602 
G. A. JOHNSON. 
but such is not the case, for the conditions, as relates to the dis¬ 
ease and the two classes, have not materially changed for many 
years. 
The only logical deduction that I have, as yet, been able to 
derive from these facts, is that the cow, in this case as least, is 
the principal factor in the spread of the disease. And what is 
true of this case should be equally true in others. Perhaps ; 
others may be able to offer a more satisfactory explanation. 
Again, if the human tubercular patient is such an impor¬ 
tant factor in the transmission of the disease, why do not the 
permanent inhabitants of resorts for consumptives more readily 
contract the disease? Or why do not the tribes of Central 
Africa become infected from the coast tribes ? 
Would it not be reasonable to expect this process to go on 
until the disease would be as prevalent among the interior as 
the coast tribes ? 
It would appear from these facts that there is very little 
tendency for the disease to spread among those peoples who do 
not use the food products of the cow. 
One of the most common, and perhaps the most fallacious 
argument that is brought forward in support of the theory of 
human transmission, is the theory that the seat of primary in¬ 
fection, or more properly speaking, the seat of the most frequent 
extensive morbid lesions, is an indication of the method of in¬ 
fection ; or, in other words, that the seat of the morbid lesions 
points out the avenue through which the germs gained an en¬ 
trance to the animal economy. 
If we reason by analogy, it is at once apparent that the 
theory is misleading. Take for illustration, small-pox, measles, 
mumps, Asiatic cholera, bubonic plague, yellow fever, etc. 
These are bacterial diseases that are transmitted, or rather con¬ 
tracted, by inhalation. Yet in none of them are the morbid 
lesions confined to the air passages or the lungs ; in fact, these 
organs are not affected, except as a complication of the disease 
proper. 
Again, anthrax and blackleg of cattle, and glanders of the 
