BEDROCK 



improved and elaborated by the selection of individuals with 

 nervous systems which compelled them to perform actions that 

 were more and more helpful in the struggle for life. 



Bergson, in his interpretation of instinct as " sympathy," relies 

 much on the well-known, wonderful procedure of the Ammophila, 

 a " Fossorial wasp," or " sand-wasp," which is believed to paralyse 

 its caterpillar prey by stinging the nerve-ganglia of the ventral 

 chain. Naturalists generally, following Fabre, have believed that 

 caterpillars thus treated will " keep " and serve as food for the grub 

 that presently hatches from the Ammophila 's egg, and will at the 

 same time be unable to do any harm by vigorous movements. 

 Much has been written about the instinct itself, and the wonderful 

 anatomical knowledge supposed to be possessed by the parent wasp. 

 But there has been great exaggeration. Thus Dr. and Mrs. Peck- 

 ham wrote after a careful study of these instincts in the American 

 species : — 



" The general impression that remains with us ... is that 

 their complexity and perfection have been greatly over-estimated. 

 We have found them in all stages of development and are con- 

 vinced that they have passed through many degrees, from the 

 simple to the complex, by the action of natural selection. Indeed, 

 we find in them beautiful examples of the survival of the fittest." * 



It is even doubtful, as it seems to the present writer, whether the 

 Ammophila does, in fact, possess the exact knowledge that has been 

 assumed. 



The nervous ganglion of a caterpillar is a minute object, and it 

 would be extremely difficult to prove that the sting had entered it. 

 It might, perhaps, be shown by microscopic sections, or by finding 

 the puncture in the skin and studying its exact relation to the under- 

 lying parts. So far as I am aware, no such convincing test has been 

 applied, and it is probable that the recorded observations merely 

 show that the poison is effective if injected by the sting anywhere 

 in the neighbourhood of the nervous centres. This interpretation 

 is supported by what we know of the methods of Fossorial wasps 

 allied to Ammophila in their attacks upon huge spiders. Here the 

 first sting is given in the rough-and-tumble of a terrific fight, when 

 it would appear to be impossible for the wasp to puncture any organ 



* Instincts and Habits of Solitary Wasps, Madison, "Wis., 1898. 



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