232 Atmospheric Life Germs. [April, 



says, the air would be so loaded with organic matter as to 

 form a thick fog. Strong as this reasoning is, it would be 

 still stronger if it were shown that different forms of life are 

 derived from different germs : this may be so, but it has not 

 been proved. 



Experimental proof of this statement, the error in which 

 lies in gross exaggeration, was made by sealing up during 

 ebullition flasks of 250 c.c. capacit}' containing about 80 c.c. 

 of various liquids. On breaking the points of these flasks 

 in certain noted places, the air entered with a rush into the 

 empty space, carrying the germs along with it ; after re- 

 sealing, the flasks were placed in a warm situation and any 

 change noted. In some cases the decomposition followed, 

 and the production of the usual forms of life ; in other cases 

 the flask remained as if they had been filled with heated air, 

 quite unchanged. In two experiments made in the open air 

 after a slight shower in the month of June, both resulted in 

 the production of organisms ; in four others, after a heavy rain 

 in the same place, two of the flasks had their contents remain 

 unchanged for at least thirteen months afterwards. These 

 experiments were made, it is easily seen, in an agitated air, 

 but Pasteur carried his labours into the cellars of the Paris 

 Observatory, where the air is quite still except when agi- 

 tated by the movements of the experimenter, and in that 

 region below the surface of the earth where the temperature 

 is unaffected by the changes of the seasons. It is to be 

 expected that air, in which there is so little to cause its dis- 

 turbance, would have deposited on the ground the germs 

 which at one time floated in it. A greater proportion of 

 flasks therefore, if opened and re-sealed in such an atmo- 

 sphere, should have their contents preserved. Out of ten 

 experiments made under such conditions with yeast water, 

 in only one was any living thing found ; while eleven expe- 

 riments made in the court-yard of the observatory at a 

 distance of 50 centimetres from the ground, and at the same 

 time, rendered in every case the usual forms of life ; a modi- 

 fication of these trials was made by letting air into flasks of 

 liquid at various mountain heights. Eighty-three flasks, 

 prepared in the manner already mentioned, were expe- 

 rimented on : twenty of these were filled up with air at the 

 foot of the heights which form the first plateau of the Jura ; 

 twenty others on one of the peaks of the Jura, 850 metres 

 above the sea-level ; and the remaining twenty were carried 

 to Montanvert, near the Mer de Glace, at an elevation of 

 2000 metres. The result was, that of the twenty opened on 

 the lowest level, eight contained organisms ; of the twenty 



