THE BEGINNINGS OF LIFE. 353 



then through the white-hot capillary orifice it would, 

 in fact, have been calcined as in Schwann's experiment. 

 The conditions of the experiment would thus have been 

 no less severe, and the only effect would be that the 

 vacuum (with which I prefer to work) would have been 

 rendered by so much the less complete. These remarks 

 are made with the view of meeting possible criticism. 

 It should be remembered, however, that M. Pasteur 

 always adopted this method when he wished to preserve 

 solutions for a time m vacua ] . 



After the flasks had been prepared in the way above 

 mentioned, they were kept in a warm place in which 

 the temperature could be maintained at night. Some 

 have been suspended in the air, whilst others have been 

 immersed in a water-bath heated by a spirit-lamp. So 

 far as I have been able to ascertain, the temperature to 

 which they have been subjected has mostly ranged 



1 Whenever he desired to make comparative trials with the air of 

 different localities, the solutions which had been prepared in this way 

 were considered by him to be contained in vacuo. The necks of the 

 flasks were broken in the several localities, in order that they might 

 become filled with the ordinary air of the respective places. After this 

 had been done the flasks were re-sealed and kept for future observation of 

 their contained fluids. M. Pasteur, M. Pouchet, and others who adopted 

 this method, carried away their experimental fluids in vacuo, during a two 

 or three days' journey to the Alps or to the Pyrenees, and it never seemed 

 to have occurred to either of them that evolutional changes might be 

 taking place during the interval. M. Pasteur, in fact, habitually shut his 

 eyes to all such possibilities ; they did not come within the range of what 

 he considered possible. Such thoughts might, however, have suggested 

 themselves to M. Pouchet and others, had they not imagined that 

 evolution in vacuo was an impossibility. 



A a 



