BRAIN PHYSIOLOGY OF WORMS 361 



area from one which was protected from the light it at once 

 turned about. 



Strange to say the reaction-time to light is not markedly 

 greater in decapitated angleworms than in normal animals. 

 The experimental animals were contained in a dark box in 

 which they could without being jarred be suddenly exposed 

 to diffuse daylight. Three to eighteen seconds after the 

 entrance of the light the decapitated angleworms first began 

 to move. It took about the same time in normal worms. 



Lumbricus foetidus lives in decaying straw and manure, and 

 it can readily be assumed that the chemical nature of certain 

 substances contained in the straw and manure holds the 

 animals that in other words they are positively chemo- 

 tropic to the substances. I could readily show that when 

 one-half of the bottom of a box was covered with white moist 

 filter-paper and the other half with a thin layer of decaying 

 straw, the normal worms which were laid upon the filter- 

 paper were soon all collected upon the manure. The poste- 

 rior pieces of transversely severed worms behave in exactly 

 the same way. When they were laid upon the filter-paper 

 they were not directly attracted by the odorous substances 

 contained in the manure. As soon, however, as they came 

 in contact with the manure in their progressive movements 

 they crept upon it, and once upon it they did not leave it 

 again. In this way it soon happened that all the brainless 

 worms were collected, without exception, upon the manure. 

 When they were laid upon a heap of decaying straw, they 

 soon buried themselves in it. That was not alone the effect 

 of the light, for the reaction occurred also in the dark. 



VII. EXPERIMENTS ON LEECHES 



If a leech is cut in two transversely the two pieces show 

 entirely different reactions. The wound soon heals and the 

 pieces may live a year or more without however, as is well 



