394 BACILLI IN CHRONIC INFECTIOUS DISEASES. 



bacilli from human tuberculosis. Of the guinea-pigs, which were 

 inoculated in the cavity of the abdomen, eleven remained in good 

 health and one only died of general tuberculosis. These experi- 

 ments show a decided difference in the pathogenic properties of 

 tubercle bacilli from the two sources, for the guinea-pig is especially 

 susceptible to tuberculosis as a result of similar inoculations with 

 bacilli from human tuberculosis. We must therefore conclude that 

 the bacillus found in spontaneous tuberculosis in fowls is a distinct 

 variety of Bacillus tuberculosis. Whether this variety would cause 

 tuberculosis in man, if introduced into susceptible subjects, has not 

 been determined ; and, as pointed out by Koch, this question can 

 only be answered in the affirmative if it should be obtained in pure 

 cultures from cases of human tuberculosis. 



Since the above was written Maffucci has published (1892) an 

 elaborate memoir upon tuberculosis of fowls. His conclusions are 

 stated as follows : 



" The bacillus cf tuberculosis in fowls is distinguished from that of tuber- 

 culosis in mammals by the following points of difference : 



"1. It does not induce tuberculosis in guinea-pigs, and seldom causes 

 general tuberculosis in rabbits. 



' ' 2. The cultures in various media have a different appearance from those 

 of the Bacillus tuberculosis of mammals. 



" 3. The temperature at which it develops varies between 35 arid 45 C., 

 and the thermal death-point is 70 C. 



"4. At 45 to 50 D C. the cultures show long, thick, and branched forms. 



" 5. The bacillus retains its vegetative and pathogenic power at the end 

 of two years. 



" 6. This bacillus produces a substance which is toxic for guinea-pigs and 

 is but slightly toxic for grown fowls. 



" 7. The tuberculosis produced in fowls by this bacillus is without giant 

 cells." 



55. BACILLUS LEPR^E. 



Discovered by Hansen (1879), chiefly in the interior of the peculiar 

 round or oval cells found in leprous tubercles. Discovery confirmed 

 by Neisser (1879) and by many subsequent observers. 



While found chiefly in the leprous tubercles of the skin and mucous 

 membranes, the bacilli have also been found in the lymphatic glands, 

 the liver, the spleen, the testicles, and, in the anaesthetic form of the 

 disease, in the thickened portions of nerves involved in the leprous 

 process. Some observers have also reported finding them in the 

 blood, but this appears to be quite exceptional. In the leprous cells 

 they are commonly found in great numbers, and they may also be 

 seen in the lymph spaces outside of these cells. They are not found 

 in the epidermal layer of the skin, but, according to Babes, they may 

 penetrate the hair follicles. 



Morphology, The bacillus of leprosy resembles the tubercle ba- 

 cillus in form, but is of more uniform length and not so frequently 



