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copper sulphats solution produced substantially the same results as boiling water.

We also found that various organic and inorganic reagents will separate the potent substance from the other extractive substances and of these benzoic acid, formed by adding sodium bensoate and hydrochloric acid to the extractive solution will unite with the potent substance as by adsorption.

In an alternative method we found that by adding an equal volume of saturated solution of ammonium sulphate to the aquous extractive solution, a solid separated out of the solution and floated to the top. This solid contained the potent substance and some of the other extractive substances. We removed the solid and after eliminating the adhering ammonium sulphate we dissolved the solid in distilled water and separately added to the resulting solution sodium bensoate and hydrochloric acid which formed a precipitate of bensoic acid and this precipitate united with the potent substance as by adsorption.

The following is an example of one method by which we obtained the potent substance or extract containing in concentrated form the internal secretion or hormone of the pancreas of mammalia:-

The fresh pancreas was minced and mixed with an equal volume of boiling water which extracted from the gland the potent substance derived from the secretion or hormone. The temperature of the resulting aqueous extractive solution was maintained at from 85 c. to 100 c. for a period of about five minutes and then suddenly reduced to about 15 c. at which it was allowed to stand. The boiling water tended to prevent the proteins going into the extractive aqueous