270 ILLINOIS STATE ACADEMY OF SCIENCE 



THE RETENTION MEAL 



' In order to obtain more information, if desired, regard- 

 ing gastric motility than is furnished by the ordinary test 

 meal, the patient may be fed a so-called retention meal. 

 This meal is fed in place of the customary evening meal 

 and contains substances readily detected. In the morning 

 before breakfast the stomach contents are removed and ex- 

 amined for food rests. A normal stomach should give no 

 evidence of food retention. A satisfactory retention meal 

 consists of six raisins. 



REMOVAL OF SAMPLES FOR ANALYSIS 



At exactly fifteen minute intervals from the time the 

 test meal is eaten until the stomach is empty, 10 c. c. 

 samples of gastric contents are withdrawn from the stom- 

 ach by means of aspiration. 



EXAMINATION OF SAMPLES 



The modern tendency among clinicians is to lay par- 

 ticular emphasis upon the value of free acidity and total 

 acidity. The determination of presence or absence of oc- 

 cult blood, mucus, and food rests are also of importance. 

 Microscopic examination may show remnants of food from 

 previous meals, red blood corpuscles, pus cells, sarcinae, ex- 

 cessive number of yeast cells, bacteria, and definite ab- 

 normal cells in an abnormal ulcerating cancer, all of which 

 are of diagnostic importance. 



DETERMINATION OF FREE HYDROCHLORIC ACID 



Principle — The indicator used is di-methyl-amino-azo- 

 benzene (Toeopfer's reagent.) 



Procedure — Measure 10 c. c. of the gastric contents and 

 introduce it into a clean 100 c. c. beaker. Add 2 drops of 

 Toeopfer's reagent, and if free hydrochloric is present the 

 solution will turn a visible pink (depth of color depending 

 upon acid concentration.) Titrate with N/10 sodium hy- 

 droxide until the red color is replaced by an orange yellow. 

 Take the burette reading and calculate for free acidity. 



