428 ACTIN0MYCETE8. 



Mycobacteria which Grow Luxuriantly at Room Tem- 

 perature. 



Literature. — The real discoverer of these organisms in butter is Petri. 

 He pointed them out to E. Koch in July, 1896, who expressed his 

 belief that they -were diSerent from true tubercle bacilli, which was 

 also the opinion of Petri. A subsequently undertaken investigation 

 by Lydia Rabinowitsch at Koch's suggestion appeared before Petri's 

 work as a preliminary communication in the Deutsch. med. Wochen- 

 schr., Aug. 5, 1897, and in detail in Z. H. xxvi, 1897, 90. Petri's 

 work was published (A. G. A. xiv, 1, 1898) after he had published a 

 note concerning it in the H. E., Aug. 15, 1897. 



Further important communications are : Hermann and Morgenroth 

 (H. E., 1898, 217 and 1081); Moeller (Verb. d. Gesell. deut. Naturf. u. 

 Aerzte, 1898 ; Deutsche med. Wochensohr., 1898 ; andC. B. xxv, 369); 

 O. Schultze and Lubarsch (Z. H. xxxi, 153). 



The most interesting discovery in the field of the mor- 

 phology of bacteria during the past three years is to be 

 considered that of the micro-organisms resembling the 

 tubercle bacillus. Three years ago every acid-proof bac- 

 terium was a "tubercle or lepra bacillus"; to-day we 

 know, through the harmonizing labors of many investi- 

 gators ^ (Petri, Rabinowitsch, Moeller, and others) that 

 acid-proof varieties occur not infrequently in the environs 

 of men and domestic animals. Still, their differential diag- 

 nosis from the Mycobacterium tuberculosis appears quite 

 easy, and yet the forms now known approach it in so 

 many characteristics that, after the experiences with diph- 

 theria and cholera, we must expect that still further diffi- 

 culties will arise after more extensive studies. The exceed- 

 ingly interesting forma piscicola of the Mycob. tuberculosis 

 described on page 420 shows us to what a degree the true 

 T. B. culture may change biologically (growth at room 

 temperature, formation of a violet pigment in milk). 

 Who knows how our newly discovered mycobacteria cul- 

 tures may change if they are cultivated at incubator tem- 

 perature or in the animal body for many generations ? 



To-day naturally it is not possible to consider the Myc. 

 tuberculosis, without further knowledge, as a form of one 

 of these organisms, which has been adapted to warm- 



' In manure acid-proof bacteria had already been found by stain- 

 ing : Severin (C. B. L. I, 98) ; Ferrdn (C. B. xxil) ; Capaldi (Z. H. 

 XXVI, 105). 



