ACID-FAST BACILLI 409 



carbol-fuchsin for half a minute. Again warm for a few seconds 

 over the flame without actual boiling. Allow it to stand and 

 stain for seven minutes. 



(3) Wash thoroughly in running water, and then decolorise in 

 either of the following solutions : 



(a) In Pappenheim's solution. 1 Place the preparation in a 

 wide-mouthed bottle containing the solution for not less than 

 four, and not longer than twelve, hours. Wash, dry, and mount. 

 Tubercle bacilli are the only organisms stained red. 



(b) In Pappenheim's solution without methylene blue. Proceed 

 as in (a) ; wash in water and counter-stain for a minute in weak 

 aqueous methylene blue solution. The tubercle bacilli are 

 brilliantly red. 



(c) In 25 per cent, sulphuric acid. Pour on a few drops of the 

 acid and allow it to act for half a minute. Pour off, and then 

 place the preparation in a wide-mouthed bottle containing the 

 acid for not less than sixteen hours and not more than twenty- 

 four hours. Wash thoroughly ; counter-stain with weak aqueous 

 methylene blue. Tubercle bacilli are the only bacilli which 

 retain the red. 



Acid-fast bacilli in milk and butter. Numerous acid-fast bacilli 

 have been obtained from milk and butter. They usually grow 

 freely and quickly on agar and on gelatin without liquefaction, 

 sometimes as a creamy layer, sometimes as a dry, crinkled film, 

 which may be pigmented (yellow, orange, pale brown or brick- 

 red). Some are pathogenic to guinea-pigs by massive intra- 

 peritoneal inoculation only, producing a plastic peritonitis, but 

 not nodules in the organs. In culture, the bacilli are acid -fast and 

 occasionally resemble B. tuberculosis, but are generally thicker. 

 (See Petri, Arb. a. d. Kais, Gesundheitsamte, xiv, 1897 ; Kabino- 

 witsch, Zeitschr. f. Hyg., xxvi, 1897 ; Grassberger, Munch, med. 

 Woch., 1899, Nos. 11 and 12; Tobler, ibid, xxxvi ; Swithinbank 

 and Newman, Bacteriology of Milk [Murray, 1903)]. 



Grass bacilli and mist bacillus. Moeller isolated from a grass 

 (Phleum arvense) an acid-fast bacillus which he termed the 



1 Pappenheirris solution consists of 1 part of corallin (rosolic acid) in 

 100 parts of absolute alcohol, to which methylene blue is added to satura- 

 tion ; 20 parts of glycerin are then added. 



