IMMUNITY IN TUBERC 
ER. 633 
If we side with Koch in the view expressed in 1901, and reiterated 
just the other day in his Nobel prize address, that, as he satys, human 
tuberculosis and tuberculosis in cattle are so distinct from each other 
that the latter is not to be feared as transmissible to man, at least, 
as his last utterance puts it, not in a form which comes in considera- 
tion in regard to tuberculosis as-a “ Volkskrankheit,” or race dis- 
ease, then it is only necessary to direct efforts to the suppression of 
tubercle bacilli of human origin. For, if the danger of infection of 
surroundings and healthy individuals is limited to the expectoration 
of persons suffering from tuberculosis of the lungs and upper air 
passages, the problem before us, while still very large, is less by a 
considerable amount than if there must also be taken into account 
the widely prevalent disease among cattle, swine, and other domestic 
animals. While I do not pretend to speak in terms of great authority, 
yet it would seem to me that the time is not yet ripe to disregard, in 
attempting to suppress tuberculosis, the disease in domestic animals. 
Greatly as I sympathize with the active propaganda which is being 
made by instruction and material help to protect tuberculous human 
beings from injuring themselves and others, and greatly as I hope 
to see promoted the means of caring for the tuberculous in sanatoria, 
etc., yet I hope that there may occur, at this time, no relaxation in 
in the efforts being madé to control the spread of tuberculosis among 
cattle and to prevent the consumption of infected milk and flesh by 
man and other animals. That, on the other hand, the suppression 
completely of tuberculosis among cattle would not be followed by a 
great reduction in the morbidity due to tuberculosis in man is shown 
io Kitasato’s statistics from Japan. In that country the human dis- 
ease prevailed with its usual activity at a time when the cattle dis- 
ease, owing to the absence of cattle, was unknown, and milk formed 
no appreciable element in the food of children, 
In dealing with the complex problem of tuberculosis—a problem 
whose difficulties enlarge with the continued growth in size of cities— 
we are materially feet by the knowledge of the manner in which 
the virus of tubercle is separated from the diseased body, the condi- 
tions of its contamination of our env ironment, and the avenues 
through which it endeavors to enter the healthy body. Though it is, 
perhaps, searcely to be hoped that a time will arrive when fubareileas 
will have become, through precautions against infection, as rare as are 
to-day smallpox and typhus fever, yet it is a most hopeful result of 
the crusade against tuberculosis that a marked reduction in the mor- 
tality, and probably in the incidence of the disease, has been going 
on in some countries—as, for instance, in England—for forty years. 
In New York, the system organized by Biggs has brought about a 
reduction since 1886 of 35 per cent in the mortality of the disease; 
and while in Prussia the mortality was stationary in the decade from 
