386 
J. F. McClendon 
stance that can hardly be differentiated in the living egg from the sub- 
stance of the yolk-platelets. Fig. Ib shows these bodies in an egg fixed 
in osmic acid. The small circles are here striated to denote that they re- 
present bodies that take the characteristic osmic impregnation for fat. 
There is some difference in the size of these fat droplets in the Ihing cyto- 
plasm and the osmicated section, but none of them in either preparation 
are as large as the yolk-platelets. If a smear of the linng egg be fixed in 
osmic acid and immediately examined, some of the fat droplets are seen 
in the act of fnsing to form larger drops, fig. Ic. By treating a smear 
Cjtoplasma of ripe OTarian egg of Bana pipiens-, 
a. living egg bnrst nnder cover-glass; b. section 
tixed in osmic; c. fresb smear fixed in formal- 
debyde vapor and stained in alcobolic solntion 
of Sndan ni. Tbe large ovals are yolk-platelets; 
tbe black dots pigment and tbe striated bodies 
gave tbe reaction for fat; tbe small circles in 
a. represent fat, tbis is also true of tbe small 
circles in d. wbicb represent fat droplets wbicb 
are too small to sbow a perceptible intensity 
of stain. 
Figr. 
2 . 
Jnnctureoftbefattylayer(above) 
and protoplasmic layer (below) 
in tbe cytoplasm of tbe egg of 
ChorophiUts triseriatus centri- 
faged in tbe fonr-cell stage, 
centrifngal force = 2771 X gra- 
Tity for seven minutes. 
of the living egg, fixed for a few seconds in formaldehyde vapor, v*ith an 
alcoholic solntion of Sudan III, the fat droplets are stained, but they 
Vary inuch more in size than in any of the above preparations, some of 
them being larger than the yolk-platelets, fig. Id. I attribute this Varia- 
tion in size of the fat droplets in different preparations to the fusion of 
the original droplets to form larger drops, a process which is due to the 
rubbing of the smears or to the addition of substances which reduce the 
surface tension of the droplets. This last point is ülustrated by the fact 
that if the osmicated smear be treated with the alcoholic solntion of 
Sudan III, the fat droplets may be seen to fuse and form larger drops. 
By Chemical analysis I found (09, 1 and 3) the pigment granules to 
be composed of a melanin containig 0,6% of siüphur and 9% of nitrogen; 
