_Inoculation._—At one time, it was attempted at Havana to prevent yellow fever by inoculation of the poison of a snake, supposed to be the _crotalus horridus_. A German adventurer assumed the respectable name of Humboldt to sustain his theory. This man had observed that the Indian prisoners, lead from Mexico to Vera Cruz, exhibited, when they were bitten by a viper, symptoms analogous to those of yellow fever. He then made some experiments with the inoculation of this substance at Vera Cruz, and at New Orleans. He came afterwards to Havana, and obtained from General Concha, then Governor of the Island, permission to make some trials at the military hospital. He proceeded in this wise: He made, said he (no one saw it), the snake bite the liver of an animal, and kept it to putrefaction. He inoculated with this substance, and gave at the same time, internally, a syrup composed of _mikiana-guaco_ and rhubarb, with the addition of iodide of potassium and gutta-gamba. The symptoms appeared in the following order: at the moment of inoculation, the subject was taken with a transient vertigo, at other times, with a nervous trembling, which lasted a longer time. Seven hours after, the pulse was modified in a permanent manner, more frequent or slower, stronger or weaker. Eleven hours after, he had febrile heat. At the end of fourteen hours, he had headache, inappetence, thirst; sixteen hours after, the face red, the conjunctiva injected. From the outset, the gums were swollen and the patient suffered from colic. Eighteen hours after, the gums were painful, and their borders became red, with pains in the salivary glands, and in the nerves of the face and teeth. Nineteen hours after, pain in the lower jaw, in the direction of the submaxillary nerve. At the twentieth hour, bad taste in the mouth, coryza, and œdema of the face; at the expiration of twenty-two hours, a sensation of contraction of the throat, without visible change. At the twenty-third hour, jaundice; at the twenty-fourth, gingival hemorrhage; at the twenty-eighth, conjunctiva injected, chills; at the twenty-ninth, tonsillary angina; at the thirtieth, pains in the loins; at the thirty-eighth, pain in the joints; at the seventy-second, swelling of the lower lip. During convalescence, prurience of the skin, with cutaneous eruptions. These symptoms are far from being those of yellow fever. They belong in part to those produced by the mixture of guaco and iodide of potassium, and in part to those, which putrifying substances produce, when they are absorbed.