338 A MANUAL OF BACTERIOLOGY 



tubercle. The occurrence of large numbers of bacilli, having the 

 same staining reactions as the tubercle bacillus and obtained from 

 the cutaneous structures, is diagnostic of leprosy (the smegma 

 bacillus may be present on, but not in, the skin). 



(2) In the tissues, sections of which are stained in the same 

 manner as tuberculous material, the diagnosis must be based on the 

 presence of the bacilli in large numbers in the so-called leprosy -cells. 



(3) Leprosy is not inoculable in guinea-pigs. 



N.B. It must be remembered that lepers not infrequently suffer 

 from coincident tuberculosis. 



(4) The differentiation of the leprosy from the tubercle bacillus 

 by staining methods cannot be said to be satisfactory. By staining 

 in a saturated aqueous solution of fuchsin in the cold for five to 

 seven minutes, and subsequently decolorising with acid alcohol 

 (nitric acid 1 part, alcohol 10 parts), it is stated that the leprosy 

 bacillus is stained, the tubercle bacillus not. 



The Smegma Bacillus 1 



The smegna bacillus is an organism found in the smegma 

 praeputii, between the scrotum and thigh, and between the 

 labia. It also occurs in the cerumen, occasionally on the 

 skin, and possibly in the sputum. 



It is a small bacillus resembling the tubercle bacillus 

 in size and appearance, and, like the latter, is difficult 

 to stain, but when stained with carbol- fuchsin, retains 

 the colour after treatment with a 25 per cent, mineral 

 acid (Plate X. 6) ; it is also Gram-positive. It has, 

 therefore, to be distinguished from the tubercle bacillus 

 in certain localities, viz. in urine and about the external 

 genitals. It is non-inoculable on animals, and does not 

 usually grow in primary cultures on ordinary media, 

 but can be isolated by the use of blood- serum or nutrose- 

 agar, on which it forms delicate, ropy colonies. After 

 isolation it grows freely on agar as a thin, slightly brownish, 

 creamy layer, in which the bacilli may be very short but 



1 See Neufeld, Arch. f. Hygiene, xxxix, p. 184; Zeitschr. /. Hyg., 

 Xxxix, 1901 ; and Moeller, Centr.f. BakL, xxxi, 1902 (Originale), p. 278. 



