= FERMENTS, FERMENTATIONS, AND LIFE. 263 
Neither patient observations, nor minute experiments, nor 
profound reasonings, have been wanting; yet some still be- 
lieve that these little bodies grow, by spontaneous genera- 
tion, within fermentable liquids, while others assert, and 
profess to have proved, that they come from germs con- 
tained in the air. Certainly, the former opinion involves 
nothing contradictory nor impossible. Those who reject 
it by begging the question, in the name of some unknown, 
mystical doctrine of life, do not even deserve to be listened 
to in the investigation. It might possibly have occurred 
that organized beings should be produced, complete at all 
points, in a medium deprived of organization ; yet experi- 
ment proves that this does not occur. We must, then, ac- 
cept the other opinion—the panspermist doctrine—that is to 
say, we inust concede that the germs of microscopic animals 
and vegetables, with which so many fermentations and 
putrefactions are connected, exist in the air. This is one 
of the conclusions, and perhaps the most legitimate and 
most fertile one, of Pasteur’s striking studies. 
He deserves the glory of it precisely because he has not 
priority in it. In truth, the originator of this idea only 
had, and could only have, a dim intuition of it. He could 
measure neither its importance nor its consequences. The 
importance and the results of a great idea, whatever it may 
be, only become apparent when, after undergoing a cer- 
tain evolution, it has gained the precision, certitude, and 
establishment, that nothing but long experience can confer 
‘upon it. A conception must have acquired some age in 
science to wear a fixed authority, and bestow fame on those 
who comprehend, and cause to be comprehended, all its 
grandeur and power. The circulation of the blood had 
long been seen by glimpses, in the schools of physiology, | 
when Harvey gave it complete and vigorous demonstration. 
Gravitation had long invited research, and suggested pre- © 
sentiment, before Newton drew its perfect system. So, 
