REPORT ON DISEASES OF DOMESTIC ANIMALS. 
227 
These may be thought, to be extreme cases, blit I am acquainted 
with districts in which 30 per cent, of the cattle suffer from tuber¬ 
culosis, and with many high priced herds in which this scourge 
yearly claims its victims. In his experiments Professor Gerlach 
had to utterly discard certain strains of high-bred swine, because 
of the astonishing frequency of tuberculosis in these subjects. 
This disease opens up an extensive field for sanitary work, 
and particularly in the neighborhood of large cities, where so 
many infants, subjected to all the depressing influences of city 
life, are sustained by the milk of cows kept in unwholesome 
stables and fed so as to secure the greatest possible yield of milk, 
irrespective of results. Here the environment of the cows 
that yield the milk and that of the children who consume it 
are altogether favorable to tubercule, and the subject requires the 
most careful supervision of the sanitary authorities. 
The great mass of the adult city population is only a degree 
better in this respect than the infants; and as the cattle that are 
no longer useful for milk are too often made into beef, or rather 
sausages, the children of a larger growth are confronted with the 
risk of tuberculous meat as well as infected milk. The same 
dangers attend on the country districts, and though they are to 
some extent counteracted by pure air and better surroundings, 
yet the taint, if once introduced into a herd, tends to undergo a 
steady increase, until, as in the case of the country herds I have 
referred to above, all fall under its baleful influence. Then, 
again, in most of our large cities the cows are not kept over one 
season, but are constantly being replaced by fresh ones from the 
c /untry; and it is only by purifying the source of the trade that 
we can secure sound cows in the cities. 
That a supervision and restriction of tuberculosis is demanded 
cannot for a moment be gainsaid; but in view of the enormous 
proportions of such a work and the great monetary interests in¬ 
volved, together with the recent data of all exact observations on 
the transmissibility of the contagion and the different results ob¬ 
tained in different cases, it would be well, before proceeding far 
in this matter, to conduct a series of experiments which would 
tend to determine more accurately the conditions in which the 
