308 FRAGMENTS OF SCIENCE. 



practical contact with either animal or vegetable life. 

 I stand carefully to leeward of the flasks, for no dust 

 or particle from my clothes or body must be blown 

 towards them. An assistant ignites the spirit-lamp, 

 into the flame of which I plunge the pliers, thereby 

 destroying all attached germs or organisms. Then I 

 snip off the sealed end of the flask. Prior to every 

 snipping the same process is gone through, no flask 

 being opened without the previous cleansing of the 

 pliers by the flame. In this way we charge our seven- 

 and-twenty flasks with clean vivifying mountain air. 



We place the fifty flasks, with their necks open, 

 over a kitchen stove, in a temperature varying from 50 

 to 90 Fahr., and in three days find twenty-one out of 

 the twenty-three flasks opened on the hayloft invaded 

 by organisms two only of the group remaining free 

 from them. After three weeks' exposure to precisely 

 the same conditions, not one of the twenty-seven flasks 

 opened in free air had given way. No germ from the 

 kitchen air had ascended the narrow necks, the flasks 

 being shaped to produce this result. They are still in 

 the Alps, as clear, I doubt not, and as free from life as 

 they were when sent off from London. 1 



What is my colleague's conclusion from the experi- 

 ment before us ? Twenty-seven putrescible infusions, 

 first in vacuo, and afterwards supplied with the most 

 invigorating air, have shown no sign of putrefaction 

 or of life. And as to the others, I almost shrink from 

 asking him whether the hayloft has rendered them 

 spontaneously generative. Is not the inference here 

 imperative that it is not the air of the loft which is 

 connected through a constantly open , door with the 

 general atmosphere but something contained in the 



1 An actual experiment made at the Bel Alp is here described. 



