130 Veterinary Medicine. 



teux and Trasbot found that horses with local sores or suppura- 

 tions fell readier victims than others ; — perhaps the germs entered 

 by the traumas ; perhaps the tone of the whole system was low- 

 ered, so that the resistance was lessened. 



Close, foul air, bad ventilation, imperfect sewerage, and over- 

 crowded stables not only contribute strongly to infection but tend 

 to aggravate the cases. Underfeedijig and overwork act in the 

 same way and in this connection may be named the excitement 

 and exkaustioti attendant on a long journey by rail. This, like 

 the foul, crowded stable, furnishes many more opportunities for 

 infection and re-infection, so that the invasion of the exposed 

 animal system is all but certain. Infection clings to the loading- 

 baitks, yards, feeding stables, mangers, troughs, buckets, cars, litter, 

 and manure, so that young horses shipped from the west to the 

 Atlantic Coast States, very frequently come down with contagious 

 pneumonia, and contaminate thestablesin which they are placed. 

 Peters suggests that the germ is preserved in the soil water, so 

 that after apparent subsidence it may be again brought to the 

 surface in time of rains or freshetsy to start a new epizootic. 

 Convalescent horses may carry the germ for weeks, on the mucosa 

 or in sequestra in the lungs, and contaminate horses with which 

 they come in contact. 



It is remarkable that the contagious pneumonia is far less dif- 

 fusible on the air than influenza, so that it is much more con- 

 stantly the result of direct contact of a sound, with an infected 

 animal, or with a place or thing that the sick animal has con- 

 taminated. It therefore spreads much less rapidly, remains con- 

 fined to individual stables for a length of time, and in the ab- 

 sence of active interchange of horses tends to die out of its own 

 accord. As the infection is not generally and speedily acquired, 

 so immunity fails to become general, and the infection tends to 

 fix itself permanently in places where many strange horses con- 

 gregate, (market stables, sale stables, livery stables, etc.), and 

 the constant influx of fresh animals keeps the flame burning by 

 accessions of fresh fuel. In such cases it is manifest that the 

 germ outside the animal body either rests in a dry condition, or 

 lives as a saprophyte in earth or organic matter, and of ten loses 

 much of its virulence. Under such circumstances animals that 

 would prove readily susceptible to a virulent germ, prove non- 



