toxin, a few minutesafter the injection of phenol red and sodium ferro-cyanide,substanceswhich are excretedchiefly by the proximal convoluted tubules and the glomeruli respectively. In a further set of experimentsa cast of plaster was applied to the injected limb immediately after the injection of the lethal dose of toxin. In a final series the toxin-treated leg was massagedafter the injection so as to diffuse the toxin more rapidly. These two sets of animals were submittedto the sameinvestigations, and integration of all the experimental data was then made so as to assessthe connexionbetweenthe redemaof the limb, the hremoconcentration,the renal function, and the demonstrable damage to the various cellular componentsof the kidney. The authorsfound that the amount of local redemacould explain the larger part of the hesmoconcentrationand the fall in the chloride content of the blood. Extrarenal factors and diminution of renal function may then be directly related to the findings in the blood. They consider that the rapid redema of the limb may be responsible for the fall in urinary excretion, as no such changewas observedin those animals which had a plaster cast applied to the limb. The kidneys showed no cellular changesdemonstrableby histological methods until one and a half to three hours had elapsedafter the giving of the toxin. Then the glomeruli showed vascular changesand swelling of the tufts, and later the swelling became sufficient to lessen filtration. After four or five hours pronouncedcirculatory failure was evident in the kidney, and the tubules as well as the glomeruli showed failure to secretedye, with severe mitochondrial damage in the cells. The authorsdiscussdetails of the mechanism of thesechanges,but it is sufficient here to point out that they produced local redema in the animals, with hsemoconcentration, a drop in blood pressure reaching shock level, and a significant reduction in renal function, which is apparentlydue to circulatory changes,direct action of toxin or both. Massage of the leg to diffuse the toxin enhanced its effects, whereas concentric pressure with plaster reduced, delayed and possibly modified the toxic effects. One interesting finding was the appearanceof severeand extensivedestructionof the kidneys after massage of the limb. These experimentsserve to emphasize the method of action of the toxin of Olostridium perj1"ingens, and to bring into line the symptomswith those observedin several well-known conditions.