John P. Munson 335 



on the reconstruction of the nucleus is due to metabolic activity of the 

 chromosomes. The granules, which accumulate in this hyaline karyo- 

 lymph in the second stage of the egg, seem also to be the result of chemi- 

 cal action of some kind. 



It is claimed by many observers that chromatin passes out from the 

 germinal vesicle in some eggs and becomes changed in the cytoplasm 

 either directly into yolk, or assuming temporarily the form of yolk- 

 nuclei, is either finally absorbed by the cytoplasm or else later converted 

 into yolk. JSTo satisfactory proof of this elimination of chromatin has 

 yet been given. In the present case, it would be natural, perhaps, to 

 infer that the yolk-nucleus in this egg has such an origin. Its relation 

 to the germinal vesicle is such as to suggest such an origin. But its 

 staining reaction is such as to render that interpretation doubtful. All 

 parts of the germinal vesicle stain deeply in nuclear stains. With pos- 

 sibly the exception of borax carmine, the yolk-nucleus resists these 

 stains more than any other part of the egg. Saffranin, acid fuchsin, 

 and eosin differentiate it, but stain also the granules of the germinal 

 vesicle. Saffranin is especially favorable in this regard. With these 

 stains, therefore, one is strongly impressed by the similarity of the 

 granules of the yolk-nucleus with those of the germinal vesicle, and 

 would very easily be convinced that the presence of the yolk-nucleus in 

 the immediate neighborhood of the germinal vesicle means the origin 

 of the former from the latter. The application of carmine or hsema- 

 toxylin, however, changes matters entirely, for, while the nucleus is 

 deeply affected, the yolk-nucleus is not in the least affected by these 

 stains. Wilson seems to recognize this difficulty, but avoids it by 

 assuming that a chemical change takes place in the chromatin on enter- 

 ing the cytoplasm. It must be evident that such a chemical change 

 would involve a contribution of some sort by the cytoplasm through 

 which the chemical change, if siich there be, is brought al30ut. 



In my work on Limulus, 6i, I differentiated the substance in the 

 neighborhood of the germinal vesicle by means of Lyon's blue. I fur- 

 ther noticed that, in certain phases of the germinal vesicles of that egg, 

 a clear zone appeared around it, which I took to mean the extrusion 

 of karyolymph. I believe that interpretation is the correct one, and 

 that the granular yolk-nucleus, even in this egg, is due to chemical 

 union of karyolymph with some substance in the cytoplasm. It is, so 

 far as I can see, an amorphous chemical substance in the cytolymph, 

 more or less fluid and capable of a flowing movement between the fibers 

 of the reticulum The frequency with which it occurs in eggs of the sec- 

 ond stage, as well as its frequency in the cytocoel, and its scattered 



