HETEROMORPHOSIS 169 



stimuli. When I stood the head piece upon its oral mouth 

 for but one hour, so that the mouth was in contact with the 

 bottom of the vessel, the animal would take up no food for 

 a long time (often as long as twenty -four hours) when again 

 turned over. By similar means I could bring about the^ 

 same effect at the new aboral mouth. But it was necessary 

 to keep the animal with its aboral mouth downward a much 

 longer time half a day perhaps and then the effect lasted 

 only an hour. In this experiment it cannot be that every abnor- 

 mal stimulus simply inhibits the irritability of the mouth. 

 For a series of artificial mouths made by transverse incisions 

 into an animal ate meat despite the wounds, immediately 

 after the division of the animal. The (transitory) loss of 

 the specific irritability of the mouth is probably due to the 

 contact stimuli which act upon the mouth. 1 



4. I laid pieces of Actinia which took up nourishment at 

 both ends upon the side and tried to see whether both mouths 

 would take up food at the same time. I first held a large 

 piece of meat against the aboral mouth, which .was, as 

 usual, tightly closed in consequence of the contraction of the 

 circular muscle fibers. The meat caused the mouth to open 

 and to seize and slowly crowd it into the body-cavity. 

 Before the piece of meat had been entirely swallowed I 

 offered another piece to the oral mouth. This was also taken 

 up. At the same moment the act of deglutition was inter- 

 rupted at the other mouth by a firm contraction of the ring 

 muscles. After a few moments, when the meat had been 

 crowded into the oral mouth, the musculature at the aboral 

 end relaxed and the piece of meat dropped out of the mouth. 

 When I fed the two mouths successively, that which had 

 been fed first gave up its food when the other began to take 

 up its food. Peristaltic waves seemed to pass frequently in 

 both directions in these animals in which the body-cavity 



i Or the lack of oxygen. [1903] 



