264 TUBERCULOSIS. 
are soon overcome by the body resistance. Careful study has shown 
that most people, by the time they have reached twenty-five years of 
age, have not only been exposed to the disease, but have had mild 
attacks, from which they have completely recovered. By building 
up a proper physical vigor, an individual may successfully combat 
these parasites. Plenty of wholesome, but not too rich food, 
exercise, life out of doors as much as possible, sleeping in rooms 
with windows open in winter as well as in summer, and deep breath- 
ing exercises, by means of which the lungs are filled with fresh air, 
are the means by which such resistance can be developed and main- 
tained. All of these conditions are usually within the reach of 
everyone, so that there is no reason why a person who will, cannot 
develop a high resistance against this dreaded disease. 
ARE BOVINE AND HUMAN TUBERCULOSIS THE 
SAME? 
Apart from its relation to the human being, the farmer is most 
naturally interested in this disease, since it attacks his cattle. 
Bovine tuberculosis is one of the most serious dangers, and threatens 
the continuance of dairying. 
The significance of the question whether human and bovine 
tuberculosis are identical is self-evident. If the two are the same, it 
will follow that the disease may pass from animals to man; if they 
are not identical such transmission is impossible. For some fifteen 
years after the cause of the disease was discovered, no question was 
raised as to their identity. Both diseases are produced by bacteria 
that appear identical, and that they were the same was taken for 
granted. In 1900, however, Prof. Koch raised the question whether 
they were not distinct, and gave experiments to show that the 
human bacillus does not produce the severe bovine tuberculosis 
when inoculated into cattle. The question caused intense interest 
and much discussion, and in spite of many experiments designed to 
settle the matter, there is still some dispute. A fair summary of the 
facts as they appear to the majority of bacteriologists to-day is as 
follows : 
