286 



Scientific Proceedings (116). 



change the hydrogen ion concentration of 100 c.c. of medium from 

 one stated hydrogen ion concentration to the other. While for 

 most purposes of interest to the sanitary or medical bacteriologist 

 the range of hydrogen ion concentration between the limits of 

 Ph 8.0 and Pr 5.0 is sufficient, the buffer index between other 

 limits may be determined for special purposes. 



The titration of a large number of samples of bouillon of sup- 

 posedly the same composition showed wide variation in their 

 buffer indices. If one is working with an easily cultivated or- 

 ganism such as Bacterium coli and wishes to determine its limiting 

 hydrogen ion concentration in a few hours, a medium of low buffer 

 index should be selected. If on the other hand a large amount of 

 growth or the fermentation of a large amount of sugar is desired, 

 a medium of high buffer index should be used. Less fermentable 

 sugar is required in a poorly buffered medium than in a medium 

 of high buffer content. In a bouillon of low buffer index a small 

 amount of dextrose may be sufficient to produce a high terminal 

 acidity whereas the same organism may ferment a much larger 

 amount of dextrose in a bouillon of high reserve alkalinity and 

 high buffer index and yet produce a terminal alkalinity. 



The author has devised a very simple method of titrating the 

 reserve acidity, reserve alkalinity, and buffer index of media, a 

 method requiring only a few cubic centimeters of medium and 

 easily carried out by a laboratory technician in a few minutes. 

 A description of this method is now in press. 



145 (1727) 



I. Gastric resection: experimental data on the duodenal loop. 



By W. HOWARD BARBER and LOUIS C. LANGE. 



[From the Department of Experimental Surgery, New York 

 University and Bellevue Hospital Medical College.] 



Operable new growths and malignant ulcers require in selected 

 cases resection of the pyloric end of the stomach. After resection, 

 the surgeon is forced to meet the problem of gastroenterostomy. 



