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 



3S. Cover-glass measurer (Edward Bausch), _ 69 



38a. Turn-table for sealing cover-glass, etc., (James \V. Queen & Co.), .... 71 



39. Cabinet for specimens, 80 



40. Cabinet drawer, face and sectional view, 81 



57. Arranging and labeling serial sections, 78 



