GROSSER PATHOLOGICO-ANATOMICAL LESIONS 213 



of a process of this kind cannot as j^et be excluded. For the formation of 

 pigment in the organism is a complicated process, and no less so its deposi- 

 tion in the tissues, particularly in the skin. Regarding the latter process 

 we are quite well informed by recent investigations, which shall briefly be 

 referred to here. 



According to these, the pathologic deposition of pigment in Addison's 

 disease occurs in the same manner as physiologic discoloration of the skin 

 (in dark races, in pregnancy, etc.) which is apparently distributed in an 

 analogous manner also in all species of animals. The main seat of the pig- 

 ment particles, all observers who have undertaken microscopic investigations 

 of the bronzed skin find to be the cells of the lowest layers of the rete Mal- 

 pighii. The previous view that the pigment development here is autochtho- 

 nous (by metabolic activity of the cells) has been almost wholly abandoned. 

 On the contrary, quite a number of recent investigators (Renaut, Kothnagel, 

 Riehl, V. Kahlden and others) have proved conclusively that the pigment from 

 the deeper layers of the corium is brought to the rete cells by motile cells, 

 and that the pigment most probably originates in the hlood. The findings 

 resemble one another very much in individual cases; almost always, beneath 

 the pigment layer of the rete, wandering cells are to be seen carrying pigment 

 through the corium; in the deeper cutis layers these cells often accumulate 

 in large groups around the vessels, partly also in their adventitia. A disease 

 of the walls of the vessels has been described in several eases, in which swelling, 

 cellular infiltration and small hemorrhages were conspicuous (Riehl), but 

 this has not been discerned by other observers, and does not appear to play 

 a role in the process. The mucous membrane of the mouth shows conditions 

 analogous to those of the cutis. 



It is obvious that this process of pigment-deposit in the skin favors the 

 assumption of an abnormal coloring material admixed with the blood as the 

 result of adrenal disease, a chromogen, for the existence of which, however 

 (as I have previously said with emphasis), our knowledge up to this time 

 gives no points of support. It must also be remembered that if there were such 

 an over-flooding of the vascular system with pigment it would be very difficult 

 to explain why no deposits of pigment are found in any areas of the internal 

 organs. At any rate, it is obvious that besides the hypothesis of the trans- 

 portation of pigment from the blood to the superficial layers of the skin we 

 should also consider the possibility that the disease may be due to an implica- 

 tion of the nervous system, upon whose vasomotor and trophic tracts the walls 

 of the vessels and the cells of the cutis are dependent to a high degree. 

 Evidently the unusual formation of pigment substance from the hemoglobin 

 (normal or modified), and the increased activity of the cells transporting 

 the pigment, can scarcely occur without the nerve elements being subjected 

 to an abnormal irritation. Also many irregularities of the pigmentation of 

 the skin occurring in Addison's disease, particularly the not infrequent occur- 

 rence of leukoderma plaques, as well as the combination with other trophic 

 cutaneous disturbances (scleredema), point to varying local processes of in- 

 nervation. Finally, it is not without significance to remember that in many 

 species of animals characterized by conspicuous staining of the skin (chame- 



