CONTRIBUTIONS TO THE STUDY OF SWINE PLAGUE, ETC. 320 
nesses’ animals. One must remark that these experiments 
were only few and that the virus had but little activity, kill¬ 
ing animals only after seven days. 
Let us, to finish, mention the contradictory conclusions of 
Canera (17), of Bunzl-Tedern (15), on the subject of the iden¬ 
tity of swine plague, hog cholera, swin pest, the researches of 
Veranus Alva Moore upon the morphology of the microbes, 
and then look at the work of Metchnikoff upon the microbe 
of the French hog cholera, who confirmed the results obtained 
by Selander with the toxine of swin pest, and observed that in 
rabbits, the blood heated produces the same symptoms as 
the virus. In the serum of vaccinated animals the microbe 
grows with its normal aspect; the serum likewise has no in¬ 
fluence upon the toxine, but it confers immunity against the 
microbe of hog cholera to fresh rabbits when it is injected into 
veins. Animals recovered by serum do not in their turn fur¬ 
nish a preventive serum. According to the researches of 
Metchnikoff, the preventive power of a serum is proportionate 
to the quantity of toxine injected. The preventive serum, 
acting neither upon the microbe or the toxine, must exercise 
its influence upon the organisms properly submitted to the 
treatment. 
It is not necessary, I believe, to remark after the above 
resume that the study of the diseases of swine known under 
the names of hog cholera, swine plague, swin pest and of infec¬ 
tious pneumoenteritis, is not yet completed. Generally speak¬ 
ing, the identification of the swine plague of Billings, of the 
hog cholera of Salmon and of the Swedo-Danish swin pest is 
granted, but the relations existing between the two forms de¬ 
scribed by Salmon have not yet been sufficiently studied. 
To this day, most of the authors have stopped to a com¬ 
parative study of the morphological characters of the microbes 
under consideration, of their virulency and of the anatomical 
lesions found at the post mortem. But the morphological 
differences existing between the microbes of swine plague and 
hog cholera are not thoroughly evident: 
1. The dimensions vary according to the age and media, 
of the culture. 
