38 Notes from the Physiological Laboratory 



nascent mercuric iodide reaction * or by the biuret 

 reaction and control test, is greatly diminished. 

 This result is not due to a slight diminution in the 

 acidity of the solution, caused by the addition of 

 an alkaline body; for the same effect is noted when 

 the acidity of the solution is at once again brought 

 up to the normal degree. The pepsin is apparently 

 but little, if at all, affected by the presence of the 

 iodide, if we may judge by the indifference of 

 ptyalin to the drug, and by the fact that quantities 

 of the iodide corresponding to the maximal thera- 

 peutic dose neither entirely suspend the peptic ac- 

 tivity, nor induce greater retardation of the diges- 

 tion than do much smaller quantities. A slight 

 effect is exerted by the iodide upon the proteid 

 food-stuffs, evidenced in an increased toughness pro- 

 duced in, e.g., fibrin, and, when the drug is abun- 

 dantly present, in the acquisition by the albuminoid 

 of a slightly yellow tinge, due to staining by iodine, 

 which is liberated by the free acid of the artificial 

 gastric juice. 



The most important factor in the delay of pep- 

 tonization lies in the power possessed by potassium 



1 Kandolph : A Keaction Common to Peptone and Bile- 

 salts. Proe. Acad. Nat. Sci. of Phila., 1884. 



