THE BACTERIA. 
INTRODUCTION. 
‘¢ Corruptio unius est generatio alterius.’’ 
Lucretius, De Rerum Natura. 
Or all the studies which have for their object 
the inferior organisms, those which relate to the 
bacteria offer, without contradiction, the greatest 
interest, as they touch the most divers problems, 
which, it is true, are the most difficult and the 
least known in biology. The history of these mi- 
nute organisms is, in truth, related to that of 
spontaneous generation, to that of the fermenta- 
tions, to the pathogeny and therapeutics of a great 
number of virulent and contagious affections, and, 
in a more general manner, to all the unknown 
which, notwithstanding the efforts of modern sci- 
ence, still surrounds the origin of life and its pres- 
ervation. 
If the relation of these inferior organisms to 
the origin of livmg beings is yet obscure, their 
role in the preservation of life is better known. 
It is known that organic matter, once produced 
and become solid, so to speak, cannot again enter 
into the general current until it has undergone 
