Organic Connection Between Physical and Psychical 251 



way. The preeminently racial utility and hereditary char- 

 acter of instincts is certainly one of the most interesting 

 things about them for the present discussion. 



Variability of Subrational Activities 



The third certainty about reflex and instinctive activities 

 is that they are by no means so stereotyped and invariable 

 as older cursory observation or as much theorizing, espe- 

 cially about tropisms and instincts, has held them to be. 

 Darwin, in the notable chapter on Instinct in The Origm of 

 Species, was the first to attack seriously the notion of such 

 invariability in dealing with instincts. He undertook to 

 show that the instinctive type of activity is subject to vari- 

 ation just as are all other aspects of animal life. 



A telling set of recent investigations under this head is 

 by the Peckhams. That on the solitary wasp, Ammophila 

 urnaria, is particularly to the point because the earlier 

 writers had used its habits of paralyzing caterpillars by 

 stinging them and storing them up as food for its young to 

 illustrate the undeviating and unerring character of in-. 

 stincts. But the extensive studies of these entomologists 

 led them to write: "The one preeminent, unmistakable and 

 ever-present fact is variability. Variability in every par- 

 ticular in shape of the nest and the manner of digging 

 it, in the condition of the nest (whether closed or open) 

 when left temporarily, in the method of stinging the prey, 

 in the degree of malaxation, in the manner of carrying the 

 victim, in the way of closing the nest, and last, and most im- 

 portant of all, in the condition produced in the victims by 

 stinging." 7 



No present-day authority so far as I know contends that 

 instincts operate in a hard-and-fast manner comparable to 

 the workings of any man-made machine. They are now 

 universally recognized to be subject to the same general 



