132 TUBERCULOSIS. 



tained by simply rubbing it into the skin (preferably of the 

 abdomen), consists of 50 per cent. O. T. in lanolin. 

 <* In cattle the tuberculin test is made usually according to 

 the directions given by the Bureau of Animal Industry, Wash- 

 ington, D. C., briefly as follows : 



1. Take temperature of the animal every two hours from 6 

 A. M. until midnight. 



2. Make injections at midnight. Adult animals are given 2 

 c.c. of a 1 : 8 dilution of O. T. Younger animals are given 

 less and large bulls may be given as much as 3 c.c. A rise of 

 temperature of two or more degrees is indicative of tubercu- 

 losis. The rise usually takes place in about six hours, reach- 

 ing its maximum in about ten hours. It is necessary to main- 

 tain strict asepsis in making these tests. 



Recently, the tubercle bacillus, on account* of its peculiar 

 growth in some cases in which it seems to present projecting 

 .* processes or branches, has been thought by some to belong to the 

 higher bacteria, being probably a streptothrix, closely related to 

 the actinomyces. 



QUESTIONS. 



When and by whom was the Bacillus tuberculosis discovered ? How does 

 the bacillus behave in the presence of oxygen ? 



What is the size of the tubercle bacillus? In what tissues and secretions 

 of tuberculous animals is it usually found ? How is it best artificially grown ? 

 What temperature is most favorable for its growth ? How high a temperature 

 does it resist? 



Give two methods of staining the tubercle bacillus in cultures or in the se- 

 cretions of animals. Give the mode of staining the bacteria in tissue ? What 

 has given rise to the idea of spores in the bacillus? 



What animals besides man are the most susceptible to tuberculous diseases? 

 What two forms of infection follow inoculation of this bacillus? What is the 

 usual mode of infection in man ? 



Mention some cases of localized tuberculosis in man. How are animals in- 

 oculated to produce the disease ? What are the usual infecting agents in man ? 



What part does tuberculous milk or tuberculous meat play in the dissem- 

 ination of tuberculosis? 



What was the subject of Koch's paper at the Congress of Tuberculosis, 

 in 1901? 



What part does heredity play in the transmission of tuberculosis? 



What is tuberculin ? 



What diagnostic purpose does tuberculin serve ? 



How is tuberculin prepared ? 



What is meant by tuberculin A, O, and E ? By Bazillen emulsion ? 



Why has the tubercle bacillus been thought to be a streptothrix ? 



Describe the methods of use of tuberculin for diagnostic purposes in man 

 and animals. 



