58 PHYSIOLOGY CHAP. 



Pick, Langley, Elliott, Gioffredi, Salvioli, Patta, Vassale, Bottazzi, 

 and many others. Contrary to the opinion of Cybulski, most 

 authors now admit in explanation of the enormous vaso-constrictor 

 action of this substance, that it acts peripherally upon the muscular 

 cells of the vascular coats (directly, or indirectly by means of the 

 sympathetic nerve endings), as was stated by the first investigators, 

 Oliver and Schafer. The experiments of Velich and Biedl, who 

 divided and destroyed the spinal centres, give direct support to 

 this view, together with those of Gottlieb, who eliminated the 

 action of the vasomotor centres by profoundly chloralising the 

 animals ; and still more the fact adduced by the last author, that 



FIG. 16. Effect of suprarenal extract on blood pressure in curarised rabbit. (Verworii.) 

 1, injection of extract ; 2, section of both vagi. 



the vaso-constrictor action also takes effect in the vessels of isolated, 

 surviving organs (kidney, mammalian heart). 



The active principle of the suprarenal capsules does not 

 produce the same contractile effect on all the plain muscle of the 

 body as is thus distinctly exerted upon the vascular muscle-cells. 

 On other involuntary fibres it has an exactly opposite effect, 

 causing their active expansion or relaxation, and depression of 

 tone (Lewandowsky, Boruttau, Langley). 



Langley (1901) described the effects of suprarenal extract on 

 various organs with plain muscle, in cats and rabbits. Com- 

 mencing with the results of minimal doses, and going on to those 

 of strong doses of the extract, an enormous increase in blood 

 pressure due to peripheral vaso-constriction first appears (Fig. 16) ; 

 then relaxation of the cardiac sphincters, intestines (rabbit) and 

 bladder, dilatation of the pupil (cat), retraction of the nictitating 

 membrane (cat), opening of the eyelid (cat). Next follows con- 

 traction of the uterus, of the vasa deferentia, spermatic vesicles 



