EXPERIMENT STATION BULLETINS. 265 



Part II. 



H. J. STAFSETH. 



A few notes on the isolation and cultivation of Bacterium abortus with 

 special reference to liver and spleen media. 



INTRODUCTION. 



To isolate Bad. abortus is not always an easy task and sometimes it 

 is even more diflScult to keep a recently isolated strain growing. One 

 may obtain colonies which answer to the description of those of Bad. 

 abortus, but may find it impossible or at least very hard to get satis- 

 factory subcultures. This consequently retards the progress of abortion 

 investigation. Abortion bacilli are usually found in association with 

 other organisms which grow well on artificial media, and may thus out- 

 grow the former and make it almost impossible to secure pure cultures. 



Giltner (1) has called attention briefly to the use of media made from 

 the uterine wall, fetal membranes, fetus and amniotic fluid. The last 

 named was used successfully alone and with the addition of agar or 

 gelatin or both. Huddleson (2) used the following: 



Blood clot agar (blood clot one volume, water two volumes) ; 



Ascitic agar (ascitic fluid taken from fetus) ; 



Amniotic agar (fluid taken from amnion) ; 



Fetal agar (aborted fetus ground and made up as meat infusion) ; 



Glycerin agar and plain agar varying in degree of acidity. 



He reports the following results : ''Bad. abortus grew well on all 

 media excepting glycerin agar, and plain agar made neutral or 1.5 acid 

 to phenolphthalein. Plain meat infusion agar or blood clot agar made 

 1.2 acid to phenolphthalein are much more to be preferred for the grow- 

 ing of Bad. abortus owing to the fact that the organism can be isolated 

 on these media without difiiculty when anaerobic conditions are employed 

 (Nowak). One should never attempt to isolate Bact. abortus without 

 employing the anaerobic method. The writer has found that it is ab- 

 solutely impossible to isolate the organism under aerobic conditions." 



Smillie (3) has improved on the method of isolating abortion bacilli 

 from mixed cultures through guinea pigs inasmuch as he has shown 

 that this organism may be found in great numbers in the spleen of a 

 guinea pig three to four weeks after inoculation. The method described 

 by Smillie has been employed with success in this laboratory, but much 

 time has often been wasted in trying to make subcultures grow satis- 

 factorily. The direct culture method as described by Theobald Smith 

 (4) has also been employed and has met with success as far as obtaining 

 the first culture is concerned ; but here again the same difficulty as that 

 mentioned above was sometimes encountered. Although attempts to 

 isolate new strains invariably were successful in the end, it was felt 

 that if some medium could be made or some method devised, which would 



