A MODIFIED PROCEDURE FOR THE PREPARATION 

 OF TESTICULAR INFUSION AGAR 



GUY W. CLARK 



From the Research Department of the Cutter Biological Laboratories, Berkeley, 



California 



Received for publication, September 16, 1919 



Different workers in the culture media department of this lab- 

 oratory have experienced some difficulty in preparing, according 

 to Hall's (1916) method, testicular infusion agar that would reg- 

 ularly provide a medium suitable for the growth of the gonococcus 

 in the production of vaccines. Without any effort to try other 

 media, experimental work was carried out with the view of so 

 modifying the above mentioned method that a satisfactory me- 

 dium could be regularly obtained. 



From the results obtained with nine strains of gonococci (some 

 rather old laboratory cultures, others recently isolated), upon 

 several lots of testicular infusion agar, the following procedure is 

 suggested : 



Remove and discard the tunica vaginalis from fresh beef testicles, 

 rinse in running water and grind. 



Mix 500 grams of ground testicle and 500 cc. of distilled water and 

 infuse overnight at room temperature. 



The following morning heat to 50°C. and keep warm for one hour 

 (the value of this step is questionable), heat in a steam kettle or double 

 boiler, stirring constantly, until the proteins are completely coagulated 

 and tend to collect in large flocculi. This material should never be 

 heated over a bare flame as it scorches easily. Strain through coarse 

 cloth and, if necessary, add distilled water to bring the volume to 750 

 cc. To the warm liquid add 20 grams of Parke, Davis and Company's 

 peptone and 3 grams of monobasic sodium phosphate (NaH 2 P0 4 .H 2 0), 

 stir to dissolve and while warm (not more than 40°C), adjust to pH 

 7.4 to 7.8, using the phosphate mixtures of Sorensen (1912) or Clark and 

 Lubs (1916) as comparative standards of pH, with phenol red as an in- 



99 



