MORBUS MACULOSUS WERLHOFII 463 



Since a rupture of the vessels could not be found microscopically (the 

 proof of this can only be certainly demonstrated with great difficulty) these 

 hemorrhages were assumed by Silbermann to be due to diapedesis, and this to 

 distention of the vessel walls. The vascular changes as well as the extravasa- 

 tions are themselves consequences, not causes, of the circulatory disturbance, 

 for alteration of the vessel wall never occurs alone but is always observed in 

 combination with thrombosis, while the opposite is very often the case. The 

 frequent closure of the capillary area by thrombosis may be explained by the 

 lessened rapidity of circulation therein, a factor which greatly favors the 

 occurrence of coagulation. The stasis which occurs in mild cases, and is fol- 

 lowed by thrombosis in the more severe ones, damages the vascular wall, how- 

 ever, so that it makes it permeable to the passage of blood. Indeed this stasis 

 may give rise to fatty degeneration and even necrosis of the vascular cells. 



Since "purpura" with swelling of the joints, hematemesis, hemorrhagic 

 diarrhea and intestinal colic had been experimentally produced in animals by 

 means of a dyscrasic blood the question arose whether human purpura — no 

 matter in what form — might also be explained as a primary disease of the 

 blood. Silbermann believes that this question must be answered in the affirma- 

 tive, for the reason that, apart from certain important blood findings, the, 

 essential connection of the pathologic phenomena can only be uniformly ex- 

 plained upon the basis of a primary disease of the blood. 



The hemorrhages into the skin and into the gastro-intestinal tract, the 

 hemorrhagic vomiting, the colic, and the swelling of the joints, which occur 

 in severe cases of purpura, Silbermann explains as due to a primary Hood 

 alteration which leads to a slowing of circulation, stasis and formation of 

 thrombi. Upon the basis of these circulatory disturbances congestive hemor- 

 rhages occur, and also hemorrhages which follow as the result of the occlusion 

 of vessels, and give rise to necrosis of the tissues. These stases and thrombi 

 damage not only the gastro-intestinal canal, but also the tissue of the liver, 

 the kidneys and the myocardium, and may cause fatty degeneration of the 

 cells and necrobiosis. All of these processes were observed lately by Tizzoni 

 and Giovannini in the organs of a girl succumbing to severe purpura. There 

 was occlusion of the vessels which had produced hemorrhage and necrosis of 

 tissue, and also caused the vascular changes previously observed in man and 

 animal attacked by purpura. Silbermann regards it as certain that this de- 

 generation of the walls of the vessels is secondary, because, in his experiments, 

 all stages of the obliteration of vessels have been followed, and the hyaline 

 deposits have been shown to be results of this obliteration. 



In literature similar views in regard to the nature of purpura are constantly 

 met with. Thus Green, du Castel, Dusch,' Mackenzie, Krauss and others 

 believe that there are alterations of the blood in certain forms of purpura. 

 Leloir, who has also observed stasis in the vessels, differentiates a purpura 

 " par modification des vaisseaux " and a purpura " par modification du sang." 

 Eiehl and v. Kogerer, on the other hand, believe the alteration in the vessels 

 to be the primary condition ; the change in the blood, i. e., the thromboses, the 

 secondary. The latter says, in his article regarding the development of cuta- 

 neous hemorrhages : " On the whole there can be no doubt that the thrombi 



