426 PHYSIOLOGY 



est danger and mistake lies always in that hopeless attitude of 

 mind which assumes that what is impossible now to our methods 

 and to our limited vision will remain so forever. I cannot myself 

 see any reason why the physiologist should be despondent of the 

 future, nor why he should depart in any way from the rule laid 

 down by Harvey, "to search out and study the secrets of nature 

 by way of experiment." l Those who criticise existing tendencies 

 and methods, and speak vaguely of a better way, have nothing 

 definite to offer, except a return to the barren and disastrous method 

 of speculation by way of the "inner sense." 2 



There are certain large problems in biology which, by defini- 

 tion at least, belong to physiology, but which as a matter of fact 

 do not at present form a subject of investigation by physiologists. 

 Such, for instance, are the great questions of development and 

 heredity, and the varied and important reactions between the 

 organism and its environment included under the term ecology, 

 or bionomics. The course of development in biology has been such 

 that in recent years these questions have fallen mainly into the 

 hands of the morphologists. But the methods employed by the 

 morphologists in their investigations tend to become more and 

 more experimental, and we may infer that the workers who devote 

 themselves to these problems will be compelled to have recourse 

 more and more to the technical methods of physiology. It is there- 

 fore a fair question as to whether or not it is desirable that the 

 specialist in physiology should give his attention to work of this 

 character. Burdon-Sanderson, in an address before the British 

 Association for the Advancement of Science, 1893, 3 took the ground 

 that the field of physiology proper, as determined by the course 

 of development, lies altogether in the province of what he calls 

 the internal relations of the organism, that is, "the action of the 

 parts or organs in their relations to each other." This definition 

 is at least an approximately accurate statement of the scope of 

 physiology as it has existed during the past two or three genera- 

 tions. I say approximately accurate, because as a matter of fact 

 some recognized physiological work has concerned itself with the 

 reactions between the organism and its environment, such work, 

 for instance, as the effect of external temperature upon heat pro- 

 duction, or the effects of altitude upon the elements of the blood. 

 Still the reaction to the environment has been studied by the 

 physiologist only in so far as the adaptation can be detected at once 

 or within a relatively short period of time. Those reactions that 

 are detectible only or mainly in the progeny have been left very 



1 Quoted from Pye-Smith, Harveian Oration, Nature, vol. xix, 1893. 



- Bnnge, loc. cit. 



3 Nature, vol. xix, 1893. 



