No. 4.] CATTLE COMMISSIONERS' REPORT. 393 



observation. However this may be, if such is the case, the 

 mere fact that the udder may be diseased and the disease not 

 recognizable simply casts suspicion upon all milk from tuber- 

 culous animals. When we consider, therefore, the prevalence 

 of tuberculosis among our cattle, and take into account the 

 hidden character of the disease, a certain amount of suspicion 

 rests upon all milk while these conditions exist. 



The State Board of Health of New York, in its recent report 

 on this matter, says : — 



There can no longer be a reasonable doubt that tuberculous cattle 

 are extensively distributed through the dairies of the State, forming 

 centres of infection in their respective herds ; that the milk from such 

 cattle is bad, and, in many cases, though not acting perniciously upon 

 all who partake of it, is still sufficiently dangerous to warrant as 

 earnest precautions and as effective prophylactic measures as in the 

 case of small pox, typhoid and cholera. 



While this Board does not for a moment contend that animal 

 tuberculosis is the main cause of consumption in the human 

 family, it is, however, an element of danger that should be 

 removed. 



The Tubeeculin Test. 



As so many descriptions of tuberculin and the method of 

 using it as a diagnostic agent in tuberculosis among neat cattle 

 have been recently published by the agricultural experiment sta- 

 tions throughout the various States and in the newspapers from 

 Maine to California, it hardly seems to be desiral)le in this report 

 to give a minute descrii)tion of its nature and manufacture. 



Briefly speaking, tuberculin is a product of the bacillus tuber- 

 culosis. It is prepared by making what is known in the labor- 

 atory as a pure culture of the bacillus in a proper fluid medium. 

 These cultivated bacilli are allowed to grow for a certain lenirth 

 of time, during which they produce their peculiar product, 

 which is known as tuberculin. This tuberculin mixes with the 

 medium in which the bacilli have been grown, and at this stage 

 the fluid is sterilized, that is to say, it is subjected to a tem- 

 perature of 212° F. for a sufficient length of time, to absolutely 

 kill any germs that may be in it. The mixture is then put into 

 a porcelain filter, which is not unlike a rather large candle in 

 appearance. The contents of the filter are then, in a proper 



