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 
onlyan 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.' 
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 
10r the lack of oxygen. [1903] 
Digitized by Microsoft® 
