GENUS BACTERIUM 239 



The Bureau of Animal Industry, Washington, D. C., pre- 

 pared mallein by growing the bacteria for five months at 

 37.5 C. in glycerin-bouillon. This is then boiled for one hour 

 and allowed to stand in a cool place for one week. The super- 

 natant fluid is then decanted and filtered through clay filters 

 by means of a vacuum pump. The filtrate is evaporated to 

 one-third its original volume on a water bath, and the evapo- 

 rated volume resupplied by a 1 per cent carbolic acid solution 

 containing about 10 per cent of glycerin. 



Mallein test. This consists in injecting subcutaneously 

 the proper dose of mallein. If glanders is present, the follow- 

 ing reaction will appear. The injection is followed in from 

 six to eight hours by a quite sharp rise of temperature often 

 reaching as high as 104 to 106 F. The high temperature 

 continues from a few to several hours and then gradually sub- 

 sides. The normal may be reached in a few hours, or it may 

 require several days. At the point of injection, there appears 

 a hot, diffuse swelling which gradually extends until it reaches 

 a size of 20 to 30 cm. in diameter. This swelling, which is very 

 tender at first, lasts from three to four days. In some cases, 

 there is what is called an ' ' organic ' ' reaction which consists in 

 general depression, roughening of the hair, and sometimes shiv- 

 ering. This may or may not occur in conjunction with the other 

 reaction and it may occur in the absence of the rise of tem- 

 perature and with slight local swelling. In testing horses with 

 mallein it is very important to know whether this "organic 

 reaction" is present, The rules for the use of mallein as 

 recommended by the Bureau of Animal Industry are as fol- 

 lows: "Make the test, if possible, with a healthy horse, as well 

 as with one or more infected or supposed to be infected with 

 glanders. Take the temperature of all these animals at least 

 three times a day for one or more days before making the 

 injection. 



"The injection is most conveniently made at 6 or 7 o'clock 

 in the morning, and the maximum temperature will then 

 usually be reached by or before 10 P. M. of the same day. 



"Use for each horse one cubic centimeter of the mallein 



