576 FRAGMENTS OF SCIENGS. 



organisms. Then I snip oil 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-tvventy 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 

 degrees 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 pro- 

 duce 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.* 



What is my colleague's conclusion from the experiment 

 before us? Twenty-seven putrescible infusions, first in 

 vacuo, and afterward 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 air, that has produced the effects 

 observed? What is this something? A sunbeam entering 

 through a chink in the roof or wall, and traversing the air 

 of the loft, would show it to be laden with suspended dust 

 particles. Indeed the dust is distinctly 'visible in the 

 diffused daylight. Can it have been the origin of the ob- 

 served life? If so, are we not bound by all antecedent 

 experience to regard these fruitful particles as the germs of 

 the life observed? 



The name of Baron Liebig has been constantly mixed up 

 with these discussions. "We have," it is said, "his 

 authority for assuming that dead decaying matter can pro- 

 duce fermentation." True, but with Liebig fermentation 

 was by no means synonymous with life. It, meunt, accord- 



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



