346 IOWA DEPARTMENT OF AGRICULTURE 



"The subject of hog cholera is an old one which we have frequently dis- 

 cussed. I have appeared before you once or twice before on this same 

 subject and if you have kept track of what I have said I don't know as 

 I have anything new to say on this question. Great progress has now 

 been made and it is exceedingly interesting. 



To go briefly into the history of the study of hog cholera I might say 

 that the department of agriculture soon after its organization began the 

 systematic study of the question. Secretary of Agriculture Coleman, before 

 the bureau was organized, appointed a number of veterinarians to study 

 hog cholera. They visited different parts of the United States and came 

 to the conclusion that hog cholera and swine plague were one and the 

 same disease. The investigation continued for some time. In 1885 one 

 man then in the bureau announced the discovery of the germ which 

 was the cause of hog cholera. At about the same time he announced a 

 second germ which he claimed to be the cause of swine plague. I might 

 say at this point that at the present time we make very little mention of 

 swine plague. We have come to believe that the disease which kills hogs 

 in large numbers in herds located in different sections of the United 

 States is what we have called hog cholera. I do not use the term swine 

 plague. 



After the discovery of this hog cholera bacillus the bureau continued 

 its investigation and began preparing serum from the horse. They were 

 trying to see if they could not find some method of vaccination from the 

 blood of the horse and I will show briefly that these experiments did not 

 turn out satisfactorily. The further study of the disease by the bureau 

 showed that a hitherto unknown organism was accountable in part for 

 the disease, it was not due to the hog cholera bacillus alone. We could 

 very readily understand why our serum made from the blood of the horse 

 failed to save the hog. We were not on the right track. We learned that 

 some unknown organism was present and what it may be we cannot learn. 

 We cannot cultivate the true germ of hog cholera but we know there is 

 something else accountable for the outbreaks. 



Taking a new start, it was found that the animal recovering from hog 

 cholera did not take a second attack and was immune. This lead to the 

 discovery that if this immune hog was injected with a large amount of 

 virulent hog cholera bacilli it could be made hyper immune. That brings 

 us then to the question of a preventive serum. I will describe how this is 

 prepared. We start with an immune animal. Then this hog is treated 

 with a large amount of blood direct from a cholera hog. (In manufactur- 

 ing this serum we get this by making a healthy hog sick.) After so 

 many days we draw blood from this hyper immune hog to obtain serum. 

 We bleed the hog from the tail on a certain day. One week later we bleed 

 again and continue this until we have four or five bleedings. These are 

 mixed together, constituting the total serum product from this animal. 

 When this is tested and proven it is ready to be used. It is simply nothing 

 more nor less than blood from an immune hog made hyper immune. 



As you are all aware, a large number of nostrums have been advertised 

 as sure cures of hog cholera. But I want to say that not one of these 



