een practically stamped out.

TUBERCULOSIS.

[Pls. XXXIV-XXXVIII.]

Tuberculosis is an infectious and communicable disease characterized in its
early stages by the formation, in various organs of the body, of minute
nodules or tubercles, which contain _Mycobacterium tuberculosis_, the cause
of the disease.

The disease, in its various manifestations, has been known for many
centuries, and legislative enactments having reference to the destruction
of affected animals and forbidding the use of the flesh date far back into
the Middle Ages. The opinions entertained regarding the nature and the
cause of the malady varied much in different periods and very markedly
influenced the laws and regulations in vogue. Thus, in the sixteenth
century, the disease was considered identical with syphilis in man. In
consequence of this belief very stringent laws were enacted, which made the
destruction of tuberculous cattle compulsory. In the eighteenth century
this erroneous conception of the nature of the disease was abandoned and
all restrictions against the use of meat were removed. Since that time,
however, its communicable nature has been established by many
investigators, and the tide of opinion has again turned in favor of
repressing the disease and prohibiting the sale of contaminated products.

_Occurrence._--The statistics concerning tuberculosis show that it is a
disease prevalent in all civilized countries. In some countries, such as
the northern part of Norway and Sweden, on the steppes of eastern Europe
and Russia, in Sicily and Iceland, and in Algiers, it is said to be quite
rare.

The returns from testing British cattle with tuberculin, supplied by the
Royal Veterinary College, as stated in March, 1900, showed that among
15,392 animals tested 4,105, or 26 per cent, reacted.

During the slaughter of cattle for pleuropneumonia careful examinations of
the carcasses were made for tuberculosis. Of 300 head killed near Edinburgh
120, or 40 per cent, were tuberculous. Of 4,160 killed in England 20 per
cent were tuberculous. Of one of these lots of cattle (451 animals) the
president of the Lancashire Farmers' Association testified that they were
fairly representative cattle--cows, heifers, and growing stock--a
thoroughly mixed lot; 20 per cent of them had tuberculosis.

Of 398 bovine animals taken haphazard in the city of Manchester, 120, or 30
per cent, were tuberculous. Among them were 168 cows, 69, or 41 per cent,
be