EXPERIMENT STATION BULLETINS. 497 



The germs causing the disease, the treatment for which the antitoxin 

 is to be used, are grown artificially in some beef tea. A very small 

 amount of this beef tea culture is then injected beneath the skin of the 

 horse, or animal used for the production of the antitoxin. This will 

 cause a slight attack of the disease and in order to combat it the body 

 produces the antitoxin. In a short time the slight fever produced sub- 

 sides and the animal returns to health. A larger amount of the beef 

 tea culture is then injected, producing similar results. This process is 

 continued, injecting larger doses each time, until very large amounts 

 of the culture can be injected without causing serious disturbance. The 

 aninial is then said to be immune, the system being charged with anti- 

 toxin. A little blood is then drawn from the animal and tested and if 

 it contains a sufficient amount of antitoxin the animal is bled, some 

 six to eight quarts of blood being withdrawn. This blood is set in a 

 cool place and allowed to clot when the serum, or liquid portion, sepa- 

 rates from the solid portion. The serum is then prepared for use by 

 filtering and sterilizing. It takes from three to four months to render 

 the horse immune, so that the serum contains sufficient antitoxin for 

 use. The same animal may be utilized again for the production of more 

 serum by repeating the process. 



In the case of hog cholera the serum is used in the treatment, and 

 also in the prevention of the disease by injecting a small amount of it 

 beneath the skin of the animal to be treated. One dose should be suffi- 

 cient. Whether the antitoxin introduced with the serum directly coun- 

 teracts the poison produced by the germs, or whether it also stimulates 

 the body to the production of more antitoxin is a disputed question. 



In the report of Dr. D. E. Salmon, Chief of the Bureau of Animal 

 Industry, to the Secretary of Agriculture, he says: "I have the honor 

 to state concerning the experiments made during the past summer 

 for the control of hog cholera that the treatment with antitoxin serum 

 gave better results than were expected from it, and that this method 

 constitutes a satisfactory plan for treating the disease and preventing 

 by far the greater part of the loss." Dr. Salmon also recommends that 

 Congress be asked to appropriate sufficient funds that the Bureau may 

 produce large quantities of antitoxin serum to be distributed through- 

 out the various states, that its value mav be more thoroughlv demon- 

 strated. 



Park, Davis & Co., of Detroit, also other private firms will no doubt 

 be prepared to furnish the serum in the course of a few months. 



It is to be hoped that the treatment will prove to be all that it has 

 promised. Even if it should, the same sanitary precautions should be 

 carried out to prevent the spread of the disease, for antitoxin cannot 

 be expected to act beneficially except under favorable circumstances. 



Agricultural College, Mich., 

 April 1, IHU8. 



63 



