The problem of splanchnic influence on the adrenal glands Elliott attacked by a still different method. Using, as a measure, the graded effects of graded amounts of adrenin on blood pressure, he was able to assay the quantity of adrenin in adrenal glands after various conditions had been allowed to prevail. The tests were made on cats. In these animals each adrenal gland is supplied only by the splanchnic fibres of its own side, and the two glands normally contain almost exactly the same amount of adrenin. Elliott[37] found that when the gland on one side was isolated by cutting its splanchnic supply, and then impulses were sent along the intact nerves of the other side, either by disturbing the animal or by artificial excitation of the nerves, the gland to which these fibres reached invariably contained less adrenin, often very much less, than the isolated gland. Results obtained by the method employed by Elliott have been confirmed with remarkable exactness in results obtained by Folin, Denis and myself,[38] using a highly sensitive color test after adding the gland extract to a solution of phosphotungstic acid. All these observations, with a variety of methods, and by a respectable number of reliable investigators, are harmonious in bringing proof that artificial stimulation of the nerves leading to the adrenal glands will induce secretory activity in the adrenal medulla, and that in consequence adrenin will be increased in the blood. The fact is therefore securely established that in the body a mechanism exists by which these glands can be made to discharge this peculiar substance promptly into the circulation. The Question of Adrenal Secretion in Emotional Excitement As we have already seen, the phenomena of a great emotional disturbance in an animal indicate that sympathetic impulses dominate the viscera. When, for example, a cat becomes frightened, the pupils dilate, the activities of the stomach and intestines are inhibited, the heart beats rapidly, the hairs of the back and tail stand erect--from one end of the animal to the other there are abundant signs of nervous discharges along sympathetic courses. Do not the adrenal glands share in this widespread subjugation of the viscera to sympathetic control?