GROSSER PATHOLOGICU-ANATOMICAL LESIONS 209 



hemosiderin deposits similar to those which occur in the so-called hemo- 

 chromatosis (a pigmentation of the skin resembling Addison's disease) (Foa). 

 A recent experiment is also to be mentioned according to which the subcutane- 

 ous (or intravenous) injection of adrenal extract in animals produces glyco- 

 suria in the majority of cases (Blum). 



From these experiments it appears that we must admit an "internal 

 secretion " of the .suprarenals, and must recognize that these organs furnish 

 to the blood a substance which acts primarily to raise Mood-pressure. 



Endeavors to isolate and more minutely to characterize the substance in 

 the adrenals which raises blood-pressure have not been lacking. These have 

 lately led to definite and fixed, even though not always uniform, results. 

 But these endeavors, like the earlier and frequently repeated chemical investi- 

 gations of the adrenal parenchyma, are not calculated to advance our knowl- 

 edge regarding the function of these organs. The most important experi- 

 ments are the following : 



The earlier investigations (conducted by Vulpian and Virchow, and dating 

 from the time when the clinical picture of Addison's disease was first made 

 known) were made with a substance which is found in the medulla of the 

 adrenals and which, with iron chlorid, gives a blachish green color. These 

 observers first called attention to the similarity of the pigment seen in the 

 parenchyma of the adrenals (particularly in the intermediary zone) to that 

 of the rete Malpighii in pathologic discoloration of the skin. Furthermore, 

 observers have made frequent attempts to isolate a peculiar coloring matter 

 from the parenchyma of the adrenals but without reaching unanimous results. 

 Some writers emphasize the brown coloration of the tissue (particularly in 

 the intermediary zone) which occurs with salts of chromic acid. Several 

 others have noted small globular structures in the blood of the adrenal veins. 

 These granules can be colored with chromic acid, and have been looked upon 

 as products of secretion of the organs. A chromogen with different deriva- 

 tives has been found by several observers in the parenchyma; by some this 

 has been believed to be identical with hemochromogen (McMunn). 



Among the substances which have been demonstrated in the parenchyma 

 of the adrenals are leucin and myelin which were referred to in earlier re- 

 ports, lecithin which has been found in large amounts (Alexander), a related 

 body resembling jecorin which contains sulphur and phosphorus (Manasse), 

 and neurin. All these are substances from the presence of which certain 

 relations between the adrenals and nervous system may be inferred. The 

 substances which give a green color with iron have been found to be chemically 

 closely related to pyrocatechin (Krukenberg), and from the extracts of the 

 medullary substances it is possible to isolate a compound from which, by 

 boiling with hydrochloric acid, pyrocatechin can be produced (Miihlmann). 

 These findings also indicate a relation with pigmentation of the skin without 

 furnishing definite proof of it. 



The "substance forming a green color with iron" and the "substances 

 resembling pyrocatechin " are identical with the products which cause a rise . 

 in hlood-pressure, and for use as substitutes for the adrenal extract in animal 

 injections have been produced from the organs by complicated chemical proc- 

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