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

  • Simon Henry Gage
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 III. Fig. 20, 200, 21 and 22. Sectional views of the Abbe Illuminator of 1.20 N. A. (?§ 18, 54*. showing various methods of illumination {'i'i 54-59). Fig. 20, axial light with parallel rays. Fig. 20a, oblique light. Fig. 21, a.-jial light with con- verging beam. Fig. 22, dark-ground illumination with a centra] stop diaphragm. Axis. The optic axis of the illuminator and of the microscope. The illumina- tor is centered, that is its optic axis is a prolongation of the optic axis of the mi- croscope. ■S1. Axis. Secondary axis. In oblique light the central ray passes along a sec- ondary axis of the illuminator, and is therefore oblique to the principal axis. A. Fig. 21 represents the upper part of the illuminator. D D. Diaphragms. These are placed in sectional and in face views. The dia- phragm is placed between the mirror and the illuminator. In Fig. 20 the opening is excentric for oblique light, and in Fig. 22 the opening is a narrow band, the cen- tral part being stopped out, and thus giving rUe to dark-ground illumination (« 60). Obj. Obj. The front of the objective. Fig. 23. Showing the method of mounting letters in stairs to show the order of coming into focus. a, b, c, d. The various letters indicated by the oblique row of black marks in the sectional view. Slide. The glass slide on which the letters are mounted. Fig. 24. Glass rod showing the appearance in air (a), and in so per cent, glycerin (b), (| 80). Fig. 25. Glass rod coated with collodion to show Doulile Contour. At the left the collodion is represented as collecting in a drop (fj 91). Fig. 26. Mammalian blood-corpuscles on edge to show a surface view (a), and an optical section (b). Fig. 27. Wollaston's Camera Laeida, showing the rays from the microscope and from the drawing surface, and the position of the pupil of the eye. Axis, Axis. Axial rays from the microscope and from the drawing surface. (8 121). Camera Lucida. A section of the quadrangular prism showing the course of the rays in the prism from the microscope to the eye. As the rays are twice reflected, they have the same relation on entering the eye that they would have by looking directly into the ocular. A B. The lateral rays from the microscope and their projection on the drawing surface. C 1). Rays from the drawing surface to the eye. A D, A' D'. Overlapping portion of the two fields, where both the microscopic image and the drawing surface, pencil, etc., may both be seen. It is represented by the shaded part in the overlapping circles at the right. Oeular. The ocular of the microscope. P. The drawing pencil. Its point is shown in the overlapping fields. Fig. 28. Figure showing the position of the microscope, the camera lucida, and the eve, and the different sizes of the image depending upon the distance at which it is projected from the eye. (a) The size at 25 cm. ; (b) at 35 cm. ('b 104). Fig. 29. Figure showing the appearance of the lines of the stage micrometer (the coarse lines) ai.d of the ocular micrometer when using a high objective (<• 117). A. One method of measuring the spaces b}' putting the ocular micrometer line opposite the center of the stage micrometer line. B. Method of measuring the space of the stage micrometer by putting one line of the ocular micrometer at the inside and one at the outside of the lines of the stage micrometer (i 117I.