114 Veterinary Medicine. 



Any change of latitude or of locality acts in the same way. 

 Riquet even alleges that this will bring about a second and even 

 a third attack. It is common, he says, for newly bought young 

 horses to have the disease at Hamburg, and after recovery to have 

 a second attack at Hanover and finally a third one after they join 

 the regiments in France. A similar exhaustion of immunity has 

 been repeatedly noticed in the case of canine distemper. 



Horse trading and the stabling of large numbers together is 

 naturally the most fruitful of infection and hence strangles is a 

 virtual plague in dealers' studs. The buildings in such cases are 

 reinfected at short intervals with virulent types of the strepto- 

 coccus, and fresh susceptible animals are being constantly intro- 

 duced to keep it up. Riquet says that in Northern Germany 

 dealers avoid this largely by traveling their purchases in bands of 

 loo or 150 head, from ten to twelve miles a day, feeding spar- 

 ingly, and turning them like sheep into an open park at night 

 regardless of the weather. Much of the advantage is doubtless 

 from the avoidance of stable infection and the warm relaxing air 

 of indoors. 



A sea voyage especially favors infection and a single victim 

 placed on board will speedily contaminate all susceptible animals 

 present. 



Finally the predisposing influence of catarrh of the air-passages 

 must not be overlooked. The inflamed mucosa furnishes a most 

 inviting infection-entrance. 



Infecting products. The streptococcus abounds in the local 

 phlegmons and abscesses, in the exudate of the submaxillary, 

 pharyngeal or other glandular swellings, in the pustular eruption 

 on the skin, and in the catarrhal discharge from the air passages. 

 It further exists in the alimentary canal, in the ingesta and in the 

 blood to a limited extent. In the bowels of an immunized animal 

 it may remain virulent for months. Thus it comes that the ma^ 

 nure is a source of infection, and that soiled fodder, litter and 

 water may prove dangerous. The infected soil can not only 

 harbor but can multiply the microbe, keeping it in readiness to 

 attack any receptive horse. On his part the horse that is im- 

 mune and in vigorous health may carry the infection for months 

 and transmit it to his less resistant fellow. 



While the streptococcus is usually found in the blood, in limited 

 numbers only, its presence there implies its general diffusion 



