DEC35MBER 2, 1921] 



SCIENCE 



537 



start the next; they can be modified by other 

 simultaneous responses, or by the effects left 

 behind by previous responses, and so may be 

 built up into the most complicated behavior. 

 But, owing to our very incomplete knowledge 

 of the physical-chemical events concerned, we 

 constantly, when describing the behavior of 

 living organisms, pass, so to speak, from the 

 physical to the mental series, filling up the 

 gaps in our knowledge of the one from the 

 other. We thus complete our description of 

 behavior in terms of mental processes we 

 know only in ourselves (such as feeling, emo- 

 tion, will) but infer from external evidence 

 to take place in other animals. 



In describing a simple reflex action, for 

 instance, the physico-chemical chain of events 

 may appear to be so completely known that 

 the corresponding mental events are usually 

 not mentioned at all, their existence may even 

 be denied. On the contrary, when describing 

 complex behavior when impulses from external 

 or internal stimuli modify each other before 

 the final result is translated into action, it is 

 the intervening physico-chemical processes 

 which are unknown and perhaps ignored, and 

 the action is said to be voluntary or prompted 

 by emotion or the will. 



The point I wish to make, however, is that 

 the actions and behavior of organisms are 

 responses, are characters in the sense described 

 in the earlier part of this address. They are 

 inherited, they vary, they are selected, and 

 evolve like other characters. The distinction 

 so often drawn by psychologists between in- 

 stinctive behavior said to be inherited and 

 intelligent behavior said to be acquired is as 

 misleading and as little justified in this case 

 as in that of structural characters. Time will 

 not allow me to develop this point of view, but 

 I will only mention that instinctive behavior 

 is carried out by a mechanism developed un- 

 der the influence of stimuli, chiefly internal, 

 which are constantly present in the normal 

 enviromental conditions, while intelligent be- 

 havior depends on responses called forth by 

 stimuli which may or may not be present. 

 Hence, the former is, but the latter may or 



may not be inherited. As in other cases, the 

 distinction lies in the factors and conditions 

 which produce the results. Instinctive and 

 intelligent behavior are usually, perhaps al- 

 ways, combined, and one is not more primi- 

 tive or lower than the other. 



It would be a mistake to think that these 

 problems concerning factors and environment, 

 heredity and evolution, are merely matters of 

 academic interest. Knowledge is power, and 

 in the long run it is always the most abstruse 

 researches that yield the most practical re- 

 sults. Already, in the effort to keep up and 

 increase our supply of food, in the constant 

 fight against disease, in education, and in the 

 progress of civilization generally, we are be- 

 ginning to appreciate the value of knowledge 

 pursued for its own sake. Could we acquire 

 the power to control and alter at will the fac- 

 tors of inheritance in domesticated animals 

 and plants, and even in man himself, such 

 vast results might be achieved that the past 

 triumphs of the science would fade into in- 

 significance. 



Zoology is not merely a descriptive and ob- 

 servational science, it is also an experimental 

 science. For its proper study and the prac- 

 tical training of students and teachers alike, 

 well-equipped modern laboratories are neces- 

 sary. Moreover, if there is to be a useful and 

 progressive school contributing to the advance 

 of the science, ample means must be given for 

 research in all its branches. Life doubtless 

 arose in the sea, and in the attempt to solve 

 most of the great problems of biology the 

 greatest advances have generally been made 

 by the study of the lower marine organisms. 

 It would be a thousand pities, therefore, if 

 Edinburgh did not avail itself of its fortunate 

 position to offer to the student opportunities 

 for the practical study of marine zoology. 



In his autobiography, Darwin complains of 

 the lack of facilities for practical work — the 

 same need is felt at the present time. He 

 would doubtless have been gratified to see the 

 provision made since his day and the excellent 

 use to which it has been put; but what seems 

 adequate to one generation becomes insuffi- 



