GONOCOCCUS STARCH MEDIUM 27 



necessary amount of N/i acid or alkali, we place the inner compartment in the outer 

 one of the rice cooker, bring to a boil and filter through filter-paper which has been 

 wetted with boiling water. The filtration can be carried out in the autoclave or in an 

 Arnold sterilizer. Of course the ordinary filtering through gauze and cotton will 

 answer where clearer media is not an object. 



GLUCOSE AGAR 



Add the agar to i or 2% glucose bouillon and pro eed as for ordinary agar. If 

 preferred, the glucose agar can be made by rubbing up meat extract 3 grams, peptone 

 10 grams, salt 5 grams, glucose 10 grams and 15 grams of agar in 1000 c.c. of water 

 containing the white of egg (one to two eggs), then boiling in the rice cooker and 

 filtering. 



GLYCERINE AGAR 



Add the agar to 6% glycerine bouillon instead of nutrient bouillon, or the gly- 

 cerine may be added to nutrient agar which has been melted. Glycerine agar with a 

 reaction of o makes an excellent base for blood and serum media for use in culturing 

 delicate pathogens. 



GLYCERINE AGAR EGG MEDIUM 



Take the white and the yolk of one egg and mix thoroughly in a vessel kept 

 between 45 and 55C. with an equal amount of glycerine agar. Tube the medium, 

 inspissate in a rice cooker as for serum tubes, and sterilize as for blood-serum tubes. 



This makes an excellent medium for growing tubercle bacilli. As egg medium has 

 a tendency to be dry, it is well to add i c.c. of glycerine bouillon to each slant before 

 autoclaving. 



VEDDER'S STARCH MEDIUM 



Macerate 500 grams of beef in 1500 c.c. of water in ice box over night. In the 

 morning filter into stew pan through doubled gauze. Bring fluid slowly to a boil and 

 add agar iH%- Boil for from twenty to thirty minutes. 



Titrate and correct reaction to 0.2 to 0.7 acid. Check reaction to show faint blue 

 on red litmus. 



Let cool to about 6oC. and add two whole eggs, well beaten, to clarify. Bring 

 very quickly to a boil, then turn down flame and allow to simmer until a complete 

 coagulum forms. 



Filter through gauze and cotton and add i % starch. 



Let stand in Arnold for about forty-five minutes, shaking about three times during 

 this period, to distribute the starch. 



Tube or flask, and sterilize in autoclave for fifteen minutes at 10 pounds. There 

 must be plenty of water of condensation and the agar must not exceed i>%. 



This is especially recommended for culturing gonococci. English workers have 

 used it in isolating meningococci from carriers. For this purpose the starch agar 

 has i% of glucose added to it and colored with litmus solution. The Meningococcus 

 acidifies the glucose while the M. Catarrhalis does not. 



