218 THE DUCTLESS GLANDS 



of total dilation. The method is now considered by Meltzer to be 

 untrustworthy, as the amount of adrenin necessary to produce 

 an action upon the frog's eye varies not only in different frogs, 

 but even in the two eyes of the same frog. Trendelenberg now 

 uses the method of perfusion through the vessels of the hind- 

 limb of the frog. Ritchie and Bruce, using the bichromate 

 coloration and the blood-pressure testing, have recently 

 reported (contrarily to Ehrmann) that in diphtheritic toxaemia 

 in guinea-pigs there is complete exhaustion of all adrenin from 

 the medulla of the adrenal bodies. 



Another test for adrenin in the blood consists in injecting 

 hypertonic solutions into the auricular vein, and noting the 

 occurrence of glycosuria. It was found that this, like the 

 diabetic puncture, also renders the serum mydriatic. It is 

 considered that these experiments show that adrenin stimulates 

 the sympathetic. It is believed also the sympathetic may be 

 stimulated by means of thyroid material, and, on the other 

 hand, stimulation of the sympathetic leads to increased secre- 

 tion of the thyroid. 



An elaborate series of metabolism experiments by Eppinger, 

 Falta, and Rudinger have been regarded as pointing to a 

 definite internal secretion on the part of the adrenal medulla, 

 or rather of the whole chromaphil system, and a functional 

 relationship between adrenal body, thyroid, and pancreas 

 through the medium of the sympathetic nervous system. A 

 relationship between pancreas and adrenal body in regard to 

 hyperglycaemia is indicated by the experiments of Zuelzer and 

 others. Ritzmann claims that the degree of glycosuria depends 

 on the quantity of adrenin present in the blood at any given 

 moment. But the quantitative result of this observer cannot 

 be regarded as correct, since it has been proved by Underhill 

 that the glycosuria obtained by Ritzmann with small doses of 

 adrenin, intravenously administered, was dependent on the use 

 of urethane as the anaesthetic. Adrenin introduced in very 

 dilute solutions (1:500,000 to 1:125,000) fails to induce 

 glycosuria in the normal rabbit. On the other hand, when the 

 animal is under the influence of urethane narcosis, these dilute 

 adrenin solutions are a sufficient stimulus for the production of 

 glycosuria. It seems, then, that urethane renders a rabbit 

 unusually sensitive to the glycosuria-inducing action of 

 adrenin. The subcutaneous administration of adrenin in a 



