386 STUDIES IN GENERAL PHYSIOLOGY 
The question now arises whether this liquefaction or fusion 
of the cleavage-cells occurs equally well and with the same 
rapidity in every stage of development. As soon as the eggs 
have reached the sixty-four- or the one-hundred-and-twenty- 
eight-cell stage, the behavior toward lack of oxygen is some- 
* what different. While in an egg 
-° which is in the eight-cell stage the 
2 a pe e. cells fuse in about one hour in the 
a absence of oxygen, a liquefaction of 
or ( -* the cleavage-cells also occurs in the 
eggs in the sixty-four- and one- 
hundred-and-twenty-eight-cell stage, 
but only at the periphery of the blastoderm, and even here 
more slowly than in the cells in the 
FIG. 107 
earlier stages of segmentation. The ee 
droplets of the refractive substance el — 
appear in the furrows, but they are QS” tg a Pes Le 
smaller than in the eggs in an earlier 3 
stage of development, and it is for this Te 
reason perhaps that large oil drops are 
formed less easily. Figs. 109-111 illustrate the process of 
liquefaction in such an egg. The egg 
was put into the gas-chamber at 2:25 
o’clock while in the sixty-four-cell 
stage. At this time its shape was 
sketched with the camera lucida 
(Fig. 109). The outlines of the cells 
within the blastoderm are not shown. 
The segmentation at first continued. 
BAG, 108 At 4 o'clock liquefaction was very 
distinct at the periphery. It occurred in this way that in 
individual cells at the periphery of the blastoderm the 
outline at first becomes invisible, after which the entire 
cell gradually disappears. Through this disappearance of the 
FIG, 108 
Digitized by Microsoft® 
