130 THE COMMON SENSE OP THE MILK QUESTION 



to have been unknown, and inoculated them with 

 tuberculous material from man, successfully trans- 

 mitting the disease." Bollinger followed, in 1879, 

 with similar experiments," and since that time there 

 have been many workers along the same lines. In 

 short, there is probably no fact in the whole range 

 of experimental pathology better attested than the 

 transmissibility of human tuberculosis to cattle. 

 Since the publication of Koch's startling theory 

 there have been numerous instances of this trans- 

 mission by inoculation, as well as by ingestion. 

 Cows and many other animals have been fed upon 

 food containing human tuberculous matter and 

 thereby infected with the disease. Dr. Mazyack P. 

 Ravenel, the well-known bacteriologist of the Penn- 

 sylvania Live Stock Sanitary Board," Dr. Ger- 

 man Sims Woodhead and Professor Macfadyean in 

 England," and the Commission of the Imperial 

 Sanitary Office of Germany" have all done what 

 Koch declared to be impossible ; and there are many 

 others whose names might be given were it necessary 

 to pile up testimony of this kind. 



Not only have these men succeeded in infecting 

 cattle with human tuberculosis by laboratory methods, 

 but the same thing has been done accidentally many 

 times. My friend. Dr. S. A. Knopf, whose work 

 in combating tuberculosis has placed him in the 

 very front rank of living authorities upon the sub- 



