EVOLUTION OF MAN SMITH. 555 



which, up to his appearance, had b(>en the law of the living world" 

 (Sir Kay Lankester); but it has been demonstrated quite definitely 

 that man, in virtue of these very heightened powere, which, to some 

 observere, seem to have secured him an immunity from what Sir Ray 

 Lankester calls "nature's inexorable discipline of death," is con- 

 stantly exposmg himself to new conditions that favor the operations 

 of natural selection, as well as other forms of "selection" to which 

 his increased powers of intelligent choice and his subjection to the 

 influences of fashion expose him. 



It is not, however, wdth such contentious matters as the precise 

 mode of operation of evolution at the present day that I propose to 

 deal; nor yet with the discussion of when and how the races of man- 

 kind became specialized and differentiated the one from the other. 

 It is the much older story of the origin of man himself and the first 

 glimmerings of human characteristics amidst even the remotest of his 

 ancestors to which I invite you to give some consideration to-day. 



In a recently published book* the statement is made that "the 

 uncertainties as to man's pedigree and antiquity are still great, and 

 it is undeniably difficult to discover the factors in his emergence and 

 ascent." There is undoubtedly the widest divergence of opinion as 

 to the precise pedigree; nevertheless, there seems to me to be ample 

 evidence now available to justify us sketching the genealogy of man 

 and confidently drawing up his pedigree as far back as Eocene times — 

 a matter of a million years or so — with at least as much certainty 

 of detail and completeness as in the case of any other recent mammal; 

 and if all the factors in his emergence are not yet laiown, there is one 

 unquestionable, tangible factor that we can seize hold of and examine — 

 the steady and uniform development of the brain along a well- 

 defined course throughout the primates right up to man — which must 

 give us the fundamental reason for "man's emergence and ascent," 

 whatever other factors may contribute toward that consummation. 



What I propose to attempt is to put into serial order those verte- 

 brates which we have reason to believe are the nearest relatives to 

 man's ancestors now available for examination and to determine 

 what outstanding changes in the structure of the cerebral hemispheres 

 have taken place at each upward step that may help to explain the 

 gradual acquirement of the distinctively human mental faculties, 

 which, by immeasurably increasing the power of adaptation to vary- 

 ing circumstances and modifying the process of sexual selection, have 

 made man what he is at present. 



The links in the chain of our ancestry supplied by paleontology are 

 few and of doubtful value if considered apart from the illummation 

 of comparative anatomy. 



1 J. A. Thomson and P. Qeddes, " Evolution," 1912, p. 102. 



