The animal which is to furnish the antitoxin is immunized as in the Pasteur method by a succession of graduated doses of rabic virus. After a treatment of 20 days the rabbit or sheep furnishes a serum which is protective when injected in the proportion of 1 of serum to 25,000 of body weight, even though its use be delayed until 24 hours after the introduction of the virus. The sheep can be immunized in 12 days by doses of 0.25 gramme of emulsion of the infected cord to every kilogramme of body weight. To maintain the serum at its highest standard the treatment must be repeated at intervals of 2 to 5 months, as the animal may be able to bear it without loss of condition. _Treatment with Sterilized Brain Matter from a Rabid Animal._ In 1886 I sterilized with heat an emulsion of the spinal cord of a man who died of hydrophobia and injected two rabbits with 3 one drachm doses each, and a third with 4 one drachm doses on as many successive days. These rabbits were afterwards inoculated with virulent spinal cord and remained well for nine months, while three control rabbits injected with virulent cord, but which had received no previous treatment died rabid. Puscarin and Vesesco have shown that the virus is rapidly weakened by heat up to 60° C. at which point the virulence is destroyed. It becomes easy therefore to secure in this way a toxin uncomplicated by any living microbe. Theoretically the sterilization and use of infecting nervous substance, should share with the Pasteur method the advantage of the selective action of the medullary matter in uniting with the toxins and robbing them to a greater or less extent of their toxicity. It has the additional recommendation that it introduces no living germ, and thus obviates any possible danger of the propagation of disease through the animal operated on. Fernandez claims an immunity from rabies for dogs that have survived the bite of a viper. Many facts and experiments are adduced in support of this. TETANUS.