DAVID I. HITCHCOCK 739 



SUMMARY. 



The amount of HCl combined with a given weight of gelatin has 

 been determined by hydrogen electrode measurements in 1 per cent, 

 2.5 per cent, and 5 per cent solutions of gelatin in HCl of various 

 concentrations, by correcting for the amount of HCl necessary to give 

 the same pH to an equal volume of water without protein. The 

 curve so obtained indicates that the amount of HCl combined with 

 1 gm. of gelatin is constant between pH 1 and 2, being about 0.00092 

 moles. 



The writer wishes to express his gratitude for the advice of Dr. 

 Jacques Loeb, under whose direction this work was done. 



