202 LOCAL TISSUE REACTIVITY 



occasional ly in the sinus in the \icinily ol the central veins and 

 nioie rarely, in small |)ortal \ein branches, l^he arteries were 

 ajjparentiy tree ol thrombi or other changes. There was great 

 \aiiatic)n in the extent ol \enoiis thrombosis. Tlie thrombi con- 

 sisted ol masses oF eosin<)j)hiles, erythrocytes and leucocytes. The 

 amount ol librin \aiied but was usually small. Serial sections of 

 \eins containing thiombi revealed no endothelial changes. Occa- 

 sionally there were seen subendothelial round cell inliltrations 

 pushing the endothelium forward and jirojecting into the lumen 

 of the vessel. Some of the subendothelial nodules were apjxri- 

 ently similar to those described by Siegmund (1925) , Hitchcock, 

 Cameio and Swift (ig^H)' ^'i^l others. These nodides were also 

 seen in control animals, particularly in those showing spontaneous 

 infiltration of the periportal connective tissue. Gerber attributed 

 them to coccidiosis. The thrombi shelved no organization and 

 tended to disappear promptly. The outstanding changes in the 

 I1UI& Avere edema, hemonhaoe, and venous thrombosis. The 

 spleen also showed focal necrosis and thrombosis of the splenic 

 sintises, splenic vein brairches and arterioles of the malpighian 

 corpuscles, followiirg a single intravenous injection of a bacterial 

 filtrate. Focal necrosis was observed in both the malpighian cor- 

 puscles and in the splenic pulp. The presence of parietal venous 

 thrombi \vas infrecjtient in the adrenals. The essential lesion 

 consisted of a sharply demarcated area of necrosis chiefly involv- 

 ing the cortex and sometimes the adjacent medulla. Microscopi- 

 cally, the necrotic area ^vas demaicated by a zone of leucocytes 

 from the normal tissue. Nc:) involvement of the arteries 'was dem- 

 onstrated. Foci of hemorrhaoe ^vere observed in the cortex but 

 they were not associated with thrombosis. There were focal necrosis 

 and capillary and venous thrombi in the bone-marroio as Avell. 

 The thrombi ^vere identical 'with those observed in other organs. 

 The cellidar components of the bone marro^v remained unaf- 

 fected. Ncj si^'iiificant lesions ^vere c:)bser\ed in the remaining" 

 organs. The {production of xenons throiubi iir the internal organs 

 of rabbits, identical xvith those described by Apitz, and Gerber, 

 Avas reported by Kusaiua follcnving the injection of vaccines of 

 typhoid bacilli, dysentery bacilli and staphylococcus. It is quite 

 possible that the vaccines employed by these aiuhors, at least 

 those of B. typhosus and B. dysenteriae bacilli, contained the ac- 

 ti\'e principles of the phenomenon. Also identical xenons thrc:)mbi 



