476 HOPE HIBBARD 



toxylin and basic fuchsin, the cytoplasm had a mottled appear- 

 ance. A distinct difference between the cytoplasm of the center 

 of the egg in which the division figure lies and the peripheral 

 cytoplasm may be seen. This regional differentiation corre- 

 sponds to the distribution of the nutritive bodies fixed so distinctly 

 in Flemming without acetic. This shows that the nutritive 

 material is present after modified Bouin fixation. Similar 

 results were found after sublimate-acetic fixation. After strong 

 Flemming followed by safranin, gentian violet, and orange G, 

 this nutritive material takes up the orange stain more strongly 

 than any other cell constituent. Therefore, while certain fixing 

 fluids are decidedly more favorable for the demonstration of 

 these plates, the material is not dissolved completely by the other 

 reagents used. 



Yolk is the only substance ordinarily found in the cytoplasm 

 of the egg in great quantities comparable to this material. But 

 these plates do not respond to all the tests for yolk given by Miss 

 Beckwith ('14). For instance, yolk turns black after Flemming 

 fixation and iron-hematoxylin stain. These bodies are not black. 

 Yolk is definitely fixed by picro-acetic and sublimate-acetic. 

 Gatenby ('19 b) states that in some animals yolk discs take a 

 deep violet after Benda's stain. He points out that this staining 

 reaction may be due to protein in the yolk in addition to lecithin. 

 The yolk plates in the egg of Echinarachnius, however, do not 

 invariably stain a deep violet, but do so only after prolonged 

 fixation. Some proof of the nature and function of these bodies 

 may be obtained by tra'^ing them through the early cleavage 

 stages to the blastula. They become gradually fewer in number 

 and in the blastula they are almost gone. Figures 19 to 24 show 

 progressive stages in which they have become fewer. Figure 24 

 illustrates a stage four hours after insemination in which there are 

 spaces left which the large plates formerly occupied and in which 

 many of the minute granules are stained violet. This may 

 be due to the breaking up of the larger masses by a process of 

 digestion. The disappearance of this material is not confined 

 to those series which have been fixed in Flemming without acetic 

 Meves, and Champy. Figure 11 (picro-acetic) shows a much 



