224 WE AT IS LIFE 



bryology has also been done, with remarkable results, 

 by not a few other distinguished investigators. 



Jacques Loeb's work included a variety of elabor- 

 ate experiments. But his crowning achievement was 

 the demonstration "that eggs which naturally de- 

 velop only when a spermatozoon enters, can be 

 caused to develop artificially by certain physical and 

 chemical means. "^^ 

 Loeb is again quoted: 



"Experiments show that it is possible to com- 

 pletely imitate by physicochemical means the 

 effect of the spermatozoon upon the sea-urchin 



egg"39 



Again : 



"It may be mentioned that in the eggs of many 

 animals the effect of the entrance of the sperma- 

 tozoon manifests itself almost instantly by a 

 characteristic change, namely, the formation of 



the so-called membrane of fertilization In 



1905 I succeeded in finding a method by which 

 it is possible to call forth the formation of a 

 membrane of fertilization without apparent 



injury to the egg It was noticed that all 



the agencies which cause cytolysis also cause 

 membrane formation."^" 



'* Jacques Loeb, Dynamics of Living Matter, 165. 



" IbicL. 171. 



" The Mechanistic Conception of Life, 129, 130, 132. 



