Illustrations 



Fig. I . Graphical representation of the changes in volume 

 undergone by gelatine /albumin gels during 1 8 hours 

 in various fixatives page 36 



Fig. 2. Pipettes used in the measurement of the rate of 



penetration of fixatives into gelatine /albumin gel 38 



Fig. 3 . Graph showing the rate of penetration of fixatives 



into gelatine /albumin gel 39 



Fig. 4. Protein coagula seen under the microscope 41 



Fig. 5 (plate), a, lobes of the liver of the rabbit left for 25 

 hours in fixatives and then cut across 



B-E, photomicrographs illustrating Young's ex- 

 periments on the addition of indifferent salts to 

 fixatives faci?tg page 67 



Fig. 6. A cell from the intestine of Oniscus (woodlouse), 

 fixed in mercuric chloride : to show the coagulation 

 of protoplasm page 67 



Fig. 7. Graph showing the thickness of rabbit-liver fixed 

 by a saturated aqueous solution of mercuric chlor- 

 ide in various times 68 



Fig. 8 (plate). The effect of fixatives on cultured cells from 

 the chorioid or sclerotic coat of the eve of the chick 

 embyro facing page 70 



Fig. 9 (plate). Sections of the testis of the mouse, to show 



good and bad fixation 74 



Fig. 10. Outlines of the fully-grown primary spermatocyte 

 of the snail, Helix aspersa, to show the effect of fixa- 

 tion and subsequent treatment on the size of the 

 cell page 79 



Fig. 1 1 . Graph showing the effect of fixation and subsequent 

 treatment on the volume of the nuclei of cartilage- 

 cells 80 



xiii 



