200 BACTERIA 



ture of human tubercle bacilli that have been grown for some 

 time on culture media, and thus attenuated. The new tuberculins, 

 if injected into a person with chronic tuberculosis, stimulate the 

 development of anti-tuberculins, which act as a means of prevention 

 or defense against further infection. Thus far anti-tubercular 

 sera are not of a pronounced or certain therapeutic value. By 

 immunizing horses, Maragliano obtained a serum that he claims is 

 effective. The milk from immunized cattle is used as a diet in 

 tuberculous patients by him. The various tuberculins, some con- 

 taining endo-toxins, or plasmins, in solution, are capable of stimu- 

 lating the formation of agglutinins in the sera of man and animals. 

 Blood from infected individuals also contains these bodies. The 

 agglutination test does not seem to be of great practical diagnostic 

 value. 



BACILLUS OF LEPROSY. 



Mycobacterium Lepra. Hansen. 



Lepra Bacillus. 



An acid-fast organism resembling the tubercle bacillus morpho- 

 logically when seen in secretions. The leprosy bacillus from 

 cultures presents a pleomorphic picture of short and long slender, 

 straight or slightly bent rods sometimes in filaments and possessing 

 deeply staining areas mixed with unstained ones. It is shorter 

 than the tubercle bacillus, is non-motile, and probably has no spores. 

 In general it greatly resembles the tubercle bacillus, morphologic- 

 ally and tinctorially, though the granules are coarser and farther 

 apart in the B. lepra. Certain branched forms appear. The 

 morphology, at times, is like the diphtheria bacillus. It stains 

 by Gram's method, also by carbol-fuchsin. It is acid-fast, but 

 does not resist the action of acids nearly so well as the tubercle 

 bacillus. 



NOTE. Tubercle bacilli causing avian and fish tuberculosis, and other acid- 

 fast bacilli exist, but not being pathogenic for man, are not described here. 



