CONTRIBUTION TO THE STUDY OF SWINE PLAGUE, ETC. 703 
VII. The guinea-pig has fever the following days (40° 3 in the morning), with 
tumefaction at the point of inoculation ; after a few days the abscess is more defined 
and the guinea pig continues to be well. 
Guinea-pig No. 3.—12-VII, ten o’clock; subcutaneous injection of 2 cc. of the 
serum from rabbit No. 107 vaccinated against swine plague; another injection of 2 
cc. the 14-VII. A quarter of an hour later injection of of virulent blood of 
pneumoenteritis, which kills the witness in 52 hours ; the guinea-pig soon recovers. 
This same serum of the rabbit vaccinated against swine plagtie has been in¬ 
jected in the dose of 2 cc. to another guinea-pig (No. 5), that afterwards I tested 
against swine plague , the animal died in 25 hours, only three hours after the witness. 
These few experiments show that the serum of a rabbit 
vaccinated against swine plague, powerless to protect animals 
against that disease, immunizes rabbits and guinea-pigs against 
pneumoenteritis. Its preventive action against the virus of 
hog cholera is as evident as for that of swine plague . 
These results confirm those obtained with vaccinated ani¬ 
mals and support the conclusion mentioned previously. 
GENERAL CONCLUSIONS. 
1st. The diseases of swine, kwown as swine plague (Salmon), 
hog cholera (Salmon), and infectious pneumoenteritis, are due 
to one and the same virus. Though differing in some mor¬ 
phological characters, the three microbes have shown them¬ 
selves analogous to the point of view of microbian products, 
of pathogenous properties, morbid symptoms and lesions in 
animals (rabbit, guinea-pigs, mice, pigeon.) 
2d. The differences of virulency and of toxicity are only 
quantitative. One can admit that they have been produced 
by external influences, as those differences are not constant. 
3. The vaccination of rabbits against the virulent microbe 
has been obtained with the sterilized blood and cultures; it 
lasts at least several months. Animals vaccinated against 
the most active virus are refractory to less virulent microbes, 
but the opposite does not take place; animals immunized 
against the less virulent microbe have succumbed to the in- 
jection of a stronger microbe, presenting, it is true, a far 
superior resistance to that of the witnesses. To generalize 
the method and obtain positive results, it is then indispensable 
to take the most virulent microbe as a starting point. 
4th. Immunization is also possible with injections of the 
serum from vaccinated animals ; in this case it is but short. 
