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two manifest, but a young skull may be readily separated into a 

 number of segments, in each of wbicli it requires but little imagina- 

 tion to trace a sort of family likeness to such an expanded vertebra 

 as the atlas. 



What can be more natural then than to take another step to con- 

 ceive the skull as a portion of the vertebral column still more altered 

 than the sacrum or the coccyx, whose vertebrae are modified in corre- 

 spondence with the expansion of the anterior end of the nervous 

 centre and the needs of the cephalic end of the body, just as those 

 of the sacrum are fashioned in accordance with the contraction of 

 the nervous centre and the mechanical necessities of the opposite 

 extremity of the frame ? 



Two generations have passed away since, perhaps, by some such 

 train of reasoning as this, such a conception of the nature of the 

 vertebrate skull arose in the mind of the philosophic poet, Goethe ; 

 and a somewhat shorter period has elapsed since a poetical, or per- 

 haps I might more justly say a fanciful, philosopher, Oken, published 

 a " Theory of the Skull " embodying such a conception ; and since 

 the excellent Dumeril allowed a like hypothesis to be strangled in 

 the birth by the small wit of a French academician. 



The progress of modern science is so rapid, that one is unac- 

 customed to see half a century elapse after the promulgation of 

 a doctrine, which is capable of being tested by readily accessible 

 facts, without either its firm establishment or its decisive overthrow. 

 But nevertheless, at the present day, the very questions regarding 

 the composition of the skull, which were mooted and discussed so 

 long ago by the ablest anatomists of the time, are still unsettled ; the 

 theory of the vertebrate skull is one of the most difficult and, appa- 

 rently inextricably confused subjects, which the philosophic anato- 

 mist can attack, and in consequence, not a few workers in science 

 look, somewhat contemptuously, upon what they are pleased to term 

 mere hypothetical views and speculations. 



Indeed, though the germ of a great truth did really lie in these 

 same hypotheses, its late or early development into a sound, and 

 consequently fruitful, body of doctrine depended upon the manner in 

 which biologists set about solving the problem presented to them ; 

 upon the clearness with which they apprehended the nature of the 

 questions they wished to put, and the consequent greater or less 



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