The ranch. [volume] (Seattle, Wash.) 1902-1914, 1905-04-01
THE DAIRY
Experiments Regarding tuberculosis.


the infectiousness of human tubercu-
losis for cattle, and also those expert
ments concerning the comparative vir-
ulence of human and bovine tubercle
bacilli for other animals, and the re-
suits may be briefly summarized as
follows: Nine fresh cultures of tuber-
culosis from as many different cases
of that disease in human beings were
isolated; four of these cultures were
isolated from children affected with
generalized tuberculosis. None OF the
cultures isolated from adults exhibited
a degree of pathogenic power for cat
tie which was in any way comparable
to that usually manifested by the DO
vine tubercle bacilli.
Of the four cultures isolated from
children, however, two produced
generalized tuberculosis in calves al
ter simultaneous incubation, and the
LESSONS produced were quite as severe
as those produced by fresh culture
of the bovine tubercle bacillus which
was isolated from case OF natural
tuberculosis in a COW. A third one OF
the cultures from children, while dis
tinctly less virulent than the two just
mentioned, was able to bring about
localized infection, which spread from
the point of incubation to several or
the neighboring lymph glands. rms
third culture should be considered
pathogenic for cattle, though in dis
tinctly less degree than the ordinary
bovine bacillus.
The incubation experiments with
hogs and rabbits gave results quite
similar to those obtained with cattle,
two of the human cultures (from chill
dren) being indistinguishable from the
bovine bacillus in respect OF their &C
ton upon these animals. The inocula-
ton of guinea pigs brought out no dis
tinctions that were worthy of note be-
tween the various cultures.
These experiments, it is believed, go
to show conclusively that it is an
error to conclude that cattle can not
be infected with human tuberculosis;
and they also indicate that the child
rem from which the two most virulent
cultures were obtained were either in
fected from bovine sources or that GER
tain forms of human tubercle bacllll
are indistinguishable from bovine ba-
Gill; both with regard to their Vlru-
lence and cultural characteristics;
furthermore, they agree in general
with those of the great majority OF in
VeStlgatOrS VINO nave SCudloQ Ln1S SUP
ject during the past two years. These
experiments not only justify but show
the desirability of rigid enforcement
of public regulations looking to the
control and the eradication of tubercu-
lOSiS in cattle.
At the experiment station of the bu-
reau certain features of the investiga-
ton in tuberculosis are carried on.
Cow No. 218, to which reference was
made in the last bureau report, is still
there. This COW received an injec-
ton of human tubercle culture into
one quarter of the udder over two
years ago. The injection was made
so as to prevent any injury to the It's
sues other than such as would result
from the presence of the infected
germs. The material secreted by the
injected quarter of the udder continues
to show the presence of the tubercle
germs, and is infectious for guinea
pigs on simultaneous injection. The
COW has lately dropped calf, and 1t
will be interesting to observe whether
the latter contracts the disease