THE PREPARATION OF BOUILLON 7 



EXEkciSE III 



THE PREPARATION OF BOUILLON 



10. Bouillon is the liquid medium most commonly employed 

 in cultivating bacteria. It is practically a beef tea containing 

 peptone. There are several methods recommended for mak- 

 ing it. (i) It may be made directly from simple meat infusion 

 or (2) it maybe made from meat extract. The meat infii- 

 sion is prepared either by allowing finely chopped lean meat 

 mixed with twice its quantity of distilled or filtered and boiled 

 tap water ( 2 c.c of water for each gram of meat ) to stand 

 in a cool place for from 12 to r8 hours, or the mixture of meat 

 and water may be heated with frequent stirring at a temperature 

 of 6^;° C. for a short time (o ne hour). Each has its advan- 

 tages. When meat extract is used in place of the meat infu- 

 sion, the bouillon does not seem to be a favorable culture fluid 

 for certain bacteria. In making bouillon therefore it becomes 

 necessary to determine the kind (whether from meat infusion 

 or extract) and the method of preparing it to suit the condi- 

 tions in hand. It is sometimes desirable in bacteriologic inves- 

 tigations to resort to all of these methods. For the routine 

 work in the laboratory, bouillon prepared directly from the 

 meat by macerating it for a short time at a high temperature 

 (65° C.) is very satisfactory. The addition of peptone and 

 the neutralization of the liquid is the same in both cases. 



Bouillon is used as the nutritive base in preparing agar and 

 gelatin. On this account the large quantities are stored in 

 flasks. (For other methods see text-books. Also Jour, of the 

 Am. Public Health Asso., Jan. 1898, p. 77.) 



References. — Chapters on making culture media in text-books, 

 p. xi., Jour, of the Am. Public Health Asso.,i Oct., 1895. Ibid., 



^ In June, 1895, a convention of bacteriologists was called in New York 

 City under the auspices of a committee of the American Public Health 



