174 
M. L. PASTEUR. 
ally small and rapidly healing. As long as recovery is not com¬ 
plete, pus from these abscesses will always show the microscopic 
organism. It is then there living, acquiring its growth, but its 
propagation at a distance does not take place. The cultures already 
mentioned injected in small quantities in the jugular of guinea 
pigs, have shown that the little organism in question does not 
grow in the blood, as the day after the injection it cannot be found 
even by the means of cultures. In a general way, I will observe 
that mrobic parasites do not easily cultivate in the blood so long 
as the blood corpuscles are in a good physiological condition. I 
have surmised that this circumstance may be explained as a kind 
of a struggle between the. affinity for the oxygen of the blood 
globules and that which is proper to the parasite in its cultures. 
As long as the blood corpuscles are the stronger, that is, when 
they take up all the oxygen, the vitality and propagation of the 
parasite become very difficult, if not impossible. It is then easily 
eliminated, or, so to speak, digested. I have often witnessed these 
facts in carbuncular infections, and even in that of the chicken 
cholera, diseases which are due to the presence of an aerobic 
parasite. 
The culture of the blood from the general circulation in the 
preceding experiments being always found sterile, it would 
seem that in the state of furuncular diathesis the small organism 
does not exist in the blood. That it does not grow, for the reason 1 
have just given, and that it is not abundant in it are all matters 
of evidence, but we must not conclude absolutely from the sterility 
of the cultures I have referred to, that the little parasite is not, 
probably at one time or another carried by the blood and trans¬ 
ported from a furuncle in the way of formation, to another 
part of the body, where it can lodge, grow, and give rise to 
another furuncle, i am satisfied that if in the furuncular diathe¬ 
sis we could place in culture, not a small drop from the general 
circulation, but several gramms or more, we should often succeed 
in obtaining an abundant growth. In the numerous experiments 
I have made upon the blood of chicken cholera, I have repeatedly 
obtained proof that at the period when the small parasites of 
that disease began to rest in the blood, repeated cultures of drops 
