BRUTE-MAN'S HELPLESSNESS 15 



the supposition, that in their passage from the outer 

 surface to the inner they do not by interactions 

 with the substances through which they are passing 

 part with any of their power. Since it is certain 

 that the opposite is the case, therefore must another 

 deduction be made, to obtain a correct estimate 

 of the diminution which the external influences 

 suffer in passing from the outer to the inner surface 

 of the cell wall. 



Since the first principle above specified would 

 apply equally if the cell wall had been divided into 

 three or four or any number of imaginary divisions, 

 it is obvious that the application cannot be taken 

 as representing literally accurate numerical results, 

 but merely as establishing the principle that the 

 efficiency of forces originating externally is greater 

 at the outer and less at the inner surface of the cell 

 wall. 



If now, it is taken into consideration that the 

 inner substance of the cell is divisible into an infi- 

 nite number of mathematical strata laying between 

 the inner surface of the cell wall and the mathe- 

 matical center, then the conclusion becomes inevi- 

 table, that the outer substance of a cell must be to 

 a very high degree subject to changes from inter- 

 actions with environing materials and conditions; 

 while the central substance, if at all, can be so only 

 to a very small extent by comparison. And from 

 this it follows that with the birth of a cell there be- 

 gins a process which tends to the differentiation of its 



