When the dose of venom is rapidly lethal, whether because it penetrates into the veins or because a larger amount of it is diffused beneath the skin, it occasions a transient hypoleucocytosis, which is, moreover, a reaction common to injections of venom, pro-peptone, extracts of organs, and microbic toxins (Delezenne, Nolf). It follows that blood collected a short time after the injection may be totally bereft of its bactericidal power, in consequence of the disappearance of the leucocytes, which have migrated into the organs. Thus it was observed by S. Flexner and H. Noguchi that the serum of a rabbit, treated with 10 milligrammes of _Cobra_-venom, showed, fifty-seven minutes after the injection, a great loss of bactericidal properties. But it is impossible to conclude, from the diminution of bactericidal power in this experiment, that the alexin becomes fixed by the venom. Since the secretion of alexin is connected with the presence of leucocytes, the hypoleucocytosis due to the venom is sufficient to explain the loss of bactericidal power. Nevertheless, the action of venom is not confined to these physiological phenomena; in diffusing itself through the organism it stays more especially in parts where the circulation has become slower, in the capillaries of the organs where the leucocytes that have disappeared from the general circulation are already to be found agglomerated and altered. Here the cytolysins of the venom, continuing their effects, are capable of neutralising the alexins set at liberty by the destruction of the leucocytes, and thus the rapid multiplication of the bacteria of putrefaction, which have come from the intestine or were carried in with the bite, is easily explained. In the same way, we can account for the suppuration that is met with as a complication of non-lethal bites, in spite of the hyperleucocytosis consequent upon the penetration of a weak dose of venom; immediate neutralisation of the alexin set at liberty at the level of the wound has sufficed to enable micro-organisms to multiply. D.--VARIOUS DIASTASIC ACTIONS OF VENOMS. So long ago as 1884, de Lacerda, in his “Leçons sur le venin des serpents du Brésil,” described the results of his researches upon the diastasic actions of venom. He proved that venom emulsifies fats, causes milk to curdle, and does not saccharise starch. But the solutions of venom employed by this author were not sterile, so that putrefactive phenomena may be believed to have occurred in the course of his experiments. The subject has been studied afresh by Wehrmann[60] in my laboratory, and afterwards by Lannoy.[61] These two investigators have shown that venoms do not hydrolyse either starch or inulin. _Cobra_-venom and that of _Vipera_ change saccharose very slightly. They do not modify the glucosides (amygdalin, coniferin, salicin, arbutin, and digitalin); they therefore do not contain emulsin.