204 INTERNAL SECRETION 



after they are wetted with suprarenal extract they become 

 relaxed, cease to contract spontaneously, and are less sensitive to 

 electric stimulus (Boruttau, Botazzi). The inhibitory action 

 which adrenalin has upon the rhythmic contractions of the 

 stomach-ring of frogs or eels, is observed with a concentration as 

 low as i : io- 6 (O. B. Meyer). 



Langley found that the intravenous injection of adrenalin 

 into rabbits was followed by an immediate relaxation of the 

 cardia, in consequence of which a fluid present in the oesophagus 

 w r as permitted to pass. In no case was there a contraction of 

 the oesophagus muscles, and even the spontaneous contractions 

 disappeared. The action of adrenalin is the reverse of that of 

 the vagus, for peripheral irritation of the vagus is followed by 

 a contraction of the gastric sphincter. If the stomach is 

 exposed, it will be seen that the action of adrenalin is t produce 

 inhibition of the spontaneous movements- As soon as the 

 relaxation of the cardia ceases, rhythmic contractions of the 

 stomach take place ; thus the effect of suprarenal extract resembles 

 that of irritation of the splanchnic nerve. Elliott was also able 

 to show that the spontaneous movements of the stomach are 

 inhibited in the same manner, by both the action of adrenalin 

 and by stimulation of the splanchnic nerve, the entire muscular 

 structure becoming relaxed ; irritation of the vagus, on the other 

 hand, produces contraction of the stomach and peristaltic move- 

 ments. The pylorus, in rabbits,, contracts in response to adren- 

 alin in the same way as after stimulation of the splanchnic nerve. 



The effect of suprarenal extract upon the small intestine is 

 shown by inhibition of the peristaltic and oscillatory movements, 

 though after a few minutes these reappear (Boruttau, Pal). 

 According to Kuliabko and Alexandrowitsch, adrenalin improves 

 the tone of the intestinal muscles, and gives rise to oscillatory 

 movements. 



The inhibitory action of suprarenal extract is even more 

 marked in the case of the large intestine. In the rabbit there is 

 relaxation of the internal anal sphincter and blanching of the 

 mucosa. In the cat and the dog there is a contraction of the 

 sphincter similar to that produced in these animals by irritation 

 of the sympathetic nerve-fibres. 



The similarity of the effects produced by adrenalin and by 

 stimulation of the sympathetic are demonstrable along the entire 

 length of the gastro-intestinal tract. With the exception of the 

 three sphincters (pyloric, ileo-caccal, internal anal), which con- 

 tract, there is a general muscular relaxation. 



This similarity of result persists in the intestines of birds 

 and amphibians, in spite of the fact that here the innervation 

 conditions are not the same. The oesophagus of frogs and 

 turtles relaxes, and the stomach contracts in response both to 

 adrenalin and to stimulation of the sympathetic. In fowls, 



