BovixE Tuberculosis in Its Relation to Man. 137 



that many supposed cases have been incorrectly interpreted. 

 Suppose one member of a family on a farm develops tuberculosis, 

 and there are one or twenty tuberculous cows on said farm, it 

 does not prove that the individual obtained the infection from 

 the bovine. It is quite probable that he has been exposed to in- 

 fection from human tuberculosis hundreds of times. Many re- 

 ported cases hang- on just such vague evidence as this. If a man 

 walks into a bank, and while there is found to have twenty dol- 

 lars in his pockets, is it prima facie evidence that he has become 

 infected with the germs of wealth of that institution? Or, is it 

 not possible that he was suffering from monetary engorgement 

 when he entered that hotbed of filthy lucre? It must be proved 

 beyond peradventure that he was penniless when he entered the 

 building if we are to blame the bank for the condition of his 

 pockets. Just as positively must we know that infection passes 

 to the human adult or child from cow's milk or its products, or 

 from beef, or through ingestion in other ways, or by inhalation 

 of bacilli from the bovine, and that they alone establish the dis- 

 ease, ere we can truthfully say there is such transmission. How 

 may we know that a human being is tuberculous when no germs 

 can be obtained from the subject, and no marked symptoms are 

 observed? If an adult or child has tuberculosis, and it is proved 

 that such patient has partaken of milk for any length of time 

 from a cow known to be tuberculous, it is by no means certain 

 that infection came from the cow unless there is proof that it 

 did not come from the human, and that it did not exist prior to 

 his ingestion of the milk. Let us take cognizance of the difficulty 

 of establishing such a fact. Humanity wanders incessantly. The 

 germs of human tuberculosis are wafted on the winds, are carried 

 by the waters, may be brought home in food or clothing, may be 

 inhaled at church, theatre, or hotel, in motor or parlor cars. They 

 do not stand out in large black masses, like the rocks the mariner 

 is ever alert to avoid, but without our ken^ noiseless, impercep- 

 tible, and intangible they surround and invade us. They do not 

 sting when they capture a victim; then how can we know the 

 time, the place, and the source of infection? Even the milk from 



