No. 7. DEPARTMENT OF AGRICULTURE. 609 



But whether these cattle will be protected as they grow up, it 

 depends upon future investigation to determine. 



CONTROL OP VACCINES. 



In regard to the general use of vaccines, I think that Mr. Love- 

 joy brought out an exceedingly important point in his talk to-day. 

 He told you of the prevention of hog cholera by an advertised sys- 

 tem of vaccination, which really infected by inoculation and appar- 

 ently produced the disease in the hogs that it was intended to pro- 

 tect. Vaccination with living organisms is always a very delicate 

 process. We cannot be too particular or take too careful supervis- 

 ion. Evidently the vaccination that was applied to his hogs was 

 made with a living culture of hog cholera bacilli and these bacilli 

 were virulent for hogs and instead of protecting them they produced 

 the disease. In discussing the matter with him last evening, and 

 from the information that he gave me then, as well as what he said 

 here this morning, from the order of occurrence of disease following 

 the vaccination, it seems there could be no doubt that his hogs were 

 infected by this process that was intended to protect them. 



Well, cattle can be infected by tuberculosis by vaccination if the 

 vaccine is not of absolutely perfect quality. And there is danger 

 that vaccines may be put upon the market which are not reliable, 

 which either are too weak and do not protect, or that are too 

 strong, and produce disease. There is already a firm of druggists 

 in New York City that is advertising very widely a vaccine against 

 tuberculosis. It is brought from Germany. They make claims for 

 it for which there is absolutely no foundation. They claim that 

 this vaccine will protect cattle for their entire lives. Nobody knows 

 W'hether it will protect cattle for their entire lives or not. The work 

 is altogether too new to justify anybody in drawing such a conclu- 

 sion. During the past summer I had an opportunity to visit all of 

 the foreign investigators who were working along this line. I 

 went abroad for the especial purpose of investigating the subject 

 of vaccination against tuberculosis. I went to nine different coun- 

 tries and visited twenty or more investigators, and saw many ani- 

 mals that had been vaccinated, and I went evervwhere that I could 

 hear of any work of this character being done. So I know pretty 

 well upon what the claims as to this German vaccine are based. 



The German work has not been carried on as long nor upon such 

 a large scale nor in such a systematic way as the work that has been 

 done in this country. As I have said before, some of the claims for 

 the vaccine that is now advertised are without foundation; and 

 anyone who uses it should use it purely as an experiment; not with 

 the thought that he is sure to gain protection, w'hich those who 

 put it out claim it will give. 



I do believe and I am convinced that vaccination against tubercu- 

 losis is going to be a practicable process. It may be that the pro- 

 cesses that we are now using will be sufficient. W^hether they will 

 be or not time alone will determine. But at any rate it can do no 

 harm, and/ we are disposed to use it on a continually larger scale 

 until we know all about it, or at least enough about it to justify 

 us in recommending it for general application. If it continues to 



39—7—1904 



