50 M. EL enberg's Researches on the Infusoria. 



exhibit many contractile organs, the power of self-division exists. 

 Perhaps the contractile organ being twofold in these last, is 

 only the commencement or preparation for the division of the 

 body which is speedily to be effected. 



Hence M. Ehrenbcrg concludes, that these contractile and 

 vesicular organs, which are provided with radiating canals, and 

 which are observed in the polygastric Infusoria, perform the 

 function of fecundation, which is accomplished in the interior of 

 the body by their conducting the seminal matter. The opaque 

 body also, which is mentioned above, and which in many spe- 

 cies is placed in the middle of the abdomen, he supposes to be 

 the testicle. He moreover supports this view by comparing the 

 convulsive movement of the vesiculae seminales of the Mammi- 

 ferae, and recognising in the Infusores similar contractions of the 

 organ just described, agreeing perfectly with the functions as- 

 signed to them. 



; It can scarcely be supposed that these contractile organs, pro- 

 vided with radiated canals, can be considered as respiratory or- 

 gans, or as hearts, because their movements are too slow, and it 

 is notorious that the motions of the heart, and the circulating 

 fluids, are more rapid and more uniform in small animals than in 

 great ones. Any one may be satisfied that the pulsations of the 

 heart in the Daphies, and the circulation in the Distomes and the 

 Planaries, are much more rapid than the movements we have 

 been considering. Before it could be admitted that these organs 

 were the respiratory apparatus, it would be previously necessary 

 more distinctly to establish the vascular system in the Infusores* 

 Although traces of a very delicate vascular system have been 

 observed in the Paramecia, it is clear there can be no discussion 

 at present concerning the circulation in this class of animals, 

 since the existence of canals in which this circulation might take 

 place has not yet been determined. 



Having demonstrated the existence of these contractile organs, 

 M. Ehrenberg well remarks, that there was no necessity for his 

 going further, or drawing any conclusions at all. At the same 

 time, as the reproductive powers of the Polygastrica, as he had 

 previously demonstrated by experiments, are so prodigiously 

 great, he conceives it warrants him in drawing this inference ; and 

 that he can scarcely deceive himself when he admits that these 



