PRESIDENTIAL ADDRESS. 9 



naturalist, Haeckel HPlate HI.] (an Hon. Member of this 

 Society) " Ontogeny recapitulates Phylogeny," 



Two years later (in 1839) Schwann discovered that all 

 plants and animals are built up of cells, the lowest forms 

 beins: one-celled, and the higher having manv cells, from 

 which result tissues and organs. This led to the dis- 

 covery, by Yon Mohl, five years later (in 1844), that these 

 cells result from the complex union into one substance of 

 the simple elements, oxygen, nitrogen, hydrogen, and 

 carbon, that substance being named by him " protoplasm.'' 



Such was about the position of biological science when 

 (in 1859) Darwin's '"'Origin of Species " appeared, a book 

 which has worked more extraordinary transformation in 

 thought than any other of our time. The publication 

 was hastened, as the author himself tells us, by his 

 having received (in June, 1858) a paper entitled " On the 

 Tendencies of Varieties to depart indefinitely from the 

 Original Type," written by his friend, Alfred Russell 

 Wallace [Plate IV.] , containing, as he says, " exactly the 

 same theory." It is a curious fact that both Darwin and 

 "Wallace should have been led to embrace the theory 

 through reading Malthus's "Essay on Population." 



That two fellow-countrymen should have quite inde- 

 pendently hit upon the same theory is of itself a very 

 remarkable fact, and it would be difficult to find a case of 

 more complete unselfishness than that of Wallace in 

 altogether sinking his own name in his love of "Dar- 

 winism." 



It was, as Romanes says, " In the highest degree dramatic 

 that the great idea of natural selection should have 

 occurred independently, and in precisely the same form, 

 to two working naturalists ; that these naturalists should 

 have been countrymen ; that they should have agreed to 

 publish their theory on the same day ; and last, but not 



