174 PHYSIOLOGICAL CHEMISTRY 



then stratified with approximately i c.c. of Wolff's reagent, 1 care being taken that 

 the liquids do not mix. The tubes should be read immediately against a dark 

 background and the tube giving a protein ring at the greatest dilution of gastric 

 juice recorded. A glance at Fig. 47 will show a pronounced case of gastric carci- 

 noma. With normal acid figures the protein concentration evolves proportionally 

 to the acidity. A case of achylia is shown in Fig. 48. 



Topfer's Method of Gastric Analysis 



This method is much less elaborate than many others but is sufficiently ac- 

 curate for ordinary clinical purposes. The method embraces the volumetric de- 

 termination of (i) total acidity, (2) free acidity (organic and inorganic), 2 and (3) free 

 hydrochloric acid, and the subsequent calculation of (4) combined acidity and (5) 

 acidity due to organic acids and acid salts, from the data thus obtained. 



Procedure. Feed the Ewald test meal as directed on page 161. At the end of 

 one hour remove the entire stomach contents and analyze as directed below. This 

 method of procedure is less accurate than the Fractional Method (see page 148). 

 Measure the volume of the gastric contents, strain it through cheese cloth and intro- 

 duce 10 c.c. of the strained material into each of three small beakers or porcelain 

 dishes 3 Label the vessels A , B, and C, respectively, and proceed with the analysis 

 according to the directions 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 200-300 c.c. may be found. 

 Very excessive volumes, e.g., 500-3000 c.c., are indicative of dilatation of the stomach 

 and suggest pyloric stenosis, either benign or malignant. 



i. Total Acidity. 4 Add 3 drops of a i per cent alcoholic solution of phenol- 

 phthalein 5 to the contents of vessel A and titrate with N/io sodium hydroxide solu- 

 tion 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 following ways: 



1. The number of cubic centimeters of N/io sodium hydroxide solution neces- 

 sary 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 i and 3, preference being 

 given to the former, particularly in clinical work. 



In making the calculation note the number of cubic centimeters of N/io 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. 



1 Phosphotungstic acid 0.3 c.c. 



Concentrated hydrochloric acid i . o c.c. 



Alcohol 95 per cent 20.0 c.c. 



Distilled water sufficient to make 100.0 c.c. 



2 For a discussion of combined acid see chapter on Gastric Digestion. 



3 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. ^ 



4 This includes free and combined acid and acid salts. 



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



