THE PROCESS OF FERTILIZATION. 281 



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 - 2 g-- nMgCl2 solu- 

 tion and sea water we can cause them to develop parthenoge- 

 netically into plutei. 



III. 



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 the same for two hours 

 with a solution of equal parts of ^ nMgC! 2 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 bind- 

 ing water. It seems probable that changes of these two quali- 

 ties 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 concentra- 

 tion 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 statements. The 

 next question that should be raised would be whether the 

 spermatozoa act in the same way. It is true that the sperma- 

 tozoon contains a considerable proportion of salts, especially 

 K 3 PO4, but it may contain enzymes or it may contain substances 

 which have similar effects upon the physical qualities of the 

 colloids, like the three agencies mentioned above. 



In the last volume of these lectures I pointed out that it is 

 impossible to derive all the various elements that constitute 

 heredity from one and the same condition of the egg. (10) Our 

 recent experiments suggest the possibility that different con- 

 stituents of the egg are responsible for the process of fertiliza- 

 tion and for the transmission of the hereditary qualities of the 



