232 CORTEX 



of fresh cortical tissue to 100°C. preserves the hormone content 

 of the adrenals, but it requires several hundred grams of this 

 tissue per day to maintain the life of an adrenalectomized dog. 246 

 Injection of fresh saline suspensions of the cortex into cats or 

 dogs desensitized to beef protein also fails to elicit any thera- 

 peutic effects because of the relatively large amount of material 

 necessary to supply an appreciable amount of the hormone. 

 The adrenal thus differs from the thyroid which may be effec- 

 tively administered by feeding the dried gland, or the pituitary 

 which when implanted elicits the effects of its growth hormone 

 in hypophysectomized animals. 



Another important difficulty in the preparation of extracts 

 of the adrenal cortical hormone results from the fact that unless 

 the medulla is thoroughly removed immediately after slaughter 

 of the animal considerable amounts of epinephrine and its 

 disintegration products will be present in the extracts. Both 

 epinephrine and its oxidation products are exceedingly toxic 

 even when ingested orally in large quantities and their removal 

 from the final extracts is therefore essential. Any beneficent 

 effect of the hormone present in a given extract will be masked 

 by the toxic effects of epinephrine or its derivatives unless these 

 be thoroughly removed. 



The adrenal glands are noteworthy for the rapidity with 

 which they undergo autolysis. The adrenal cortical hormone 

 is very rapidly destroyed after death and hence proper preser- 

 vation of the fresh glands is essential for the preparation of an 

 active extract. 245 



The failure to appreciate the importance of the factors just 

 enumerated accounts undoubtedly for the results of the early 

 workers who attempted to prepare extracts containing the 

 hormone. They failed to effect a sufficient concentration of 

 the hormone, did not thoroughly remove the noxious impurities 

 present in their extracts, and improperly preserved the glands 

 so that only traces of the hormone were present in their final 

 extracts. It is not unexpected therefore that their products 



