134 The Mechanistic Conception of Life 



membrane formation had been called forth by a fatty acid. 

 Such eggs begin to develop, but do not go beyond the first 

 nuclear division at room temperature. If, however, the eggs 

 are treated for half an hour with hypertonic sea-water they 

 can develop to normal plutei, i.e., larvae with skeletons. 



The second group of cytolytic agencies is formed by the 

 specific fat solving hydrocarbons like amylen, benzol, toluol, 

 and in a much lesser degree chloroform, etc. Hertwig had 

 already observed that chloroform calls forth the membrane 

 formation and Herbst had seen the same effect brought about 

 by benzol and toluol. But these substances act so violently 

 that the membrane formation is followed almost immediately 

 by a cytolysis of the egg, and for this reason these authors could 

 not notice that the membrane formation was followed by the 

 development of the egg. I have, however, been able to con- 

 vince myself that if amylen or benzol are allowed to act only 

 for one moment and if the eggs are then quickly transferred 

 into normal sea-water a membrane formation can be produced in 

 some of them without subsequent cytolysis. If such eggs were 

 afterward treated with hypertonic sea-water they developed 

 into larvae. 



A further group of cytoljrtic agencies is ether or alcohols. 

 Cytolysis of the eggs by these agencies is also preceded by a 

 membrane formation. If the eggs are taken out from such 

 solutions immediately after membrane formation they can be 

 saved from cytolytic destruction (Figs. 44-47). 



Bases can also call forth membrane formation, but their 

 action is rather slow and depends on the presence of free oxygen. 

 One gains the impression as if the alkali acted in this case only 

 as an accelerator of oxidations and as if a product of oxidation 

 was the proper cause for the membrane formation. The 

 membrane formation usually becomes manifest only if one 

 treats the eggs afterward for a short time with a hypertonic 

 solution; such a treatment causing them to develop into larvae. 



