366 ANNUAL OF SCIENTIFIC DISCOVERY. 



with elements purely mineral, or to animate them with the organic 

 influence. 



M. Pasteur further informs us that, in order that vegetation may be 

 developed, or fermentation produced, there must be a liquid contain- 

 ing water, a salt having ammonia as a base, a carbonaceous sub- 

 stance, and a phosphate : air is necessary only for the moment while 

 we introduce into the flask some spores of penicilium, or a little of 

 the calcined asbestos exposed to air by the process indicated above. 

 The rnycodermic (mouldy) vegetation is then developed in less than 

 a day ; and, what is particularly remarkable, it is developed in the 

 dark as well as in the light. The ordinary law does not govern these 

 little organizations, for they neither give out oxygen nor absorb free 

 carbonic acid ; but, on the contrary, they disengage carbonic acid, 

 and increase by fixing ammonia and phosphoric acid. The germs 

 which produce these marvellous effects are not uniformly distributed 

 in the air ; thus Pasteur, making comparative experiments with one 

 and the same liquid arranged in flasks completely deprived of air, 

 found that the air from the cellars of the observatory contained only 

 one-tenth part as many germs as the air from the court of that es- 

 tablishment ; and that the air contained fewer germs in proportion to 

 its elevation in the atmosphere. This chemist has performed com- 

 parative experiments in the mountains of Jura, at an altitude of eight 

 hundred metres, and in the Alps at Montanvert (Savoy), at two 

 thousand metres above the level of the sea ; and he has proposed to 

 take the air from a much greater elevation by the aid of a balloon. 



The following, in brief, are the conclusions which seem to be satis- 

 factorily deducible from Pasteur's experiments : 



1. That the air of inhabited places contains a greater relative num- 

 ber of fruitful germs than the air of uninhabited regions. 



2. That the ordinary air contains only here and there, without any 

 continuity, the condition of the first existence of generations some- 

 times considered spontaneous. Here there are germs, and there 

 there are none. 



3. There are few or many, according to the localities. Rain dimin- 

 ishes the number, but after a succession of fine days they are more 

 numerous. Where the atmosphere has been for a long time quiet, 

 germs are wanting, and putrefaction does not take place as in ordi- 

 nary circumstances. 



Gay Lussac, Schwann and Pouchet have performed various experi- 

 ments upon liquids in contact with common air, with heated air, with 

 artificial air, and with oxygen gas, using a mercurial bath to isolate 

 the substances experimented upon. Some of their results have ap- 

 peared to favor the theory of spontaneous generation. Pasteur has 

 ascertained that mercury taken from the bath in any laboratory is 

 itself loaded with organic germs. He took a globule of mercury, sur- 

 rounde'd by an atmosphere of calcined air, and passed it into a flask 

 of putrescible fluid by the process detailed in the former part of this 

 paper. In every experiment of this kind, after two days, an abun- 

 dant growth of organic products appeared. 



The same experiments were repeated with the same liquids, with 

 no change of manipulation, with the same kind of mercury, except 

 that the mercury was first heated to destroy the germs it contained, 

 and no growths whatever appeared in the flasks. 



