828 M. N. Lieberkuhn on the Anatomy of the Infusoria. 



in the most minute examination, he was unable to discover that 

 the contents of the contractile vesicle were expelled externally in 

 the systole. Actinophnjs is better suited to the settlement of 

 this question than a ciliated Infusorium. I have many times 

 sought for currents in the fluid surrounding Actinophrys Sol and 

 A, Eichhoj-nii, when the fluid contained masses of fine globules 

 immediately in front of the projection of the contractile reservoir; 

 but I have never seen, any more than Claparede, any correspond- 

 ing displacement when the vesicle contracted. In Bursaria 

 leucas, B. Vorticella, Paramecium Aurelia and P. Chrysalis, I 

 obtained the following results : — The contraction takes place 

 exactly in the manner described by Schmidt ; the vesicle contracts 

 i'rom the interior of the animalcule towards a point lying near 

 the surface, and it expands on the entrance of the fluid in such 

 a manner, that it increases in diameter gradually from the 

 surface of the animalcule inwards toward the centre. But does 

 this teach us what Schmidt concludes from it, that the reservoir 

 expels its contents outwardly every time when it contracts 

 toward the outside, and becomes filled from without when it 

 expands toward the interior? If the contractile reservoir is 

 attached by that part turned toward the surface of the animal- 

 cule, to the internal surface of the cortical substance, while the 

 portion projecting into the interior of the body is free in the 

 soft medullary mass, — will not the contraction take place from 

 within outwardly, and the expansion from without inward, 

 whether the fluid flow inwards or outwards ? In Actinophrys, 

 sometimes in Arcella vulgaris, and in Urostyla grandis, a totally 

 different import must be attributed to the contractile reservoir, if 

 Schmidt^s criterion be valid; for here the reservoir does not 

 contract toward the surface, but toward the interior of the 

 body, and forms an elevation on the surface when it becomes 

 filled, as described minutely in Actinophrys by both Von Siebold 

 and Claparede. But it is not on this alone that Schmidt rests 

 his opinion : he asserts that he has observed also an actual 

 external orifice of the contractile vesicle. I must admit that 

 Bursaria Vorticella has a distinct orifice at the hinder part of the 

 body, and this exactly at the place to which the contractile vesicle 

 contracts until it vanishes. But regarding this orifice which I 

 saw, only so much is established, that it is the anal orifice which 

 Ehrenberg has already described. I have seen the emergence of 

 remains of devoured substances, of loricse of Bacillarise, of fine 

 undeterminable granules, &c., from this very hole, so frequently, 

 that there can be no doubt on this point ; and it is even not rare 

 for a corpuscle to slip out from the anal orifice during the 

 diastole, — that is to say, at the very time when, according 

 to Schmidt, the fluid should flow in from the outside. I 



