462 THE HEMORRHAGIC DIATHESES 



In another ease (with melena) the bacillus lactis aerogenes was fotind, 

 but to this he ascribes no pathologic importance. 



Lebreton describes in a young girl a case of fatal purpura which developed 

 very acutely after great fright. Large confluent ecchymoses appeared, from 

 the blood of which, upon culture, the staphylococcus albus and the staphylo- 

 coccus aureus were obtained in mixture. The disease was therefore looked 

 upon as infectious purpura. 



Wikner also found the staphylococcus pyogenes albus in a case of morbus 

 maculosus Werlhofii. 



In a number of cases of purpura I have examined small areas of the skin 

 covered with petechia which were excised during life, and I have never been 

 able to determine the presence of microbes. 



Later investigations and reports of this malady are not at hand; in the 

 last four volumes of the Virchow-Hirsch Year-Books, I have not observed a 

 single report of purpura in man. In this article publications up to the year 

 1898 have been referred to. 



We now come to another series of reports which had their origin partly in 

 anatomical studies of the vessels in the course of the hemorrhage, and partly 

 in certain experiments. 



Silbermann, who conducted one series of experiments, started from the 

 well-known researches of Armin Koehler, who, in his work at Dorpat upon 

 thrombosis and its relations to the fibrin ferment, mentions a series of experi- 

 ments in dogs, in which, by infusion of blood very rich in ferment, a disease 

 resembling Henoch's purpura (see below) was produced, inasmuch as, in a 

 short time after the transfusion, multiple capillary ecchymoses were noted in 

 the subciitaneous cellular tissue, and hematemesis, hemorrhagic diarrhea, and 

 intestinal colic occurred. The fulminant, and almost invariably fatal, course of 

 the pathologic process produced by Koehler, on account of the great amount of 

 ferment contained in the injected blood, caused Silbermann to choose a method 

 in which the animals either did not die or did not succumb so rapidly, and in 

 which the purpuric spots appeared more numerously and were distributed over 

 the entire skin. He tried this plan: The dogs, prior to the ferment intoxica- 

 tion, received small doses of pyrogallic acid (0.05 per kilogram of weight of 

 the dog), by which only a moderate stasis in the veins and capillaries occurred. 



This property of pyrogallic acid in small amounts depends upon a very 

 slight damage to the blood, a slight " shadow formation " and fragmentation 

 of the erythrocytes, by reason of which the circulatory disturbance occurs. 



In a number of dogs, after stasis of the veins and capillaries of the entire 

 circulation had been produced by suitable doses of pyrogallic acid, Koehler's' 

 experiments were repeated, with the expectation that the cutaneous capillaries,, 

 •which, like all other capillaries of the body, were under high pressure with 

 decided strain on their walls, would become more permeable by the ferment, 

 blood. As a result of these experiments it was shown that in the animals thus 

 prepared — by injections of ferment blood — thromboses and hyaline vascular 

 changes could be invariably produced in the internal organs, less constantly; 

 in the skin. The consequences of these vascular changes were multiple hemor-. 

 phages into the internal organs and partially also into the skin. 



