ACID-FAST BACILLI IN BUTTER AND MILK 361 



Neufeld and others have obtained acid-fast organisms from 

 smegma, and Neufeld concludes that some of these may be described 

 as similar to B. diphtherias and others to the tubercle bacillus. 



(b) Acid-fast Tubercle Bacilli in Animals. The members of 

 this group are provisionally assumed to be related to the tubercle 

 bacillus. Eeference is made to these organisms under Tuberculosis 

 (see p. 349). 



(c) Acid-fast Bacilli in Butter and Milk. Several years after 

 Koch's discovery of the tubercle bacillus, species of bacteria were 

 found possessing acid-fast properties, but it was not until 1896 that 

 Koch and Petri isolated such organisms from the milk and butter of 

 Berlin, and in the following year Lydia Rabinowitsch carried out her 

 research on the same subject. In 1899, Korn discovered two bacilli 

 in the butter of Freiburg, Binot a bacillus in the butter of Paris, 

 and Coggi a bacillus in the butter of Milan, all four of which were 

 acid-fast. In the same year G-rassberger published a statement upon 

 acid-fast organisms occurring in butter and margarine. In 1900, 

 Beck and Santori met with similar organisms in milk; and in 1901, 

 Maria Tobler, Markl, and Moeller and Jong isolated acid-fast bacilli 

 from both butter and milk. All these organisms were bacilli, but 

 they showed much variation in form and polymorphism, some 

 appearing to be like B. diphtheria, and others like actinomyces. 

 The staining properties were, in all cases, those of the true bacillus 

 of Koch, except that the power of resistance to decoloration by acid 

 was rather less.* Swithinbank has cultured many of these organ- 

 isms upon different media, and has found them to show various 

 modifications in form, chromogenicity, vitality, polymorphism, etc. 

 By a series of cultures, he showed the various characters of ten of 

 these acid-fast species compared with the human and bovine tubercle 

 bacillus, all the cultures having been grown on the same media, for 

 approximately the same length of time, under precisely the same con- 

 ditions. The cultures were in each case composed of one colony only, 

 and admirably revealed the differences between the species. These 

 acid-fast bacilli live and develop on all ordinary media at room tem- 

 perature and blood-heat, preferably under aerobic conditions. They 

 do not form indol or liquefy gelatine, nor do they possess much patho- 

 genic action.-f 



The Butter Bacillus of Petri- Rabinowitsch. Morphologically, this 

 organism is like the ordinary tubercle bacillus, though somewhat 

 shorter and thicker. It stains in the same manner, but grows readily 

 at room temperature and rapidly at blood-heat. It is non-motile. 



* Report of Medical Officer of Local Government Board, 1900-1, pp. 331-3. 



t See Bacteriology of Milk (Swithinbank and Newman) ; in The Journal of State 

 Medicine, 1903-4, will be found a useful summary of present knowledge of acid-fast 

 bacteria, by A. C. Coles ; Potet's work should also be consulted. 



