76 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



type may be changed by suitable treatment. The chief peculiarities 

 of the two more important types are given in the following table : 



Morphology in 

 cultures. 



Occurrence in 

 nature. 



Pathogenicity 

 in animals. 



Growth in cul- 

 tures. 



Human. Bovine. 



Long, slender, irregular. Shorter, thicker, more regular. 

 i 



Most cases of tubercle | In cattle, pigs, etc. In many 

 in man, especially pul- cases of "surgical tubercle," 

 monary, and in adults, i especially in children ; in ab- 

 Never in the lower , dominal tuberculosis ; rarely 

 animals. in phthisis. 



Inrabbits slightnon-pro- ; In rabbits generalized tubercle, 

 gressive tuberculosis. I In cattle local lesion, usually 

 In cattle local lesion ". becoming generalized, 

 undergoing spontaneous 

 cure. 



Growth abundant and Much slower and less abundant. 

 rapid. 



LEPROSY 



The leprosy bacillus resembles that of tubercle, but it is 

 somewhat straighter and more uniform. It occurs in leprous 

 lesions in great profusion, and can be easily detected. It can 

 only be cultivated with extreme difficulty, if at all. 



In a suspected case of leprosy films should be made from the 

 nasal discharge, for the nasal cavities are very frequently 

 affected. Indeed, it seems highly probable that the primary 

 lesion through which the bacilli gain access to the body is in 

 the nose in most cases. A small portion of one of the leprous 

 nodules may also be removed, and films made by rubbing the 

 cut surface against a clean slide. If there is an ulcer, films 

 may be made from the secretion from it. 



IJilms should be stained by the method which we have 

 recommended for the tubercle bacillus. If bacilli are present 

 in large quantities, the case is almost certainly one of leprosy, 

 for tubercle bacilli are never found in similar situations 

 except in scanty numbers. 



The organism is, as a rule, straighter than the tubercle 

 bacillus, and its protoplasm usually contains irregular 

 vacuoles. It is often found arranged in bundles, like a packet 

 of cigarettes. It is stained more easily than the tubercle 

 bacillus, not requiring the use of^a mordant. When stained 

 by the ordinary Ziehl-Neelsen's method it has been stated to 



