The microscope and histology / by Simon Henry Gage ... pt. I. The microscope and microscopical methods.

  • Gage, Simon Henry, 1851-1944.
Date:
1892
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Licence: Public Domain Mark

Credit: The microscope and histology / by Simon Henry Gage ... pt. I. The microscope and microscopical methods. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    EXPLANATION OF PLATE V. Fig. 41. Effect of the cover-glass on the rays from the object to the objective (Ross). Axis. The projection of the optic axis of the microscope. F. Focus or axial point of the objective. V and V. Points on the axis where rays 2 and 3 appear to originate if traced backward after emerging from the upper side of the cover-glass (cover). It is for the correction of this disturbance or so-called negative aberration produced by the cover-glass that objectives are fixed in their mounting for a given thickness of cover, or that the combinations making up the objective are made adjustable ; that is so that the back combinations may be brought nearer the front lens or combination as the cover thickens, and separated with a thinner cover or for uncovered objects. The thicker the cover, the nearer the front and back com- binations ; the thinner the cover the farther apart are front and back placed (J 63). Fig. 42. Showing the course of the rays passing through a cover-glass from an axial point of the object, and the number that finally enter the front of a dry ob- jective. Fig. 43. Rays from the axial point of the object traversing a cover of the same tbickness as in Fig. 42, and entering the front lens of a water immersion objective. Fig. 44. Ravs from an axial point of the object traversing a cover-glass and en- tering the front of a homogeneous immersion objective. Figures 42-44, are somewhat modified from Ellenherger, and are introduced to illustrate the relative amount of utilized light, with dry, water immersion and homogeneous immersion objectives (''/?/, 9, 10, 18). Fig. 45. Absorption Spectrum of Oxy-Hiemoglobin or arterial blood (1) and of Haemoglobin or venous blood (2). (From Gamgee and MacMunn.) A, B, C, D, E, F, G, H. Some of the principal Fraunhofer lines of the solar spectrum ($ 129). .90, .So, .70, .60, .50, .40. Wave lengths in microns, as shown in Angstrom's scale (i{ 138). It will be seen that the wavelengths increase toward the red and de- crease toward the violet end of the spectrum. Red, Orange, Yellow, etc. Color regions of the spectrum. Indigo should come between the blue and the violet to complete the seven colors usually given. It was omitted through inadvertence. Fi. 46. Centering card to enable one easily to put objects in the center of a slide. It is made by drawing concentric circles in the center of a card and pasting pieces of board, or card board in the proper position to serve as guides to the slide. Fig. 47. Small spirit lamp modified into a balsam bottle or a glycerin or glycerin- jellv bottle. By adding a small brush, it answers well for a shellac bottle also. Fif. 48. Pipette for delivering drops or a small stream of any liquid. Made by tving sheet rubber over the top of a thistle bulb and connecting the bulb with a tapering '.'lass tube by a piece of rubber tube. Fig. 49. Glass slide with cover-glass, a drop of reagent and a bit of absorbent paper to show method of irrigation (? 197). Fig. SO. Slide and cover-glass showing method of anchoring a cover-glass with a glycerin preparation when no cell is used. A cover-glass so anchored is not liable to move when the cover is being sealed (4. 169). Fjcr. 52-56. Various apparatus for the preparation of fibrin and for counting blood corpuscles, milk globules, etc. (These figures belong to Part II).