XJV ILLUSTRATIONS 



Fig. 12. Graph showing how the volume of the eggs of Ar- 

 bacia pustulosa is affected by the addition of non- 

 fixative sahs to formaldehyde solution P^S^ 82 



Fig. 13. Diagram showing the coefficient of elasticity of the 



belly-muscle of the cat, fixed in various ways 87 



Fig. 14. Graphical representation of the ions present in a 

 2*5% aqueous solution of potassium dichromate 

 and in a solution of chromium trioxide containing 

 the same weight of chromium 105 



Fig. 15. Photomicrographs of lecithin smeared on glass. A, 

 in distilled water, showing outgrowth of myelin 

 forms; B, in a concentrated solution of calcium 

 chloride, showing absence of myelin forms 115 



Fig. 16. Three Ringkorner and a cap or hood (Kapuze) 

 formed by partial solution of lipid globules : osmium 

 preparations 125 



Fig, 17. Graph showing the transmission of light through a 

 layer i cm thick of basic fuchsine, 0-00062% 

 aqueous 161 



Fig. 18. Graph showing the reciprocals of the transmission 

 of light through a layer i cm thick of basic fuchsine, 

 0-00062% aqueous 162 



Fig. 19. Graph showing the optical density of a layer i cm 



thick of basic fuchsine, 0-00062% aqueous 163 



Fig. 20. Graph showing the transmission of light through 

 a layer i cm thick of acid fuchsine, 0-00293% 

 aqueous 165 



Fig. 21 (plate). Haematoxylon campechianum facing page 172 



Fig. 22 (plate). The cochineal insect and its food-plant 176 



Fig. 23 (plate). Apparatus for cataphoretic experiments 



with dyes 189 



Fig. 24 (plate). Ehrlich at the age of 24 193 



Fig. 25. Diagrammatic representation of the dyeing of 

 collodion by typical basic, amphoteric, and acid 

 dyes page 194 



Fig. 26. Diagrammatic representation of the dyeing of gela- 

 tine by typical basic, amphoteric, and acid dyes 1 95 



