570 WILLIAM S. STURGES AND LEO F. RETTGER 



tion of ammonia. Analysis by the Folin micro-method revealed 

 less than 2 mgm. of ammonia nitrogen per 100 cc. of the sus- 

 pension, while there were 20 mgm. of amino nitrogen to be ac- 

 counted for. The deamidizing action of the autolysate was 

 tested on a weak solution of glycocoU, but little, if any, increase 

 in ammonia nitrogen could be detected. The long incubation 

 of the suspension may, however, have brought about a loss of 

 deamidizing action by this time. The hydrogen ion concentra- 

 tion was, at the end of the incubation period, approximately 

 pH 7.0, which does not suggest the liberation of any considerable 

 amount of ammonia. 



It may be of some interest to note (chart 11) the close agree- 

 ment of the initial determinations of the three saline suspensions. 

 In preparing these it was attempted to give lb a concentration 

 twice as strong, and Ic 6 times as strong as that of la. WTiile 

 this involved careful portioning of the pasty bacterial material, 

 which must have varied more or less in concentration in its 

 different parts, the first determinations of both biuret and amino 

 nitrogen show that the 3 suspensions bore the concentration 

 relationship of 1, 2 and 6. 



A liver extract agar was employed for the massive growth 

 of meningococcus required in the following meningococcus ex- 

 periment. A very luxuriant growth developed on this medium 

 (employed in 1-Uter Blake bottles) which was removed by scrap- 

 ing across the surface with a heavy wire bent into a loop at the 

 end. Thirty of the Blake bottles yielded enough growth to 

 make 11 grams of moist scrapings. This material was trans- 

 ferred to a sterile glass-stoppered bottle and kept in a freezing 

 mixture for three days, or until the experiments could be started. 

 Five grams of the viscid material were suspended in 100 cc. of 

 sterile distilled water (le). The remainder was divided and one 

 part made into a dilute (1 gram in 30 cc.) and the other into a 

 concentrated suspension in (2 grams in 30 cc.) physiological 

 saline solution. For the purpose of obser\-ing the effects of 

 incubation at 37° versus low temperature, each of these two 

 suspensions was divided into 2 parts. Five different suspensions 

 were used, therefore, namely; 



