Our second problem is to ascertain the nature of the change in the nerves, to find out, if possible, whether it is merely functional or an actual interference with the structure of either cells or fibres. With this end in view we once more consult the microscope. We make two preparations, one of nerve fibres and of nerve cells of the poisoned frog, and, under the microscope, compare them carefully with an analogous one from the killed healthy frog. The result is purely negative as regards structural change. Both present identical and perfectly normal pictures of apparently healthy cells and fibres. There being no visible structural change we are driven to the conclusion that only a functional one has been effected by the poison, and with the symptoms observed all pointing in that direction, that it is of central origin. The writer's theory as to the action of snake-poison, formed, in the first instance from observations made at the bedside of his patients only, is thus confirmed by experiments specially instituted by him for that purpose. Further proof of its correctness we have in the brilliant results of the strychnine treatment of snakebite in Australia, which is the outcome and practical application of this theory. In those desperate cases more especially, reported from all parts of the colonies, in which death was imminent, and pulse at wrists as well as respiration had already ceased, the strychnine injections could not possibly have effected complete recovery within a few hours if the structure of the nerve centres had been impaired or blood changes brought about incompatible with life. Feoktistow's experiments, made with viper poison, fully bear out the correctness of the writer's theory, besides proving that there is no essential difference between the action of the viperine and colubrine poisons. He proved conclusively that snake-poison does not destroy protoplasm or interfere with infusorial life, that injected into the heart of a mollusc it causes an almost immediate cessation of its action, that hypodermic injections of it in fish produce contraction of the pigment cells and bleaching of the integuments, followed by asphyxial respiration, general paralysis and death. Similar results were observed on frogs. In mammals the symptoms were: dyspnoea, asphyxia, paresis and paralysis of the lower extremities with succeeding general paralysis, sometimes tonic and clonic convulsions, hæmorrhages from bowels, lungs, nose and bladder, and finally complete paralysis of respiration and of heart. Action of Snake-Poison on Special Nerve Centres.