POUCHET, ON ATMOSPHERIC CORPUSCLES. 259 



undergoing fermentation ? I have not yet arrived at any- 

 fixed conclusion with respect to these grave questions. I am 

 endeavouring to pursue the inquiry with all the attention it 

 merits j hut the really capital difficulty of these studies con- 

 sists in the isolated, individual production of the various 

 ferments. I may assert that there are a great many distinct, 

 organized ferments, which excite chemical transformations, 

 varying according to the nature and organization of the 

 ferment. But in most cases the nutriment suitable to 

 some allows of the development of others of them, whence 

 arise the most complicated and the most variable phenomena. 

 If we could only isolate one of these ferments, in order 

 to develop it by itself, the chemical transformation cor- 

 responding to it would take place with remarkable precision 

 and simplicity. 



I shall, in a short time, give a new instance of this, in 

 describing the organized ferment proper to the fermentation 

 termed "viscous." 



Researches on the Corpuscles introduced by the Atmo- 

 sphere into the Respiratory Organs of Animals. By 

 M. F. Pouchet. 



('Comptes Rendus, 5 1860, p. 1121.) 



I have thought for a long time that the study of the 

 bodies conveyed by the air into the respiratory passages of 

 animals would offer interesting physiological results, and 

 throw considerable light upon the subject of atmospheric 

 Micrography. Nor have I been deceived in this. In fact, 

 in almost every class of animals, the examination of the 

 respiratory apparatus clearly reveals the various modifi- 

 cations of the medium inhabited by them. But it seemed 

 to me that the most important notions on this subject would 

 be presented in those animals in which the air penetrates 

 the most deeply into the organism. Birds, consequently, 

 have become the objects of particular attention, seeing that 

 in them the air, after traversing the lungs, pervades not only 

 the different cavities of the trunk, but reaches also the inte- 

 rior of the osseous system. In these animals I have devoted 

 particular attention to the examination of the bones which 

 contain most air, and chieflv to the humerus. And as in 



