THE. SUPRARENAL SYSTEM 243 



liferation (Erb, Kiilbs, Saltykow) ; fatty degeneration of the 

 proliferated endothelium (Saltykow, Klotz) ; and connective tissue 

 thickening of the intima (Papadia, Watermann). According to 

 K. Ziegler, the proliferation of the intima is wholly compensatory, 

 its purpose being to till up the inequalities of the inner surface 

 of the vessel. This can apply, however, to a small proportion of 

 cases only. F. Falk has frequently observed proliferation of the 

 intima and of its component parts in portions of the small vessels 

 which had become pouched as a result of the process. Fissure 

 of the lamina elastica interna is frequently observed, as well as 

 the occurrence of nuclei (unstriated muscles) in the intima of the 

 small vessels. It is probable that changes (softening) do not take 

 place in the media of the small vessels, or if they do, they can 

 only be of the slightest description. Here and there, pronounced 

 connective tissue traits appear in the portions of the media border- 

 ing upon the adventitia (Falk). 



K. Ziegler explains the sporadic appearance of the diseased 

 condition by the implication of the vasa vasorum. With regard 

 to the primary localization of the disease, .all authors, with the 

 exception of Loeper, Papadia and Boveri, are agreed that the 

 changes in the media are essential, the changes in the intima 

 secondary, in character. Whether, however, this rule applies 

 equally to the small vessels, is a point upon which no certain 

 pronouncement can at present be given. The tissue which is 

 first affected is the muscular structure of the vessels (B. Fischer, 

 Falk, &c.), although v. Rzentkowski, Marchand, Scheidemandel 

 and Trachtenberg localize the site of earliest affection in the 

 elastic portions of the vessel walls. 



The pathogenetic factors in the changes brought about by 

 adrenalin in the arteries are : its effect in raising blood-pressure ; 

 its toxic action upon the vessel walls ; and perhaps, also, a 

 direct influence upon the vasa vasorum. 



Changes similar to those in the aorta are also observed in 

 the pulmonary artery, in the veins (d'Amato), and in the 

 lymphatics (Donzello and Vito Tardo), in all of which the con- 

 ditions governing pressure could hardly be altered, to any appre- 

 ciable extent, by the action of adrenalin. These facts militate 

 against the view that the increased blood-pressure is the sole 

 pathogenetic factor. Moreover, L. Braun, and later Waterman, 

 both observed identical changes in the arteries in cases where, 

 by injecting adrenalin in combination with amyl nitrite, they had 

 excluded every possibility of increased blood-pressure. Similar 

 results were obtained where adrenalin was administered simul- 

 taneously with other substances which lower blood-pressure; 

 Boveri, for instance, employed adrenalin with opothyroidin ; 

 Mironescu adrenalin plus euphthalmin, which is a substance of 

 the atropine group. 



B. Fischer proved that changes in the vessels may be also 



