170 



THE DUCTLESS GLANDS 



times the inhibitory effect is shown only after a few minutes. 

 The effects obtained with the isolated frog ventricle were less 

 striking than those in mammals. 



Finally, it was proved by these authors that extracts of 

 the cortex of the gland are quite inactive, the active principle 

 being confined strictly to the medulla. Their general conclusion 

 was that the medulla of the adrenal secretes a material whose 

 action is to increase the tone of all muscular tissue, and espec- 

 ially that of the heart and arteries. 





>'''" ' " ff< ' 



FIG. 41. Tracing showing the effect of adrenalin after previous administra- 

 tion of a dose of atropin. Dog, 15 kilogrammes. Ether and morphine- 

 Lower curve is that of the carotid blood-pressure, upper one the volume 

 of the left hind-limb. 



The work of Oliver and Schafer was confirmed in its main 

 outlines by Cybulski and Szymonowicz. The Polish physio- 

 logists independently observed many of the same phenomena, 

 and brought corroboration of many of the observations. 

 But in some details and upon one important point they 

 obtained different results ; they considered that the extract 

 produces its vasoconstriction effects not peripherally, but 

 centrally upon the medulla. This was, as has been proved 

 by all subsequent investigations, an erroneous conclusion. 





