452 FRANK R. LILLIE 
Momente zerlegen liisst—im ersten findet die Cytolyse, im zweiten die 
Regulierung der im ersten Akt bereits eingetretenen inneren Reaktionen 
im Hiorganismus statt. 
There is nothing in the results of these authors inconsistent 
with the idea that the regulating effect of the second agent in 
artificial parthenogenesis may be attained through the re-estab- 
lishment of normal interchange between the nucleus and the cyto- 
plasm, which is the view to which I have been led by the results 
described in this series of papers. And this suggestion contains 
the possibility of a complete accord between the results of the 
analysis of fertilization by methods of artificial parthenogenesis, 
and the more direct method of analysis contained in my papers. 
If the egg be put in a healthy metabolic state by the resump- 
tion of normal nucleo-plasmic relations following the penetration 
of the spermatozoon, it can no doubt regulate its own external 
affairs. And so it seems to me that the regulation of cortical 
permeability and cytolysis is probably a secondary effect of the 
re-establishment of normal nucleo-plasmic interchange. Even 
in artificial parthenogenesis, where the sperm nucleus is lacking, 
the action of the second agent may proceed in the same way, 
by causing the re-establishment of normal interchange between 
the egg nucleus and cytoplasm, restoring thus healthy conditions, 
which then regulate the cortical changes. But whether the tend- 
~ency to cytolysis be checked thus secondarily, or by some direct 
effect of the second agent on the cytoplasm, development certainly 
cannot proceed without the establishment of normal metabolic 
interchange between the nucleus and the cytoplasm, and this must 
certainly be regarded as a fundamental function of the second 
agent in artificial parthenogenesis. 
To sum up the conclusions in a sentence we may say: the action 
of the spermatozo6n in fertilization involves two distinct phases, 
the first of which may be effected before penetration and brings 
about a sudden and marked increase in permeability of the egg- 
membrane; the second, which follows after penetration, consists 
essentially in the establishment of normal interchange between 
nucleus and cytoplasm, and consequent normal regulation of all 
the activities of the cell. , 
