A further study of the origin of blood vascular tissues in chemically treated teleost embryos, with especial reference to haematopoesis in the anterior mesenchyme and in the heart

Abstract

As first shown by Loeb,' certain chemicals are capable of inhibiting, arresting, or preventing complete circulation in embryos of Fundulus heteroclitus.The same phenomena have since been recorded by Stockard2 and W e r b e ~. ~ Stockard's highly interesting study is apparently based on the following postulate: I n embryos "in which the blood fails to circulate on account of the fact that the heart is either blind a t one end or both, or fails to connect with the veins" (p.124) it is safe to conclude that any place in which blood-cells are found may be considered their locus of origin, even though in some cases the "embryo develops in a fashion closely approximating the normal when the heart beat is fairly strong."Incidental to this main postulate his work relies on the proposition that tissues devoid of blood-cells under such conditions are proved to be, and always to have been, devoid of haematopoetic potentiality.Thus the demonstration of endothelial-lined cavities which contain no blood-cells demonstrates likewise the inability of all endothelium to produce blood-cells.The absence of blood-cells in the liver disposes of that organ as a blood producer in the bony fishes (p.125).,Inother highly interesting observation of Stockard's