756 
C. W. FISHER. 
The temperature reaction is explained by Gainabia in this 
way : The toxines of the tubercle bacilli in the tuberculin has 
a poisonous action on the elements of the tubercle, causing ne¬ 
crobiosis. The ptomaines resulting from the decomposition of 
the elements excite a local exudative inflammation and leuco¬ 
cytic infiltration. This local reaction results in the breaking 
up and elimination of the tuberculin foci. The febrile reaction 
must be attributed to the absorption of the necrosed tissues. 
The Koch tuberculin is usually diluted one to ten in a one 
per cent, solution of carbolic acid and about 2 c. c. or 30 min¬ 
ims given to an ordinary adult animal. The United States and 
Canadian governments each prepare it ready for use, but vary¬ 
ing a little in the strength and dose. The size of the dose must 
be regulated for the condition, age, and sex of the animal. 
Adult"males usually take a half more than females; very old 
animals more than medium ; suspicious advanced cases should 
get a much larger dose ; also retests within a short time should 
get a double dose. 
Tuberculin is injected with an ordinary hypodermic syringe 
under the skin on the cervical, or just posterior to the scapular 
region, care being taken not to inject into the large lymphatic- 
glands. Some directions give instruction to shave and disinfect 
the parts before injecting, but many of extensive experience say 
this is unnecessary. Unfavorable results so seldom follow that 
it will hardly compensate the trouble, unless it is a herd which 
is unusually filthy or has some other disease present at the time. 
The temperature must be taken once, and better two 01 
three times, before injecting, especially if the veterinarian is 
not thoroughly acquainted with the woik. The time of injec¬ 
tion makes no special difference,'but much clearer reactions 
will be given if the test period comes early in the morning, when 
the animals are quiet and the diurnal variation is the lowest. 
From ten to twelve hours is the usual time given before the tem¬ 
perature is taken, then once in two hours until eighteen or twenty 
after the injection. If the injection is very early, one can wait 
as safely twelve hours as ten if a late injection is made, as the re- 
