226 METHODS FOR THE ANALYSIS OF GASTRIC JUICE 



introduce 10 c.c. of the strained material into each of three small 

 beakers or porcelain dishes. 1 Label the vessels A, B, and C, 

 respectively, and proceed with the analysis according to the direc- 

 tions given below. The volume of fluid present in the stomach 

 one hour after an Ewald meal varies under normal conditions 

 between 50 and 100 c.c. In cases of hypersecretion or defective 

 motility 200 to 300 c.c. may be found. Very excessive volumes, 

 e.g., 500 to 3000 c.c., are indicative of dilatation of the 

 stomach and suggest pyloric stenosis, either benign or 

 malignant. 



1. Total Acidity. 2 Add 3 drops of a 1 per cent alcoholic solu- 

 tion of phenolphthalein 3 to the contents of vessel A and titrate 

 with N/10 sodium hydroxide solution until a faint pink color is 

 produced and persists for almost two minutes. Take the burette 

 reading and calculate the total acidity. 



Calculation. The total acidity may be expressed in the fol- 

 lowing ways: 



1. The number of cubic centimeters of N/10 sodium hydroxide 

 solution necessary to neutralize 100 c.c. of gastric juice. 



2. The weight (in grams) of sodium hydroxide necessary to 

 neutralize 100 c.c. of gastric juice. 



3. The weight (in grams) of hydrochloric acid which the total 

 acidity of 100 c.c. of gastric juice represents, i.e., percentage of 

 hydrochloric acid. 



The forms of expression most frequently employed are 1 and 3, 

 preference being given to the former, particularly in clinical 

 work. 



In making the calculation note the number of cubic centimeters 

 of N/10 sodium hydroxide required to neutralize 10 c.c. of the 

 gastric juice and multiply it by 10 to obtain the number of cubic 

 centimeters necessary to neutralize 100 c.c. of the fluid. If it is 

 desired to express the acidity of 100 c.c. of gastric juice in terms of 

 hydrochloric acid, by weight, multiply the value just obtained 

 by 0.00365. 4 



1 If sufficient gastric juice is not available it may be diluted with water 

 or a smaller amount, e.g., 5 c.c., taken for each determination. 



2 This includes free and combined acid and acid salts. 



3 One gram of phenolphthalein dissolved in 100 c.c. of 95 per cent alcohol. 



4 One c.c. of N/10 hydrochloric acid contains 0.00365 gm. of hydrochloric 

 acid. 



