FEDERAL GOVERNMENT INSPECTION 353 



crude tuberculin; it is a fairly stabile product, and can be kept in a 

 refrigerator for a long time. Before use it is diluted with nine times 

 its bulk of a sterile J per cent, watery carbolic-acid solution. This old 

 tuberculin is today still considered the best preparation for diagnostic 

 use in man and cattle. 



A good tuberculin should kill in a minimal dose of 0.5 c.c. a guinea- 

 pig which has been infected with tuberculosis three to four weeks 

 before the tuberculin is tested. Death should occur within six to 

 thirty hours. Sometimes tuberculins are much stronger and kill a 

 guinea-pig previously infected (three to four weeks) in doses of 0.1 c.c. 

 to 0.05 c.c. Guinea-pigs infected eight to ten weeks previously will 

 be killed in centigram doses of a good strong tuberculin. 



In testing cattle with tuberculin for latent tuberculosis the following 

 doses of the dilute tuberculin are used: 



For large bulls or steers, 4 c c 



For large cows, 3.5 c.c. 



For medium-sized cows and steers, 3 c.c. 



For heifers and young bulls, one to two years old, 2 c.c. 



For calves under one year, 1 c.c. 



For sheep and goats, 0.5 to 1 c.c. 



For pigs of various ages, 1 to 3 c.c. 



For pigs under four months, 1 c.c. 



For pigs from four to nine months, 1.5 to 2 c.c. 



For pigs from nine to sixteen months, 2.5 c.c 



For pigs above eighteen months, 3 c.c. 



Different brands of tuberculin furnished by government and private 

 institutions generally state the exact doses for various animals at 

 various ages. 



Federal Government Directions for Inspecting Herds with the Tuber- 

 culin Test. Inspections should be carried on while the herd is stabled. 

 If it is necessary to stable animals under unusual conditions or among 

 surroundings that make them uneasy and excited, the tuberculin 

 test should be postponed until the cattle have become accustomed 

 to the new conditions. The inspection should begin with careful 

 physical examination of each animal. This is essential, because in 

 some severe cases of tuberculosis no reaction follows the injection 

 of tuberculin on account of saturation with toxins, but experience 

 has shown that these cases can be discovered by physical exami- 

 nation. The latter should include a careful examination of the 

 udder and of the superficial lymphatic glands and auscultation of 

 the lungs. 



Each animal should be numbered or described in such a way that 

 it can be recognized without difficulty. It is well to number the 

 stalls with chalk and transfer these numbers to the transfer sheet, 

 so that the temperature of each animal can be recorded in its appro- 

 priate place without danger of confusion. The following procedure 

 has been used extensively and has given excellent results : 

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