PATHOGENIC BACTERIA. 295 



sembles it in having alternate colored and unstained spots. 

 Although several observers have reported success in attempts 

 to cultivate the bacillus of leprosy, their claims have been dis- 

 puted. Rost* claims to have succeeded in cultivating the 

 lepra bacillus upon a peculiar medium consisting of a distillate 

 of beef-extract. The distillation is performed by a special 

 arrangement in the autoclave as follows : 



Pieces of pumice stone dried in the sun and sterilized are 

 saturated with a solution of beef-extract and transferred to a 

 wide-mouthed jar. The jar is tightly corked, and has two tubes 

 inserted through the cork, one running to near the bottom 

 and opening just outside the cork: the other tube opens near 

 the top of the jar and the end projecting out of the cork is 

 bent to an elbow and is brought through an opening in the 

 autoclave. The end of this tube which is in the jar terminates 

 in a rectangular j — , shaped extremity. When the autoclave is 

 set going, the steam passes into the jar through the tube first 

 described, impinges on the saturated pumice stone, extracts 

 certain substances from the latter, and passes out through the 

 other tube, out of the autoclave, where it is condensed by suita- 

 ble arrangements. This distillate forms the basis of Rost's 

 various media for the lepra bacillus. The organism is said to 

 grow only in the absence of every trace of sodium chloride. 



Rost has also prepared a substance ahalogous to tuberculin 

 from cultures of lepra bacilli. This he calls leprolin, and it 

 consists of a glycerin extract of a culture grown for three weeks 

 at body temperature. The culture is first evapotated to one- 

 tenth the original volume in vacuo over sulphuric acid, and equal 

 amounts of glycerin added. Subcutaneous injection of 5 c.c. 

 of leprolin is said to cause a temperature of 104° F. in tWenty- 

 four hours in a person affected with leprosy, and is being used 

 for diagnostic purposes and also as a therapeutic agent. Its 

 use, however, for either purpose is yet in the experimental stage. 



* Indian Medical Gazette. Vol. XXXIX. 1904. 



