60 ORGANIC EVOLUTION — THE FACTORS 



somatic cells, by billions, and during every moment of 

 time some of the somatic cells are perishing and others 

 are proliferating. Therefore to discover the number 

 of gemmules sent off by the somatic cells of an 

 organism to its germ cells, we must multiply the 

 millions of the germ cells by the billions of the somatic 

 cells, and then multiply tbe product by the moments 

 of time, multiplied by the number of the separate acts 

 of cell-proliferation and death occurring during each 

 moment of time. This consideration renders the 

 theory wholly incredible, and it is rendered almost 

 unthinkable if we take into consideration also that 

 each germ cell is a mere speck as compared to the 

 rest of the body; that the blood, a fluid mass of 

 considerable volume, must accurately bring from every 

 part of the body to each of these specks its appropriate 

 billions of gemmules, and that, when arrived, each 

 gemmule must take up its proper position in the germ 

 cell so as to cause it, when fertilized, to develop into 

 an organism similar to that of which it (the germ cell) 

 forms an infinitesimal part. It is hard to believe that 

 such a theory can ever have been seriously entertained 

 by biologists of note, and that notwithstanding the fact 

 that it is wholly inapplicable, as is the preceding 

 theory, to plants, the nutrient fluids of which flow 

 generally in one direction and do not circulate in the 

 sense that the nutrient fluids of animals circulate. 



The third theory is one formulated by Mr. Herbert 

 Spencer. I give his own words as far as space permits. 



" As we shall have frequent occasion hereafter to refer 

 to units, which possess the property of arranging them- 

 selves into the special structures of the organisms to 

 which they belong, it will be well here to ask what 

 these units are, and by what name they may be most 

 fitly called ? 



