464 THE HEMORRHAGIC DIATHESES 



which have been found are the direct cause of the hemorrhage. The thrombi 

 themselves are due to the combined action of local and general causes; hence 

 vascular changes, as is evident from the constancy of the finding, play the 

 main role even if they do not form a conditio sine qua nan." The view of v. 

 Kogerer that the thrombi are due to general and local causes is also the opin- 

 ion of Silbermann who, however, looks upon the alteration of the blood as the 

 general cause, and the pathologic change in the blood current of the capil- 

 laries (due to ferment blood) as the local cause. On account of these con- 

 stant anatomic findings v. Kogerer calls purpura a primary disease of the 

 vessels, while Silbermann believes these changes to be secondary. Other ob- 

 servers, for example, Leloir, have not noted the constant occurrence of dis- 

 ease of the vessels. He believes the occlusion of the vessels to be embolic, 

 while V. Kogerer and Silbermann declare this to be thrombotic. 



V. Kogerer defines the result of his investigations in purpura in the follow- 

 ing scheme : 



(a) Vascular disease, 



(&) Thromboses, 



(c) Extravasations of blood, 



(d) Pigmentation. 



While Silbermann comes to the following conclusions : 



(a) Thromboses, 

 (6) Vascular disease, 



(c) Extravasations of blood, 



(d) Pigmentation. 



As will be noted these authors agree that the disease of the vessels is the 

 underlying cause of the hemorrhages, but Silbermann looks upon stasis and 

 thrombus-formation (in the small veins and capillaries) as the primary condi- 

 tion which leads to disease of the vessels ; while v. Kogerer believes thrombus- 

 formation to arise as the result of the disease of the vessels. The latter con- 

 dition in either case causes hemorrhage. 



V. Kogerer examined 13 cases which ran their course with cutaneous hemor- 

 rhages; in these he excised particles of the skin, and studied microscopically 

 the changes in the different layers of the cutis and subcutaneous cellular tissue. 

 The diseases represented were scurvy, morbus maculosus, tuberculosis pul- 

 monum, carcinoma ventriculi, marasmus senilis, peliosis rheumatica, sepsis, 

 vitium cordis, etc. In all cases in which careful search was made thrombi 

 were found. These were mostly situated in the small venous trunks, but were 

 also found in the small arteries. Besides this many minute arteries and 

 capillaries were filled with fibrin coagula and blood-corpuscles, and it was 

 impossible in some cases to decide whether the condition was one of actual 

 thrombosis or only a vessel surcharged with blood ( !). The thromboses were 

 occasionally numerous, at other times more scant, and frequently repeated 

 search was necessary to find them. In some cases the degeneration of the vas- 

 cular wall was conspicuous. 



Eiehl, even prior to v. Kogerer, invariably found changes in the blood- 



