M. F. Dujardin on the Digestive Organs of Infusoria. \*5 



cognise the generative organs in all the Infusoria, and the 

 locomotive filament of the Monadince and the Euglence, &c. 

 Now would not a fact as important as that which served as 

 basis to the physiology and classification of the Polygastrica 

 deserve, not only ten, but even a hundred confirmations ? 

 Ought it not to have been confirmed a hundred times with 

 the means of observation, which the author informs us has 

 become more and more powerful in his hands ? Ought it not 

 to be especially clearly expressed in most of his figures so as 

 to be capable of being verified ? Far from this, the fact, di- 

 minished and almost entirely disappearing in the vast extent 

 of the grand treatise on Infusoria, is limited to the same ex- 

 amples previously cited and become in some sort superan- 

 nuated by the very deed of the author. And M. Ehrenberg, 

 not condescending to reply to the objections made to him al- 

 ready for many years since, traverses the continent to go and 

 hear at Newcastle in presence of the British Association ob- 

 jections no less forcible. 



I attempted in 1835 (Ann. Sc. Nat. Dec.) to prove the non- 

 existence of the intestine in Infusoria by this sole fact; — that to 

 be so extensible and contractile as supposed, it ought to con- 

 tain in its tissue at least some fibres which would remain and 

 become visible when the animalcule decomposed by difHuence. 

 Now I said that in this kind of dissolution not one single 

 trace of intestine can be perceived, and this phenomenon of 

 cliffluence moreover tends to prove in every way the simplicity 

 of the organisation of the Infusoria. Having seen in 1836 

 several Nassulce swallow some long fragments of Oscillatoria 

 which were curved in the interior and distended the animal- 

 cules in the form of a sac, I cited this fact in a subsequent 

 memoir, as proving, it is true, the deglutition which I was wrong 

 in previously denying, but also as quite incompatible with the 

 hypothesis of an intestine and true stomach. In fact I no- 

 ticed other vesicles containing fragments of Oscillatoria at the 

 same time entirely independent one of the other ; and the large 

 vesicle excavated by the elasticity of the Oscillatorium com- 

 municated in its entire breadth with the mouth and not by a 

 tube or branch of the central canal. The objection which I 

 then made against the existence of an intestine, the fibres of 



