MUSCULAR SYSTEM 115 
“ A free subcutaneous position, sheht relations to the skele- 
ton, and the absence of definite fasciz, 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 he 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 
ereat variability in the facial musculature of the lower animals 
cannot be denied @ priovz ; 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 he 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 
