No. G. DEPARTMENT OF AGRICULTURE. 95 



from the produots of tuberculai' cattle, and it was also lecoin- 

 meoded that investigations should be instituted to further test the 

 point raised by Dr. Koch. 



It is interesting to note that Koch was not the first to make the 

 observations that he reported, if he was the first to construe them 

 as he did. Similar observations were made in America four years 

 ago by Smith, Frothingham and Dinwiddie. In order to more closely 

 examine this subject, to compare the virulence of bovine and human 

 tubercle bacilli and to measure, so far as possible, the capacity of 

 bovine tubercle bacilli to produce disease in animals other than cat- 

 tle, an exteosive series of experiments was instituted at the labora- 

 tory of the State Live Stock Sanitary Board in 1898. These experi- 

 ments were reported by Dr. Ravenel at the London Congress, and his 

 report upon them is published, together with his report on the con- 

 gress, in another part of this volume. 



These experiments are confirmed by those of Koch and Schuetz, but 

 they do not confirm Koch's deductions. On the contrary, they appear 

 to show that Koch's deductions are illogical and unsound. They 

 show, beyond peradventure, that bovine tubercle bacilli are for most 

 animals more virulent and in all cases, so far as tested, quite as viru- 

 lent as tubercle bacilli from man. Hence, instead of indicating that 

 bovine tubercle bacilli are not a probable source of tuberculosis in 

 man, these experiments furnish cause to fear, if oot to believe, that 

 tubercle bacilli from cattle are at least as virulent and deadly for 

 persons than are those from other human beings. Other experi- 

 ments and observations have been made that tend to show the gteat 

 care that should be exercised in the use as food of the products of 

 some tubercular cattle, and these will soon be reported. 



It is important to observe that Koch's deductions have not been 

 drawn, nor is his opinion held, by aoy other research worker in the 

 field of sanitary science. Moreover, Koch's dogma is not allowed in 

 any country of Europe to limit the work of the suppression of tu- 

 berculosis of cattle nor to interfere with the inspection of milk or 

 of meat. 



The result of this whole discussion will be to stimulate observa- 

 tions and experiments that will soon settle the case in some way 

 so that the subject will be removed from the field of controversy 

 to establish fact, and opinion in regard to it will crystallize. To con- 

 tribute to the solution of this important question is a duty and a 

 privilege, and there is reason for pride in the knowledge that the State 

 Live Stock Sanitary Board of Pennsylvania is doing its share. 



It seems pertinent at this time to consider an opinion that was 

 offered during the summer, when there was so much discussion of 

 Koch's alleged discovery, namely, that if it should develop that tu- 

 Berculosis is not transmissible from cattle to man, there will be 



