1895. | NEW YORK ACADEMY OF SCIENCES. 227 
but a secretion from the chromatin might be similarly placed. 
In the other cases cited where the yolk-nucleus originates from 
the chromatin network there seems to be no doubt about its be- 
ing truechromatin. Fol (’84) Blochmann (’84) and Scharff (’88), 
for example,asserted that portions of the nucleus containing parts 
of the chromatin network are budded off and that these parts 
become the yolk-nuclei. Van Bambeke (’93) claimed that the 
chromatin threads pass unbroken through pores in the nuclear ° 
membrane, although he is not satisfied that the eliminated part 
is a true yolk-nucleus. His figures leave little doubt on the 
subject, however, for the extra-nuclear chromatin is pictured as 
breaking up into granules which become ranged around the nu- 
cleus and in the cytoplasm of the egg ina manner similar to 
that so often described for a yolk-nucleus. 
The most satisfactory answer to this question is afforded by 
the micro-chemical color reactions of the yolk-nucleus and the 
chromatin. As is well known, chromatin contains a large per- 
centage of nucleic acid and has a marked affinity for basic 
stains. Cytoplasm, on the other hand, contains a great percent- 
age of albumen with little or no nucleic acid and has an equally 
marked affinity for acid stains. If, therefore, the yolk-nucleus 
stains the same as does the chromatin, it may be inferred that 
it is composed of a similar substance. In Van Bambeke’s fig- 
ures of safranin preparations the mass of granules and the chro- 
matin are the same color, and as he asserts and pictures the 
granules as coming directly from the nuclear network one can 
only conclude that they also are chromatin. 
The micro-chemical reactions on the egg cells of Lumbricus, 
as shown by differential staining, reveal two facts: first, the 
mass of granules around the nuclear membrane stains the same 
as the chromatin; second, the disintegrated parts of the yolk- 
nucleus in the older eggs, as shown in figure 5, stain the same as 
the cytoplasm. These differences can be seen in the same sec- 
tion, so that the criticism of different treatment cannot be sus- 
tained. 
The combination stain of Heidenhain’s hematoxylin and 
orange makes the chromatin and the yolk-nucleus a blue-black, 
while the nucleolus of the germinal vesicle and the cytoplasm 
are orange. The Biondi-Ehrlich mixture stains the young yolk- 
nucleus a bright green, while in the older eggs the disintegrated 
yolk-nucleus is stained a bright red. The principal constituents 
of the Biondi-Ehrlich mixture are methyl green (basic) and acid 
fuchsin (acid). To remove all doubt in regard to the chemical 
action of these colors a solution was made containing basic 
fuchsin and acid green (Lichtgrtin). The result was a reversal 
