THE ADRENAL GLANDS. 459 



methods which may be employed for their isolation, the reader is 

 referred to Oswald's paper. 1 



The extractives of the thyroid gland are represented by traces 

 of xanthin, hypoxanthin, leucin, succinic acid, and paralactic acid. 

 In addition, notable quantities of kreatinin may be obtained. 



Among the mineral constituents of the thyroid gland the presence 

 of traces of arsenic is of interest ; according to Gautier and Bert- 

 rand, it represents a normal and constant component of the gland. 



THE ADRENAL GLANDS. 



Of the function of the adrenal glands, nothing definite is known- 

 Their integrity, however, is essential to life, and, as in the case of the 

 thyroid, their removal leads to the death of the animal. It has been 

 noted, moreover, that the injection of blood from a dog which has 

 died as a result of the operation, into the circulation of a second 

 animal that has been operated in the same manner, will hasten the 

 fatal end, while in normal dogs no deleterious results are observed. 

 It has hence been concluded that the glands normally furnish a 

 secretion which renders certain metabolic products innocuous, and 

 that the fatal result which follows the removal of the organs is the 

 result of an auto-intoxication. 



In man, disease of the adrenal glands leads to the complex of 

 symptoms which is commonly known as Addison's disease, and like- 

 wise results in death ; but as in the case of the thyroid gland, it has 

 been observed that the fatal issue may here also at least be retarded 

 by the administration of an aqueous extract of the organs. Experi- 

 ments with such extracts have further shown that the gland contains 

 a substance which has a very marked effect upon the blood-pressure, 

 raising this far beyond the normal. This substance is found in the 

 medullary portion of the glands. Further investigations have then 

 demonstrated the existence of a chromogen which on exposure to the 

 air in aqueous solution yields a beautiful carmin-colored pigment, 

 which, like its mother- substance, is soluble in water. The same 

 result is reached at once on treating with chlorine-, bromine-, or 

 iodine- water. This chromogen is present in the intracellular fluid of 

 the medullary portion of the gland. When this is extracted with a 

 dilute acid, a violet-red precipitate results on the addition of an 

 excess of ammonia, which suggests that the pigment is of a basic 

 nature. 



With a solution of ferric chloride the juice that can be expressed 

 from the glands gives a bright emerald-green color. This reaction 

 has been referred to the supposed presence of pyrocatechin, but thus 

 far this has never been isolated. 



Modern researches lead to the conclusion that the blood-pressure- 

 raising constituent of the gland, as also the chromogen, which gives 

 rise to the carmin color and the pyrocatechin reaction, are identical 

 1 Zeit. f. physiol. Chem., vol. xxvii. p. 14. 



