28 THE UNIVERSITY SCIENCE BULLETIN. 



3. Stain in the cold, with carbol-gentian violet, for two or three 

 minutes. 



4. Drain off the stain and treat with Lugol's solution until no 

 more metallic mirrors appear. Blot dry with filter paper. 



5. Decolorize with absolute alcohol and ether (equal parts) 

 until no more color comes from the slide. 



6. Counter-stain with methylene blue. 



7. Wash in distilled water and dry, and examine. 



The tubercle bacilli appear as bright red rods containing blue 

 granules. The other members of the acid-fast group, as well as 

 other Gram positive organisms, appear Gram positive. 



The scope of this paper is an investigation of the value of Gab- 

 bet 's, Ziehl-Neelsen 's, Pappenheim 's, Bunge and Trantenroth 's, 

 and Fonte 's methods as a means of differentiating between Bacil- 

 lus tuberculosis, B. leprae, B. smegma, Moeller's grass bacillus, 

 and the butter bacillus. 



This work was undertaken because of the various conflicting 

 statements in the literature as to the value of these solutions in 

 differentiating between true tubercle bacilli and the rest of the 

 acid-fast group ; because Pappenheim 's, Bunge and Trantenroth 's, 

 and Ziehl-Neelsen 's methods are accepted and used in many lab- 

 oratories as giving a reliable differentiation. 



Alvarez and TraviF (1885), Klemperer and Bittu,"* and Cowie-'^ 

 (1900- '01), as well as others, have described peculiar bacilli in 

 smegma taken from the genitals of man and the lower animals, 

 as well as from moist skin in the folds of the groin, the axilla and 

 the arms. They also mention its presence in normal urine and 

 sometimes in saliva and sputum. They are described as mor- 

 phologically resembling the tubercle bacillus and resisting decol- 

 orization by mineral acids, but being decolorized by alcohol. 



Moeller^ (1898) found in milk, butter, timothy hay, cow dujig, 

 etc., acid-fast organisms. They were acid-alcohol-fast but non- 

 pathogenic for laboratory animals. Moeller (1902) cultivated acid- 

 fast organisms from the skin. He concluded that all acid-fast 

 organisms that he had worked with were tinctorially like the true 

 tubercle bacillus. 



Marzinowski^" (1900) found saprophytic acid-fast organisms 

 associated with bronchitis. Frinkel" (1898), and Rabinovitch" 

 (1900), found acid-fast organisms associated with pulmonary gan- 

 grene; they were saprophytes. Petri (1897), Rabinovitch'- 

 (1899) and Korn" (1899) have described as Bacillus butyricus an 

 acid-fast organism, morphologically like the tubercle bacillus, 



