326 
W. 8ILBERSCHMIDT. 
The infection takes place through the digestive canal, and, 
perhaps, by the respiratory apparatus. 4 . . 
Experiments of vaccination by repeated inoculation o 
very weak doses of cultures, or by ingestion of virulent cu - 
tures, or by injection of sterilized cultures have given no pos¬ 
itive results. Attempts to attenuate the virulency by heat ! 
have decided Salmon to give up that means of vaccination on 
account of the impossibility to obtain uniform cultures at the 
same heat. The biological properties, the mobility for instance, 
are not always constant. 
Salmon considers the swine fever of English, the Swedo- 
Danish epidemy, and pneumoenteritis of Marseilles as varieties 
of hog cholera. 
On the contrary, Racuglia (28, 29) differentiates swine 
plague from the disease of Loeffler-Schutz. By inoculation in 
the intestine or by ingestion of culture of swine plague he 
obtained a disease resembling dysentery and bringing on 
death, while the animals had resisted the bacillus of Loeffler- 
Schutz. This last gave rise to very severe local reaction, 
while it was scarcely visible after subcutaneous injection of 
swine plague. It seems that the culture of swine plague was 
very virulent, while that of the bacillus of schweineseuche was 
much less. The author also tries to differentiate the two 
microbes in the morphological point of view, and comes to 
the conclusion that the diseases are two, and differ by their 
specific microbe and the localization of the anatomical lesions. 
Frosch (20) studies the bacilli of swine plague of Billings, 
of the hog cholera of Salmon, of the Deutsche schweineseuche , 
of the chicken cholera, septicaemia of rabbits and other diseases 
of the same category. For him, especially by the morpholog- ; 
ical characters, the virulency and the anatomical lesions, he 
considers the hog cholera of Salmon identical with the swine 
plague of Billings. . , , . , 
In 1890, Selander (49) recognizes the microbe of swinpest 
as those of the American hog cholera and of the infectious pneu- 
moenteritis of the French. 
Besides the morphological characters of the bacillus, the 
author has specially occupied himself with the strengthening 
