SIMPLEST FORM OF DIGESTION. 221 



The outer layer is formed into long tentacular filaments, 

 which, like the tentacles of a Polype, seize hold of young 

 animalcules, or even minute Crustaceans. The resem- 

 blance to the Polype is carried further : no sooner does 

 one of the filaments seize a prey than it retracts ; all 

 the others bend their points over the captive, and grad- 

 ually enclose it ; they then retract, and bring the food 

 in contact with the body of the animal. The point of 

 contact is next seen to yield inwards, retracting as the 

 filaments had retracted, and, as it deepens, the food 

 sinks into the substance of the body, the edges of the 

 cavity closing over it. In the centre of the body the 

 soluble parts are dissolved, the body having resumed 

 its original appearance. This done, the insoluble parts 

 make their way out, much as they made their way in ; 

 and thus the whole process of ingestion and egestion is 

 accomplished. 



We need not pause to trace the episodes of the com- 

 plex story of Digestion in the higher animals, episodes 

 of mastication, insalivation, chymification, chemical 

 transformations aiding mechanical actions ; every one 

 is familiar with the general facts. Let us only note 



distinct membrane, optical delusion being easy in this matter, I cannot 

 resist the conclusion that something of the kind does exist, inasmuch 

 as there are currents inside the body of the Amoeba; and after watch- 

 ing these currents, or rather oscillations, carrying the large dark glob- 

 ules with them into the various prolongations of the body and back 

 again, for upwards of an hour, I felt convinced that the Amoeba was a 

 cell, or at any rate a closed cavity with liquid contents. As regards 

 what is said in the text, the point is of no importance ; and this note 

 is" mainly added for the sake of directing the reader's attention to 

 Auerbach's interesting essay. 



