File:Principles of Microscope - Plate 3.jpg

English: a. A film preparation of blood in which the elements are delineated by dark outlines upon a bright field. (Dark outline picture.) The preparation is mounted in air, is illuminated by narrow-angled beams and is viewed with a narrow-angled objective (vide p. 22, Exp. 1; p. 41 (b); and p. 42, Exp. 2).

b. A film preparation of blood in which the elements are delineated by bright outlines upon a dark field. (Dark ground illumination.) The preparation is mounted in water, is illuminated by hollow wide-angled beams (furnished by a wide-angled condenser fitted with a central spot stop as shown in Figs. 75 and 90), and is viewed with a narrow-angled objective (vide p. 23, Exp. 2).

c. Film preparation of blood seen as a picture in relief. The preparation is mounted in air, is illuminated by such a system of obliquely incident beams as is shown in Fig. 76, and as is obtained by the arrangement shown in Plate XII, Fig. 1 (vide p. 23, Exp. 4).

d. Film preparation of blood in which the elements are visible only in so far as they are coloured (colour picture). The preparation is illuminated by a focussed fully-open wide-angled condenser in the field of which is the window bar shown in the upper part of the figure (vide p. 23, Exp. 3; p. 99, Exp. 1, and p. 174).

e. Film preparation of blood in which the elements are differentially stained by Leishman's stain (vide p. 24).

f. Film preparation of blood stained diffusely with eosin (see p. 36, Exp. 6).

g. The same preparation partially discolourized by the agency of a weak alkali (see p. 36, Exp. 5).

h. The same preparation after further staining with methylene blue (see p. 36, Exp. 7).