288 



SCIENCE 



[N. S. Vol. XL. No. 1026 



the year of Sir David Gill, a former presi- 

 dent of this association, himself one of the 

 outstanding great. His greatness lay in 

 the power of making big foundations. He 

 built up the Cape Observatory; he organ- 

 ized international geodesy; he conceived 

 and carried through the plans for the 

 photography of the whole sky, a work in 

 which Australia is bearing a conspicuous 

 part. Astronomical observation is now 

 organized on an international scale, and of 

 this great scheme Gill was the heart and 

 soul. His labors have ensured a base from 

 which others will proceed to discovery 

 otherwise impossible. His name will be 

 long remembered with veneration and 

 gratitude. 



As the subject of the addresses which I 

 am to deliver here and in Sydney I take 

 Heredity. I shall attempt to give the 

 essence of the discoveries made by Men- 

 delian or analytical methods of study, and 

 I shall ask you to contemplate the deduc- 

 tions which these physiological facts sug- 

 gest in application both to evolutionary 

 theory at large and to the special case of 

 the natural history of human society. 



Recognition of the significance of hered- 

 ity is modern. The term itself in its scien- 

 tific sense is no older than Herbert Spencer. 

 Animals and plants are formed as pieces 

 of living material split from the body of 

 the parent organisms. Their powers and 

 faculties are fixed in their physiological 

 origin. They are the consequence of a 

 genetic process, and yet it is only lately 

 that this genetic process has become the 

 subject of systematic research and experi- 

 ment. The curiosity of naturalists has of 

 course always been attracted to such prob- 

 lems ; but that accurate knowledge of 

 genetics is of paramount importance in 

 any attempt to understand the nature of 

 living things has only been realizjed quite 

 lately even by naturalists, and with casvial 



exceptions the laity still know nothing of 

 the matter. Historians debate the past of 

 the human species, and statesmen order its 

 present or profess to guide its future as if 

 the animal man, the unit of their calcula- 

 tions, with his vast diversity of powers, 

 were a homogeneous material, which can 

 be multiplied like shot. 



The reason for this neglect lies in ignor- 

 ance and misunderstanding of the nature 

 of variation; for not until the fact of con- 

 genital diversity is grasped, with all that 

 it imports, does knowledge of the system 

 of hereditary transmission stand out as a 

 primary necessity in the construction of 

 any theory of evolution, or any scheme of 

 human polity. 



The first full perception of the signifi- 

 cance of variation we owe to Darwin. The 

 present generation of evolutionists realizes 

 perhaps more fully than did the scientific 

 world in the last century that the theory of 

 evolution had occupied the thoughts of 

 many and found acceptance with not a few 

 before ever the "Origin" appeared. "We 

 have come also to the conviction that the 

 principle of natural selection can not have 

 been the chief factor in delimiting the 

 species of animals and plants, such as we 

 now with fuller knowledge see them actu- 

 ally to be. We are even more sceptical as 

 to the validity of that appeal to changes in 

 the conditions of life as direct causes of 

 modification, upon Avhich latterly at all 

 events Darwin laid much emphasis. But 

 that he was the first to provide a body of 

 fact demonstrating the variability of living 

 things, whatever be its causation, can never 

 be questioned. 



There are some older collections of evi- 

 dence, chiefly the work of the French 

 school, especially of Godron- — and I would 

 mention also the almost forgotten essay of 



2 " De 1 'Esp6ee et des Races dans les Etres Or- 

 ganises," 1859. 



