246 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
It is a remarkable fact that, so far as our present knowl- 
edge goes, with regard to those eggs in which the entry of the 
spermatozoon is the determining factor both of maturation 
and development, the same chemical substances that will 
induce artificial maturation also induce development; whereas 
in the egg of the starfish, in which the spermatozoon does not 
enter until after maturation, that is apparently not the case. 
In nature everything is so adjusted that when the eggs are 
laid they are (usually, if not invariably) susceptible of immediate 
fertilization. Hence, what we attain in these experiments by 
artificial means must be accomplished by the organism in the 
natural order of affairs. I had started to investigate these 
processes, and it appeared to me that they might depend on 
the effect of the blood or circulatory fluid. If an investigator 
obtains by chance eggs which have almost matured within the 
organism, he cannot, of course, fail to observe that they are 
able to complete the maturation process without the aid of the 
processes used by us. But it would be wrong to follow Mathews 
and conclude from a casual observation that alkali may not be 
necessary for maturation because he observed in one case that 
(all?) the eggs of a starfish completed their maturation in a 
neutral NaCl solution. There is nothing surprising in tbis, as 
in starfish the eggs of the same female show different degrees 
of maturity, in that a few mature at once in sea-water, others 
slowly, and others again very late, or perhaps never; while 
by a temporary raising of the concentration of the hydroxylions 
the maturation generally can be accelerated. 
Physiology will have one day to answer the question why in 
the eggs of many animals the spermatozoon causes both matura- 
tion and development, whereas in other cases maturation takes 
place spontaneously, the egg afterward entering into a resting 
condition, out of which it is aroused only by fertilization. In- 
vestigations upon the germination of oily seeds give us a hint as 
to one of the possibilities here present. For if some substance 
