THE SUPRARENAL SYSTEM 165 



strong sunshine, pressure, and friction. Even more characteristic 

 than the discoloration of the skin, is the affection of the mucous 

 membranes of the cheeks, lips and gums, and of the conjunctiva. 

 Anatomically, the pigment is principally deposited in the cells of 

 the rete Malpighii, and, as far as we know (v. Kahlden, Riehl, 

 Schmorl) is conveyed there from the blood-vessels of the cutis by 

 means of wandering cells (chromatophores). It is almost 

 exclusively deposited in the lower epithelial layers, the upper cefls 

 generally remaining free from pigment. 



The pigment is free from iron, but nothing further is known 

 regarding its chemical constitution, though, as far as we can 

 judge, it is identical with that of other cuticular pigments. Its 

 formation is generally believed to be associated with a colourless 

 pre-stage in the blood, though certain observers consider that it 

 may be formed autochthonously within the epithelium. It has 

 also been referred to the increased destruction of blood corpuscles 

 in Addison's disease, together with the retarded flow of the stream 

 due to the decrease in blood-pressure, but there is no ground to 

 warrant such an assumption. 



The effects of adrenalin upon the pigment of Addison's 

 disease have recently been investigated. v. Furth and H. 

 Schneider found that, when tyrosinase was added to tyrosin, the 

 latter acquired a red, then a violet, and finally an ink-black 

 coloration. Neuberg next discovered that the extract of a 

 melanotic suprarenal tumour acted upon adrenalin in such a 

 manner that pigment was formed; and he discovered a ferment in 

 the ink-bag of Sepiidas which converted adrenalin into a black 

 product of oxidation. Adami supports the view advanced by 

 Halle and Frankel that tyrosin is the matrix of adrenalin, and he 

 believes, further, that in suprarenal disease the matrix (tyrosin and 

 allied bodies) is unable to form adrenalin, and therefore accumu- 

 lates in the tissues. Where the skin is exposed, these substances 

 become converted by the action of oxydases into a black-coloured 

 pigment. The entire question of pigmentation in Addison's 

 disease is urgently in need of further investigation. 



SUPRARENAL SUBSTITUTION. 



Numerous experiments have been undertaken with the object 

 of counteracting the results of suprarenal suppression in animals 

 by means of a substitution therapy. This has been attempted by 

 two methods, the one by the exhibition of the organic extract 

 (organo-therapy), the other by transplantation. 



ORGANO-THERAPY. 



Speaking generally, experimental organo-therapy has not 

 been attended by satisfactory results. Abelous and Langlois 

 attempted, but without success, to keep frogs, from which both 



