SIMPLEST FORM OF DIGESTION. 209 



tentacular filaments, which, like the tentacles of a Polype, 

 seize hold of young animalcules, or even minute Crustaceans. 

 The resemblance 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 gradually 

 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 re- 

 tracted, 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 complex 

 story of Digestion in the higher animals, episodes of masti- 

 cation, insalivation, chymification, chemical transformations 

 aiding mechanical actions ; every one is familiar with the 

 general facts. Let us only note that even milk, which con- 

 tains all the substances needed for the nourishment of the 



argtiment in fovovir of the unicellular sti-ucturo of these animals. Although I 

 have been unable, in repeated examinations, to convince myself of the existence 

 of a 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 watching these cuiTcnts, or 

 rather onclllations, carrying the lar;j:e dark globules with them into the various 

 prolongations of the body and back again, for upwards of an liour, I felt con- 

 vinced that the Amceba was a cell, or at any i"ate 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 AUEUBACH'S interesting essay. 



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