86 IMMUNITY 



culosis. It certainly causes a local reaction about tuberculous 

 foci, and no doubt aids in the building up of healthy tissue. 



The dose of tuberculin for testing purposes should be .5-2. mg. 

 for a child, 2-6. mg. for a young or weak person, and 5--io. mg. 

 for a larger person. It is well to give the highest dose that it is 

 believed the patient will stand in order to get a prompt and 

 definite result thus avoiding the necessity of a repetition. Re- 

 peating the injection of such amounts is not without danger as 

 it might light up a latent lesion. Any focus that is at the bottom 

 of a clinical condition requiring such a test, will give a positive 

 reaction with the quantities mentioned. For therapeutic pur- 

 poses one begins with an injection of .000000 1 gram or smaller 

 and increases .slowly according to the patient's condition. Tuber- 

 culin should only be administered by experts. 



Ma lie in 



Mallein is a preparation made from the toxin of the glanders 

 bacilli, and is prepared precisely as the old tuberculin. By in- 

 creasing the virulence of the glanders bacilli, by passage through 

 a series of guinea pigs, a highly virulent bacillus is obtained. It 

 is then grown in glycerinized bouillon for a month at 37C. The 

 resulting fluid is sterilized by heat and filtered through a Pasteur 

 filter. The filtrate is evaporated to one-tenth its quantity 

 when intended for conjunctival use or left in its natural state 

 when for subcutaneous use. A small amount of carbolic acid 

 is added in order to preserve it. 



In a horse with glanders, the injection of mallein is followed by 

 a large painful swelling at the injection site. With this there 

 is a rise of temperature, which is the diagnostic reaction that 

 indicates infection with glanders. In this respect the reaction 

 is like tuberculin. In healthy horses no rise of temperature 

 follows the injection, and the resulting swelling more quickly sub- 

 sides. A convenient test is the introduction of a drop of concen- 

 trated mallein into the conjunctival sac. Positive reaction is 



