ANALYSIS OF CONTINENTAL JOURNALS. 
761 
and delicate than the determination of the intimate agents of 
virulence ? No; therefore the necessity, in studying this sub¬ 
ject experimentally, for exercising the greatest care in collect¬ 
ing the elements of the demonstration thatthis study furnishes. 
Everything is to be gained by this carefulness, everything to 
be lost by its neglect. In being too indifferent with regard 
to the positive proofs necessary to transform into demon¬ 
strated propositions certain hypothetical notions, we some¬ 
times place a wrong value upon very interesting researches. 
Take, for instance, from among those works which are most 
closely allied to our subject, the important investigations of 
Davaine on the motionless bacteria of anthrax. 
Are these bacteria, as Davaine maintains, the essential 
cause of, and the agents that transmit the disease to the 
animals experimented upon ? I have no reason to doubt it; 
and you will find in the course of the conferences that I fully 
accept Davaine's interpretation. 
Nevertheless, there is no more justification for affirming, in 
the scientific sense of the word, this interpretation, as it only 
rests on a single order of facts : those which show the parallel 
development of motionless bacteria and the symptoms of 
anthrax in the inoculated animals. If the inoculating matter 
contained nothing more than these elementary organisms, 
this would of course be a direct and peremptory demonstration 
of the part attributed to them; but it is not so. When 
anthrax blood is introduced beneath the skin of the animal, 
the creature is inoculated not only with bacteria but many 
other substances. Who knows that it is not to one of these 
substances that the production of anthrax is due ? Who will 
prove that the multiplication of the bacteria is only a simple 
epiphenomenon ? We shall have occasion to speak presently 
of a really virulent malady, with eventual development of 
bacteria in the inoculable fluids, in the blood itself; but in 
which these bacteria are absolutely foreign to the specific 
activity of the humour. Since we allude to this example, 
we cannot leave it without having exhausted all the sources 
of information it can furnish us with regard to the subject 
now under examination ; and pointing out the necessity of 
applying, with the greatest rigour, the principles of the me¬ 
thod which should preside in researches of this kind. 
The author of the work on the bacteria of anthrax is too 
enlightened not to have perceived that his task had everything 
to gain by a peremptory demonstration of the important part 
attributed to these proto-organisms. The best course would 
doubtless have been to isolate these bacteria, and experiment 
