TRANSMISSION OF MODIFICATIONS 397 



too much to say that in the last analysis instinct is a function 

 of structure ; that the ultimate causes of instinctive acts lie in 

 the nature and the surroundings of the protoplasm, its internal 

 activities upon the one hand and its natural reactions to accidental 

 contact with outside forces upon the other. 



If this be true, then the causes of instincts lie in the structure 

 of the organism, using the word "structure" in its broadest 

 sense, chemical and physiological as well as anatomical. Thus if 

 a new creature should suddenly be created, its instincts could be 

 fairly well foretold by any one who knew the morphology of its 

 structure and the nature of its protoplasm. Three fundamental 

 facts should be borne in mind in this connection : 



1. Any living being will make use of any organ, part, or 

 faculty with which it is endowed by birth. 



2. The impulse to make use of a part may arise either from 

 within (desire) or from without (light, heat, chemical action, 

 gravity, electricity, contact). 



3. Manifestly the acts of an organism are limited to its natural 

 organs and faculties. Therefore instincts, like intelligent acts, 

 differ, being restricted to the range of natural endowment, a 

 restriction which no amount of " willing " will remove or modify. 



Intelligence not necessary to the control of even complicated 

 acts. At first thought it seems incredible that a long and com- 

 plicated series of acts, culminating in a purposeful end, can be 

 directed by any other agency than intelligence. Yet such is the 

 fact, and a mistake at this point has led more than one evolu- 

 tionist into fatal error. 



When we see an insect light upon a particular part of a partic- 

 ular animal, sting it perhaps in such a manner as to paralyze but 

 not to kill, drag it to a cavity wherein eggs have been deposited, 

 store it away as food for the larvae, seal all up safely as if with the 

 greatest care, it is difficult not to attribute the highest intelligence 

 and the most careful foresight to so remarkable a series of acts. 



Yet we are not to be deceived by the attitude of busy pre- 

 occupation or the appearance of intelligent effort. Acts as com- 

 plicated as these are going on about us every day, with no sug- 

 gestion of intelligent control. The growth of the embryo in 

 utero, and the vital processes generally, are even more orderly 



