Fig. i. Double convex lens showing the principal plane, the principal focus, and the focal distance. 2. Converging lens showing formation of a virtual image. 3. Converging lens showing formation of a real image. 4. Simple microscope with retinal image, and its projection as a virtual image. 5. Compound microscope, tracing the rays from the object to the final, virtual image. 6. Huygenian ocular or eye-piece, showing action of field-lens (Ross). 7. Huygenian ocular showing the eye-point. PLATE II. 9. Tripod magnifier. 10. Stand of a compound microscope with names of parts. 11. Section of stage of compound microscope showing proper position of dia- phragms. 12. Section of a low, dry objective and reflected light. 13. Section of an adjustable, immersion objective, transmitted axial and oblique light. 14. Diagram showing how to put on a cover-glass. 15. Slides showing how to enclose the lines of a micrometer or of some part of a preparation by a small ring. 16. Double eye-shade. PLATE III. 20-22. Sectional views of the Abbe illuminator showing various methods of illu- mination, — with parallel rays of central light, with oblique light, with con- verging rays, and for dark-ground illumination. 23. Letters mounted in stairs to show order of coming into focus. 24. Glass rod in air and in glycerin. 25. Glass rod coated with collodion to show double contour. 26. Blood corpuscles on edge, to show surface and optical sections. 27. Wollaston's camera lucida in section, showing the overlapping fields. 28. Position of the microscope for determining magnification with Wollaston's camera lucida ; also the necessity of ,a standard distance at which to measure the image. 29. Figures of the image of the stage and ocular micrometers, showing correct mu- tual arrangement of lines in determining the ocular micrometer valuation. PLATE IV. 30. Sectional view of the Abbe camera lucida with a 45 mirror and a horizontal drawing surface. 31. Geometrical figure of the preceding showing the angles made by the axial ray with the drawing surface and with the mirror. 32. Sectional view of the Abbe camera lucida with a 35° mirror, showing the nec- essary elevation of the drawing surface to avoid distortion. 33. Geometrical figure of the preceding showing angles of axial ray and of draw- ing board, and that the drawing board must be raised twice as many degrees as the mirror is depressed below 45 . 34. Diagram showing arrangement of drawing board with mirror at 35 and with the microscope inclined 30 (Mrs. Gage). 35. Upper view of the prism of the camera lucida. 36. Eye-point of an ocular. 37. Quadrant with graduations to be added to the mirror of the Abbe camera lucida to determine the inclination of the mirror. PLATE V. 41. Effect of the cover-glass on the rays from the object to the objective (Ross). 42. Direction of the rays from an object through a cover-glass in a dry objective. 43. Direction of the rays with a water immersion objective. 44. Direction of the rays with a homogeneous immersion objective. (Fig. 42-44 are modified from Ellenberger). 45. Absorption spectrum of arterial and venous blood ; some of the principal Fraunhofer lines and an Angstrom scale are also shown. (From Gamgee and MacMunn). 46. Centering card. 47. Small spirit lamp used as a reagent bottle for Canada balsam, glycerin jelly, shellac cement, etc. 48. Pipette or dropper for delivering small quantities of any liquid. 49. Slide and cover-glass showing the method of irrigation. 50. Showing the method of anchoring the cover-glass previous to sealing glycerin- mounted objects. 51-56. Various apparatus for the study of fibrin and the counting of blood corpus- cles. (These figures appertain to Part II). FIGURES IN THE TEXT. Fig. Page. 8. Triplet for the pocket (Bausch & Lomb Optical Company), 2 8a. Simple microscope with stand (R. & J. Beck), 2 8b. Figure showing parts included in tube-length by various opticians, ... 6 17. Double nose-piece or revolver (Bausch & Lomb Optical Co.), 11 18. Ward's eye-shade (Bausch & Lomb Optical Co.) 27 19. Oil-globule and air-bubble, with oblique light, 32 38. Cover-glass measurer (Edward Bausch) 69 38a. Turn-table for sealing cover-glass, etc., (James W. Queen & Co.), .... 71 39. Cabinet for specimens, ... 80 40. Cabinet drawer, face and sectional view, 81 57. Arranging and labeling serial sections, . . .... 78 THE MICROSCOPE AND HISTOLOGY. CHAPTER I. THE MICROSCOPE AND ITS PARTS— CARE AND USE. APPARATUS AND MATERIAL FOR THIS CHAPTER. « A simple microscope ($ 2, 4) ; A compound microscope with nose-piece (Fig. 17), eye-shade (Fig. 16, 18), achromatic (g 12), apochromatic (? 14), dry ((! 9), immersion ($10), unadjustable and adjustable objectives (g 15, 16), Huygenian or negative {I 20, 22), positive (§ 21) and compensation oculars (£ 23), Abbe illuminator (54), homogeneous immersion liquid (g io, 65-69), benzine and distilled water (? 64, 69). Mounted letters or figures (§ 34) ; Ground-glass and Japanese filter or bib- ulous paper ($ 34, 72) ; Mounted preparation of fly's wing ((S 50) ; Mounted' prepa- ration of Pleurasigma {\ 52, 53, 58) ; Stage or ocular micrometer with lines ' filled with graphite {\ 52, 53, 59) ; Glass slides and cover glasses ($ 52) ; 10 per ct. solution of salicylic acid in 95 per ct. alcohol (§ 60) ; Preparation of stained mi- crobes (§ 67) ; Vial of equal parts olive or cotton seed oil and benzine (g 71). Of the above, the laboratory furnishes all except the tripod magnifier, the glass slides and cover-glasses ; these must be obtained by the student. A MICROSCOPE. I 1. A Microscope is an optical apparatus with which one may obtain a clear image of a near object, the image being always larger than the object ; that is, it enables the eye to see an object under a greatly increased visual angle, as if the object were brought very close to ^he eye without affecting the distinctness of vision. Whenever the microscope is used for observation, the eye of the observer forms an integral part of the optical combination (PI. I, Fig. 4 and 5). I 2. A Simple Microscope. — With this an enlarged, erect image of an object may be seen. It always consists of one or more converging lenses or lens-systems (PI. I, Fig. 1, 2 and 4), and the object must be placed within the principal focus (§ 4). The simple microscope may be held in the hand or it may be mounted in some way to facilitate its use (Fig. 8 a ). \ 3. A Compound Microscope. — This enables one to see an enlarged, inverted image. It always consists of two optical parts, — an objective, to produce an en- larged, inverted, real image of the object, and an ocular acting in general like a. simple microscope to magnify this real image (PI. I, Fig. 5). There is also usually present a mirror, or both a mirror and some form of condenser or illuminator for lighting the object. The stand of the microscope consists of certain mechanical arrangements for holding the optical parts and for the more satisfactory use of them (PL II, Fig. 10). EXPLANATION OF PLATE I. In all of the figures, Virtual Images and rays traced backward or produced rays, are indicated by dotted or broken lines, real rays or paths of rays by full or un- broken lines. Fig. i. Sectional view of a double convex lens showing : (A B) the principal plane at which the refractions of the curved surfaces are most conveniently shown ; (c) Optical Center of the lens. Rays traversing this center undergo no deviation. Axis. Principal optic axis of the lens, *. 35.5 ; C., pp. 161, 206 ; N. & S., p. 176 ; R., p. 29 ; Robin, p. 126 ; Amer. Soc. Micrs., 1884, p. 183; 1889, p. 22; Amer. Jour. Arts and Sciences, 1890, p. 50; Jour. Roy. Micr. Soc, 1888, 1889. § 105. Table of Magnifications and of the Valuations of the Ocular Micrometer. — The following table should be filled out by each student. In using it for Micrometry and Drawing it is necessary to keep clearly in mind the exact conditions under which the determinations were made, and also the ways in which variation in magnification and the val- uation of the ocular micrometer may be produced (§§ 103, 104, 1 14, 1 16). OCULAR OCULAR 50 mm. 25 mm. Object- ive. Tube IN. ;Tube OUT Tube in. Tube out MM. Ocular Micrometer Valuation, tube in. out MM. %, 18 mm. x ijl. x 6% mT *$H ■O^Wl Ai'mu Y%, 3 mm- X X X X 1/4 x//f x /<* x *^ * tfa fc* V* Simple. Microscope. x 10 MICROMETRY. § 106. Micrometry is the determination of the size of objects by the aid of a microscope. 41 MAGNIFICATION AND DRA WING. MICROMETRY WITH THE SIMPLE MICROSCOPE. § 107. With a simple microscope, (A) the easiest and best way is to use dividers and then the simple microscope to see when the points of the dividers exactly include the object. The spread of the dividers is then obtained as above (§ 99). This amount will be the actual size of the object, as the microscope was only used in helping to see when the divider points exactly enclosed the object, and then for reading the di- visions on the rule in getting the spread of the dividers. (B) One may put the object under the simple microscope and then as determining the power (§ 98), measure the image at the standard dis- tance. If now the size of the image so measured is divided by the magnification of the simple microscope, the quotient will give the actual size of the object. Use a fly's wing or some other object of about that size and try to determine the width in the two ways described above. If all the work is accurately done the results will agree. MICROMETRY WITH THE COMPOUND MICROSCOPE. There are several ways of varying excellence for obtaining the size of objects with the compound microscope, the method with the ocular micrometer (§§ 116, 117) being most accurate. § 108. Unit of Measure in Micrometry. — As most of the objects measured with the compound microscope are smaller than any of the originally named divisions of the meter, and the common or decimal fractions necessary to express the size are liable to be unnecessarily cumbersome, Harting, in his work oh the microscope (1859), proposed the one thousandth of a millimeter ( l0 1 00 mm. or 0.001 mm.) or one millionth of a meter C i ooio 00 or 0.000001 meter) as the unit. He named this unit micro-millimeter and designated it mmm. In 1869, Listing (Carl's Repet'orium fur Experimental-Physik, Bd. X, P. 5) favored the thousandth of a millimeter as unit and introduced the name Mikron or micrum. In English it is most often written Micron, plural micro, or microns, pronunciation Mic'ron, or Mi'cron. By uni- versal consent the sign or abbreviation used to designate it is the Greek p. Adopting this unit and sign, one would express five thousandths of a millimeter (-n^nr or o.oosths mm.) thus, 5/*.* * The term Micromillimeter ab. mmm. is very cumbersome, and besides is en- tirely inappropriate since the adoption of definite meanings for the prefixes micro and mega, meaning respectively one millionth and one million times the unit be- fore which it is placed. A micromillimeter would then mean one-millionth of a millimeter, not one-thousandth. The term micron, has been adopted by_the great microscopical societies, the international commission on weights and measures and by original investigators, and is in the opinion of the writer the best term to em- ploy. Jour. Roy. Micr. Soc, 1888,, p. 502 ; Nature, Vol. XXXVII, (1888), p. 388. 42 MA GNIFICA TION AND DRA WING. \ 109. Micrometry by the use of a stage micrometer on which to mount the ob- ject. — In this method the object is mounted on a micrometer and then put under the microscope and the number of spaces covered by the object is read off directly. It is exactly like putting any large object on a rule and seeing how many spaces of the rule it covers. The defect in the method is that it is impossible to properly arrange objects on the micrometer. Unless the objects are circular in outline they are liable to be oblique in position and in every case the end or edges of the object may be in the middle of a space instead of against one of the lines, consequently the size must be estimated or guessed at rather than really measured. § no. Micrometry by dividing the size of the image by the magnifi- cation of the microscope. — For example, employ the 3 mm. objective, 25 mm. ocular, and a Necturus' red blood-corpuscle preparation as object.* Obtain the size of the image of the long and short axes of three cor- puscles with the camera lucida and dividers exactly as in obtaining the magnification of the microscope (§ 102). Divide the size of the image in each case by the magnification and the result will be the actual size of the blood-corpuscle. Thus, suppose the image of the long axis of the corpuscle is 18 mm. and the magnification of the microscope 400 diameters (§ 97), then the actual length of this long axis of the cor- puscle is 18 mm. ^-400= .045 mm. or 45 /* (§ 108). § in. Micrometry by the use of a Stage Micrometer and a Camera Lucida. — Employ the same object, objective and ocular as before. Put the camera lucida in position, and with a lead pencil make dots on the paper at the limits of the image of the blood-corpuscle. Measure the same three that were measured in § no. Remove the object, place the stage micrometer under the microscope, focus well, and draw the lines of the stage micrometer so as to include the dots representing the limits of the part of the image to be meas- ured. As the value of the spaces on the stage micrometer is known, the size of the object is determined by the number of spaces of the mi- crometer required to include it. This simply enables one to put the image of a fine rule on the image of a microscopic object. It is theoretically an excellent method, and nearly the same as measuring the Spread of the dividers with a simple microscope (§§ 99, 117). OCULAR MICROMETER. §112. Ocular Micrometer, Eye- Piece Micrometer. — This, as the name implies, is a micrometer to be used with the ocular. It is a * As the same three blood corpuscles are to be measured in three ways, it is an advantage to put a delicate ring around a group of three or more corpuscles and make a sketch of the whole enclosed group, marking on the sketch the corpuscles measured. The different corpuscles vary considerably in size, so that accurate com- parison of different methods of measurement can only be made when the same corpuscles are measured in each of the ways. 43 MA GNIFICA TION AND DRA WING. micrometer on glass, and the lines are sufficiently coarse to be clearly- seen by trie ocular. The lines should be equidistant and about ^th or ^Vth mm. apart and every fifth line should be longer and heavier to facili- tate counting. If the micrometer is ruled in squares {net-micrometer) it will be very convenient for many purposes. The ocular micrometer is placed in the ocular, no matter what the form of the ocular (z. e., whether positive or negative), at the level at which the real image is formed by the objective, and the image appears to be immediately upon or under the ocular micrometer and hence the number of spaces on the ocular micrometer required to measure the real image may be read off directly. This is measuring the size of the real image, however, and the actual size of the object can only be de- termined by determining the ratio between the size of the real image and the object. In other words it is necessary to get the valuation of the ocular micrometer in terms of a stage micrometer. § 113. Valuation of the Ocular Micrometer. — This is the value of the divisions of the ocular micrometer for the purposes of microm- etry, and is entirely relative, depending upon the magnification of the real image formed by the objective, consequently it changes with every change in the magnification of the real image and must be specially determined for every optical combination (z. e., objective and ocular) and for every change in the length of the tube of the microscope. That is, it is necessary to determine the ocular micrometer valuation for every condition modifying the real image of the microscope (§ 103). § 114. Obtaining the Ocular Micrometer Valuation. — As an ex- ample, employ the 25 mm. ocular and 18 mm. objective. Place the stage micrometer under the microscope for an object, and put the ocular micrometer in position, either through a slit in the ocular, or remove the eye-lens and place it upon the ocular diaphragm.* Ivight the field well, and look into the microscope. The lines on the ocular micrometer should be very sharply defined. If they are not, raise or lower the eye-lens to make them so ; that is, focus as with the simple magnifier. When the lines of the ocular micrometer are distinct, focus the mi- * It is a great convenience to have a micrometer ocular ( millimeter (see table, § 17). It is better never to use a cover glass over T 2 ^ mm. thick then the preparation may be studied with a 2 mm. oil immersion as well as with lower objectives. Except for objects wholly unsuited for high powers, it is a great mistake to use cover-glasses thicker than the working distance of a homogeneous objective (§ 38). The cover-glass should always be considerably larger than the object over which it is placed. § 161. Cleaning Cover-Glasses. — New cover-glasses should be put into a glass dish of some kind containing one of the cleaning mix- tures (§ 164) and allowed to remain a day or longer. In putting them in, push one in at a time and be sure that it is entirely immersed, otherwise they adhere very closely, and the cleaning mixture is unable to act freely. Soiled covers should be left a week or more in the cleaning mixture. An indefinite sojourn in the cleaner does not seem to injure the slides or covers. After one day or longer, pour off the cleaning mixture into another glass jar, and rinse the cover glasses, moving them around with a gentle rotary motion. Continue the rinsing until all the cleaning mixture is removed. One may rinse them occasionally, and in the meantime allow a very gentle stream of water to flow on them or they may be allowed to stand quietly and have the water renewed from time to time. When the cleaning mixture is removed rinse the covers well with distilled water, and then cover them with 50% to 75 % alcohol. Wiping the cover-glasses. — When ready to wipe the cover-glasses re- move several from the alcohol and put them on a soft dry cloth or on some of the Japanese paper, to let them drain. Grasp a cover-glass by its edges, cover the thumb and index of the other hand with a soft clean cloth or some of the Japanese paper. Grasp the cover between the thumb and index and rub the surfaces. In doing this it is neces- sary to keep the thumb and index well opposed or on directly opposite 68 MOUNTING AND LABELING. faces of the cover so that no strain will come on it, otherwise the cover is liable to be broken. When a cover is well wiped, hold it up and look through it toward some dark object. The cover will be seen partly by transmitted and partly by reflected light, and any cloudiness will be easily seen. If the cover does not look clear, breathe on the faces and wipe again. If it is not possible to get a cover clear in this way it should be put again into the cleaning mixture. As the covers are wiped put them in a clean paper box. Handle them always by their edges, or use fine forceps. Do not put the fingers on the faces of the covers, for that will surely cloud them. § 162. Cleaning Large Cover-Glasses. — For serial sections and especially large sections, large quadrangular covers are used. These are to be put one by one into cleaning mixture as for the smaller covers and treated in every way the same. In wiping them one may proceed as for the small covers, but special care is necessary to avoid breaking them. A safe and good way to clean the large covers, is to take two perfectly flat, smooth blocks considerably larger than the cover- glasses. These blocks are covered with soft clean cloth, or with sev- eral thicknesses of the Japanese paper ; if now the cover-glass is placed on the one block and rubbed with the other the cover may be cleaned as by rubbing its faces with the cloth covered ringer and thumb. §163. Measuring the Thickness of Cover-Glasses. — It is of the greatest advantage to know the exact thickness of the cover-glass on an object ; for, (a) One would not try to use objectives in studying the preparation of a shorter working distance than the thickness of the cover (§ 3,8) ;: (b) In using adjustable objectives with the collar gradu- ated for different thicknesses of cover, the collar might be set at a favorable point without loss of time ; (c) For unadjustable objectives the thickness of cover may be selected corresponding to that for which the objective was corrected 9 (see table § 17). Furthermore, if there is a variation from the standard, one may remedy it, in part at least, by lengthening the tube if the cover is thinner, and shortening it if the cover is thicker than the standard (§ 63). In the so called No. 1 cover-glasses of the dealers in microsopical supplies, the writer has found covers varying from j 1 ^ mm. to ^ mm. To use cover-glasses of so wide a variation in thickness without knowing whether one has a thick or a thin one' is simply to ignore the fundamental principles on which correct microscopic images are ob- tained. It is then strongly recommended that every preparation shall be cov- ered with a cover-glass whose thickness is known, and that this thick- ness should be indicated in some way on the preparation. 6 9 MOUNTING AND LABELING. For the purpose of measuring cover-glasses two very convenient cover-glass measures or cover-glass testers have been devised, one made and furnished by Zeiss, Reichert, etc., in Europe, and -the other, de- vised by Edward Bausch and furnished by the Bausch and Eomb Opti- cal Co. of Rochester, N. Y. With either of these the cleaned covers may be very quickly and accurately measured. The different thick- nesses can then be put into different boxes and properly labeled. Unless one is striving for the most accurate possible results, cover- glasses not varying more than yf^ mm. may be put in the same box. For example, if one takes y 1 ^ mm. as a standard, covers varying T § 7 mm. on each side may be put into the same box. In this case the box would contain covers of yW y 1 ^, yW, y 1 ^, and y 1 ^ mm. Fig. 38. Cover-Glass Measurer {Edward Bausch). The cover-glass is placed in the notch between the two screws, and the drum is turnea by the milled head at the right till the cover is in contact with the screws. The thickness is then indicated by the knife edge on the drum, and may be read off directly in -xw^th mm. or nrmth inch. In other columns is given the proper tube-length for various unadjustable ob- jectives (y, \, \, and yj, in.) made by the Bausch and Lomb Optical Co. 70 MOUNTING AND LABELING. § 164. Cleaning Mixtures for Glass. — The cleaning mixtures used for cleaning slides and cover-glasses are those commonly used in chem- ical laboratories : (A) Dichromate of Potash and Sulphuric Acid. Dichromate of potash (K 2 Cr 2 O,) 200 grams. Water, distilled or ordinary 1000 cc. Sulphuric acid (H 2 S0 4 ) 1000 cc. Dissolve the dichromate in the water by the aid of heat. Pour the solution into a bottle that has been warmed. Add slowly and at inter- vals the sulphuric acid. For making this mixture > ordinary water, commercial dichromate and strong commercial sulphuric acid should be used. It is not neces- sary to employ chemically pure materials. This is a very excellent cleaning mixture and is practically odorless. It is exceedingly corrosive and must be kept in glass vessels. It may be used more than once, but when the color changes markedly from that seen in the fresh mixture it should be thrown away. (B) Sulphuric and Nitric Acid Mixture. Nitric acid (H N0 3 ) 200 cc. Sulphuric acid (H 2 SOJ 300 cc. The acids should be strong, but they need not be chemically pure. The two acids are mixed slowly, and kept in a glass-stoppered bottle. This is a more corrosive mixture than (A) and has the undesirable fea- ture of giving off very stifling fumes, therefore it must be carefully covered. It may be used several times. It acts more rapidly than the dichromate mixture but on account of the fumes is not so well adapted for general laboratories. MOUNTING, AND PERMANENT PREPARATION OF MICROSCOPICAL OBJECTS. § 165. Mounting a microscopical object is so arranging it upon some suitable support (glass slide) and in some suitable mounting medium that it may be satisfactorily studied with the microscope. Some objects are mounted dry or in air, others in some liquid misci- ble with water, as glycerin, and still others in some resinous medium like Canada balsam. Special methods of procedure are necessary in order to mount objects successfully in each of these ways. The best mounting medium and the best method of mounting in a given case can only be determined by experiment, unless some previous observer has already supplied the information. The cover-glass on a permanent preparation should always be consider- ably larger than the object ; and where several objects are put under one cover-glass it is false economy to crowd them too closely together. 7 1 MOUNTING AND LABELING. § 166. Mounting Cells. — Many objects are of considerable thickness and require a space or cell in which to be mounted, the wall of the cell serving to support the cover-glass and to contain the mounting medium. Where objects are mounted dry, that is in air, a cell must always be used to support the cover-glass and to prevent the soft cement used in sealing the preparation from running in by capillarity and thus flooding the preparation. Fig. 38a. Turn-Table for Sealing Cover-Glasses and Making Shallow Mounting Cells. {Queen & Co.) §167. Preparation of Mounting Cells. — (A) Thin Cells. These are most conveniently made of some of the microscopical cements. Shellac is one of the best and most generally applicable (§ 193). To prepare a shellac cell, place the slide on a turn-table (Fig. 38") and center it, that is get the center of the slide over the center of the turn-table. Select a guide ring on the turn-table which is a little smaller than the cover- glass to be used, take the brush from the shellac, being sure there is not enough cement adhering to it to drop. Whirl the turn-table and hold the brush lightly on the slide just over the guide ring selected. An even ring of the cement should result. If it is uneven, the cement is too thick or too thin or too much was on the brush. After a ring is thus prepared remove the slide and allow the cement to dry spontan- eously or heat the slide in some way. Before the slide is used for mounting, the cement should be so dry when it is cold that it does not dent with the finger nail applied to it. A cell of considerable depth may be made with the shellac by adding successive layers as the previous one drys. (B) Deep cells are sometimes made by building up cement cells, but more frequently, paper, wax, glass, hard rubber or some metal is used for the main part of the cell; Paper rings, block tin or lead rings are easily cut out with gun punches. These rings are fastened to the slide by using some cement like the shellac. § 168. Sealing the Cover-Glass. — (A) For dry objects mounted in- cells. When an object is mounted in a cell, the slide is warmed until the cement is slightly sticky, or a very thin coat of fresh cement is put 72 MOUNTING AND LABELING. on. The cover-glass is warmed slightly also, both to make it stick to the cell more easily, and to expel any remaining moisture from the ob- ject. When the cover is put on it is pressed down all around over the cell until a shining ring appears, showing that there is an intimate con- tact. In doing this use the convex part of the fine forceps or some other blunt, smooth object ; it is also necessary to avoid pressing on the cover except immediately over the wall of the cell for fear of breaking the cover. When the cover is in contact with the wall of cement all around, the slide should be placed on the turn-table and carefully ar- ranged so that the cover-glass and cell wall will be concentric with the guide rings of the turn-table. Then the turn-table is whirled and a ring of fresh cement is painted, half on the cover and half on the cell wall (Fig. 40). If the cover-glass is not in contact with the cell wall at any point and the cell is shallow, there will be great danger of the fresh cement running into the cell and injuring or spoiling the preparation. When the cover-glass is properly sealed, the preparation is put in some safe place for the drying of the cement. It is advisable to add a fresh coat of cement occasionally. (B) Thick or deep cells. These may be made of paper, sheet lead or block tin, etc. They should be slightly deeper than the object to be mounted is thick. It is sometimes advisable to have a circular opening and an oblong wall instead of using a mere ring. In any case the cell wall is cemented to the slide and the cement well dried before use. If the ce.ll is for dry objects or for those in glycerin, a ring of fresh cement is added just before putting on the cover-glass. If glycerin jelly, a res- inous substance, or Farrant's solution is to be used as the mounting medium no cement on the top is necessary. § 169. Sealing the Cover-Glass when no Cell is Used. — (A) For glycerin mounted specimens. The superfluous glycerin is wiped away as carefully as possible with a moist cloth, then four minute drops of cement are placed at the edge of the cover (PI. V, Fig. 50), and allowed to harden for half an hour or more. These will anchor the cover-glass, then the preparation may be put on the turn-table and a ring of cement put around the edge while whirling the turn-table. (B) For objects in glycerin jelly, Farrant's solution or a resinous me- dium. The mounting medium is first allowed to harden, then the su- perfluous medium is scraped away as much as possible with a knife, and then removed with a cloth moistened with water for the glycerin jelly and Farrant's solution or with alcohol, chloroform or turpentine, etc. , if a resinous medium is used. Then the slide is put on a turn-table and a ring of the shellac cement added. (C) Balsam preparations may be sealed with shellac as soon as they are prepared, but it is better to al- low them to dry for a few days. One should never use a cement for 73 MOUNTING AND LABELING. sealing preparations in balsam or other resinous media unless the solvent of the cement is not a solvent of the balsam, etc. Otherwise the ce- ment will soften the balsam and finally run in and mix with it, and partly or wholly ruin the preparation. Shellac is an excellent cement for sealing balsam preparations, as it never runs in, and it serves to avoid any injury to the preparation when cedar oil, etc., are used for ho- mogeneous immersion objectives. § 170. Order of Procedure in Mounting Objects Dry or in Air. 1. A cell of some kind is prepared. It should be slightly deeper than the object is thick (§§ 166, 167). 2. The object is thoroughly dried (desiccated) either in dry air or by the aid of gentle heat. 3. If practicable the object is mounted on the cover-glass, if not it is placed in the bottom of the cell: 4. The slide is warmed till the cement forming the cell wall is some- what sticky, ox a thin coat of fresh cement is added ; the cover is warmed and put on the cell and pressed down all around till a shining ring indicates its adherence (§ 168). 5. The cover-glass is sealed (§ 168). 6. The slide is labeled (§ 179). 7. The preparation is cataloged and safely stored (§§ 181-183). MOUNTING OF OBJECTS IN MEDIA MISCIBI. 96 /sso ^ycri/e. /Hers Cai 70 MOUNTING OBJECTS — EXPERIMENTS. ■ \ 184. Mounting Dry, or in Air ($ 170). — Pre- pare a shallow cell and dry it (\ 167). Select a clean cover-glass slightly larger than the cell. Pour upon the cover a drop of a 10 per cent, solution of salicylic acid in 95 per cent, alcohol. Let it dry spontaneously. Warm the slide till Fig. 40- the cement ring or cell is somewhat sticky, then warm the cover gently and put it on the cell, pressing down all around (§ 170). Seal the cover, label and catalog (?? 179, 181). A preparation of mammalian red blood corpuscles may be made very satisfac- torily by spreading a very thin layer of fresh blood on a cover with the end of a slide. After it is dry, warm gently to remove the last traces of moisture and mount precisely as for the crystals. One can get the blood as directed for the Mi- cro-spectroscopic work (§ 146). § 185. Mounting in Glycerin Jelly. — For this select some stained and isolated muscular fibers. Arrange them on the middle of a slide, using the centering card, and mount in glycerin jelly as directed in \ 174. Air bubbles are not easily re- moved from glycerin jelly preparations, so care should be taken to avoid them. \ 186. Mounting in Balsam by Desiccation (§ 176). — Find a fresh fly, or if in winter procure a dead one from a window sill or a spider's web. Carefully remove the fly's wings, being especially careful to keep them the dorsal side up. With a camel's hair brush remove any dirt that may be clinging to them. Place a clean slide on the centering card, then with fine forceps put the two wings within one of the guide rings. Leave one dorsal side up, turn the other ventral side up. Spread some Canada Balsam on the face of the cover-glass and with the fine for- ceps place the cover upon the wings (PI. II, Fig. 14). Probably some air-bubles will appear in the preparation, but if the slide is put in a warm place these will soon disappear. Label, catalog, etc., ($176, 179, 181).* \ 187. Mounting in Balsam by Displacement (£§ 175, 177). — For this experi- ment select a stained section of any organ or tissue, as the skin, or myel (spinal cord), then proceed exactly as described in §§ 175, 177. * The Faber's pencils for writing on glass, china, etc., are very convenient for writing temporary labels, etc., on slides and bottles. 82 MOUNTING AND LABELING. PREPARATION QF MOUNTING MEDIA. (S 188. Glycerin. — One should procure pure glycerin for a mounting medium. It needs no preparation, except in some cases it should be filtered through filter paper or absorbent cotton to remove dust, etc. For preparing objects for final mounting, glycerin 50 cc, water 50 cc, form a good mixture. For many purposes the final mounting in glycerin is made in an acid medium, viz., Glycerin 99 cc, Glacial acetic or formic acid, 1 cc. By extreme care in mounting and by occasionally adding a fresh coat to the sealing of the cover-glass, glycerin preparations last a long time. They are liable to be very disappointing, however. In mounting in glycerin care should be taken to avoid air-bubbles, as they are difficult to get rid of. A specimen need not be discarded unless the air-bubbles are large and numerous. g 189. Glycerin Jelly. — Soak 25 grams of the best dry gelatin in cold water in a small agate-ware dish. Allow the water to remain until the gelatin is softened. It usually takes about half an hour. When the gelatin is softened, as may be readily determined by taking a little in the fingers, pour off the superfluous water and drain well to get rid of all the water that has not been imbibed by the gelatin. Warm the softened gelatin over a water bath and it will melt in the water it has absorbed. Add to the melted gelatin about 5 cc. of egg albumen (white of egg) ; stir it in well and then heat the gelatin in the water bath for about half an hour. Do not heat above 75 or 8o° C, for if the gelatin is heated too hot it will be transformed into meta-gelatin and will not set when cold- The heat will coagu- late the albumen and form a kind of floculent precipitate which seems to gather all fine particles of dust, etc., leaving the gelatin perfectly clear. After the gela- tin is clarified it should be filtered thr.ough a hot filter and mixed with an equal volume of glycerin and 5 grams of chloral hydrate and shaken thoroughly. If it is allowed to remain in a warm place (z. £., in a place where the gelatin remains melted) the air-bubbles will rise and dissapear. -In case the glycerin jelly remains fluid or semi-fluid at the ordinary temperature (i8°-2o° C), the gelatin has either been transformed into meta-gelatin by too high temperature or it contains too much water. The amount of water may be lessened by heating at a moderate temperature over a water bath in an open vessel. This is a very excellent mounting medium. Air-bubbles should be avoided in mounting as they do not disappear. \ 190. Farrant's Solution. — Take 25 grams of clean, dry, gum arabic ; 25 cc. of a saturated aqueous solution of arsenious acid ; 25 cc. of glycerin. The gum ara- bic is soaked for several days in the arsenic water, then the glycerin is added and carefully mixed with the dissolved or softened gum arabic. This medium retains air-bubbles with great tenacity. It is much easier to avoid than to get rid of them in mounting. For the method of mounting in this see \ 173. \ 191. Canada Balsam, Balsam of Fir. — This is one of the oldest and most sat- isfactory of the resinous media used for mounting microscopical preparations. Sometimes it is used in the natural state, but experience has shown that it is bet- ter to get rid of the natural volatile constituents. A considerable quantity, half a liter or more, of the natural balsam is poured into shallow plates in layers about 1 or 2 centimeters thick, then the plates are put in a warm, dry place, on the back of a stove or on a steam radiator, and allowed to remain until the balsam may be powdered when it is cold. This requires a long time, the time depending on the temperature and the thickness of the layer of balsam. 83 MOUNTING AND LABELING. When the volatile products have evaporated,' the balsam is broken into small pieces or powdered in a mortar and mixed with about an equal volume of xylol, turpentine or chloroform. It will dissolve in this and then should be filtered through absorbent cotton or a filter paper, using a paper funnel.* The balsam is too thin in this condition for mounting, but so made for the sake of filtering it. After it is filtered it is evaporated slowly in an open dish or a wide-mouth bottle or jar till it is of a syrupy consistency at the ordinary temperature. It is then poured into a bottle with a glass cap like a spirit lamp. For use it is put into a small spirit lamp (PI. V, Fig 47). The xylol is much the best substance to use for thinning the balsam. Such xylol balsam, as it is then called, may be used for mounting any object suitable for balsam mounting. The dehydration must be very perfect, however, as xylol is wholly immiscible with water. I 192. Clearing Mixture {I 175).— One of the most satisfactory and generally ap- plicable clearers is made by mixing carbolic acid crystals {Acidum carbolicum, A. phenicum crystallizatum) 40 cc. with rectified oil of turpentine {Oleum tere- binthinae rectificatum) 60 cc. I 193. Shellac Cement. — Shellac cement for sealing preparations and for making shallow cells {\\ 167, 168) is prepared by adding scale or bleached shellac to 95 per cent, alcohol. The bottle should be filled about half full of the solid shellac then enough 95 per cent, alcohol added to fill the bottle nearly full. The bottle is shaken occasionally and then allowed to stand until a clear stratum of liquid appears on the top. This clear, supernatant solution is then filtered through absorbent cotton, using a paper funnel {\ 189), into an open dish or a wide-mouth bottle. To every 50 cc. of this filtered shellac 5 cc. of castor oil and 5 cc. of Vene- tian turpentine are added to render the shellac less brittle. This filtered shellac will be too thin and must be allowed to evaporate till it is of the consistency of thin syrup. It is then put into a capped bottle and for use into a. small spirit lamp (PI. V, Fig. 47). In case the cement gets too thick add a small amount of 95 per cent, alcohol or some thin shellac. I 194. Liquid Gelatin. — Gelatin or clear glue 75 to 100 grams. Commercial acetic acid (No. 8) 100 cc, Water 100 cc, 95 per cent, alcohol 100 cc. Glycerin 15 to 30 cc. Crush the glue and put it into a bottle with the acid, and set in a warm place, and shake occasionally. After three or more days add the other ingredi- ents. This solution is excellent for fastening paper to glass, wood or paper. The brush must be mounted in a quill or wooden handle. For labels, it is best to use linen paper of moderate thickness. This should be coated with the liquid gelatin and allowed to dry. The labels may be cut of any desired size and attached by simply moistening them as in using postage stamps. Very excellent blank labels are now furnished by dealers in microscopical sup- plies, so that it is unnecessary to prepare them one's self except for special pur- poses. * For filtering balsam and all resinous and gummy materials, the writer has found a paper funnel the most satisfactory. It can be used once and then thrown away. Such a funnel may be very easily made by rolling a sheet of thick writing paper in the form of a cone and cementing the paper where it overlaps, or winding a string several times around the lower part. Such a funnel is best used in one of the rings for holding funnels. 84 MOUNTING AND LABELING. ARRANGING AND MOUNTING MINUTE OBJECTS- \ 194. Minute objects like diatoms and the scales of insects may be arranged in geometrical figures or in some fanciful way either for ornament or more satisfac- tory study. To do this the cover-glass is placed over the guide. This guide for geometrical figures may be a net-micrometer or a series of concentric circles. In order that the objects may remain in place, however, they must be fastened to the cover-glass. As an adhesive substance, liquid gelatin (§ 194) thinned with an equal volume of 50 per cent, acetic acid answers well. A very thin coating-of this is spread on the cover with a needle or in some other way and allowed to dry. The objects are then placed on the gelatinized side of the cover and carefully got into position with a mechanical finger, made by fastening a cat's whisker in a needle holder. For most of these objects a simple microscope with stand (Fig. 8) will be found of great advantage. After the objects are arranged, one breathes very gently on the cover-glass to soften the gelatin. It is then allowed to dry and if a suitable amount of gelatin has been used, and it has been properly moistened the objects will be found firmly anchored. In mounting, one may use Canada Balsam or mount dry on a cell {\\ 170, 176). See Newcomer, Amer. Micr. Soc's Proc. 1886, p. 128 ; see also E. H. Griffith and H. L. Smith, Amer. Journal of Mi- cros., iv, 102, y, 87; Amer. Monthly Micr. Jour., i, 66, 107, 113. Cunningham, The Microscope, viii, 1888, p. 237. MICRO-CHEMISTRY AND CRYSTALLOGRAPHY — EXPERIMENTS. § 196. The student of science and especially chemistry so frequently requires a knowledge of the appearance of minute crystals to aid in the determination of an unknown substance or for his information in studying objects where crystals are liable to occur, that a few experiments have been introduced to give him a start in preparing and permanently mounting some of the common crystals. It is recommended that the crystals be made in several ways, that is from alco- holic solutions, aqueous solutions saturated and dilute, by spontaneous drying and crystallization and by rapid crystallization by the aid of heat. The modifications in crystallization under these different methods of treatment are frequently very striking. In every case the student is advised to study the appearance of the crystals in the "mother liquor." As a rule their characteristics are more clearly shown in the "mother liquor" than under any other conditions. It is of very great advantage to examine all crystalline forms with polarized light (§156). § 197. Determination of the Character of ths Solid Sediment in Water. — Take some of the sediment from a filter or allow a considerable volume of water to stand in a tall glass vessel to deposit its sediment. Take a concentrated drop of this sediment and mount it on a. slide under a cover-glass. Study the preparation with the microscope. Probably there will be an abundance of animal and vegeta- table life as well as of solid sediment. Put a drop of dilute sulphuric acid {Acidum sulphuricum dilutum, i. e., strong sulphuric acid 1 gram, water 9 grams) at the edge of the cover and at the opposite edge a small piece of the Japanese paper (PI. V, Fig. 49). The acid will gradually diffuse, and if the solid particles are carbonate of lime, minute bubbles will be seen to be given off. If they are silica or clay no change will result. Sulphuric acid is recommended for this; as the mi- 85 MOUNTING AND LABELING. croscope would be far less liable to injury than as if some acid giving off fumes were used. ^ 198. Herapath's Method of Determining Minute Quantities of Quinine.— For a so-called test fluid 12 c.c. of glacial acetic acid, 4 c.c. of 95 per cent, alcohol and 7 drops of dilute sulphuric acid (§ r97) are mixed. A drop of the test fluid is put on a slide and a very minute amount of quinine added. After this is dissolved, add an extremely minute drop of an alcoholic solution of iodine. "The first ef- fect is the production of the yellow cinnamon-colored compound of iodine and quinine which forms as a small circular spot ; the alcohol separates in little drops, which by a sort of repulsive movement, drive the fluid away ; after a time, the acid liquid again flows over the spot, and the polarizing crystals of sulphate of iodo- quinine are slowly produced in beautiful rosettes. This succeeds best without the application of heat." Dr. Herapath used this method to determine the presence of quinine in the urine of patients under quinine treatment. See Hogg, p. 150 ; Quarterly Jour. Micr. Sc, vol. ii, pp. 13-18. For further papers on micro-chem- istry by Dr. Herapath, see the Royal Society's Catalog of Scientific Papers. § 199. List of Substances for the Study of Crystallography with the Micro- scope.* — The substances are crystallized on the cover glass in all cases, and in all cases, except where otherwise stated, a saturated aqueous solution of the substance was first prepared. 1. Ammonium chloride ; 2. Ammonium copper chloride ; 3. Barium chloride ; 4. Cobalt chloride (Beautiful crystals obtained by mixing the saturated aqueous solution with an equal volume of 95 per cent, alcohol. Crystallization in a cur- rent of dry air some distance above an alcohol or Bunsen flame ; Mount in xylol balsam {\\ 176, 191). 5. Copper acetate ; Mount dry (§ 170). 6. Copper sulphate. Crystals much more satisfactory when examined in the ' ' mother liquor. " 7. Lead nitrate ; 8. Mercuric chloride (Corrosive sublimate), mount in xylol balsam (g$ 176, 191). 9. Nickel nitrate; obtain crystals by heating. Mount in xylol balsam {\\ 186, 191); 10. Potash alum; 11. Potassium chlorate; 12. Potassium dichro- mate. Compare specimen crystallized by heat and spontaneously ; mount dry or in xylol balsam (H 170, 176). 13. Potassium iodide. Dilute with one or two vols, water and crystallize by heat. 14. Potassium nitrate ; 15. Potassium oxalate ; 16. Po- tassium sulphate ; 17. Salicine. Fuse the dry salicine on the cover-glass, mount dry ($ 170) ; 17. Salicylic acid. Make a 10 per cent, solution in 95 per cent, alco- hol. Let it crystallize spontaneously in the air. Mount dry (j! 170) ; 18. Sodium chloride (common salt). Mix sat. aq. sol. with one or two volumes of water, and heat. Mount dry or in balsam (H 170, 176). § 200. For directions and hints in micro-chemical work and crystallography, consult the various volumes of the Journal of the Roy. Micr. Soc, Zeitschrift fur physiologische Chemie and other chemical journals ; Wormly ; Kl^ment & Reg- nard ; Carpenter ; Hogg ; Behrens Kossel und Schiefferdecker ; Frey. * Most of the chemicals here named were suggested to the writer by Prof. L. M. Dennis of the Chemical Department. BIBLIOGRAPHY. The books and periodicals named below in alphabetical order, are in the labora- tory or the University library. They pertain wholly or in part to the microscope, microscopical or histological methods. They are referred to in the text by initial letters or by fuller, recognizable abbreviations. For current microscopical and histological literature, the Journal of the Royal Microscopical Society, the Index Medicus, the Zoologischer Anzeiger, and the Zeitschrift fur wissenschaftliche Mikroskopie, Auatomischer Anzeiger, Biolog- isches Centralblatt and Physiologisches Centralblatt, taken together furnish nearly a complete record. References to books and papers published in the past may be found in the peri- odicals just named, in the Index Catalog of the Surgeon General's library ; in the Royal Society's Catolog of Scientific Papers, and in the bibliographical references given in special papers. BOOKS. Angstrom. — Recherches sur le spectre solaire, spectre normal du soleil. Up- sala, 1868. Anthony, Wm. A., and Erackett, C. F. — Elementary text- book of physics. 7th ed. Pp. 527, 165 Fig. New York, 1891. Bausch, E. — Manipulation of the microscope. Pp. 95, illustrated. Rochester, 1891. , Beale, L. S. — How to work with the microscope. 5th ed. Pp. 518, illustrated. London, 1880. Structure and methods. Beauregard, H., at Galippe, V. — Guide de l'dleive et du praticien pour les trav- aux pratiques de micrographie, comprenant la technique et les applications du microscope a l'histologie vegetale, a la physiologie, a la clinique, a la hygiene et a la m£decine legale. Pp. 904, 570 Fig, Paris, 1880. Behrens, J. W. — The microscope in botany. A guide for the microscopical in- vestigation of vegetable substances. Translated and edited by Hervey and Ward. Pp. 466, illustrated. Boston, 1885. Behrens, W., Kossel, A., und SchiefTerdecker, P. — Das Mikroskop und die Methoden der mikroskopischeu Untersuchung. Pp. 315, 193 Fig. Braunschweig. Browning, J.— How to work with the micro-spectroscope. Referred to in Beale and Carpenter. y Carnoy, J. B., Le Chanoiue. — La Biologie Cellulaire ; Etude cornparde de la cellule dans les deux r£gnes. Illustrated (incomplete). Paris, 1884. Structure and methods. > Carpenter, W. B. — The microscope and its revelations. 6th ed. Pp. 882, illus- trated. London and Philadelphia, 1881. Methods and structure. Cooke, M. C. — One thousand objects for the microscope. Pp. 123. London, no date. 500 figures and brief descriptions of pretty objects for the microscope. Daniell, A. — A text-book of the principles of physics. Pp. 653, 254 Fig. Lon- don, 1884. 87 BIBLIOGRAPHY. Dippel, L. — Grundziige der aUgetneinen Mikroskopie. Pp. 524, 245 Fig. Braunschweig, 1885. Excellent discussion of the microscope and accessories. Ebner, V. v.— Untersuchungen iiber die Ursachen der Anisotropic organischer Substanzen. Leipzig, 1882. Large number of references. Ellenberger, W. — Handbuch der vergleichenden Histologic und Physiologie der Haussaugethiere. Berlin, 1884+. Fol, H. — Lehrbuch der vergleichenden mikroskopischen Anatomie, mit Ein- schluss der vergleichenden Histologic und Histogenie. Illustrated (incomplete). Leipzig, 1884. Methods and structure. Poster, Frank P. — An illustrated encyclopaedic medical dictionary, being a dic- tionary of the technical terms used by writers on medicine and the collateral sci- ences in the Latin, English, French and German languages. Illustrated, quarto volumes. Vol. I, 1888 ; Vol. II, 1890 ; Vol. Ill, in press. Frey, H. — The microscope and microscopical technology. Translated and ed- ited by G. R. Cutter. Pp. 624, illustrated. New York, 1880. Methods and structure. Frey, H. — Hand-book of the histology and histo-chemistry of man. Translated by Barker. Illustrated. New York, 1875. Structure and chemistry. Also the 5th German edition. Leipzig, 1876. Gamgee, A. — A text-book of the physiological chemistry of the animal bod3'. Part I, pp. 487, 63 Fig. London and New York, 1880. Structure and methods. Gibbs, H. — Practical histology and pathology. Pp. 107. London, 1880. Meth- ods. Goodale, G. L. — Physiological botany. Pp. 499-1-36, illustrated. New York, 1885. Structure and methods. Halliburton, W. D. — A text-book of chemical physiology and pathology. Pp. 874, 104 illus. London and New York, 1891. Hogg, J. — The microscope, its history, construction and application. New edi- tion, illustrated. Pp. 764. London and New York, 1883. Much attention paid to the polariscope. James, F. L. — Elementary microscopical technology. Part I, the technical his- tory of a slide from the crude material to the finished mount. Pp. 107, illustrated. St. Louis, 1887. Element and Regnard. — Reactions microchemiques a cristaux et leur applica- tion en analyse qualitative. Pp. 126, 8 plates. Bruxelles, 1886. Kraus, G. — Zur Kentniss der Chlorophyllfarbstoffe. Stuttgart, 1872. Le Conte, Joseph. — Sight — an exposition of the principles of monocular and bi- nocular vision. Pp. 275, illustrated. New York, 1881. Lee, A. B. — The microtomist's vade-mecum. A hand-book of the methods of microscopic anatomy. Lehmann, C. G. — Physiological chemistry. 2 vols. Pp. 648+547, illustrated. Philadelphia, 1855. Lehmaun, O. — Molekularphysik mit besonderer Beriicksichtigung mikroskop- ischer Untersuchungeu und Anleitung zu solchen, sowie einem Anhang iiber mikroskopische Analyse. 2 vols. Illustrated. Leipzig, 1888-1889. Lockyer, J. N. — The spectroscope and its application. Pp. 117, illustrated. London and New York, 1873. M'Kendrick, J. G. — A text-book of physiology. Vol. I, general physiology. Pp- 516, 318 illus. New York, 1888. Macdonald,J. D. — A guide to the microscopical examination of drinking water. Illustrated. London, 1875. Methods and descriptions. 88 BIBLIOGRAPHY. MacMunii, C. A. — The spectroscope in medicine. Pp. 325, illustrated. Lon- don, 1885. Maya.ll, Jr , John. — Cantor lectures on the microscope, delivered before the so- ciety for the encouragement of arts, manufactures and commerce. Nov. -Dec, 1885. (History of the microscope, and figures of many of the forms used at vari- ous times). Nageli und Schwendener. — Das Mikroskop, Theorie und Auwendung desselben. 2d ed. Pp. 647, illustrated. Leipzig, 1877. Phin, J. — Practical hints on the selection and use of the microscope for begin- ners. 6th edition. Illustrated. New York, 1890. Preyer, W. — Die Blutkrystalle. Jena, 1871. Full bibliography to that date. Priugle, A — Practical photo-micrography. Pp. 193, illustrated. New York, 1890. Proctor, R. A. — The spectroscope and its work. London, 1882. Prudden, T. M. — A manual of practical normal histology. Pp. 265. 2d ed. New York, 1885. Methods and structure. Queckett, J. — A practical treatise on the use of the microscope, including the different methods of preparing and examining animal, vegetable and mineral structures. Pp, 515, 12 plates. 2d ed. London, 1852. Ranvier, L. — Traits technique d'histologie. Pp. 1109, illustrated. Paris, 1875- 1888. Structure and methods. Also German translation 1888. Reference Hand-Book of the medical sciences. Albert H. Buck, editor. 8 quarto vols. Illustrated with many plates, and figures in the text. New York, 1885-1889. Richardson, J. G. — A hand-book of medical microscopy. Pp. 333, illustrated. Philadelphia, 187 1. Methods and descriptions. Robin, Ch. — Traite du microscope et des injections. 2d ed. Pp. 1101, illustrat- ed, Paris, 1877. Methods and structure. Roscoe, Sir Henry. — Lectures on spectrum analysis. 4th. ed. London, 1885. Rutherford, W. — Outlines of practical histology. 2d ed. Illustrated. Pp. 194. London and Philadelphia, 1876. Methods and structures. Satterthwaite, P. E. (editor). — A manual of histology. Pp. 478, illustrated. New York, 1881. Structure and methods. Schafer, E. A. — A course of practical histology, being an introduction to the use of the microscope. Pp. 304, 40 Fig. Philadelphia, 1877. Methods. Schellen, H. — Spectrum analysis, translated by Jane and Caroline Lassell. Ed- ited with notes by W. Huggins. 13 plates, including Angstrom's and Kirchhoff's maps. London, 1885. Science Lectures at South Kensington. 2 vols. Pp. 290 and 344, illustrated. One lecture on microscopes and one on polarized light. London, 1878-1879. Seiler, C. — Compendium of microscopical technology. A guide to physicians and students in the preparation of histological and pathological specimens. Pp. 130, illustrated; New York, 1881. Silliman, Benj., Jr. — Principles of physics, or natural philosophy. 2d edition, rewritten. Pp. 710, 722 illustrations. New York and Chicago, i860. Stowell, Chas. H. — The students' manual of histology, for the use of students, practitioners and microscopists. 3d ed. Pp. 368, illustrated. Ann Arbor, 1884. Structure and methods. Strasburger, E. — Das botanische Practicum. Anleitung zum Selbststudium der mikroskopischen Botanik, fur Anfanger und Fortgeschrittnere. Pp. 664, illus- trated. Structure and methods. Also English translation. 89 BIBLIOGRAPHY. Suffolk, W. T. — On microscopical manipulation. 2d ed. Pp. 227, illustrated. London, 1870. Suffolk, W. T. — Spectrum analysis applied to the microscope. Referred to in Beale. Trelease, Wm. — Poulsen's botanical micro-chemistry, an introduction to the study of vegetable histology. Pp. 118. Boston, 1884. Methods. Valentin, G. — Die Untersuchung der Pflanzen uud der Tiiiergewebe in polarisir- tem Licht. Leipzig, 1861. Vierordt. — Die quantitative Spectral analyse in ihrer Anwendung auf Physiologie, Chemie und Technologie. Tubingen, 1874. Whitman, C. O. — Methods of research in microscopical anatomy and embryolo- gy. Pp. 255, illustrated. Boston, 1885. Wilder and Gage.— Anatomical Technology as applied to the domestic cat. An introduction to human, veterinary and comparative anatomy. Pp. 575, 130 Fig. 2died. New York and Chicago, 1886. Wood, J. G. — Common objects for the microscope. Pp.132. London, no date. Upwards of 400 figures of pretty objects .for the microscope, also brief descriptions and directions for preparation. Wormly, T. G. — The micro-chemistry of poisons. 2d ed. Pp. 742, illustrated. Philadelphia, 1885. Wythe, J. H. — The microscopist, a> manual of microscopy and a. compendium of microscopical science. 4th ed. Pp. 434, 252 Fig. Philadelphia, 1880. See also Watt's Chemical dictionary, and the various general and technical en cyclopaedias. The American journal of microscopy and popular- science. New York, 1876- 1881. Illustrated. Methods and structure. The American monthly microscopical journal. Illustrated. 1880+. Methods and structure. American naturalist. Illustrated. Salem and Philadelphia, 1867+-. Methods and structure. American quarterly microscopical journal, containing, the transactions of the New York microscopical society. Illustrated. New York, 1878. Structure and methods. American society of microscopists. Proceedings. Illustrated. 1878+. Meth- ods and structure. Anatomischer Anzeiger. Centralblatt fur die gesammte wissenschaftliche Ana- ' tomie. Amtliches Organ der anatomischen Gesellschaft. Herausgegeben von Dr. Karl Bardeleben. Jena, 1886-)-. Besides articles relating to the microscope or histology, a full record of current anatomical literature is given. Archiv fur mikroscopische Anatomic Illustrated. Bonn, 18654-. Structure and methods. Centralblatt fur Physiologie. Unter Mitwirkung der physiologischeu Gesell- schaft zu Berlin. Herausgegeben von S. Exner und J. Gad. Leipzig und Wien, *NoTE. — When a periodical is no longer published, the dates of the first and last volumes are given ; but if still being published, the date of the first volume is followed. by a plus sign. 90 BIBLIOGRAPHY. 1887-f . Brief extracts of papers having a physiological bearing. Full biblio- graphy of current literature. Index Medicus. New York, 1879-)-. Bibliography, including histology and microscopy. Journal of anatomy and physiology. Illustrated. London and Cambridge, 1867+. Structure and methods. Journal de micrographie. Illustrated. Paris, 1877+. Methods and Structure. Journal of the New York microscopical society. Illustrated. New York, 1885+. Methods and structure. Journal of Physiology. Illustrated. London and Cambridge, 1878+- Journal of the American Chemical Society. New York, 1879+. Journal of the Chemical Society. London, 1848+. Journal of the royal microscopical society. Illustrated. London, 1878+. Bib- liography of works and papers relating to the microscope, microscopical methods and histology. It also includes a summary of many of the papers. The Lens, a quarterly journal of microscopy and the allied natural sciences, with the transactions of the state microscopical society of Illinois. Illustrated. Chicago, 1872-1873. Methods and structure. The Microscope. Illustrated. Trenton, N. J., 1881+. Methods and structure. Microscopical Bulletin, and science news. Illustrated. Philadelphia, 1883+. The editor, Edward Pennock, introduced the term "par- focal" for oculars (see vol. iii, p. 31, also, the note to \ 48, p. 18). Monthly microscopical journal. Illustrated. London, 1869-1877. Nature. Illustrated. London, 1869+. Philosophical Transactions of the Royal Society of London. Illustrated. Lon- don, 1^65+. Proceedings of the Royal Society. London, 1854+. Quarterly journal of microscopical science. Illustrated. London, 1853+. Structure and methods. Science Record. Boston, 1883-4. Methods and structure. Zeitschrift fur Instrumentenkunde. Zeitschrift fur physiologische Chemie. Strassburg, 1877+. Zeitschrift fur wissenschaftliche Mikroskopie und fur mikroskopische Technik. Illustrated. Braunsch. 1884+. Methods and bibliography. Besides the above-named periodicals, articles on the microscope or the applica- tion of the microscope appear occasionally in nearly all of the scientific journals. One is likely to get references to these articles through the Jour. Roy. Micr. Soc. or the Zeit. wiss. Mikroskopie. INDEX. Abbe camera lucida, 4S ; arrangement of, 49 ; drawing with, 51 ; hinge for prism, 52 ; inclined microscope with, 50 ; laboratory microscope with, 28. Abbe condenser, 19. Abbe illuminator, Tg ; experiments, 20, laboratory microscope with, 28 ; light, axial and oblique, 20 ; mirror with, 20. Aberration, chromatic, 4 ; spherical, 4. Absorption spectra, 54, 55, 56 ; amount of material necessary and its proper manipulation, 59 ; Angstrom and Stokes' law of, 55 ; banded, not given by all colored objects, 6r ; of blood, 60; of colored minerals, 62 ; of per- mangate of potash, 60. Achromatic objectives, 3, 4 ; triplet, 2. Achromatism, 4. Adjustable objectives, 5 ; and microme- . tr y> 46- Adjusting collar, graduation of, 23. Adjustment of analyzer, 63 ; of object- ive, 5, 22 ; of objectives for cover- glass, specific directions, 23 ; with graduated collar, 23. Aerial image, 13. Air bubbles, 31 ; with central and oblique illumination, 31. Air and oil, distinguished optically, 32 ; by reflected light, 32. Amici prism, 54. Anipl fier, 39. Amplification of microscope, 36. Analyzer, 63 ; adjustment and putting in position, 63. Angle of aperture, 6, 7. Angstrom and Stokes' law of absorption spectra, 55. Angular aperture, 6, 7. Anisotropic, 64. Aperture of objective, 6, 7 ; angular, 6, 7 ; formula for, 7 ; numerical, 7. Aplanatic objectives, 4. Apochromatic objectives, 4. Apparatus and material, 1, 29, 36, 54, 66. Appearances, interpretation, 29. Arranging and mounting minute ob- jects, 84. Axial light, 16 ; experiments, 19 ; with Abbe illuminator, 20. Axial point, 6 ; ray, 16. Axis, optic, 6, 16. Back combination or system of objec- tive, 3, 5. Bacillus tuberculosis, 25. Balsam, Canada, preparation of, 82 ; re- moval from lenses, 27. Banded absorption spectra not given by all colored objects, 61. Birefriugent, 64. Blood, absorption spectrum of, 60 ; or other albuminous material, remov- al, 26. Bread crumbs, examination of, 35. Brownisn movement, 34. Brunswick black, removal from lenses, 27. Bubble, air, 31. Burning point, 2. Butterfly scales; 35. Cabinet for microscopical preparations, 80. Camera lucida, Abbe, 48, arrangement of, 49, drawing with, 51, hinge for prism, 52, with inclined microscope, 50; Camera lucida, definition, 47 ; Wollas- ton's, 38, 48. Canada balsam, preparation of, 82 ; re- moval from lenses, 27. Carbonate of lime, pedesis, 35. Card, centering, 74. Care of eyes, 27 ; microscope, mechani- cal parts, 25, optical parts, 26 ; water immersion objectives, 24. Carmine to show currents and pedesis, 34- Catalogs and labels, ink for, 79. Cataloging, formula, 79 ; preparations, 79- Cells, mounting, 71. Centering and arrangement of illumin- ator, 19, 20 ; Centering card, 74. Central light, 16; with a mirror, 19. Chromatic aberration, 4 ; correction, 4. Chemical focus, 4 ; rays, 4. Cleaning back lens of objective, 27 ; homogeneous objectives, 25 ; mix- tures for glass, 70 ; slides and cover glasses, 66-7 ; 9 2 INDEX. Clearer, clearing, 75. Clearing mixture, preparation of, 83. Clothes moth, examination of scales, 35. Cloudiness, of objective and ocular, how to determine, 29, 30 ; removal, 26. Coarse adjustment of microscope, 12. .Collective, 9. Collodion for coating glass rod, 33. Color images, 22, 25 ; law of, 55. Colored minerals, absorption spectra of, 62 ; substances, spectra of, 55. Coma, 23. Combination of lenses, back and front, 3. Comparison prism, 57 ; spectrum, 57. Compensating ocular, 4, 9. Complementary spectra, 56. Compound microscope, see under micro- scope. Concave lenses, 4 ; mirror, use of, 17. Condenser, 1 ; Abbe, 19 ; optic axis of, 20. Condensing lens, 20. Continuous spectrum, 54. Contoured, doubly, 33. Converging lens, 1, 3 ; lens-system, 3. Convex lenses, 4. Corn starch, examination of, 35. Correction, chromatic, 4. Cotton, examination of, 35. Cover-glass, or covering glass, 67 ; ad- justment, specific directions, 23 ; ad- justment and tube length, 24 ; clean- ing, 67, 68 ; larger than object, 67 ; measurer, 69 ; measuring thickness of, 68 ; non-adjustable objectives, table of thickness, 6 ; No. 1, varia- tion of thickness, 68 ; putting on, 74 ; sealing, 71-72 ; tester, 69 ; thick- ness of, 5 ; wiping, 67. Currents in liquids, 34. Crystals from frog for pedesis, 35. Crystallization under microscope, 22. - Crystallography, 84 ; list of substances for, 84. Damar, removal from lenses, 27. Dark-ground illumination with Abbe il- luminator, 2r ; with mirror, 21. Dehydration, 75. Desiccation in mounting objects in resin- ous media, 75, 76. Designation of oculars, 10. Determination of magnification, 38. . Diaphragms and their employment, 16 ; effect of one too small, 30 ; iris, 16 ; ocular, 12; pin-hole, 20; size and position of opening, 16 ; Diffraction grating, 54. Direct light, 15 ; vision spectro-scope, 54. Dispersing prism, 54. Displacements, in mounting objects in resinous media, 75-76. Distance, standard at which the virtual image is measured, 39 ; working d. of simple microscope or objective, 15 ; working d. of compound micro- scope, 15. Distinctness of outline, 32. Distortion in drawing, avoidance of 48 ; spherical, 4. Dividers, measuring spread of, 37. Double spectrum, 57. Doubly contoured, 33. Draw-tube, pushing in, 18. Drawing with Abbe camera lucida, 51, 52 ; distance at which done (250 mm. more or less), 40 ; distortion, avoid- ance of, 48 ; with microscope, 47 ; regulating size of, 52 ; scale and en- largement, 53 ; size of, and magnifi- cation of microscope with Abbe cam- era lucida, 52. Dry objectives, 4 ; for laboratory micro- scope, 28. Dust of living rooms, examination of, 35 ; on objectives and oculars, how to determine, 29, 30 ; removal, 26. Erect image, 1. Equivalent focal length, 3 ; focus of ob- jectives, 3; focus of oculars, 10. Examination of dust of living rooms, bread crumbs, corn starch, fibres of cotton, linen, silk, human and ani- mal hairs, potato, rice, scales of but- terflies and moths, wheat, 35. Experiments, Abbe illuminator, 20 ; with adjustable and immersion ob- jectives, 22-25 ! compound micro- scope, 10 ; homogeneous immersion objective, 24 ; lighting and focusing, 17 ; with micro-spectroscope, 60 ; with micro-polarizer, 64 ; in mount- ing, 81 ; simple microscope, 2. Extraordinary ray of polarized light, 63. Eyes, care of, 27 ; effect on magnifica- tion, 40. Eye-lens of the ocular, 8, 9. Eye-piece, 8 ; micrometer, 42. Eye-point, 2 ; of ocular, demonstration, 14- Eye-shade, Ward's, 27, double, PI. II. Parrant's solution, in mounting objects, order of procedure, 74 ; preparation of, 82. Feather, examination of, 35. Fibers, examination of, 35. Field, 2 ; with orthoscopic ocular, 12 ; with periscopic ocular, 12 ; of view with microscope, 11, 36, 47. INDEX. 93 Field-lens, 8, 9; action of, 14 ; of ocular, 8. Filter paper, Japanese, 26. Filtering balsam, etc., paper funnel for, 83- Fluid, immersion, 4. Focal distance or point, principal, 3 ; length, equivalent, 3 ; Focus, 2 ; always up, 18 ; chemical, 4 ; of objectives, equivalent, 3 ; of ocu- lars, equivalent, 10 ; optical, 4 ; prin- cipal, 1-3. Focusing, 2, 15 ; with compound micro- scope, 15 ; experiments, 17 ; with high objectives, 18 ; with low ob- jectives, 17 ; objective for micro- spectroscope, 59 ; with simple micro- scope, 15 ; slit of micro-spectroscope, 56- Fraunhofer lines, 55. Front combinatioft or lens of objective, 3 ; system, 5. Function of objective, 12, 13 ; of ocular, 13. H- G Gelatin, liquid, preparation of, 83. Glass, cleaning mixture for, 70 ; rod ap- pearance under, microscope, 33 ; slides or slips, 66 Glue, liquid, preparation of, 83. Glycerin, mounting objects in, order of procedure, 73 ; removal, 26. Glycerin jelly, mounting objects in, or- der of procedure, 74 ; preparation of, 82. Gold size, removal from lenses, 27. Goniometer ocular, 9. Graduation of adjusting collar, 23. Grating, diffraction, 54. Ground glass, preparation of, 12. H Hasmaglobin, 61 ; reduced h., 61. Hairs, examination of, 35. Herapath's method of determining mi- nute quantities of quinine, 85. High oculars, 5, 9. Highly refractive, 33. Homogeneous immersion objectives, 4 ; cleaning, 25 ; experiments, 24 ; for laboratory microscope, 28. Homogeneous liquid, 25. Huygeniau ocular, 9. I-J Illumination for Abbe camera lucida, 51 ; artificial, 15, 20 ; central with air and oil, 31 ; dark-ground, 16 ; dark- ground, with Abbe illuminator, 21 ; dark-ground, with mirror, 21 ; oblique, with air and oil, 32 ; for Wollaston's camera lucida, 48. Illuminator, 1 ; Abbe, 19 ; Abbe, axial and oblique light, 20 ; Abbe, exper- iments, 20 ; Abbe, mirror and light for, 20 ; centering and arrangement, 19, 20; immersion, 20. Image, aerial, 13 ; color, 22, 25 ; erect, 1 ; inverted, 1 ; inverted, real of ob- jective, 13 ; real, 1 ; real, inverted, 3 ; refraction, 22, 25. Immersion fluid, 4 ; illuminator, 20 ; liquid, 4 ; objective, 4, 24. Incandescence spectra, 56. Incident light, 15. Index of refraction of medium in front of objective, 7. Ink for labels and catalogs, 79. Interpretation of appearances under the microscope, 29. Inverted image, 1. Iris diaphragm, 16. Isotropic, 64. Japanese filter or tissue paper, 12, 13, 26. Labels and catalogs, ink for, 79; prep- aration of, 79. Labeling microscopical preparations, 77, serial sections, 78. Laboratory compound microscope, 27. Lamp-light, 20. Lenses, combination of, 3 ; concave, 4 ; condensing, 20 ; converging, 1, 3 ; convex, 4 ; systems of, 3. Lens-system, 1 ; converging, 3. Letters in stairs, 30. Light with Abbe illuminator, 20 ; axial, 16 ; axial with Abbe illuminator, 20 ; direct, 15 ; central, 16 ; incident, 15 ; oblique, 16 ; oblique, experiments, 19 ; oblique with Abbe illuminator, 20 ; polarized, 63 ; reflected, inci- dent or direct, 15 ; transmitted, 16 ; wave length of, 58. Lighting, 15 ; for Abbe camera lucida, 51 ; artificial, 15 ; experiments, 17 ; axial, experiments, 19; kind of light, 15 ; for micro-polariscope, 63 ; for micro-spectroscope, 58 ; with a inir- or, 17; Line spectrum, 54. Linen, examination of, 35. Liquid, currents in, 34 ; homogeneous, 25 ; immersion, 4. M Magnification, effect of adjusting object- ive, 46 ; determination of, 38 ; ex- pressed in diameters, 36 ; method of binocular or double vision in obtain- ing, 36-37 ; of microscope, 36 ; of microscope with Abbe camera lucida, 94 INDEX. 52 ; of microscope, compound, 37 ; of microscope; simple, 36 ; relation to eyes, 40 ; varying with compound microscope, 39. Magnifier, 2. Magnifying power of microscope, 36. Malezeit sand, spectrum of, 62. Marking objects, 11, note. Material and apparatus, 1, 29, 36, 54, 66. Measurer, cover-glass, 69. Measuring the spread of dividers, 37. Mechanical parts of compound micro- scope, 3 ; of laboratory microscope, 28 ; of microscope, care of, 25. Mechanical stage, 28. Medium, mounting, 5, 7. Micro-chemistry, 84. Micrometer, filling lines of, 37 ; object or objective, 37 ; ocular or eye-piece, 10, 42, 43 ; ocular, micrometry with, 44 ; ocular, valuation of, 43 ; ocular, varying valuation of, 44 ; ocular, ways of using, 45 ; stage, 37. Micrometry, .definition, 40 ; with adjust- able objectives, 46 : comparison of methods, 46-47 ; with compound mi- croscope, 41 ; by dividing the size of image by magnification of micro- scope, 42 ; limit of accuracy in, 46 ; with ocular micrometer, 44 ; with simple microscope, 41 ; remarks on, 46 ; by stage micrometer and camera lucida, 42 ; by stage micrometer 011 which is mounted the object, 42 ; unit of measure in, 41. Micro-millimeter, 41. Micron, 41 ; for measuring wave-length of light, 58. Micro-polariscope, 35, 62 ; for laboratory microscope, 28 ; lighting for, 63 ; ob- jectives to use with, 63 ; purpose of, 64. Microscope, definition, 1 ; adjustment, 12 ; amplification of, 36 ; care of, 25 ; field of, 11 ; focusing, 15 ; magnifi- cation, 36 ; polarizing, 34. Microscope compound, definition, 1 ; drawing with, 47 ; experiments with, 10 ; focusing with, 15 ; for labora- tory, 27 ; magnification or magnify- ing power, 36, 37 ; magnification and size of drawing with Abbe camera • lucida, 52 ; mechanical parts, of, 3 ; micrometry with, 41 ; optic axis of, 16 ; optical parts of, 3 ; polarizing, pedesis with, 34 ; stand of, 1 ; vary- ing' magnification, 39. Microscope, simple, definition, 1 ; ex- periments with, 2 ; focusing with, 15 ; magnification of, 36 ; microm- etry with, 4r. Microscopic objective, 3 ; ocular, 8 ; slides or slips, 66. Microscopical preparations, cabinet for, 80 ; cataloging, 79 ; labeling, 77 ; tube-length, 5. Micro-spectroscope, 54 ; adjusting, 56 ; experiments, 60 ; for laboratory mi- croscope, 28 ; lighting for, 58 ; ob- jectives to use (with, 59.; slit-mechan- ism of, 54. Micrum, 41. Mikron, 41. Minerals, colored, absorption spectra of, 62. Mirror, 1 ; for Abbe illuminator, 20 ; concave, use of, 17; light with, cen- tral and oblique, iq ; lighting with, 17; plane, use of, 17 ; position of con- cave, 17. Molecular movement, 34. Mono-refringeut, 64. . Mounting cells, preparation of, 71 ; me- dium, 5, media, preparation of, 82. Mounting objects, dry in air, order of procedure, 73 ; examples in air, gly- cerin jelly and balsam. 81 ; in Far- rant's solution, order of procedure, 74 ; in glycerin, order of procedure, 73 ; in glycerin jelly, order of pro- cedure, 74 ; in media rhiscible with water, 73 ; microscopical objects, 70 ; in resinous media, by drying or des- iccation, order of procedure, 75, 76 ; in resinous media by successive dis- placements, order of procedure, 75, 76. Movement, Brownian, or, molecular, 34. Myopia, effect on magnification, 40. N Negative oculars, 8, 9. Net-microineter, 50. Nicol prism, 62. Nomenclature of objectives, 3. Non-achromatic objectives, 4. Non-adjustable objectives, 5 ; thickness of cover-glass for, table, 6. Nose-piece, n. Numerical aperture of objectives, 7. Object micrometer, 37 ; putting under microscope, 11 ; having plane or ir- regular outlines, relative position in a microscopical preparation, 30 ; transparent with curved outlines, relative position in microscopic pre- parations, 30; shading, 25. Objective, 1 ; achromatic, 3, 4 ; adjusta- ble, 5 ; adjustable, experiments, 22 ; adjustment for, 22 ; aerial image of, 13 ; aperture of, 6, 7 ; aplanatic, 4 ; INDEX. 95 apochromatic, 4 ; back combination of, 3 ; cleaning back lens of, 27 ; col- lar, graduated for adjustment, 23 ; compound, 7 ; cloudiness or dust, how to determine, 30 ; dry, 4 ; equiv- alent focus of, 3 ; focusing for micro- spectroscope, 59 ; front combination of, 3 ; function of, 12, 13 ; high, focus- ing with, 18 ; homogeneous immer- sion, 4 ; homogeneous immersion, cleaning, 25 ; homogeneous immer- sion, experiments, 22, 24 ; immersion, 4 ; index of refraction of medium in front of, 7 ; inverted, real image of, 13 ; for laboratory microscbpe, 27, 28 ; lettering, 3 ; of low and medi- um power, 4 ; low, focusing with, 17 ; micrometer, 37 ; to use with micro-polariscope, 63 ; microscopic, 3 ; to use with micro-spectroscope, , 59 ; for micro-spectroscope, focus- ing, 59 ; nomenclature of, 3 ; non- achromatic, 4 ; non-adjustable, 5 ; non-adjustable, thickness of cover- glass for, table, 6 ; numbering, 3 ; oil -immersion, 4 ; putting in position and removing, 10 ; single-lens, 7 ; terminology of, 3 ; unadjustable, 5 ; water immersion, 24 ; water immer- sion, experiments, 22 ; working dis- tance of, 15. Oblique light, 16 ; with Abbe illuminat- or, 20 ; experiments, 19 ; with a mir- ror, 19. Ocular, 1 ; achromatic, 8 ; aplanatic, 8 ; binocular, 8 ; cloudiness, how to de- termine, 29 ; Campani's, 8 ; compen- sating, 4, 9 ; compound, 8 ; deep, 8 ; designation by magnification or com- bined magnification and equivalent focus, 10 ; dust, how to determine, 29 ; equivalent focus of, 10 ; erect- ing, 8 ; eye-point of, demonstration, 14 ; field-lens, 8 ; focus, equivalent of, 10; function of, 13, 14; goniom- eter, 9 ; high, 5, 9 ; holosteric, 9 ; Huygenian, 9 ; Kellner's, 9 ; letter- ing of, 10 ; low, 9 ; micrometer, 9, 10, 42, 43 ; micrometer, micrometry with, 44 ; micrometer, putting in po- sition, 43 ; micrometer, valuation of, 43 ; micrometer, varying valuation, 44 ; micrometer, ways of using, 45 ; micrometric, 9 ; microscopic, 8, 9 ; negative, 8, 9 ; numbering, 10 ; or- thoscope, 9, 12 ; par- focal, 1 8 ; peri- scopic, 9, 12 ; positive, 8, 9 ; projec- tion, 9 ; projection, designation of, 10 ; putting in position and remov- ing, 10 ; Ramsden's, 9 ; searching, 9 ; shallow, 9 ; solid, 9 ; spectral, 9, 10, 54 ; spectroscopic, 9, 10, 54 ; stereo- scopic, 8 ; working, 9. Oil and air, appearances and distinguish- ing optically, 31, 32. Oil-globules, with central illumination, 31 ; with oblique illumination, 31, 32. Oil-immersion objectives, 4. Optic axis, 6 ; of condenser, or illumina- tor, 20 ; of microscope, 16. Optical, combination, 1 ; focus, 4 ; parts, 1 ; parts of compound microscope, 3 ; parts of microscope, care of, 26 ; section, 33. Order of procedure in mounting objects, dry or in air, 73 ; in Farrant's solu- tion, 74 ; in glycerin, 73 ; in glycer- in jelly, 74 ; in resinous media by desiccation, 76 ; in resinous media by successive displacements, 76. Ordinary ray with polarizer, 63. Orthoscopic ocular, field with, 12. Outline, distinctness of, 32. Oxy-haemoglobin, 61. Paper, bibulous, filter or Japanese, 12 13 ; for cleaning oculars and obj ect ives, 26. Paraffin, removal from lenses, 27. Parfocal oculars, 18. Parts, optical and mechanical of micro- scope, 1. Pedesis, 34 ; compared with currents, 34 ; with polarizing microscope, 34 ; proof of reality, 35. Periscopic ocular, field with, 12. Permanganate of potash, absorption spectrum of, 60. Pin-hole diaphragm, 20. Photography, 4. Plane mirror, use of, 17. Pleochromism, 64, 65. Pleurasigma angulatum, 19. Point, axial, 6. Polarized light, 63 ; extraordinary and ordinary ray of, 63. Polarizer, 62 ; and analyzer, putting in position, 63. Polarizing microscope, pedesis with, 34. Position of objects or parts of same ob- ject, 30. Positive oculars, 8, 9. Potato, examination of, 35. Power of microscope, 36. Preparation of Canada balsam, Farrant's solution, glycerin, glycerin jelly, 82. Preparation of clearing mixture, liquid gelatin and shellac cement, 83. Presbyopia, effect on magnification, 40. Price of American and foreign micro- scope, 28. Principal focus, 1, 2, 3 ; focal distance, 3 ; point, 2. 9 6 INDEX. Prism of _ Abbe camera lucida, 49-50 ; Amici, 54 ; comparison, 57 ; dispers- ing. 54 ; Nicol, 62 ; reflecting, 57 ; and slit of micro- spectroscope, mu- tual arrangement, 56. Projection ocular, 9 ; designation of, 10. Pumice stone for pedesis, 34. Pushing in draw-tube, 18. Putting on cover-glass, 74 ; an object under microscope, 11. Q-R Quinine, Herapath's method of deter- mining minute quantities of, 85. Ray, chemical, 4 ; ordinary of polarized light, 63 ; extraordinary, 63. Real image, 1 ; inverted, 3. Reflected light, 15. Reflecting prism, 57. Refraction images, 25 ; index of medium in front of objective, 7. Refractive, doubly, 64 ; highly, 63 ; sin- gly, 64- Resinous media, mounting objects in, order of procedure, by drying or desiccation, 75 ; by series of dis- placements, 75, 76. Revolver, 11. Rice, examination of, 35. Rule or scale for magnification and mi- crometry, 37. s Scale, of magnification and micrometry, 37 ; of wave lengths, 57. Scales of butterflies and moths, examin- ation of, 35. Screen of ground glass, 12, 13. Sealing cover-glass, 71, 72. Section, optical, 33 ; serial, 28, 78. Sediment in water, determination of character, 84. Selenite plate for polariscope, 65. Serial sections, 28 ; arranging and label- iug, 78; determining thickness of, 78. Shading object, 25 ; for micro-polari- scope, 35. Shellac cement, preparation of, 83 ; re- moval from lenses, 27. Sight, injury or improvement in micro- scopic work, 27. Silk, examination of, 35. Simple microscope, see under micro- scope. Slides, 66 ; cleaning, 66. Slips, 66. Slit mechanism of micro-spectroscope, 54 ; adjusting and focusing, 56 ; slit and prism, mutual arrangement, 56. Solar spectrum or s. of sunlight, 54. Spectral, colors, 4 ; ocular, 10, 54. Spectroscope, direct vision, 54. Spectroscopic ocular, 10, 54. Spectrum, 4, 54. Spectrum, absorption, 54 ; amount of material necessary and its proper manipulation, 59, Angstrom and Stokes' law of, 55 ; banded, not given by all colored objects, 61 ; of blood, 60 ; of colored minerals, 62 ; of per- manganate of potash, 60. Spectrum, comparison, 57 ; complement- ary, 56 ; continuous, 54 ; double, 57 ; incandescence, 56 ; line, 54 ; of male- zeit sand, 62 ; single-banded, 61 ; solar, 54 ; two-banded, 61. Spherical aberration, 4 ; distortion, 3. Stage, mechanical, 28 ; micrometer, 37. Stand of microscope, 1 ; for laboratory microscope, 28. Standard distance (250 mm.) at which the virtual image is measured, 39. Starch, examination of, 35. Stokes and Angstrom's law of absorp- tion spectra, 55. Swaying of image, 21. System, back, front, intermediate, of lenses, 3, 5. T Table of magnifications and valuation of ocular micrometer, 40 ; of tube- length and thickness of - cover- glasses, 6. Of weights and measures (see inside of cover). Terminology of objectives, 3. Tester, cover-glass, 69. Textile fibers, examination of, 35. Thickness of cover-glass for non-adjust- able objectives, table, 6. Transmitted light, 16. Transparent objects having curved out- lines, relative position in micro- scopic preparations, 30. Triplet, achromatic, 2. Tripod, 2. Tube-length, 5 ; for cover-glass adjust- ment, 24 ; importance of, 24 ; micro- scopical, 5 ; of various opticians, table, 6. Turn-table, 71. u— V— w TJnadjustable objectives, 5. Unit of measure in micrometry, 41. Valuation of ocular micrometer, 43. Varying ocular micrometer valuation, 44. Ward's eye-shade. 27. Water immersion objective, 24. Water for immersion objectives, 24 ; re- moval, 26. Wave length, designation of, 58 ; scale of, 57- Weights and measures.see inside of cover. Wheat, examination of, 35. Wollaston's camera lucida, 38, 48. Working distance of simple microscope or objective, 15. TABLE OF METRIC AND ENGLISH MEASURES. The measures of length, volume and weight most frequently employed in micro- scopical and histological work are the following : LENGTH. 1000 Microns (/i) = I Millimeter. 10 Millimeters (m.m.) = i Centimeter, ioo Centimeters (cm. or ctm.) = I Meter (unit of length), i ix = 0.000039 inch, ?s^ 51 ;th in. approximately. 1 cm. = 0.3937 in. 1 Meter — 39.3704 in. VOLUME. 1000 Cubic centimeters (cc. or cctm.) or milliliters = 1 Liter (1000 grams of water) (unit of volume) . 1 Fluid ounce (8 Fluidrachms) = 29.578 cc. WEIGHT. 1000 Grams = 1 Kilogram (the weight of 1000 cc. or 1 liter of water). 1 Gram (unit of weight) = 15.432 Grains. 1 Kilogram = 2.204 Avoirdupois pounds. I Ounce Avoirdupois (437j£ grains) = 28.349 Grams. . 1 Ounce Troy or Apothecaries (480 grains) = 31.103 Grams. TEMPERATURE. To change Centigrade to Farenheit : (C. X }) + 32 = F. For example, to find the equivalent of io° Centigrade C. = io° (10° X 1) + 32 = 50 F. To change Farenheit to Centigrade : (F. — 32 ) Xf = C. For example, to re- duce 50° Farenheit to Centigrade, F. = 50°, and (50° — 32 ) X f = 10° C. ; or — 40 Farenheit to Centigrade : F. = — 40° ( — 40° — 32 ) = — 72 , whence — 72 X % = - 40° C. For the price of Microscopes and Microscopical supplies, the student is advised to obtain a catalogue of one or more of the Opticians named in the table of Tube- length and thickness of Cover-glass, (page 6), or of the following dealers in Micro- scopes and Microscopical supplies : Eimer & Amend, 205-211 Third Avenue, New York. The Mcintosh Battery and Optical Co., 141-143 Wabash Avenue, Chicago, 111. James W. Queen & Co., 924 Chestnut St., Philadelphia, Pa. Spencer & Smith, 250 Allen St., Buffalo, N. Y., (in place of H. R. Spencer & Co., Geneva). W. H. Walmsley, 1022 Walnut St., Philadelphia, Pa. Williams, Brown & Earl, 10th and Chestnut Sts., Philadelphia, Pa. G. S. Woolman, 116 Fulton St., New York.