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SCIENCE 



[N. S. Vol. XXV. No. 635 



himself issued with Balfour a well-known 

 volume on the 'Embryology of the Chick,' 

 and this too as a morphological, not a phys- 

 iological, treatise. In view of these evi- 

 dences of Balfour's preoccupation with 

 morphological problems, it is interesting to 

 learn from Dr. A. C. Haddon, one of his 

 students, that Balfour always looked upon 

 this preoccupation as temporary and that 

 he intended to devote himself eventually 

 to comparative physiology. Huxley, again, 

 omitted all reference to physiology in 

 embryology when in 1878 he defined the 

 latter as 'an account of the anatomy of a 

 living being at the successive periods of its 

 existence, and of the manner in which one 

 anatomical stage passes into the next.' 

 And yet he incidentally recognized the 

 equality of physiology and morphology by 

 remarking that ' ' geology is, as it were, the 

 biology of our planet as a whole. In so 

 far as it comprises the surface configura- 

 tion and the inner structure of the earth 

 it answers to morphology; in so far as it 

 studies changes of condition and their 

 causes it corresponds with physiology." 



This supremacy of morphology continued 

 well on into the nineties, but about ten or 

 twelve years ago signs of a change began 

 to appear, and no one who has observed 

 even superficially the progress of biology 

 during the last decade can have failed to 

 perceive an immense and increasing in- 

 terest in general and comparative physi- 

 ology, accompanied by a decline of interest, 

 relatively speaking, in pure morphology. 

 Investigations in chemical physiology, 

 mental physiology, embryological physi- 

 ology, cytological physiology, comparative 

 physiology, and in the general physiology 

 of the response and the behavior of ani- 

 mals, have rapidly come to the front, while 

 the field of vegetable physiology is being 

 cultivated as never before. In its various 

 aspects general physiology is to-day prob- 

 ably receiving from investigators more at- 



tention than special or mammalian (in- 

 eluding human) physiology, and displacing 

 in the hands of zoologists, to a remarkable 

 extent, more strictly morphological studies 

 of a systematic, phylogenetic or ontogenetic 

 character. 



Twenty years ago to be a zoologist meant 

 to be a morphologist, but to-day many pro- 

 fessors of zoology are either becoming or 

 have already become veritable physiolo- 

 gists. Most of the 'experimental zoology' 

 and 'embryology' of the present is really 

 general physiology. So also are large parts 

 of physiological chemistry, physiological 

 psychology, cytology, protozoology, micro- 

 biology and bacteriology. Hygiene, clima- 

 tology, experimental medicine, pharma- 

 cology, and many other modern branches 

 of biology are also chiefly physiological 

 rather than morphological. Foster's 

 guarded prophecy of 1885 had an almost 

 hopeless tone, for he put 'most distant,' 

 and in 'the far future,' the day when 

 'perhaps' morphology and physiology will 

 come together once more; and here again, 

 for the thousandth time, prediction touch- 

 ing the future of science has proved to be 

 empty and vain— for scarcely had a score 

 of years gone by before Foster's 'most dis- 

 tant' day was already brightly dawning, 

 and physiology and morphology were again 

 'joining hands' in experimental zoology. 

 So far, indeed has this movement extended 

 that even the general biologist may now 

 claim the workers in the newer fields as 

 i m migrants into his own, pointing with 

 pride to the breadth and depth of their 

 work as justifying that still older idea of 

 physiology in which it was essentially what 

 we now call 'biology'; or even that oldest 

 idea of all, in which physiology was the 

 equivalent of the ultima thule of all these 

 sciences, 'natural philosophy' — a term hal- 

 lowed on its mathematical side by the name 

 of Isaac Newton, and in its entirety reach- 

 ing back to the pupils of Aristotle. 



