TUBERCULOSIS AND ITS RELATION TO THE VETERINARIAN. 
755 
mal ^ is exercised ; upon auscultation the different rales and 
crepitation may be heard, or the lack of normal sounds. In ad¬ 
vanced cases crepitation may be felt by carefully placing the 
hands on either side of the thorax ; the animal will now have a 
general unthrifty appearance. There may be enlargement of 
any of the lymphatic glands, such as the supra-mammary, in¬ 
guinal, prescapular or retro-pharyngeal ; also the udder may be 
. affected. The appetite may be abnormal until late in the de¬ 
velopment, when it will gradually diminish and the animal will 
emaciate quite rapidly ; there may also be present a chronic 
diarrhoea. The cough and respiratory symptoms will now be 
exaggerated and the animal will have a hectic fever of from i° 
to 3° F. 
Many of the preceding symptoms may be present and yet 
the veterinarian is not certain of his diagnosis of tuberculosis, as 
oUier diseases may give similar symptoms. The most common 
disease which the veterinarian may mistake from these symp¬ 
toms for tuberculosis is chronic bronchitis, but with this there 
is usually more discharge from the nostrils. 
The tuberculin testis of the greatest value in diagnosing the 
disease. It consists in the subcutaneous injection of a small 
quantity of tuberculin ; the taking of the temperature before or 
at the time of injection, also during the period of from lo to 20 
hours after injection, and the noting of physical as well as tem¬ 
perature reactions. 
Tuberculin was first used as a diagnostic agent in veterinary^ 
practice in 1891 by Prof. W. Gutmann, of the Veterinary Insti¬ 
tute, Dorpat, Russia ; in America by Prof. W. L. Zuill, of the 
Philadelphia Veterinary College. It is a glycerine extract of 
tubercle bacilli. Tuberculin is prepared by growing pure cul¬ 
tures of the bacillus in serum or other suitable media until! 
highly concentrated. Glycerine and carbolic acid are them 
added, and the whole passed through a porcelain filter to re¬ 
move the bacilli, after which the liquid is heated for a time to 
kill the germs, if any are present. The liquid is then concen¬ 
trated by evaporation in a vacuum until of the proper strength. 
