174 ORGANIC EVOLUTION — MENTAL 



ment than did his lost powers. His acquired habit of 

 bi-pedal progression, a habit acquired anew by every 

 individual, has resulted in immense and obvious 

 structural changes. But certainly, above all other ac- 

 quired traits, his acquired trait of speech has most 

 influenced his survival rate, and has therefore been the 

 cause of the most far-reaching evolution and retrogres- 

 sion. To this acquired trait very much of the evolution 

 and retrogression directly traceable to other acquired 

 traits is indirectly traceable. By means of it, more 

 than by means of any other of his acquired traits, has 

 he been placed in harmony with the environment. For 

 it is clear, that those individuals who had the best 

 powers of speech, i.e. of communicating information, 

 and the best powers of understanding speech, i. e. of 

 acquiring information, had the best powers of placing 

 themselves in harmony with the environment. Owing 

 to the acquirement by generation after generation 

 through innumerable generations of language, man has 

 retrogressed so far in structure and instincts that, but 

 for speech, and all that is communicated by one genera- 

 tion to another through the medium of speech, he is as 

 certainly unfit for existence as F. rufescens is with- 

 out its slaves. If for a single generation this all-im- 

 portant trait were not acquired, and man, were it 

 possible, survived, he would at once be reduced to the 

 condition of a brute, and, his equipment of instinct 

 being small, a very helpless brute. His highest faculty, 

 his enormous power of varying mentally in response 

 to stimulation, of acquiring fit mental traits, would be 

 rendered nugatory, since it would no longer receive 

 appropriate stimulation. Under the new condition of 

 things, the fit who survived would no longer be the same 

 as heretofore, and since the power of acquiring the 

 higher mental traits would no longer be a principal 

 factor in survival, that power would necessarily decline 



