1906.] 



Special Excitable Substances in Cells. 



191 



the effect of adrenalin is, in general, proportional to the effect of electrical 

 excitation of the nerves. The arteries of the lungs, according to Brodie and 

 Dixon,* and the coronary arteries, according to Schafer,f are equally unaffected 

 by electrical stimulation of the sympathetic nerves and by adrenalin ; the 

 like absence of effect is found with many of the veins of the body. 



The sympathetic nerves supplying a given organ may produce different 

 effects in different animals. In all these cases, so far as observed, the effect 

 of adrenalin corresponds with the effect of the nerves. This has been shown 

 in mammals chiefly by Elliott,;]; and in amphibia and fish by Bottazzi.§ 



The differences which are found between the effects of adrenalin and of 

 electrical stimulation of sympathetic nerves are, first, that in a tissue which 

 receives both motor and inhibitory nerve-fibres from the sympathetic, the 

 balance of motor and inhibitory effects are not necessarily the same with 

 the two stimuli ; thus, in some cases adrenalin produces much greater and 

 more lasting inhibition than can be caused by electrical nerve stimulation, 

 and, secondly, that some tissues are readily affected by stimulation of the 

 sympathetic nerves, and barely at all, or only in enormous doses, by 

 adrenalin. 



Furthermore, it has been shown by Dale|| and confirmatory evidence has 

 been given by Elliott, that ergot abolishes all the constrictor effects of the 

 sympathetic, without impairing any of the effects of the cranial or sacral 

 autonomic nerves, or the inhibitory effects of the sympathetic. In this 

 state adrenalin, according to Dale and to Elliott, causes inhibition in many 

 of the regions innervated by the sympathetic, and has no constrictor effect 

 whatever. Thus, for example, the bladder of the ferret normally contracts 

 when either the sympathetic or the sacral nerves are stimulated, or when 

 adrenalin is injected. After ergot the sacral nerves cause contraction as 

 before, the sympathetic nerves and adrenalin cause inhibition. 



The special relationship of adrenalin to the sympathetic system is, primd 

 facie, strongly supported by the close developmental connection of the supra- 

 renal body with the sympathetic ganglia. This argument, however, loses 

 some of its i'orce in consequence of Dale's discovery that ergot, which is not 

 formed at all in the body, has also a special action on the tissues innervated 

 by the sympathetic system. 



* Op. cit. supra. 



f Schafer, ' Archives Intern, de Physiol.,' vol. 2, p. [141], 1904. 

 % Elliot, op. cit. supra. 



§ Cf. Bottazzi and Costanzi, ' Nuove Ricerche sull' Azione dell- Adrenalina e d. Para- 

 ganglia' (Napoli), 1905. 



|| Dale, 'Proc. Physiol. Soc.,' p. lviii ('Journ. of Physiol.,' vol. 32) and 'Journ. of 

 Physiol.,' vol. 34, in the press. 



