1 6 Veteriiiary Medicine. 



outbreak of two distinct varieties of microorganisms, in place of 

 one, giving rise of course to modifications in the symptoms, le- 

 sions, progress, mortality, etc. 



Apart from the microorganism the whole class tends to show 

 a close family relationship in their pathological phenomena shown 

 under different conditions : 



ist. Under a large dose, or specially virulent germ, in a par- 

 ticularly susceptible animal, all tend to a manifestation of an 

 acute septicaemia, with generally diffused petechise of the skin, 

 mucosae, serosae and internal organs, blood extravasations, and 

 an early high mortality. 



2d. Under a smaller dose, or a le.ss potent germ, or in a less 

 susceptible animal the tendency is to necrotic processes in the 

 seat of inoculation or the point of election of local lesions. Ne- 

 crotic alcers are especially common in cases that survive one, two 

 or three weeks, or that develop in a subacute or chronic form. 



3d. With a minimum dose of a germ of little potency, and in a 

 very resistant subject even the necrotic lesions raaj' be absent, 

 and there may be suppuration only or ulceration of serosae and 

 joints. 



The question of the primary identity, or disparity of the whole 

 class of germs, causing the septicaemic swine plagues, may be 

 practically ignored in this work ; it is important rather with our 

 present knowledge to note the diseases associated with particular 

 germs, or varieties of germs, and to describe these as far as possi- 

 ble as independent affections. This is as permissible as it is to 

 describe small-pox, sheep-pox, and cow-pox as distinct affections, 

 no matter what may be the truth or falsity as to their alleged or- 

 iginal identity. 



Rouget in Europe and Hog Cholera and Swine Plague, as the 

 best established types in the United States deserve primary men- 

 tion, to be followed by references to additional types which have 

 been found to be associated with other distinct microorganisms. 



