Statement of Weismanris System (1886). 5 



be packed into a single ovum or spermatozoon — 

 Darwin opposes a calculation that a cube of glass or 

 water, having only one ten-thousandth of an inch to 

 a side, contains somewhere between sixteen and a 

 hundred and thirty-one billions of molecules. Again, 

 as touching the supposed power of multiplication on 

 the part of his gemmules, he alludes to the fact 

 that infectious material of all kinds exhibits a ratio 

 of increase quite as great as any that his theory 

 requires to attribute to gemmules. Furthermore, with 

 respect to the elective affinity of gemmules, he 

 remarks that "in all ordinary cases of sexual repro- 

 duction, the male and female elements certainly have 

 an elective affinity for each other " : of the ten 

 thousand species of Compositae, for example, " there 

 can be no doubt that if the pollen of all these 

 species could be simultaneously placed on the stigma 

 of any one species, this one would elect, with unerring 

 certainty, its own pollen." 



Such, in brief outline, is Mr. Darwin's theory of 

 Pangenesis. 



Professor Weismann's theory of Germ-plasm is 

 fundamentally based upon the great distinction, 

 in respect of their transmissibility, between char- 

 acters that are congenital and characters that are 

 acquired. By a congenital character is meant any 

 individual peculiarity, whether structural or mental, 

 with which the individual is born. By an acquired 

 character is meant any peculiarity which the individual 

 may subsequently develop in consequence of its own 

 individual experience. For example, a man may be 

 born with some malformation of one of his fingers ; or 

 he may subsequently acquire such a malformation as 



