TUBERCULOSIS 137 



the Bacillus tuberculosis is not confined to that organism alone, as other 

 species of bacilli, when similarly treated, react in the same way, e.g. : 



1. The smegma bacillus, located in the smegma, often seen beneath 

 the prepuce and upon the vulva, both normally and in disease. 



2. Lustgartens bacillus of syphilis, found principally in the primary 

 sores associated with that disease. 



3. The bacillus of leprosy. 



1 4. The acid-resisting bacteria found in butter. 



Hueppe differentiates the first three organisms and the Bacillus 

 tuberculosis as follows : 



1. Treat the preparation, stained with carbol fuchsin, with sulphuric 

 acid, and the syphilis bacillus is decolorized almost instantaneously. 



2. If not at once decolorized, treat with alcohol, and if it is the 

 smegma bacillus, it will lose its colour. 



3. If it is still not decolorized, it is either the leprosy or tubercle 

 bacillus. According to Baumgarten, the Lepra bacillus is stained by an 

 exposure of six or seven minutes to a cold, saturated, watery solution of 

 fuchsin, and retains the stain when subsequently treated with acid alcohol 

 (nitric acid 1 part, alcohol 10). When treated for the same length of 

 time, the bacillus of tuberculosis does not ordinarily become stained. 



Biological Characters. It is very difficult to obtain a pure culture 

 of tubercle bacilli, because they grow extraordinarily slowly, and require 

 for their development an incubator temperature of minimum, 29 ; 

 maximum, 41 ; and optimum, 37 to 38 C. 



The Koch bacillus grows well on blood serum, 4 to 6 per cent, glycerine 

 agar, and in glycerine bouillon. The isolation of the tubercle bacillus 

 from the mixture of bacteria in tubercular sputum by means of glycerine 

 agar plates is almost impossible ; on account of the tubercle bacilli 

 growing so slowly, the other bacterial colonies outgrow and overwhelm 

 them easily. It is only possible to obtain a pure culture when the 

 material is quite pure at the commencement. The following is the 

 method of procedure : 



Inoculate some guinea-pigs (which are very susceptible) with material 

 containing tubercle bacilli. In about four weeks the first inoculated 

 animal dies, the autopsy revealing a well-marked tuberculosis of the 

 internal organs. One of the other guinea-pigs is now killed, the skin dis- 

 infected with warm water and sublimate solution (1 to 1000), and removed 

 with a knife heated in the Bunsen flame. The peritoneum is opened 

 with other sterilized instruments, and the spleen removed with forceps 

 previously heated in the flame. By this mode of infection the spleen is 

 usually the most strongly affected. A portion containing the tubercles 

 is removed from the spleen with sterilized forceps, and pressed between 

 two aseptic scalpels or glass slides in order to obtain material containing 

 bacilli, which is conveyed by means of a stout sterile platinum needle 



