APPENDIX 471 



free HC1, owing to digestive action, would be difficult, this is less so in the typical 

 case with its absent free HC1. To carry out the test it is best to give the patient 

 only a light supper and follow this with mild cathartic the same evening. Give 

 the Ewald test breakfast the next morning and withdraw contents in one hour. Fil- 

 ter the contents and of the nitrate deposit i c.c., 0.5 c.c., 0.25 c.c., o.i c.c., 0.05 c.c., 

 and 0.025 c.c. in six test-tubes. Make up contents of each tube to 10 c.c. with 

 distilled water. The dilutions will be from i to 10 in the first tube to i to 400 in the 

 sixth tube. After mixing the tubes superimpose i c.c. of the reagent on each tube. 

 The reagent is phosphotungstic acid 0.3 gram, concentrated HC1 i c.c., 96% alcohol 

 20 c.c., distilled water to make 200 c.c. 



Normal gastric juice gives a turbid albumin ring in the first two or occasionally 

 in the third (i to 40) tube. Turbidity in the i to 100 or over is suggestive of car- 

 cinoma. 



The increase of albumin content in malignant achylias is thought to be due to 

 the action of a specific ferment capable of acting on the protein content of the 

 meal forming the soluble albumin we test for. 



PEPSIN 



The determination of the quantity of pepsin is rather troublesome by the older 

 methods, and in consequence a simple method, which also uses a protein, will be given. 

 The protein used is edestin, a globulin obtained from hempseed. Dissolve o.i 

 gram of the edestin in 100 c.c. of 0.1% HC1. (This is most quickly done by 

 sprinkling the edestin over the surface of the acid.) In each of six small test-tubes 

 place exactly 2 c.c. of the edestin solution (thus giving 2 mg. of the substance 

 to each tube). Dilute i c.c. of stomach contents to 20 c.c. with water. To the above- 

 mentioned test-tubes are added, respectively, 0.2, 0.4, 0.6, 0.8, and i c.c. of the 

 diluted sample, the last test-tube being left as a blank. Shake each test-tube so 

 that its contents will be mixed. Allow the tubes to stand for thirty minutes. Then 

 to each tube add 0.3 c.c. of a saturated solution of NaCl. In those tubes which do 

 not contain sufficient pepsin to digest 2 mg. of edestin a white cloud or precipitate 

 will be produced while all others remain clear. (The blank or sixth tube must give 

 a copious precipitate or the edestin solution is worthless.) The tube containing the 

 smallest quantity of the dilute sample and giving no cloud or precipitate is selected. 

 Then by the formula 2 x dilution divided by the volume of dilute sample present is 

 obtained the number of milligrams of edestin that will be digested by i c.c. of the 

 undiluted sample. This quantity normally is said to be 100. If all but the sixth 

 tube failed to give the cloud or precipitate a greater dilution of the sample must be 

 made and the test repeated. The edestin solution rapidly decomposes and must 

 be made fresh when needed. 



Mett's Method for Quantitative Estimation of Pepsin. Capillary glass tubes, 

 i or 2 mm. in diameter are filled with white of egg, and after plugging one end with 

 bread crumbs the tubes are placed in water at 97 or 98C. for five minutes. The 

 tubes are sealed with plasticine or sealing wax. For the test dilute i c.c. of gastric 

 juice with 15 c.c. N/20 HC1 and put some into a test-tube. Then file off two 2 cm. 

 columns of the capillary tube with coagulated egg albumin. Place test-tube with its 

 albumin tubes in incubator for twenty-four hours. Then measure the digested ends 



