36 Notes from the Physiological Laboratory 



above indicated, but it seems very probable that by 

 immediate combination with albuminoids it loses 

 somewhat of its characteristic activity. This is il- 

 lustrated by an observation made in the course of 

 this study, namely, that the addition of small 

 amounts of potassium iodide to dilute solutions of 

 acid-albumen containing two-tenths of one per cent, 

 of hydrochloric acid does not result in the libera- 

 tion of iodine. The addition of the same amount 

 of the iodide to the same quantity of an aqueous 

 solution of hydrochloric acid of the same degree 

 of acidity results in an immediate liberation of 

 iodine. 



This interesting discovery of two stages of acidity 

 in the gastric juice has, I believe, not yet been in- 

 corporated in the text-books. It serves to reconcile 

 the contradictory opinions so frequently found as to 

 the value to the economy of saliva as a digestive 

 fluid, and explains the completely diverse results 

 obtained . by such careful workers as Frerichs, 1 and 

 Bidder, and Schmidt. 2 



Besides an observance of the time-limitations just 

 indicated, I would suggest the advisability of milk 



1 Wagner, Handwoerterbuch. d. Physiologie, iii., a, 772. 



2 Bidder und Schmidt, Verdauung u. Stoffwcchsel, p. 27. 



