ACTIVE IMMUNISATION AGAINST TUBERCLE. 255 



The remaining deposit was again dried, bruised, treated 

 with water and centrifugalised, the clear fluid being again 

 decanted. This process was repeated with successive 

 residues till, on centrifugalisation, at last no residue remained. 

 All the fluids were then put together, and these form what 

 Koch calls " tuberculin R." He states that it differs from 

 tuberculin O, and also from tuberculin as originally made, 

 in that it contains the substances present in the bacilli, 

 which are insoluble in glycerine. Tuberculin O produces 

 the tuberculin reaction like the original glycerine extract, 

 but tuberculin R only does so in large doses. Koch states 

 that the latter when injected into animals in repeated and 

 increasing doses, -^-^ mgrm. being the initial dose, produces 

 immunity against the original extract, against tuberculin O, 

 and against living and virulent tubercle bacilli. As supplied 

 commercially, each c.c. corresponds to 10 mgrms. of dried 

 bacilli. He also treated guinea-pigs already infected, and 

 stated that there was a tendency to improvement in the 

 tubercular lesions. Baumgarten, however, in a series of 

 experiments found that this did not occur. Cases of early 

 phthisis in man and of lupus have been treated with 

 " tuberculin R," no dose being given which raises the 

 temperature more than .5 F. Though cases of lupus have 

 been recorded in which improvement has taken place little 

 success has attended the use of this substance as a remedial 

 agent. 



Smegma Bacillus. This organism is of importance, as in form and 

 staining reaction it somewhat resembles tubercle bacillus and may be 

 mistaken for it. It occurs often in large numbers in the smegma pne- 

 putiale and in the region of the external genitals, especially where there 

 is an accummulation of fatty matter from the secretions. Morphologi- 

 cally it is a slender slightly curved organism, like the tubercle bacillus 

 but usually distinctly shorter (Fig. 68). Like the tubercle bacillus it 

 stains with some difficulty and resists decolorisation with strong mineral 

 acids. Most observers ascribe the latter fact to the fatty matter with 

 which it is surrounded, and find that if the specimen is treated with 

 alcohol the organism is easily decolorised. Czaplewski, however, 

 who claims to have cultivated it on various media, finds that in 

 culture it shows resistance to decolorisation both with alcohol and 

 with acids, and considers, therefore, that the reaction is not due to 



