26 GEORGINA B. SPOONER 



Sections of normal eggs which have just been deposited in the 

 sacs contain the second polar spindle (fig. 1). The spindle is 

 small and lies embedded in a disc of purple staining granules at 

 the periphery of the egg. The rest of the egg is filled with the 

 characteristic large yolk spheres, which are separated from each 

 other by a film of purple granules like those surrounding the 

 spindle. The purple granules occupy the areas which in living^ 

 eggs are clear protoplasm. This has been seen in centrifuged eggs. 

 Whether these '^ granules" are real granular inclusions in the more 

 fluid protoplasm or simply coagulation products is an open ques- 

 tion. If they are coagulation products only, then their position 

 in the section probably represents the extent of the protoplasm 

 in the centrifuged egg. But if they are true granular inclusions 

 it may well be that they are to some extent separated from the 

 surrounding protoplasm and consequently that the entire proto- 

 plasmic portion of the egg is not indicated by the position of these 

 granules. The evidence, discussed later on, pointing to a '* ground 

 substance" which is undisturbed by the centrifuge, concurs with 

 the latter idea. 



The polar spindles which I found (five in number) were all 

 late anaphases (fig. 6) with no evidence of astral rays at either 

 pole. Half an hour after the eggs have been deposited in the sac 

 the segmentation nucleus lies in the center of the cell and is much 

 enlarged. The two pronuclei that compose the segmentation 

 nucleus, however, have not fused but lie flattened against each 

 other. Haecker has described gonomery in another species of 



G in 95 per cent alcohol, to make it more plainly visible and then wrapped in 

 a piece of epithelium from which as much water as possible had been drained. 

 Care must be taken to avoid air bubbles inside the bundle in the process of wrap- 

 ping, else the sections will be torn to pieces in cutting. It is also well to let the 

 epithelial ball dry off somewhat on the outside before replacing in 95 per cent alco- 

 hol in order to stick the folds together and prevent unwrapping and loss of mate- 

 rial in the paraffin. The eggs were imbedded in fifty-eight paraffin and sections 

 cut 3 /i in thickness. The method proved very successful not only with single egg 

 sacs but also with groups of sacs and even adult animals. 



Delafield's haematoxylin followed by orange G has been used for practically 

 all the staining. I tried iron haematoxylin counterstained with orange G. While 

 it offers an interesting contrast in some cases to the Delafield stain, it does not 

 bring out very well the relation of the centrifuged materials. 



