174 THE DUCTLESS GLANDS 



and remains so for thirty seconds. Then it becomes flushed, 

 and the flushing lasts longer than the secretion caused by the 

 injection. The pallor is not so great as that produced by 

 stimulating the cervical sympathetic, nor is the flushing so 

 great as that produced by stimulating the chorda tympani. 

 Both of these nerves have their usual action on the blood- 

 flow, if stimulated while the secretion is going on. 



In the dog pallor of the bucco -facial region is produced by 

 adrenal extract. This is the effect produced by weak stimula- 

 tion of the cervical sympathetic (Langley). 



Brodie and Dixon were unable to obtain evidence of con- 

 striction of the pulmonary vessels on injection of adrenalin, 

 and thought this was because the pulmonary arterioles possess 

 no vasomotor nerve-supply. (Adrenalin, they considered, acts 

 on the nerve endings.) Plumier, using larger doses, succeeded 

 in getting a positive result that is to say, he recorded some 

 constriction of the pulmonary vessels on injection of adrenalin ; 

 but, according to Schafer, the action is far less than upon the 

 sympathetically innervated vessels. 



It was stated by Spina that the injection of adrenal extract 

 causes reddening of the brain, so that the peripheral vessels 

 were not constricted, but Wiggers, using the isolated dog's brain 

 and perfusion with Locke's fluid containing adrenalin, has 

 been able to observe a diminution of the outflow of fluid, from 

 which he concludes that the brain possesses vasomotor nerves, 

 and that adrenalin acts on the ends of these. As for the 

 coronary vessels, it is usually stated that adrenin does not 

 constrict these. Schafer correlates this with the absence of 

 vaso-constrictors from the cardiac accelerators, and concludes 

 that, with both forms of excitation, quickening of the flow 

 through the coronaries was brought about. It may be sup- 

 posed, however, that heart muscle is dilated by adrenin just 

 as skeletal muscle is. Elliott suggests that in the beating heart 

 such an action cannot be dissociated from a possible secondary 

 dilatation by metabolites from the increased work of the heart 

 muscle. He states that when perfusing a strip of the cat's 

 ventricle by a single coronary artery he has seen almost instant 

 increase of flow after addition of adrenalin to the Locke's 

 solution used. This occurred with a strip that did not beat, 

 and therefore independently of muscular metabolites. Langen- 

 dorff has recently immersed strips of the vascular wall attached 



