INHERITANCE 107 



the utmost caution in criticising the theory : 

 yet it cannot be denied that it involves certain 

 difficulties which seem of great weight, and which 

 have not yet been satisfactorily met. In the first 

 place, there is the mechanical difficulty of the 

 extraordinary numbers of these gemmules which 

 must be present. Gemmulee must be derived from 

 every component cell of the body : for Mr. Darwin 

 lays much stress on the independence of these cells, 

 quoting Virchow to the effect that " Every single 

 epithelial and muscular fibre cell leads a sort of 

 parasitical existence in relation to the rest of the 

 body .... every single bone corpuscle really 

 possesses conditions of nutrition peculiar to itself." 

 Again, Sir James Paget speaks of each cell as 

 living its appointed time, and then dying and being 

 cast off or absorbed ; while further on Mr. Darwin 

 continues, "I presume that no physiologist doubts 

 that, for instance, each bone-corpuscle of the finger 

 differs from the corresponding corpuscle in the 

 corresponding joint of the toe ; and there can 

 hardly be a doubt that even those on the two 

 sides of the body differ, though almost identical 

 in nature." 



Again, these gemmules must not only be 

 formed from every cell, but must be present in 

 enormous numbers from every cell, and at every 

 period of life : for it is well known that a portion 

 of a leaf of Begonia or Asplenium can reproduce 

 the whole plant ; and to do this there must, on the 

 theory of Pangenesis, be present in this portion of 

 the leaf gemmules from every part of the plant. So 

 again, the repair of mutilations can only be possible 



