I7Z 



THE QUARTERLY REVIEW OF BIOLOGY 



consequent new position of total equilib- 

 rium. In each kind of animal this 

 complex equilibrium is different; in any 

 two closely related species the equilibrium 

 has taken a different cast or set; and the 

 differences increase as we pass in succession 

 from the species to the genus, from the 

 genus to the family, and so on. We 

 know, too, that these equilibrium differ- 

 ences are even tied up with chemical 

 differences in the body proteins of the 

 various organisms. Now, experience has 

 amply taught us that the structural 

 parts of any animal may be crudely 

 mutilated without damage to the essential, 

 specific or phylogenetic, equilibrium. So, 

 too, did the atoms of terrestrial chemistry 

 remain in equilibrium, notwithstanding 

 all kinds of apparent rough usage, until 

 Rutherford discovered a means of bom- 

 barding them in a special way. We may 

 not yet have hit upon the proper type of 

 bombardment effectively to upset the 

 specific or phylogenetic equilibrium. We 

 may not be clear as to what constitutes an 

 acquired character in the sense of phylo- 

 genetic modification, and in our experi- 



mental attempts at phylogenetic modifica- 

 tion we may have been dealing only with 

 trivial characters, not with any of the 

 pivotal equilibrium-deciding factors. 



Mere speculation is however a profitless 

 matter. Enough has perhaps been said 

 to enable a physiological reader to realize 

 that his subject is intimately involved and 

 can render important assistance in some 

 of the wider issues concerning comparative 

 anatomy and the process of evolution. 

 The great service rendered by comparative 

 anatomy, apart from furnishing material 

 in proof of evolution, has been to raise 

 problems which it does not of itself 

 possess the means of solving. Without 

 recourse to experiment the ultimate issues 

 must necessarily remain unsettled. The 

 eventual solution of the broad problem of 

 adaptation, or what we have here called 

 plasis, would seem to lie with the physiol- 

 ogist, provided only that he were willing 

 to give his deliberate attention to com- 

 parative problems. It might equally be 

 with the comparative anatomist, pro- 

 vided he should adopt the discipline and 

 the methods of physiology. 



LIST OF LITERATURE 



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 Bensley, R. R. 1914-1915. Harvey Lectures, 



Series X, (2.50-Z89). 

 Bolton, J. S. 1900. Phil. Trans. Roy. Soc, Sec. 



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London, E. Arnold, (Z84-350). 

 Braus, H. 1904. Verhandl. d. Anat. Gesel., 



Anat. Anz., Erg— Bd., xxv, (53-65). 



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Brodmann, K. 1903-1907. Journ. f. Psychol, u. 



Neurol., Bd. z, 4, 6, io, various communications. 

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Localisation of Cerebral Function. Cambridge 



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(67-74)- 



Gaupp, E. 1913. Kultur der Gegenwart. Zellen- 



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Lankester, E. Ray. 1870. Ann. Mag. Nat. Hist., 



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