New York AGRICULTURAL EXPERIMENT STATION. 193 
sin in gastric digestion does not act upon pure proteids but only 
upon their compounds with acids, in this case hydrochloric acid. 
While this general view has been held for some time, there have 
not, so far as we know, been any actual experiments previously 
made in testing the action of pepsin upon pure compounds 
formed by proteids with acids. We have done this only in the 
case of the unsaturated paracasein lactate, but this appears as 
the first instance to furnish proof in an individual case of what 
may be found true, in general, of all cases of peptic digestion. 
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