ARTIFICIAL PARTHENOGENESIS AND HEREDITY 301 
sperm to the eggs the nuclei of the latter had begun to undergo 
an increase in size In consequence of the previous treatment 
with fatty acid. In a large number of such eggs Herbst found 
that the chromatin of the sperm nucleus had undergone a mi- 
totic division and modification. Herbst considers it likely 
that this is responsible for the partial elimination of the heredi- 
tary influence of the sperm. 
It is very interesting that Herbst found plutei which on 
one side of their bodies were purely maternal while on the other 
side the paternal influence was noticeable. This he explains 
on the assumption that the two first cleavage cells received 
a different amount of paternal chromatin, or, more correctly, 
different paternal chromosomes. In this way the results of 
Herbst are in harmony with the modern results concerning 
the rdle of the chromosome in heredity. 
Tennent has produced results similar to those of Herbst by 
a different method, namely, by modifying the concentration of 
HO ions in the sea-water. These experiments, however, have 
no relation to the problem of artificial parthenogenesis and 
therefore need not be discussed in this connection. 
