THE ADRENAL BODIES 217 



arrangement, but an organ arranged in the form of definite 

 columns of cells, with intervening blood-spaces in fact, a 

 " gland." It is therefore a priori probable that the adrenal 

 medulla may secrete into the blood-stream an active material 

 which is of benefit to the economy. Again, a careful compara- 

 tive study of the chromaphil tissues in general, and the adrenal 

 medulla in particular, has led to the conclusion that the latter 

 is probably to be regarded as a specialized development of the 

 former (see p. 116). 



Considerable evidence has, however, been accumulated that 

 adrenin under certain conditions is secreted through the adrenal 

 veins into the general blood-stream. It has been stated by 

 several authors that the blood of the adrenal vein contains a 

 sufficient amount of the active principle of adrenal extract to 

 produce marked rise of blood-pressure when intravenously 

 injected. This, however, has not been confirmed. 



Ehrmann, basing his investigations upon the discovery of 

 Lewandowsky, and relying upon the observations of Meltzer 

 and Auer that frogs, after adrenin injection, show a^ maximum 

 dilatation of the pupil, worked out a method for the estimation 

 of adrenin. He used the enucleated frog's eye, as recommended 

 by Meltzer and Auer, and measured the amount and rapidity of 

 widening of the pupil on placing the eye in adrenin solution. 

 By this method it could be shown that the blood coming from 

 the adrenal bodies contains the active substance, adrenin, and 

 Ehrmann concludes that it passes into the blood as a physio- 

 logical secretion. Pilocarpine and atropine lead to no marked 

 increase or diminution. In diphtheria intoxication it is some- 

 what increased. Raising or lowering the blood-pressure has no 

 effect on its amount, which varies considerably in different 

 animals. According to Ehrmann, the rabbit pours into its 

 adrenal veins adrenin in a concentration of between 1 : 1,000,000 

 and 1 : 10,000,000. There is a parallelism between the amount 

 secreted and the sensibility of the animal to the actipn of the 

 substance. 



Waterman and Boddaert, however, have shown that the 

 mydriatic action on the enucleated frog's eye is not absolutely 

 specific for adrenin. Gautier says that the solutions employed 

 must befaintly acid, since dilute alkaliin sodium chloride solution 

 gives by itself a positive result. Schultz says that the time taken 

 for a certain degree of widening is of more value than the extent 



