ON DIGESTION IN THE CCELENTERA. 453 



means of sections, the German observer was able to prove 

 that both on the mesenteries and the general body wall 

 the endoderm cells do swallow, probably in an amoeboid 

 manner, the food that is given to them in a finely divided 

 state. 



The general results obtain by Willem have been 

 confirmed by Chapeaux, and our knowledge of the process 

 of digestion extended by an investigation of the chemical 

 character of the digestive fluid secreted by the endoderm, 

 and its effect upon the food material. 



Chapeaux found that when the anemone Adamsia is 

 removed from the shell on which it lives, it emits a liquid 

 which contains a number of refracting vesicles and fine 

 granules. This liquid is distinctly more alkaline than sea- 

 water, and is capable of digesting fibrin and emulsifying 

 fats but exercises no action upon starch and cellulose. 

 The extracellular digestion then is due to a ferment which 



o 



acts in an alkaline medium. 



When particles of litmus are injected into an anemone 

 they are greedily taken up by the endoderm cells and 

 acted upon by some acid secretion within the cell-substance. 

 When olive oil is injected it becomes rapidly emulsified, 

 and in the course of from five to twelve hours the endo- 

 derm cells become gorged with fatty granulations. Small 

 particles of fibrin are in like manner taken up by these 

 cells and rapidly digested. The intracellular ferment, 

 however, does not, according to Chapeaux's investigations, 

 effect any change in cellulose, and fragments of Cladophora 

 and Ulva are rejected intact after remaining twelve hours 

 in the ccelenteron. 



Chapeaux is of opinion that the mesenterial filaments 

 as well as the general endoderm take part in this process 

 of intracellular digestion, but his statements on this point 

 are not accompanied by any figures, and must be received 

 with caution. 



The results of Chapeaux's investigations, that there is 

 an extracellular alkaline digestion of fibrin on the one hand, 

 and a subsequent intracellular acid digestion of fibrin on the 

 other, are undoubtedly of great interest, and will, it is to 



