Cholera Suis, Hog Cholera, etc. 29 



sion, without constant disinfection ; the purchase of stock swine 

 at public markets ; the return of swine from public fairs and 

 exhibitions ; the feeding and watering of pigs on the line of 

 streams that have drained pig pens or pastures higher up ; the 

 use for pigs of premises that have harbored infected ones at an 

 earlier (even distant) date: the supply of food or litter from 

 barns where pigs have recently died ; the admission to the pens 

 or yards of butchers, dealers or others who are likely to carry 

 infection on their persons ; the admission even of wagons, dogs 

 or other animals, including birds, tame and wild, which are liable 

 to carry infection. Of all birds the buzzard is the most to be 

 shunned as having presumably just come from infected carrion, 

 but barnyard fowl and small birds that feed from the same trough 

 with the pig are to be feared as well. The same remark applies 

 to rats and mice, squirrels, skunks, woodchucks and rabbits 

 which may easily carry the infection on their paws. If the infec- 

 tion is near, flies and other insects, in the warm season, will con- 

 vey it for some distance from herd to herd. A common cause is 

 the feeding of swine about abattoirs where they devour the offal 

 and waste in a raw condition. Another is the feeding of board- 

 ing house, hotel or other kitchen slops, raw, or without the most 

 exhaustive precautions in the way of cooking. Many outbreaks 

 can be traced in this way to the consumption by the animals of the 

 products of infected swine. Some indeed are fostered by the 

 utter neglect of the parties in charge of an infected herd, in leav- 

 ing the infected carcasses exposed so that they are eaten by 

 wandering hogs, or portions are carried away by buzzards, car- 

 rion crows, dogs and other animals. In some cases a strong wind 

 will carry the infection on dust, straw or other light object into 

 sound herds at a distance. The introduction into a hitherto 

 healthy herd of an apparently sound pig may be the occasion of 

 a deadly outbreak. The strange new pig maj' have already had 

 the disease, and in a condition of immunity, may without hurt to 

 itself, carr}* the germ which becomes so fatal to the susceptible. 



This susceptibility is one of the most important factors. It 

 may be inherent in a given family or strain of blood. It may be 

 enhanced by a constitutional weakness, engendered by too close 

 breeding, by breeding from the young and immature, or from the 

 old and worn out. It may be favored by a general debility from 



