122 The Mechanistic Conception of Life 



In this case it was shown, that although these eggs received the 

 same sea-water as the ones which developed, and although 

 they were injured less than the ones which developed, yet not 

 one single egg formed a membrane or reached the blastula 

 stage. If the sea-water had contained any spermatozoa these 

 eggs should have reached the blastula stage.^ Hence, as in 

 nine different series of experiments these results were confirmed, 

 we may assume that by treating the eggs for two hours with a 

 solution of equal parts of a ^ n MgCl, solution and sea-water 

 we can cause them to develop parthenogenetically into plutei. 



Ill 



What conclusions may we draw from these results ? If we 

 wish to avoid wild and sterile speculations, I think we should 

 confine ourselves to the following question: What alterations 

 can be produced in an egg by treating it for two hours 

 with a solution of equal parts of ^^n MgClg and of sea-water ? 

 Even in this regard we can only give a very indefinite answer 

 which, however, will have to be in the following direction: The 

 bulk of our protoplasm consists of colloidal substances. This 

 material easily changes its state of matter and its power of 

 binding water. It seems probable that changes of these two 

 qualities are mainly responsible for muscular contraction and 

 perhaps amoeboid motions. Among the agencies that cause 

 changes of these physical qualities we know of three that are 

 especially powerful. The one is specific enzymes (trypsine, 

 plasmase, etc.). The second is ions in definite concentration. 

 The concentration varies for various ions. The third agency 

 is temperature. In our experiments it is obvious that only the 

 second possibility can have been active. I do not consider 

 it advisable to enter into theoretical discussions beyond these 



1 Through other control experiments I convinced myself that a treatment of 

 eggs or spermatozoa with equal parts of a -g'^n MgClg solution and sea-water 

 diminishes the impregnability of the eggs and annihilates the fertilizing power of 

 spermatozoa in a very short time. 



