408 A MANUAL OF BACTERIOLOGY 



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 retain their 

 acid-fast properties ; on potato it forms minute (0-5- 

 1 mm.) greyish colonies. 



Staining and Differentiation 



Film preparations of smegma may be stained in exactly the 

 same manner as for tubercle, after treating the preparations with 

 ether to get rid of fatty material. 



The urine should be drawn off with a catheter when it is to be 

 examined for the tubercle bacillus ; this will generally exclude the 

 smegma bacillus. Young and Churchman l conclude that the 

 smegma bacillus is a scant invader of the male urethra, and that 

 by washing the glans and irrigation of the urethra it may be 

 eliminated from the urine. 



If there is reason to suspect the presence of the smegma bacillus 

 when staining for tubercle, Bunge and Trautenroth 2 recommend 

 that the film specimens should be treated as follows : 



( 1 ) Immerse in absolute alcohol for three hours. 



(2) Immerse in 5 per cent, chromic acid for fifteen minutes. 



(3) Stain in warm carbol-fuchsin. 



(4) Decolorise in 25 per cent, sulphuric acid for two to three 

 minutes. 



(5) Counter-stain in a concentrated alcoholic solution of 

 methylene blue for five minutes. 



The smegma bacillus will be decolorised by this method (see 

 also p. 398). 



Coles recommends (Journal of State Medicine, vol. xii, 

 1904, p. 225) the following staining method : 



(1) Spread thin and even films on slides, and fix by heat, in the 

 ordinary way. 



(2) While still warm from the heat fixation flood with filtered 



1 Johns Hopkins Hospital Rep., vol. xiii, 1906, p. 15. 



2 Fortechrit. der Med., xiv, 1896, Nos. 23 and 24. See also ibid. No. 9. 



