GASTRIC ANALYSIS 



167 



(b) Determination of Free Acidity. The reagent most widely used 

 clinically, for the determination of free hydrochloric acid in stomach 



100 



acidity 



O 

 



40 



Freeaciditg 



V* y* */4 I I 1 /* IVz 1 V4 2 hours 



FIG. 52. ACIDITY CURVES FROM A CASE OF HYPERACIDITY. 



contents is Topf er 's reagent (see page 176). It has been found, however, 

 that this reagent gives rather inaccurate results due to the uncertain 



FIG. 53. ACIDITY AND PROTEIN CURVES IN GASTRIC CARCINOMA. (Clarke and Rehfuss: 

 Jour. Am. Med. ^4w', 64, 1737, 1915.) 



end point. For this reason we have employed Sahli's reagent. 1 This 

 reagent contains KI and KIOs and liberates iodine in the presence of 



1 A mixture of equal parts of a 48 per cent solution of potassium iodide and an 8 per cent 

 solution of potassium iodate. 



