CHEMICAL CORRELATION OF PROCESSES OF DIGESTION 371 



converted into substances devoid of the typical activities of adrenaline. 

 It is, however, a question that is still being debated whether or not the 

 small amounts normally present in the blood-stream actually influence 

 the tone of the vascular system, and help to maintain the normal 

 blood-pressure. The extremely low blood-pressure in Addison's 

 disease, however, and the marked effect of adrenaline in raising it, 

 stated even to be more marked than in normal individuals, would 

 seem to point rather decisively to a constant relationship between the 

 functional activity of the suprarenals and the maintenance of normal 

 blood-pressure. 



According to Cannon, however, one of the most important functions 

 of the suprarenals is to assemble a group of conditions appropriate for 

 the defense of the organism in an emergency. Violent Emotional 

 States, such as fear, rage or pain (and also anesthesia) lead to a marked 

 discharge of adrenaline from the suprarenal glands, and to all the effects 

 which arise from intravenous injection of adrenaline. The intravenous 

 injection of adrenaline in the cat will, as a matter of fact, elicit very 

 many of the most easily recognizable external signs of fear without the 

 application of any other stimulus. Thus the hair of the back and tail 

 is raised, and the pupils of the eyes are widely dilated. It is to the 

 presence of an excess of adrenaline in the blood that the glycosuria of 

 violent emotions, the so-called Emotional Glycosuria, is partly due. It 

 has been shown by Macleod that stimulation of the splanchnic nerves, 

 which innervate the suprarenal glands, results in the production of 

 glucohemia which is partially attributable, however, to the direct stimu- 

 lation of the liver through the hepatic branches of the splanchnics. 



The effect of emotional stimulation, operating through the splanch- 

 nics, is to increase the adrenaline in the blood and thereby to increase 

 the blood-pressure, quicken the heart-beat and thus enhance the mobil- 

 ity of the blood and the rate of access and exit of the raw materials 

 and products of metabolic activities. The liability to external hemor- 

 rhages is reduced owing to the constriction of peripheral vessels, and 

 also to a definite reduction of the coagulation-time of the blood, which 

 is another result of adrenaline administration. The instantly avail- 

 able nutritive materials for the muscle-cells are increased by the 

 mobilization of sugar-reserves. In short the animal is placed in the 

 best attainable condition for a sudden extreme effort and the sustain- 

 ment of possible injury. In conflicts, or in efforts to escape from more 

 powerful predatory forms, the suprarenal glands probably constitute 

 an essential factor in success or failure. 



THE CHEMICAL CORRELATION OF THE PROCESSES OF 

 DIGESTION. 



The arrival of foodstuffs in the stomach is preceded by a considerable 

 secretion of Gastric Juice, and, in consequence, the processes of gastric 

 digestion are enabled to go forward without delay. The correlation 



