236 CORTEX 



is, therefore, necessary to use a lipid solvent (acetone, alcohol, 

 or ether) which extracts the adrenal lipids and incidentally the 

 cortical hormone. Acetone is by far the most practical sol- 

 vent, for it not only extracts the hormone efficiently but re- 

 moves less extraneous matter, and hence leads to the easier 

 production of a relatively pure product. 



The fresh glands are thoroughly macerated and shaken at 

 intervals for some hours with the acetone into which they were 

 originally ground. This operation is carried out at room 

 temperature for the acetone apparently inhibits the enzymic 

 activity which acts so deleteriously in the intact unfrozen 

 glands. 



The supernatant solvent is now poured off from the glandular 

 material. This glandular residue is refluxed three times with 

 approximately one-third of the acetone which was poured off, 

 the mixture being pressed after each refluxing. In this way 

 one carries out the three refluxings with the 2.5 to 3 volumes 

 of acetone originally used. The refluxing of the glands is 

 essential in order to extract the hormone which is tenaciously 

 held by the lipids of the adrenal tissue. Three successive 

 refluxings for about one-half hour, at the boiling point of ace- 

 tone, extracts about 95 per cent of the hormone present in the 

 glands. A fourth and fifth reextraction and refluxing give 

 only small amounts of the hormone. Since the purified 

 preparations of the hormone are soluble in acetone, it would 

 be improbable that this solvent fails, in subsequent extrac- 

 tions, to dissolve the hormone. Moreover, extraction of the 

 glandular residue with ethyl alcohol, ether, ethylene dichloride, 

 acid, or alkali fails to yield any appreciable amount of the 

 hormone. 



Since the adrenal cortical hormone is not completely ad- 

 sorbed from aqueous acetone solution by charcoal, the acetone 

 must be removed before proceeding to adsorb the hormone on 

 charcoal. After being chilled in the ice chest, the acetone 

 extract, obtained as described in the preceding paragraph, is 



