POUCHET, ON ATMOSPHERIC MICROGRAPHY. 191 



sowed many other bodies, and have found, in all these cases, 

 that the atmospheric dust was never more productive than 

 they, and often even not so much so. 



It seems to me, I would say in conclusion, that whenever 

 an experimenter asserts that he collects in the atmosphere 

 ova or spores of proto-organisms, he should be required to 

 show them. Several of these germs, in fact, are perfectly 

 well known. Such, especially, as divers spores of Muce- 

 dinese, in which certain modes of illumination discover 

 microscopic characters altogether peculiar ; and the same 

 with the ova of several Polygastricae. 



[The author proposes to employ his instrument for the 

 microscopic analysis of the air of hospitals and marshes, &c, 

 and promises to communicate the results on a future occa- 

 sion.] 



