576 FRAGMENTS OF SCIENCE. 
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 
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 rny 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, meant, accord- 
* An actual experiment made at the Bel Alp is here described. 
