80 DIFGOMANUAL 



The formula for Bacto-Brain Heart Infusion with PAB and Agar is identical 

 with Bacto-Brain Heart Infusion except for the addition of 0.05 gram of p-amino- 

 benzoic acid and 1 gram of Bacto-Agar per liter. The addition of this small 

 amount of agar to the medium provides optimum conditions for the rapid luxu- 

 riant development of obligate anaerobes, micro-aerophiles and aerobes. To rehy- 

 drate the medium suspend 38 grams of Bacto-Brain Heart Infusion with PAB 

 and Agar in 1000 ml. distilled water and heat to boiling to dissolve the medium 

 completely. 



Both of these media are distributed in tubes or flasks and sterilized in the 

 autoclave for 15 minutes at 15 pounds pressure (121°C.) Final reaction of the 

 media is pH 7.4. 



BACTO 



HEART INFUSION BROTH (B38) 



DEHYDRATED 



Beef Heart, Infusion from 500 g. 



Bacto-Tryptose 10 g. 



Sodium Chloride 5 g. 



Bacto-Heart Infusion Broth is a liquid medium containing the extractives 

 from fresh beef heart. It is recommended as a general laboratory medium for 

 pathogenic as well as non-pathogenic bacteria. A liquid medium, prepared from 

 an infusion of beef heart, is recommended in "Diagnostic Procedures and Re- 

 agents"^ of the American Public Health Association for blood culturing the 

 meningococcus and for other purposes. The "Standard Methods for the Exami- 

 nation of Dairy Products"^ specify the use of a Heart Infusion Broth for their 

 study of pathogenic streptococci. 



Bouillon, or a liquid medium containing an infusion of meat, was one of the 

 first media used for cultivation of bacteria. Many modifications of this medium 

 have been used from time to time for a wide variety of purposes. Huntoon^ using 

 fresh beef heart and Bacto-Peptone, prepared a "hormone" broth in a special 

 manner, to retain the growth-promoting substances. In order to have such a 

 liquid infusion medium readily available, Bacto-Heart Infusion Broth was devel- 

 oped. Bacto-Tryptose, as employed in this medium, is better suited for the nutri- 

 tional requirements of pathogenic bacteria than is Bacto-Peptone which was 

 used by Huntoon in the preparation of his "hormone" media. 



The cultural value of Bacto-Heart Infusion Broth is greatly increased by the 

 addition of 0.1-0.2 per cent Bacto-Agar as discussed on page 77 under Bacto- 

 Brain Heart Infusion. Many other modifications of the medium may also be 

 made, such as the addition of dextrose, blood, or other ingredients to give an 

 unlimited number of media for a variety of purposes. 



To rehydrate the medium, dissolve 25 grams of Bacto-Heart Infusion Broth 

 in 1000 ml. distilled water, distribute in tubes and sterilize in the autoclave for 

 15 minutes at 15 pounds pressure (121°G.). The final reaction of the medium is 

 pH 7.4. 



For best results, the medium should be freshly prepared. If it is not used the 

 same day as sterilized, heat in boiling water or flowing steam for several minutes 

 to remove absorbed oxygen and cool quickly without agitation, just prior to 

 inoculation. 



One pound of Bacto-Heart Infusion Broth will make 18.1 liters of medium. 



1 Dia^ostic Procedures and Reagents, 2 Standard Methods for the Examination 



3rd Edition: 13: 1 950. of Dairy Products, 9th Edition: 141: 1948. 



8 J, Infectious Diseases, 23:169:1918. 



