MUSCULAR SYSTEM 115 



" A free subcutaneous position, slight relations to the skele- 

 ton, and the absence of definite fasciae, offer most favourable 

 conditions for the initiation of new combinations. The muscular 

 elements can naturally only enter upon new departures in various 

 directions for the attainment of a greater functional activity, as 

 the result of very definite causes. These causes are undoubtedly 

 present in Man, and lie in his mental qualities and in the faculty 

 of speech. The latter calls the muscles around the mouth into 

 activity, and the former seek expression in the play of the 

 features. These causes of the differentiation of new facial muscles 

 hardly exist in the lower animals, which fact accounts, it appears 

 to me, for the absence among them of those signs of progressive 

 variation with which we shall become acquainted in the muscula- 

 ture of the human face. It may be different, however, in the 

 case of variations due to quite other causes. The possibility of 

 great variability in the facial musculature of the lower animals 

 cannot be denied d priori ; nor can we dismiss the objection that 

 the few observations which have been made on animals have by 

 no means settled what must be considered as the normal condi- 

 tion for them. In answer to this, I would, however, emphasise 

 (1) the fact that variation in the muscles of animals is rarer 

 in the wild state than under domestication ; and (2) the con- 

 sideration (to which Dobson has rightly called attention) that 

 variation in that most domesticated of all animals, Man, ought 

 to be far greater than in animals, which, being subject to natural 

 selection, in which the fittest survives, have, in some respects, 

 a narrower field allotted to them for modification." 



" The chief factor in the transformation and diversity of form 

 of the facial muscles in Man, as opposed to the other Primates, 

 is the extensive development of the brain-case. This transforma- 

 tion alone is enough to account for changes in those muscles 

 which lie upon it. But the development of the brain is closely 

 connected with the acquisition of mental powers in Man. The 

 development of language has necessarily determined a correspond- 

 ing development of the muscles round the mouth and nose. If 

 we can only demonstrate some slight progressive development in 

 these parts something will be gained, for we shall be able to say 

 that where the higher development of Man leads us to expect 

 more complicated anatomical arrangements, these are actually 

 found. Vivacity and diversity of expression of the mouth and 

 eye are a peculiarity of Man ; they mirror forth the higher 

 psychical activity, and can only be acquired by the perfecting of 



