214 QUEENSLAND AGRICULTURAL JOURNAL. [1 Man., 1899. 
cent. of glycerine, the evaporated product contains about 50 per cent., which 
explains why it retains its activity for so long. During the inoculation of & 
large number of flasks of nutrient media on different occasions, the number of 
tubercle bacilli introduced cannot possibly be the same in quantity for every 
flask ; it therefore naturally follows that there must be a corresponding 
difference in the quantity and quality of the tuberculin produced. ‘This difli- 
culty can only be overcome by the delicate operation of “ standardising,” 
which is carried out by injection of the tuberculin into healthy guinea-pigs. 
On the Use of Tuberculin—The injection of tuberculin in recognise 
standard quantities is always innocuous; performed on milking cows, it in nO 
way affects either the quantity or quality of the milk produced, and it in no 
way interferes with gestation, even in animals about to calve. The usual 
practice in applying tuberculin as a means of diagnosing tuberculosis in cattle 
is first of all to determine the normal temperature of the animal, which is done 
by the use of the clinical thermometer. For ordinary purposes tuberculin is 
. employed diluted to the extent of one-tenth in carbolised water, 5 per 1,000. 
The best plan is to inject at one time beneath the skin, behind the shoulder, 3 
to 4 cubie centimetres of the dilution (8 cubie centimetres for cows of medium 
size, 834 for large cows, and 4 for bulls and high-class animals). The temperature 
of the animal must be taken before the injection, which in general practice 1 
is usually desirable to make about 6 p.m. ‘The temperature of the suspected 
animal is taken again next morning at 6 o’clock, then at 9 a.m., 12 noon, 3 p.M-y 
and the last one at 6 p.m. The diagnostic reaction is measured by the differ 
ence between the initial normal temperature, which is about 101°5 Fahrenheit, 
and the highest temperature recorded after injection. If this difference exceeds 
1:5 Centigrade, equal to 2:7 degrees Fahrenheit, it may be affirmed that the 
animal is tuberculous. It may happen that the animal at the time of the 
proposed injection is feverish. This is caused often enough by hot weather, 
excitement, or by some passing irregularity of the digestive functions, and other 
physiological changes. It is better in such cases to defer the operation. It18 
important also to remember that in yery tuberculous animals, those especially 
which are phthisical in the proper seuse of the word, the injection of tuberculit 
may produce no rise of temperature whatsoever; but there is no difficulty 1” 
these cases, as the clinical diagnosis is always very easy. 
As an example of the certainty of tuberculin as a means of diagnosing 
tuberculosis in cattle, I will refer to the testing of the historical ‘ Althorp 
Park” herd of high-class pedigree Jerseys, belonging to Lord Spencer. In 
September, 1893, Professor Mc¥Fadyean, of the Royal Veterinary Colleg® 
London, paid a visit to Althorp Park in order to inspect the herd, as two ° 
the animals were reported to have died a short time previously from tubert- 
culosis. ‘The herd comprised 18 cows, 1 bull, and 4 yearling heifers, On 
clinical examination only one of the animals was suspected—viz., a cow 12 
which there was a distinct enlargement of one of the pharyngeal-lymphatle 
glands. In none of the animals were the respiratory movements notably dis- 
turbed. ‘The man in charge reported that all the animals fed well, and that he 
had not observed that any of them had a cough. With one exception, the 
general condition of every animal in the herd was excellent, and this exception 
was the cow referred to, which was thirteen years old. The result of Professor 
McFadyean’s examination may be summed up by saying that certainly in not 
more than one of the twenty-three animals could he, with any degree of conli- 
dence, have diagnosed tuberculosis. But, since two members of the herd had 
recently died from tuberculosis, there was a very strong presumption that more 
than one or two of the survivors must have become intected, and the only hope 
of saving the yet healthy individuals lay in being able to “weed out’ these 
infected animals. Ordinary clinical examination being then of little service 
the case appeared to be one eminently suitable for the employment of the 
tuberculin test, which Lord Spencer promptly consented to have carried out. 
The general result of the injection of tuberculin was truly startling, for 
appeared that not a single anima! was free from the disease. As a preliminaty 
