﻿80 Darwin, and after Darwin. 



And, of course, this example — like that of with- 

 drawing the feet from a source of stimulation, which 

 a frog will do as well as a man — does not stand alone. 

 Without going further a-field than this same animal, 

 any one who reads, from our present point of view, 

 Goltz's work on the reflex actions of the frog, will 

 find that the great majority of them — complex and 

 refined though most of them are — cannot conceivably 

 have ever been of any use to any frog that was in 

 undisturbed possession of its brain. 



Hence, not to occupy space with a reiteration of 

 facts all more or less of the same general kind, 

 and therefore all presenting identical difficulties to 

 ultra-Darwinian theory, I shall proceed to give two 

 others which appear to me of particular interest in 

 the present connexion, because they furnish illus- 

 trations of reflex actions in a state of only partial 

 development, and are therefore at the present moment 

 demonstrably useless to the animal which displays 

 them. 



Many of our domesticated dogs, when we gently 

 scratch their sides and certain other parts of the body, 

 will themselves perform scratching movements with 

 the hind leg of the same side as that upon which the 

 irritation is being supplied. According to Goltz l , 

 this action is a true reflex; for he found that it is 

 performed equally well in a dog which has been 

 deprived of its cerebral hemispheres, and therefore 

 of its normal volition. Again, according to Haycraft 2 , 



1 Pfliigers Archiv, Bd. xx. s. 23 (1879). 



* Brain, part xlviii, pp. 516-19 (1889). — There is still better proof 

 of this in the case of certain rodents. For instance, observing that rats 

 and mice are under the necessity of very frequently scratching themselves 

 with their hind-feet, I tried the experiment of removing the latter from 



