SOME OBSERVATIONS UPON ENDOTHELIAL SEPARATION IN THE SMALLER ARTERIES AND VEINS

Endothelial separation is a subject which appears to have received very little attention. At the first meeting of the German Pathological Society' this subject was discussed by Heller. He described "peculiar findings of endothelial separation" which he had observed in the arterioles and venules, and which he believed to be a vital process because the cells lay embedded among red blood corpuscles. Schmorl stated that he had seen this condition and had formerly believed it an intra-vital one, but now he considers it a post-mortem change, because if intravital, emboli of endothelial cells would be found. Several others agreed with the statement of Schmorl, and Chiari remarked that in a gangrenous lung he had once found almost all the endothelium separated from the walls of the vessels. The following observations are based upon a study of specimens and records of ~64 post-mortems in the Pathological Laboratory of Rush Medical College. About half of the specimens were hardened in alcohol and formalin, the others in Zenker's fluid ; most of them were embedded in celloidin, stained with eosin and haematoxylin, and mounted in Canada balsam. The endothelial separation observed is not at all uniform, varying from individual cells to large plates of endothelium, and from a few cells to a number almost or quite filling the lumen of the vessel, many cells being free in the lumen, others still attached to the vessel wall. This has made it seem wise to