226 Atmospheric Life Germs. [April, 



with air previously heated to redness, not a single doubtful 

 result was obtained, although repeated at least fifty times ; 

 not a single trace of any organised production was seen 

 even after eighteen months, keeping at a temperature of 

 2 5° to 30 C. ; while, if the liquid be left to ordinary air 

 for a day or two, it never fails to become filled with bacteria 

 or vibriones, or covered with mould. The experiment of 

 Schwann applied to this sugar solution is, therefore, of 

 irreproachable exactitude. Schwann, however, did not 

 always succeed so well as he wished, and the experience of 

 Mantegazza and Pouchet was at variance with his general 

 conclusions ; even Pasteur himself in some experiments 

 failed to preserve his liquids. These are the particular in- 

 stances: — Five flasks of 250 c.c. capacity, containing 80 c.c. 

 of the sugar solution, were boiled, and during ebullition 

 sealed up. The points were broken under mercury, and 

 pure gases in all cases but one let into the flasks. Organisms 

 were found in every case after four days. In all these ex- 

 periments, as in those likewise of Schwann, which were 

 contrary to the result of his first experiment with extract of 

 meat, it was the mercury that introduced the germs. In 

 making such experiments with a mercury trough, preserva- 

 tion of the liquid will not always succeed, even if it succeeds 

 sometimes. If the sugar solution be replaced by milk and 

 treated by either of the methods above described, the milk 

 putrefies. These results, so different and contradictory, find 

 a natural explanation further on, but so far they are facts of 

 a troublesome nature. 



Germination of the Dust which exists suspended in the A ir, in 

 Liquids suitable to the Development of the Lowest Organisms. 

 The facts ascertained so far are : — 



1. That there exist suspended in the air organised 

 corpuscles exactly like the germs of the lowest organisms. 



2. That sugar solutions with the liquor from beer yeast, 

 a fluid extremely alterable in ordinary air, remains un- 

 changed and limpid, without even giving rise to infusoria 

 or fungi, when left in contact with air previously heated. 



The question now arises, how is it possible to sow an 

 albuminous sugar solution with germs collected by means 

 of pyroxyline in the manner already described ? 



Taking a flask containing such a sugar solution kept at 

 25 to 30° C. for one or two months unchanged, in contact 

 with previously heated air, the sealed-up end is connected 

 by means of a caoutchouc tube with one part of a T tube, 

 while another is in connection with an air-pump, and a 



