124 JOHN T. HALSEY 



(c)), up to the present no one has succeeded in proving that pineal 

 substance can exert any therapeutic influence. 



The claims made by Dana and Berkeley that, in a number of defective 

 children at the Vineland institution and from New York public schools, 

 its administration for a period of some months brought about an improve- 

 ment of mental condition, have been deprived of most if not all of their 

 value by the later report of Goddard, who followed some of these cases for 

 over a year and concluded that the Vineland experiment had had only 

 negative results. Negative results have also been reported by Block. 



The Suprarenals 

 Pharmacodynamic Actions of Epinephrin 



In the chapters on the physiology and pharmacology of the suprarenals 

 a detailed account of the actions of epinephrin is given. The data that 

 pertain more particularly to the therapeutic possibilities of this drug will 

 be summarized briefly at this point. The pharmacodynamic properties 

 of epinephrin have been well characterized by Langley and Elliott in 

 the statement that its peripheral effects are everywhere essentially the 

 same as those produced by the stimulation of the sympathetic nerves of 

 the tissues involved. 39 Perhaps the most striking demonstration of this 

 fact is found in the different reaction of the same organ in different species 

 of animals. For example, in certain species epinephrin causes relaxa- 

 tion of the bladder, in others contraction. 



Seat of Action. Various investigations, but particularly those of 

 Langley, on its effects after nerve degeneration, have placed the seat of 

 action in the histologieally undemonstrable so-called intermediary re^ 

 ceptivo substance where nerve structure ends and muscle structure begins,, 



Circulatory Action. Intravenous injection of epinephrin is followed 

 promptly by a striking rise in the blood-pressure and almost immediately 

 thereafter by slowing and irregularity of the heart. The rise in blood- 

 pressure is ; under normal conditions, mainly due to the general vasocon- 

 striction, but some of it is duo to the increased force and extent of the 

 cardiac contraction which brings about, at least at the beginning, an 

 increased cardiac output. The slowing of the heart is the result of in- 

 creased vagus tone, which probably is chiefly or entirely the result of 

 the increased blood-pressure, although direct stimulation of this center 

 cannot bo excluded. The irregularity is due to variation in vagus tone or 

 to premature (wtopic) contractions of the heart, or to both of these factors. 



39 Its lack of effect on sweat glands is an apparent contradiction to this general 

 law. While anatomically the secretory nerves supplying these glands are sympathetic, 

 according to tlieir pharmocodynamic reaction they belong to the parasympathetic por- 

 tion of the vegetative nervous system. 



