296 MANUAL OF BACTERIOLOGY. 



The results of inoculation into man and the lower ani- 

 mals of material coming from cases of leprosy have been 

 uncertain. The bacillus of leprosy has been found so con- 

 stantly in the tissues of those having the disease that it is gener- 

 ally admitted to be the specific cause. The skin and the periph- 

 eral nerves are the parts most affected, although other tissues 

 and the internal viscera may be involved. A granulation 

 tissue, forming nodules and thickenings, appears in the affected 

 parts. The bacilli are found in large numbers in the nodules, 

 partly outside of the cells, but mostly within the cells. It is 

 still uncertain whether or not the disease can be transmitted 

 directly from one individual to another, in extra-uterine Hfe, or 

 whether it can be inherited from the parents. However, no ex- 

 planation can be given for the appearance of the infection in any 

 patient, except communication with some other case. Trans- 

 mission by contact seems at any rate not to take place easily. 



Bacillus mallei (bacillus of glanders). — A slim bacillus with 

 round or pointed ends, which often shows alternate hght 

 and dark spots in stained preparations. Branching forms 

 have been described. It is not motile. It probably does not 

 form spores. It does not retain the stain by Gram's method. 

 After staining with the ordinary aniline dyes it is easily decolor- 

 ized, and on that account it is difficult to demonstrate in sections 

 of tissues. It is facultative anaerobic. It grows at the room 

 temperature, but better in the incubator. It grows slowly on 

 gelatin, and does not liquefy it, or only after a long time. On 

 agar it produces a moist, white growth; on blood-serum, a yel- 

 lowish or brownish growth; blood-serum is not liquefied. Milk 

 is coagulated slowly, and the reaction becomes acid. On potato 

 the growth is characteristic in one or two days in the incubator, 

 becoming translucent amber-yellow, later a reddish brown, 

 while the surface of the potato becomes discolored. 



It is killed in five minutes by a 5 per cent, solution of carbolic 

 acid; in two minutes by 1-5000 bichloride of mercury. It 

 may survive drying for a number of weeks. 



