974 THE INTERNAL SECRETIONS 



blood-vessels and produces a second rise in pressure. Attention has 

 already been called to the fact that the stimulation of the aforesaid 

 nerve evokes a rise in the arterial pressure which really consists of two 

 parts, the first elevation being caused by the direct constriction of the 

 blood-vessels of the splanchnic organs, and the second by the constric- 

 tion of the blood-vessels of the general circuits in consequence of the 

 delayed entrance of adrenin. 



The fact that the adrenal bodies may be influenced reflexly, has 

 given rise to the assumption that this mechanism is held in reserve 

 to be activated at irregular intervals by afferent stimuh which find 

 their origin in different parts of the body. Even emotions are said to 

 give rise to a discharge of adrenin which then evokes the peculiar 

 vascular reactions and sensations usually experienced during anger and 

 fright.^ In continuance of this line of thought it is generally believed 

 that the condition of hypertension, which is developed in nephritis, 

 is the direct outcome of a continuous liberation of adrenin and that 

 this agent, owing to its power of mobilizing sugar, must be instrumental 

 in the production of hyperglycemia and glycosuria. All these and 

 similar statements, endeavoring to equip the adrenals with emergency 

 functions of this kind, should be received with scepticism, because 

 they are still lacking a definite experimental basis. Some writers, 

 for example, are of the opinion that emotional hyperglycemia may be 

 produced so easily in animals that it is difficult to ascertain the normal 

 sugar content of their blood unless precautions are taken to shield 

 them against excitement. ^ Others, again, hold that a real emotional 

 glycosuria does not exist. ^ Besides, Stewart and Rogoff^ have not 

 been able to demonstrate any increase in the percentage of sugar in 

 the blood of normal cats which could justly be referred to emotional 

 states. Nor have these authors been able to detect any difference in this 

 respect between normal cats and cats deprived of their adrenals by 

 enucleation or nerve-section. Accordingly, it must be concluded that 

 the mobilization of sugar occurring during experimental hyperglycemia 

 is not evoked by adrenin, nor is the so-called emotional hyperglycemia 

 a common phenomenon. This diversity of opinion demands that care 

 be exercised in attributing to the adrenal bodies an array of functions 

 which in reality are mere conjectures. 



Other Actions of Epinephrin. — Since epinephrin serves more es- 

 pecially as a stimulant of the sympathetic division of the autonomic 

 nervous system (Langley), it may be conjectured that its action is a 

 very general one, involving all the smooth muscle tissue and gland 

 tissue ordinarily under the control of these elements. Moreover, 

 since it acts as a general excitant of the sympathetic system, the effect 



1 Cannon, Am. Jour, of Psych., xxv, 1914, 256. 



2 Schaffer, Jour. Biol. Chem., xix, 1914, 297. 



3 Ross and McGuigan, ibid., xxii, 1915, 407. 

 * Am. Jour, of Physiol., xlvi, 1917, 543. 



