Evolution 



of any other animal. The voice is frequently well modulated, 

 and the expression of the emotions, whether by it or by the 

 countenance, is very man-like. The position of the group was 

 summed up by Huxley, after a most thorough investigation of 

 their anatomy, in these words : " Thus, whatever system of 

 organs be studied, the comparison of their modification in the 

 ape series leads to one and the same result that the structural 

 differences which separate man from the Gorilla and Chimpanzee 

 are not so great as those which separate the Gorilla from the 

 lower apes." An interesting physiological proof of the close 



FIG. 136. Skeletons (left to right) of Gibbon, Orang-Utan, Chimpanzee, 

 Gorilla, and Man. 



From Huxley's Man's Place in Nature. 



relationship between the anthropoids and man has more lately 

 been discovered. It is found that the blood serum of any animal 

 destroys the blood corpuscles of any other when these are mixed 

 with it, except those of closely related species. Now the human 

 blood serum is destructive of the corpuscles of all the lower 

 animals, so far as is known, except those of the anthropoids. 



As regards the inter-relationships of the four species, it is 

 certain that the Gibbon is the lowest, and the nearest to the 

 common ancestor of the other three and of man. It has indeed 

 the man-like characteristic of walking in the erect position ; but 



it has thirteen or fourteen pairs of ribs, as against the normal 



146 



