tification,
than the well-known "_perlsucht_" of the Germans, or "grapes" of the
English veterinarians--both names being derived from the curious rounded
masses or nodules of exudate found in the pleural cavity and the
peritoneum (around the lungs and the bowels), and supposed to resemble
pearls and grapes respectively--were identified as tuberculosis, and
cows were found very widely infected with it. This unfortunately still
remains the case with the large mass of dairy cattle. But certain of the
more intelligent breeders owning valuable cattle proceeded to take steps
to protect them.

The first step was to test their cows with tuberculin, promptly weeding
out and isolating all those that reacted to the disease. It was at first
thought necessary to slaughter all these at once. But it was later found
that, if they were completely isolated and prevented from communicating
the disease to others, this extreme measure was necessary only with
those extensively diseased. The others could be kept alive, and if their
calves were promptly removed as soon as born, and fed only upon
sterilized or perfectly healthy milk, they would be free from the
disease. And thus the breeding-life of a particularly valuable and
high-bred animal might be prolonged for a number of years. They must,
however, be kept in separate buildings and fields, and preferably upon a
separate farm from the rest of the herd.

Those cows found healthy were given the best of care, including a marked
diminution of the amount of housing or confinement in barns, and were
again tested at intervals of six months, several times, to weed out any
others which might still have the infection in their systems. In a short
time all signs of the disease disappeared, and no other cases developed
in these herds unless fresh infection was introduced from without. To
guard against this, each farm established a quarantine station, where
all new-bought animals, after having been tested with tuberculin and
shown to be free from reaction, are kept for a period of at least a
year, for careful observation and study, before being allowed to mix
with the rest of the herd. It is now a common requirement among
intelligent breeders of pedigreed cattle to demand, as a formal
condition of sale, their submission to the tuberculin test, or the
certificate of a competent veterinarian that the animal has been so
tested without reacting. Protected herds have now been in existence
under these condi