G56 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



Such a.re the external conditions which may favor the extension of 

 hog-cholera. The condition of the animals themselves is of great 

 importance in favoring or preventing infection. When pigs are fed 

 with liquids in which the specific bacterium only is present, those 

 that have been deprived of food for some time previous take the 

 disease, while those whose stomachs contain food that is undergoing 

 digestion do not take it readily. If, besides starving the animal, 

 they are fed with some alkaline solution by which the alkalinity of 

 the stomach is increased, the pathogenic effect is still more pro- 

 nounced. Any disorder of digestion by vv'hich the secretion of gas- 

 tric juice is diminished or checked and the mucus is increased in 

 quantity will increase the susceptibility of the animal to infection, 

 because the alkalinity of the mucous membrane v; ill favor rather 

 than destroy the virus. Any mode of feeding which produces con- 

 stipation and overdistension of the large intestine is likely to favor 

 the disease, as the virus is retained for a longer time. It multiplies 

 there and destroys the mucous membrane before it is discharged. 

 Keeping these facts in mind, we may formulate a few rules, which 

 must be carefully observed if the disease is to be kept in check. 



In the first place, there should be no communication between in- 

 fected herds and such as are still free from the disease. The virus 

 may be carried in various ways, even on the shoes of persons. A 

 small quantity thus introduced may multiply in the soil and water 

 until it becomes a center of infection for many animals. Streams 

 into which sick animals have dropped discharges or in which dead 

 ones have lain must be considered as vehicles of the disease for all 

 herds below the source of infection. This is especially true in Avaim 

 weather, when the virus multiplies very rapidly and extensively. 



When the disease has appeared in a herd, the ground upon which 

 the animals lived at the time must be considered as infected, and it 

 is much safer to remove all the well ones to uninfected grounds than 

 to simply remove the sick ones. But how are we to know that the 

 disease has gained a foothold in the herd ? It is quite common for 

 the disease to announce itself by a few sudden deaths. The stricken 

 animals may seem well a day, perhaps only a few hours, before 

 death. Such animals should always be immediately destroyed by 

 careful deep burial, or by burning, which is much better, for the 

 bodies are as a rule crowded with the specific poison of hog-cholera. 

 In order to remove any doubts as to the precise nature of the disease, 

 it is best to examine such animals before burying or burning them. 

 This should be done in a secluded place which pigs cannot reach, and 

 the ground thoroughly disinfected, as will be described later. The 

 disease in the sudden cases can be easily recognized. The spleen is 

 as a rule very black and enlarged. Spots of blood from the size of a 

 pin's head to a quarter inch or more will be seen in the fat under the 

 skin, on the intestines, lungs, heart, and kidneys. The lymphatic 

 glands are purplish instead of a pale pink. When the large intes- 

 tines are opened they are found covered with these dark spots of 

 blood more or less uniformly and entirely. Often the contents are 

 covered with clotted blood. Any or all of these may be considered 

 as signs of the disease in its most virulent form. In these animals 

 the virus has penetrated into all of the vital organs, and they should 

 be immediately removed and destroyed. It must be borne in mind 

 that for any animal to consume portions of these carcasses would be 

 certain death; that the blood and fluids from these dead bodies con- 

 tain the virus, and when scattered over the soil or thrown into 



