30 CORA SENNER WINKIN 



nic system in the anemic response makes the activity, or some pro- 

 duct of the activity, of the adrenal glands of considerable significance 

 for the problem of its control. Following the discovery by Oliver and 

 Schafer (68) of the pressor action of injected extract of adrenal tissue, 

 workers have tended to emphasize the close physiological relation of 

 the glands and their pressor activity to the splanchnic system. The 

 literature is extensive (69), (70), (71), (72), (73), (74), (75), but it will 

 not be reviewed at this time. Nor will the literature on the liberation 

 of adrenalin (75 to 90) be considered here. The evidence for the parti- 

 cipation of adrenalin in the response to asphyxia and other conditions 

 of stress is also extensive (91 to 98), but its consideration will be left 

 for a later paper. The relation of the contour of the typical curve 

 obtained on electrical stimulation of the splanchnic nerves to the ad- 

 renals, and also to the cardiac mechanism, has been dealt with by 

 several authors (104), (105), (106), (107). A further analysis of this 

 contour is also postponed. 



Effect of repeated occlusion cm intact cats. Elliott's assumption (75) 

 that adrenalin is consumed under conditions of stress makes it con- 

 ceivable that the rapid repetition of so radical a procedure as arterial 

 occlusion could influence the amount of circulating adrenalin. Since 

 the relation of adrenalin to the myo-neural junction has been experi- 

 mentally demonstrated, Professor Pike has suggested that, physiolo- 

 gically, it may be associated with the process of conduction from sym- 

 pathetic nerve fiber to smooth muscle, and directly or indirectly with 

 the processes of excitation in smooth muscle. The work of Keith Lucas 

 would suggest such a possibility (108). Accordingly, such an increase 

 of activity of sympathetic nerve and smooth muscle as accompanies 

 cerebral anemia should lead to a more rapid consumption of adrenalin. 

 This conclusion follows from Elliott's hypothesis of the consumption 

 of adrenalin. The procedure of repeated occlusion has accordingly 

 been attempted first in intact animals in order to reach a control condi- 

 tion of maximal exhaustion of circulating adrenalin, and then in animals 

 in which the adrenal glands had been permanently ligated. 



The great resistance of the animals to repeated occlusion has been 

 frequently demonstrated in the experimental material already given. 

 Numerous other evidences of the relative indefatigability of vasomotor 

 responses are found in the literature. Notable here are the analogous 

 experimental conditions in the work of Gushing (99), who found that 

 the process of raising the blood pressure by increasing the intracranial 

 tension, and thus also inducing a partial anemia, could be repeated 



