TESTICULAR INFUSION AGAR 



349 



REACTION 



The inclusion of 0.3 per cent NaH2P04 permits a considerable 

 variation in the amount of sodium hydroxide added to reduce 

 the titrable acidity. The results of a typical controlled experi- 

 ment upon this point are shown in table 3. I might mention here 

 having previously encountered some difficulty in the addition of 



TABLE 3 

 Range of reaction of testicular infusion agar 



*Assuming no unsaturated compounds. 



t Media darkened by caramelization — end point uncertain. 



more than sufficient alkali to saturate the phosphate, the glucose 

 being thereby caramelized on heating with resultant inhibition 

 of growth of the gonococcus. 



A liter of medium was prepared with the usual testicular 

 infusion, 2 per cent peptone, 3 per cent agar, 0.5 per cent glucose 

 and 0.3 per cent Na H2PO4. Before neutrahzation 5 cc. titrated 

 hot with phenolphthalein required 6 cc. N/20 NaOH to show 



