9     Life was endangered by injecting a little pure water into a vein. (Vide Mullen, quoted by Birch in the History of the Royal Society.)      Atmospheric air injected into the blood-vessels caused death. (Vide J. M. Voigt, Magazin für den neuesten Zustand der Naturkunde, i, iii, p. 25.)      Even the mildest fluids introduced into the veins endangered life. (Vide Autenreith, Physiologie, ii, § 784.)