Modified a?id Complex Fevers of Swine. 53 



Jensen who are familiar with the svinpest (hog cholera) of 

 Scandinavia ; Kitt, Friedberger and Frohner who are familiar 

 with the Schiveineseuche (swine plague) of Germany ; Raccngla, 

 Canova and others in Southern Europe ; and L,ignieres and others 

 in France who have studied the hog cholera and pasturellose por- 

 cine (swine plague). 



But the conceded duality of these two diseases as they occur in 

 typical examples in swine, does not account for all the infectious 

 fevers of swine, in which these microbes or others closety allied 

 to them may figure. Salmon, Smith and their coadjutors describe 

 double infections in the same system, in which both the bacillus 

 cholerse suis and the bacillus pestis suis figure, and in which there 

 result a combination of symptoms and lesions, that together 

 represent both of these germs. It may be that one or other of 

 these germs in a given outbreak, shows a predominance in po- 

 tency so that the symptoms are more characteristic of it than of 

 its companion ; it may be that the more potent germ kills the 

 victim, quickly by an acute septicaemia and gross lesions that 

 would apply almost as well to one germ as to the other ; or it 

 may be that both act moderately and the attack is protracted with 

 resulting lesions in both lungs and bowels that respectively sug- 

 gest the plague and the cholera. 



Then as regards varieties in the individual germ. Th. Smith 

 recognizes this as a frequent condition and describes no less than 

 seven different types of bacillus cholerse suis which he had 

 studied and which varied in morphology, cultural qualities and 

 virulence. Ljgnieres found that the virulence especially of 

 bacillus suis pestis is very easily affected by successive passages 

 through the bodies of small experimental animals. We ought 

 not to be surprised then if we find in different epizootics, in 

 different countries and even in the same, bacilli which for the 

 time at least show characteristics different from those to which we 

 have been accustomed. These give us varying phases of sep- 

 ticaemia which however come together in one great class. Two 

 of these types which have been placed on record may be here 

 named. For others see septicaemia haemorrhagica of cattle and 

 sheep. 



McFadyean's Swine Fever Bacillus. The characters of 

 this microbe found constantly by McFadyean in swine fever, 



