Washington standard. [volume] (Olympia, Wash. Territory) 1860-1921, 1916-06-09
Concluded from Last Week.
How to Detect and Control

Concluded from Last Week.
] How to Detect and Control.
we have now discussed the disease
ltseif, SO let us take up the question
OF 1ts detection and methods of con.
troll or how we are going to get rid
or the seed of the disease. AS we
nave already seen, it is a very difficult
matter to diagnose tuberculosis in
cattle from its symptoms alone or the
physical appearance of the animal:
therefore, after the organism causing
the disease had been discovered by
DIR. Koch in 1882 the scientists then
proceeded to work out some practical
test whereby the disease could be
recognized in animals. After a num-
Der of years of research and experi-
mentation, the same DR.. Koch who
first discovered the tubercular germ
succeeded in preparing substance
known as tuberculin, with which the
disease can be diagnosed and which
is generally considered to be SO per
cent accurate.
The tubercular germ, as have
stated, is a living thing and must
nave soil or media to grow in the
same as any seed. 1t grows best in
the body of the animal, but can also
be grown in an artificial manner in
the laboratory. Now tuberculin is
prepared in the laboratory from these
germs, which are grown on what we
call culture media, or food. It is a
fluid containing the products of the
tubercle germ without the germs
themselves. AS it contains no living
germs, it cannot convey the disease.
Great skill Is required in it's prepana-
ton. A special fluid Cor culture me-
dium) is prepared and the tubercle
bacilli planted in it, great care being
taken to keep all other germs out.
The fluid is then placed in a special
kind Of incubator and kept at the
temperature of the animal. Under
these conditions the germs grow and
multiply. Gradually the fluid be-
comes filed with the products of the
germs, which are then strained out.
The remaining fluid is tuberculin.
Tuberculin does not harm healthy
cattle, in large doses. but on diseased
animals it produces a marked effect.
There are several kinds of tuber-
culin tests. The test formerly used
by the state was the temperature test.
The test we now use is known as the
tuberculin test. We have
found the latter test to be more salts
factory because 1t does not have the
same limitations. as the animals are
not confined during the time Of test
but are allowed the usual freedom
So we see that the first step in the
Ct adication Of tuberculosis is its de-
lection by use of tuberculin tests and
physical examinations.
The tuberculin test is very search
ing and delicate and single small
tubercule in an obscure part of the
body is enough to cause reaction,
If the COW is tubercular.
Where Errors Are Made.
We cannot usually tell from the
reaction Just how badly diseased the
animal is. 1t may be very slight or
fairly we'll advanced. The error of
test is not so much in animals which
react as in animals which do not re-
act. On some generalized cases,
which cannot be recognized by a
physical examination, there is no re-
action to tuberculin. This is due to
the fact that this class of animals
have in their system so much natural
tuberculin that they are insensible to
the average dose used in test. For
tunately this class Of cases is very
rare. especially when the intrader-
NAL method is used, and are usually
recognized by the owner himself after
he knows that tuberculosis is among
his herd.
There is another class of cases
which do not react to the test and
these are what is known as very re-
cent infections or where the disease
germ has just gained entrance into
the animals body. These cases do
not become dangerous until a later
date and are detected on a second
test. This explains some Of the criti-
cism the test has received, as some
farmers cannot understand why 1t is
that 10 or IS "reactors" are taken
from the herd at the first test and that
a test applied six months later dis
closes several more. We may sue
coed in Graduating the disease in one
test, but usually it requires several
tests, especially where the percentage
of "reactors" in the first test is very
great