_Absorption of Toxic Matters._ The theory of a poisoning of the nerve centres is indicated in the familiar name of _milk fever_, suggesting an absorption, or poisonous condition of the milk. Lafosse charged the trouble on the _uterine milk_ secreted in the cotyledons and reabsorbed in quantity. Abadie and Kaiser attributed it to the products of gastro-intestinal ferments, which acted on the nerve centres like a deadly organic alkaloid. Hartenstein incriminated the products of muscular contraction in the womb and systemic muscles during parturition. Ehrhardt invoked a similar auto-intoxication, going on before parturition and only reaching its climax in connection with that act. Allemani and Gratia attribute the disease to the absorption of the first milk (colostrum), and there are several considerations that strongly favor this hypothesis. The disease sets in always in connection with the parturient development and congestion of the udder and the secretion of the first milk. In exceptional cases it may even appear just before parturition. Even upon the calf the colostrum operates as an irritant and purgative. Is it wonderful that, in the parturient cow, with a high state of plethora, a highly susceptible state of the nervous system, and the various concurrent conditions already referred to above, a direct poisoning of the nerve centres should appear? It is worthy of notice that the absorption from the mammæ takes place without any metabolic change, such as occurs in the stomach and liver in the case of materials digested. It is to be presumed that the hypothetical mammary poison is delivered in the brain in its pristine condition and possessed of its full force. The doctrine is corroborated even more strongly by the successful results of treatment by the injection of a solution of potassium iodide into the udder. The iodide solution may presumably act in one or more of several ways. It is unquestionably an antiseptic, and would tend to arrest or control microbian growth and activity, thus preventing the further formation of toxins. It has a potent deobstruent action on glandular tissue, tending not only to dry up the milk, but to hold in check the leucocytic function of producing dangerous leucomaines. There is reason to believe that with regard to some poisonous ptomaines iodine acts as a direct antidote, probably uniting with these and forming new and comparatively harmless compounds. It manifestly acts in this way in the case of cryptogamic diuresis, and in cerebral congestions arising from spoilt fodder. The iodide tends further to act as a calmative to the nerve centres, and as a diuretic, serving to eliminate the poison that may be present in the blood.