Commissioner of Agriculture 283 



tion, nor even the difference of the genus (sheep, swine) proves any 

 protection. All cloven footed animals exposed to the infection suc- 

 cumb to it with almost equal readiness. The fact that cowpox 

 rarely develops twice in the same animal but takes only the newly 

 calved animals introduced for the first time into an infected place, 

 avoiding the old cows that have suffered in some previous year, is a 

 further distinguishing feature. Aphthous fever will appear in the 

 same animal again and again after a series of intervals of 5 

 months each. 



The vesicular exanthema of breeding cattle is easily distin- 

 guished from aphthous fever by attacking the breeders mainly and 

 by the fact that the eruption is usually confined to the generative 

 organs while the month, teats, and feet, in the main, escape. When 

 it extends beyond the generative organs it is usually to hind parts, 

 legs, thighs, perineum or quarters. The small ruminants and 

 horses escape. Though it shows a similar vesicular eruption, 

 one chamber, and has a similar duration in its victim as 

 aphthous fever, yet it is easily distinguished by its subjects 

 (cattle and especially breeders shortly after service) and by the 

 predilection of the lesions for the internal generative passages. 



Gangrenous stomatitis in calves is recognized by its attacking 

 young calves only or mainly and in many cases by the presence of 

 bacillus necrophorus, a long straight micro-organism, in the ulcers. 

 Gangrenous stomatitis in young pigs has a similar origin and may 

 be distinguished in the same way. 



So with ulcerous stomatitis in sheep. This occurs almost ex- 

 clusively at the period of weaning. Old sheep mostly escape, 

 though in breeders it may invade the generative organs and be 

 propagated by copulation. As in the aforementioned forms of 

 mouth ulcers, the disease is usually restricted to the one genus of 

 animals, more commonly spares the teats and feet, has a duration 

 of 15 to 20 days, and yet may reappear a few weeks later in con- 

 nection with a new infection. 



Necrotic stomatitis is a common result of feeding ergoted 

 grasses, and smutty corn and cereals, as also of the destructive 

 changes in the lining membrane of the mouth which attend the 

 presence of various different cryptogams in the fodder, but this 

 is unattended by fever, gives rise to no distinct blisters, and is 



