ACID-FAST ORGANISMS 359 



resisting decolorisation by the acid following the red stain.* In 

 England such bacilli are termed acid-fast, in Germany saurefcste, 

 and in France acidopliile. The group is one of great importance, 

 partly on account of the ease with which its members may be 

 mistaken for the " true " tubercle bacillus, and partly on account of 

 the relationship which appears to exist between them and the 

 tubercle bacillus. Some bacteriologists hold that possibly these 

 acid-fast bacilli represent a saprophytic stage in the life-history of 

 the true tubercle bacillus. 



In his description of the tubercle bacillus, Koch foretold the 

 probability of other acid-fast organisms being discovered, and some 

 fourteen years after, in 1896, Koch and Petri actually demonstrated 

 the occurrence of such bacilli in the butter and milk of Berlin. In 

 the years immediately following, Eabinowitsch, Korn, Coggi, Tobler, 

 and others, found further organisms of this nature in such articles 

 of food. In 1898 Moeller showed that these acid-fast bacilli 

 occurred naturally in animals and plants. Dust, grass, hay, manure, 

 and similar substances yielded them, and now it is known that a 

 considerable family of these bacteria exists. It should, however, be 

 understood that the group is provisional only. Further knowledge 

 may reveal facts which would considerably modify present views. 



Classification of Acid - fast Bacilli. These bacilli may be 

 divided provisionally and for convenience into four chief sub- 

 divisions : 



(a) The acid-fast bacilli of other diseases or conditions affecting 

 man (e.g., B. leprce, B. smegmatis, B. of syphilis of Lustgarten, etc.). 

 Other non-tubercular acid-fast bacilli have been found in lung 

 gangrene (Frankel), in the nasal cavities (Karlinski), in excreta, 

 and in certain chronic eye diseases, etc. 



(b) The acid-fast bacilli occurring in other animals (e.g., B. 

 tuberculosis avium of Maffucci; the B. tuberculosis piscium of Dubard, 

 Bataillon, Terre ; B. tuberculosis ranicola of Lubarsch ; B. tuberculosis 

 anguicola of Moeller, etc.). 



(c) The acid -fast bacteria of butter and milk (e.g., B. laticola 

 planus,perrugosum, Friburgense, etc.), of Petri, Moeller, Eabinowitsch, 

 Binot, Markl, Coggi, Tobler (Nos. i.-v.), Grassberger, and Korn (Nos. 

 i. and ii.). 



(d) The acid-fast bacilli of grass (e.g., B. pJilei or Timothy lacillus, 

 and Grass bacillus, No. ii., of Moeller), the "manure bacillus" of 

 Moeller, the urine bacillus of Marpmann. 



All these various organisms are morphologically and in staining 



* Acid-fastness is due, in all probability, not to fat in the bacillus, but to a 

 substance of the nature of wax, which can be extracted by acid-alcohol, ether, or 

 other wax solvents. For a discussion of this subject, see Trans. British Congress of 

 TvbtreuMi, 1901, vol. iii., pp. 498-502 (Bulloch). 



