Bacillus Histolyticus 



501 



246 (2206) 



The aerobic cultivation of bacillus histolyticus. 



By IVAN C. HALL. 



[From the Department of Bacteriology and Experimental Path- 

 ology, University of California, Berkeley, Calif.] 



A strain of B. histolyticus (No. 141) received from the Pas- 

 teur Institute in Paris in March, 1921, and described by me 1 

 last year, was recently found capable of repeated and successive 

 aerobic culture upon the surface of meat infusion and blood 

 agar slants without resort to any method of reducing the oxygen 

 pressure. The accuracy of this observation is guaranteed not 

 alone by the unique pathogenicity, but as well by the particular 

 combination of morphologic and cultural properties of this 

 species which enable one to identify it without reference to its 

 oxygen requirements. 



All authors dealing with B. histolyticus have regarded it as 

 an obligate anaerobe and my own previous failure to observe 

 aerobic growth can only be explained by my reliance upon meat 

 extract, instead of meat infusion, agar slants, for detecting 

 aerobic growth until recently. Even the growth upon meat in- 

 fusion agar is extremely delicate and might be easily overlooked 

 by any but a highly critical dye. My first supposition upon ob- 

 serving the delicate transparent aerobic growth upon a meat in- 

 fusion blood agar slant was that a contamination had occurred. 

 This assumption was clearly denied when as many as 31 suc- 

 cessive transplants of this culture were made upon blood and 

 plain meat infusion agar during a period of about 60 days with- 

 out altering any of its morphologic, cultural or pathogenic char- 

 acteristics permanently; there were temporary differences ob- 

 served, however, in the morphology of the first few aerobic cul- 

 tures, but later transplants appeared to be identical in every way 

 with a corresponding strain cultured anaerobically in brain 

 medium. 



The possibility of contamination was also excluded by find- 

 ing no significant differences in well separated deep agar col- 

 onies and in the observation that subcultures from such deep 



iHall, Jour. Inf. Bis., 1922, xxx, 445. 



