362 ANNUAL HECOKD OF SCIENCE AND INDUSTRY. 



little or nothing of their primitive freshness. When the 

 flasks containing the pntrescible matters terminated in tubes 

 provided with cotton-wool, or which were recurved many 

 times upon themselves, and whose tapered points were her- 

 metically sealed so that at any given moment, by breaking 

 the points, their contents could be exposed anew to contact 

 with the air deprived of germs he found that, by waiting 

 until the contents had arrived at a state of complete inertia 

 before establishing this contact, the air no longer produced 

 the least phenomenon of putrefaction or appreciable altera- 

 tion ; proving that the Bacteria, as well as their germs, were 

 not only dead, but that the organic matters are not suscep- 

 tible of spontaneously producing others. 



Organisms Suspended in the Atmosphere. 



M. P. Miquel, after alluding to the statements of M. Charles 

 Robin, that the atmosphere contains (besides all kinds of de- 

 bris) spores, pollen, skins of insects, and (rarely) eggs of In- 

 fusoria, and also to the experiments of Drs. Madclox and Cun- 

 ningham, describes his own newly contrived " aeroscopes," by 

 means of which he collected from 500 to 120,000 organized 

 cellules per cubic meter of air; thus showing the atmosphere 

 to contain at least 100 times more germs than Drs. Maddox 

 and Cunningham have stated. M. Miquel states two gen- 

 eral facts as applicable to all organized corpuscles of the 

 atmosphere whose diameter is greater than the -5^- of a mil- 

 limeter : 



1. The average number of Microlria of the air, small in win- 

 ter, augments rapidly in spring, remains nearly stationary in 

 summer, and diminishes in autumn. 



2. Rain always provokes the recrudescence of these Micro- 

 bia. The increase brought about by rain is not simply sen- 

 sible, it is often surprising. For example, in summer, when 

 to great heat succeeds a storm, or a rain somewhat sus- 

 tained, the instruments, which the day before recorded 5000 

 to 10,000 germs, record more than 100,000 the next day. 

 Temperature and moisture seem the principal causes of vari- 

 ation in micro-germs in our atmosphere. The cellules most 

 diffused in the air are undoubtedly spores of the Mucedinm ; 

 then fructifications of certain fungi; then come pollens of 

 variable size and color; and, lastly, green alga?, voluminous 



