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XI 



would contain such an enormous number of these 

 germs, that it would Be a continual fog. But M. 

 Pasteur replied that they are not there in any- 

 thing like the number we might suppose, and that 

 an exaggerated view has been held on that subject; 

 he showed that the chances of animal or vegetable 

 life appearing in infusions, depend entirely on the 

 conditions under which they are exposed. If they 

 are exposed to the ordinary atmosphere around 

 us, why, of course, you may have organisms ap- 

 pearing early. But, on the other hand, if they are 

 exposed to air at a great height, or in some very 

 quiet cellar, you will often not find a single trace 

 of life. 



So that M. Pasteur arrived at last at the clear 

 and definite result, that all these appearances are 

 like the case of the worms in the piece of meat, 

 which was refuted by Kedi, simply germs carried 

 by the air and deposited in the liquids in which 

 they afterwards appear. For my own part, I con- 

 ceive that, with the particulars of M. Pasteur's ex- 

 periments before us, we cannot fail to arrive at his 

 conclusions ; and that the doctrine of spontaneous 

 generation has received a final coup de grdce. 



You, of course, understand that all this in no 

 way interferes with the possibility of the fabrica- 

 tion of organic matters by the direct method to 

 which I have referred, remote as that possibility 

 may be. 



