120 Manual of Veterinary Microbiology. 



A. Fluid media. 

 1. Bouillons. 



Bouillons are the media most commonly used.* 

 They are prepared from the flesh of the different do- 

 mesticated animals, but especially from that of the 

 calf, the ox, and the chicken. 



One kilogram of lean meat, free from bone, is 

 finely minced and allowed to macerate for twenty-four 

 hours in two liters of water, in a cool place. The 

 reddish fluid which bathes the meat is expressed, 

 brought up to its original volume, and to it is added 

 one-half per cent of table salt and a trace of potas- 

 sium phosphate, occasionally, also, from one to three 

 per cent of peptone, glycerin, and glucose. The 

 liquid is then cooked for an hour at 100° in the Koch 

 sterilizer, by which means a certain amount of its al- 

 bumen is coagulated; it is strained through linen and 

 then neutralized with a one per cent solution of 

 caustic potash, or a five per cent solution of sodium 

 carbonate. The filtered and neutralized bouillon is 

 subjected, during ten minutes, to 115° in the auto- 

 clave, then again filtered. This bouillon, introduced 

 into a conical fiask stopped by a plug of wadding, is 

 finally sterilized by a last heating of a quarter of an 

 hour at 115°. It is then ready to be introduced into 

 the culture vessels. The culture vessels most com- 

 monly employed are the Pasteur bulbs. These are 

 small vials of thin glass, flat on the bottom, and with 



* [Except for special purposes, or where a Large quantity of the 

 culture is required, solid media are now more in use than bouil- 

 lons.— D.] 



