248 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
over the whole egg, contracts and gathers the fat-droplets into 
one hemisphere of the egg. Hence there arise two phases on 
the surface of the egg, one of which apparently contains no 
fat or pigment, while the other obviously contains both. 
This observation led me to consider whether the importance 
of fat-solvents as well as, in part, that of the alkalies at the 
maturation of the egg may not perhaps consist in the liquefac- 
tion of solid layers of fat. In the egg of Heteronereis (of Pacific 
Grove) there is a confluence of the droplets and a migration of 
the larger drops and of the pigment mass to one hemisphere of 
the egg, and this could easily be explained as the effect of 
surface tension. There is obviously an analogy between the 
artificial production of maturation and of membrane formation. 
In both eases, the process of solution of the chorion or of a 
substance lying at the surface of the egg appears to play a part. 
