394 STUDIES IN GENERAL PHYSIOLOGY 
boid pseudopodia. A few minutes later all of the cells sent 
out such pseudopodia, which soon became shorter, however, 
as if the substance of the pseudopodia had been torn, e. g., 
through an emulsion (Fig. 120). The outlines of the germ 
= then again became smooth, but not 
entirely so (Fig. 121), and finally the 
blastoderm gradually disappeared (Fig. 
122). The entire series of changes 
shown in Figs. 118—22 took about forty- 
five minutes. Besides these changes, 
another series 
took place in | hy f 
EIS 8 the blasto- S ly Mf 
derm and the yolk, which, however, 
I am not as yet able to interpret, == 
and which I therefore do not de- —7 
scribe, as their description would Wa 
take up much room without at CO 
present being of 
any use. 
May, If eggs in an eet 
te, advanced state 
es oN of division are introduced into CO,, 
! a solution of the cleavage-cells occurs 
is. at the periphery Just as in hydrogen. 
‘\nrpe { VI. THE EFFECT OF PURE OXYGEN 
UPON CLEAVAGE 
~n In embryological literature one 
at times encounters the statement 
that the processes of development in 
pure oxygen at atmospheric pressure go on differently from 
those in air. Demoor also states that nuclear division is 
accelerated in pure oxygen. 
Now, it is one of the established facts of physiology that 
FIG. 120 
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