168 CIIILODON AND PARAMECIUM. 



different interpretation of the relation of parts, and yet not de- 

 tracting in the least from the reliability of Ehrenberg as a micro- 

 scopic observer. 



Suppose, for instance, that a solid body were hollowed out in 

 such a way as to leave numerous projections pointing toward 

 the centre, the effect when seen in profile would be to give it 

 the appearance of being divided part way across by numerous 

 partitions which separate as many little side-chambers, and thus 

 you would have the same aspect presented as that represented 

 here, with this exception, that in the Chilodon (fig. 98) it is, ac- 

 cording to Ehrenberg, a sort of bag whose thickness is puckered 

 or drawn out into little side-pockets, and the whole suspended 

 within the body of the animalcule. As I said, the appearance is 

 nearly the same in both ; but the possibility for the circulation 

 of the food is far more easily conceived in the supposititious body 

 than in the other ; and such do I believe to be the true state of 

 the digestive system, rather than as our author has avowed. By 

 Ehrenberg's theory, the pellets of food would have to pass from 

 one pouch toward the centre of the body and then outwards 

 into the next pouch, and then again in the same way into the 

 next and the next, and so on in a very tortuous course, all along 

 one side of the body backwards and along the other side for- 

 wards, in order to complete such a circuit as you have had illus- 

 trated in Paramecium ; whereas in this latter it progresses in an 

 even tenor, almost insensibly gliding, from the right to the left, 

 from one end of the body to the other, and yet this could be 

 done notwithstanding the presence of the above-mentioned pro- 

 jections which I believe to lie across the path, and which falsely 

 seem to be the walls of numerous side-chambers.* 



The system which is analogous to the blood-circulation of the 

 higher animals is represented in Paramecium by two contractile 

 vesicles, (fig. 96, cv, cv l , i, n, in.) both of which have a degree 



* By killing this infusorian with a drop of the extract of opium, the effect is 

 to partially condense the circulating contents, when the same appearance is pre- 

 sented as Ehrenberg has represented for the form of the digestive system of 

 Trachelius ovum ; but the lateral branches are much more numerous in the 

 former. 



