Typhus Fever

Abstract

cells of the growth proper and, indeed, I think it likely that the two varieties represent different evolutionary phasesin the developmentof primitive mesoblasticcells, such cells being capableof developing through fibroblasts to white fibrous tissue on the one hand and through endothelial cells to the formation of blood vessels and spaceson the other. The walls of these vessels are so thin that rupture readily takesplace and the red cells insinuatethemselves betweenthe strandsconstituting the growth. In parts of the growth, especiallywhere myxomatouschangesare present,quite large heemorrhagesare to be seen. I amdoubtful whether, in some instanceswhere red cells are seen separatingindividual spindle cells, it might not be that the spindle cells are invading the blood as happensfor instancein the organizationof a thrombosedhremorrhoid. I am the more inclined to think that this may be so, becausethere are in places among the red blood cells not only spindle cells correspondingto fibroblasts, but also young, thin-walled blood capillaries. If this theory be correct, it would seem that these spindle cells can on occasion forego their purposelessproliferation and carry out the functions which cells of such a type are wont to -perform in health. Regarded from this point of view these portions of the tumour are analogous to young granulationtissue invading blood clot. In addition to the types of blood vesselsalreadydescribed thereis still anothervariety (FigureV.). At first sight this type appearsto be a very thick-walled vessel surrounded by a clear zone of degeneratetissue which takes . on a faint cytoplasmic stain. Closer examination shows that the lining layer is composedof cells shl1ilar to those consituting the thin-walled blood vessels elsewhere and that what appearsto be a thick vessel wall is really a sheathof tumour cells. Why the sheathends abruptly at the edge of the clear zone and why there is a clear zone is obscure. In some instancesthe clear zone extends to the actual single layer of cells forming the wall of the vessel,so that degenerationfrom inanition scarcelyseems an adequateexplanation. _ Many of the thin-walled vesselsin parts of the tumour are almost filled with leucocytes mainly polymorphonuclear cells (Figure I). The fact that the patient had a well marked leucocytosisis interesting in this regard. No satisfactoryexplanationof the leucocytosisis apparent; If the new growth were responsible, it might have accountedfor the leucocytosisin one of two ways: (c) As the result of necrosis with secondarysuppuration in the tumour leading to stimulation of the leucoblastic marrow. (b) By the formation of leucocyteslocally in the tumour. With regard to the former of these two alternativesit must be statedthat grosssuppurationwas not observedin the tumour. The secondof these alternativesis at least worthy of consideration,for it is now widely acceptedthat hrematopoiesisis not a function of bone marrow only. Unfortunately no blood films were made from the specimen in the fresh state and, though a little suggestive in places,the histological picture revealedno convincing evidence that active blood formation was occurrtng in the tumour. • IReUiews.