^6 M. Ehrenberg's Researches on the Infusoria. 



apparatus, or branchiae, somehow modified almost to infinity. 

 Every point of the skin more especially destined to respiration, 

 and still more the branchiae, ought especially to present the pri- 

 mitive movements, that is to say, oscillations. In the lowest 

 links of the animal kingdom, among the Protozoaires, the Infu- 

 sores exhibit in the circles of the delicate cirri with which they 

 are provided, the most convincing example of the disposition 

 just stated. The filaments, fine and transparent as glass, which 

 are found in the Leucophrys, the Kolpoda, the Vorticella, the 

 Rotiferes, and others, and which usually occasion by their ex- 

 cessively rapid oscillations, the optical illusion of a turning- 

 wheel, belongs wholly to the series of these organs."" After this 

 opinion, founded upon the principles of modern philosophy, the 

 existence of a heart and vasculatory system may not be always 

 necessary for the carrying on of respiration ; and the rotatory 

 movements of the Infusores would be a mode of perfect respi- 

 ration, since they effect in the ambiant liquid certain movements 

 of attraction and repulsion. 



After reviewing these various hypotheses, and more particu- 

 larly the last, M. Ehrenberg rejects the whole of them, and for 

 this reason, especially, that he distinguishes expressly between 

 simple movements and respiration, properly so called, and be- 

 cause, in the infusores, at least, they are two distinct processes. 

 Moreover, he cannot believe that there is in this phenomenon 

 any particular influence exerted by the ambiant medium upon 

 the body of the animal, and, without this, respiration, in any way, 

 could not take place. But instead of entering more into detail 

 concerning previously admitted doctrines on this point, M. 

 Ehrenberg proceeds at once to certain positive observations, 

 which he has been happy enough to make. Many years pre- 

 viously he had remarked a local vibration in certain points of 

 the interior of the bodies of many of the Rotatoria, and especi- 

 ally in the Brachionus urceolaris. And latterly, after having 

 informed himself concerning the direction of the internal mus- 

 cles of the body, it occurred to him that these vibrations were 

 effected by several portions of the muscular substance, which 

 induced him at the time not to attach any great import- 

 ance to their examination. It was when maintaining these 

 views that he alluded to this discovery in his first treatise on 



