540 ON THE THEORY OF THE VERTEBRATE SKULL 



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 b)- the ablest anatomists of the time, are still unsettled ; the 

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

 apparently inextricably confused subjects, which the philosophic 

 anatomist 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 

 fitness of the method by which their interrogation of nature was 

 conducted. 



I apprehend that it has been and is, too often forgotten that 

 the phrase " Theory of the Skull " is ordinarily employed to denote 

 the answers to two very different questions ; the first. Are all 

 vertebrate skulls constructed upon one and the same plan ? — the 

 second, Is such plan, supposing it to exist, identical with that of the 

 vertebral column ? 



It is also forgotten that, to a certain extent, these are independent 

 questions ; for though an affirmative answer to the latter implies the 

 like reply to the former, the converse proposition by no means holds 

 good ; an affirmative response to the first question being perfectly 

 consistent with a negative to the second.^ 



As there are two problems, so there are two methods of obtaining 

 their solution. Employing the one, the observer compares together 



1 There is a wide difiference, too, in the relative importance of either question to the 

 student of comparative anatomy. Unless it can be shown that a general identity of con- 

 struction pervades the multiform varieties of vertebrate skulls, a concise, uniform, and 

 consistent nomenclature becomes an impossibility, and the anatomist loses at one blow the 

 most important of aids to memory, and the most influential of stimulants to research. The 

 second question, on the other hand, though highly interesting, might be settled either one 

 way or the other without exerting any very important influence on the practice of comparative 

 anatomy. 



