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 this, 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 



