158 THE DUCTLESS GLANDS 



L. The Pharmacodynamics of Extracts of Adrenal 

 Medulla (Chromaphil Tissues) and of Adrenin 



1. The General Physiological Effects of Chromaphil Tissue 

 Extracts and of Adrenin 



It has already been noted in connection with the account of 

 extirpation experiments that a few observers have obtained 

 beneficial results after removal of the gland from adminis- 

 tration of adrenal substance either in the form of the gland 

 itself (grafts) or as watery or saline extracts. 



In the present section we have to deal with the effects 

 produced by the administration of the active principle to the 

 normal animal. In the first instance we shall confine ourselves 

 to the general effects (toxic) produced upon the animal as a 

 whole, reserving the special effects upon different systems 

 e.g., the hsemodynamics for a subsequent section. 



The earliest important investigations upon the effects of 

 injecting adrenal extracts into animals are those of Foa and 

 Pellacani. In their earlier experiments these observers em- 

 ployed aqueous solutions of fresh animal substances, includ- 

 ing the adrenal body. They succeeded in causing death in a 

 dog by injecting subcutaneously the adrenals of a calf in the 

 form of neutral extract. Similar but more rapidly fatal effects 

 were obtained in experimenting upon guinea-pigs and rabbits, 

 but when injected intravenously they obtained like results 

 from extracts of liver and kidney. So they concluded that the 

 effect was not a specific one. 



In their later work, the Italian observers eliminating the 

 injurious effects of fibrin ferment in their extracts, found 

 that the toxic action was specific for the adrenals. They 

 further determined that the toxicity is not due to the acids 

 present, for if one separates these out the extracts remain 

 active. Further, the toxic effects are not due to a ptomaine 

 which the authors found in the glands, for this is physio- 

 logically inactive. They conclude that the active principle 

 of the adrenals paralyses the spinal cord and the medulla 

 oblongata, destroys completely all motion and sensation, 

 and kills by paralysis of the respiratory centre. These authors 

 prepared their extracts by boiling, evaporating to dry ness. 



