512 DISEASES OF SWINE 



ered as a very important disease of the hog, and Dr. Billings, of 

 the University of Nebraska, several years ago wrote a large book 

 which was devoted entirely to a discussion of the disease. At 

 that time a special germ was described and heralded as the cause 

 of swine plague, and an entirely separate set of pathologic findings 

 and clinical symptoms were outhned for the disease from those 

 given for hog-cholera. 



In the past few years our opinions regarding swine plague 

 have underwent a great deal of change, and at present it may be 

 rightfully questioned whether there really is such a disease as 

 swine plague. Most of the cases of what was formerly classed 

 as swine plague are now known to be hog-cholera in which the 

 germs are acting principally upon the lungs, and, accordingly, the 

 symptoms are mostly of a pulmonary type. The cough in these 

 cases is a marked feature of the disease. 



That there is such a disease as swine plague I think may very 

 reasonably be questioned. It is possible that the disease may, 

 and perhaps does, exist, but it most certainly is only in the form 

 of isolated cases and never as a widespread epidemic such as is 

 seen in hog-cholera. Whenever hogs begin to get off feed, droop, 

 lose energy and liveliness, and die in large numbers without any 

 explainable cause it can be said in ninety-nine cases out of a hun- 

 dred that the cause of death is hog-cholera. 



If there was a second epidemic disease, such as swine plague, 

 it would be of great importance from the standpoint of the use 

 of serum. Serum which would protect an animal against hog- 

 cholera could not be expected to protect hogs that had been ex- 

 posed to swine plague, no more than small-pox vaccination in the 

 human race could be expected to protect the man from typhoid 

 fever. It would be necessary that we have two forms of serum, 

 one for cholera and the other for swine plague. Fortunately, it 

 has been found with the use of the serum that the two conditions 

 are, in reality, one and the same in almost every instance, the 

 only difference being that in the one case the germs act more 

 powerfully on the lungs, while in another animal they are more 

 active in the bowel, kidneys, and other organs of the abdominal 

 cavity. 



