A quarter of an hour after, an ounce of saturated solution of nux vomica was injected into the same vessel. This also was followed by no particular symptoms. An hour after the first injection, half an ounce of a weak infusion of tobacco was introduced into the same artery. Excessive pain immediately followed, accompanied by great rapidity of breathing. The animal now appeared as if he were going to die; however, he slowly recovered, appeared giddy and inclined to vomit, and kept himself in a continual state of restlessness. This condition was succeeded by fever, accompanied by extreme sensibility of the limb, and irregularity of the pulse. At the expiration of some hours, he appeared better; the pulse became more regular and less feverish, but the leg continued swollen, and extremely painful upon pressure. During the night, the pain returned, indicated by howling and restlessness. There were several evacuations of fæces and urine. The following morning, there was great prostration with much fever, and apparent suffering. The limb was slightly emphysematous, swollen, inflamed, and infiltrated with serum. On the following day, two ounces and a half of water, in which some nux vomica had been boiled, were injected into the crural artery of the opposite limb. The dog expressed no pain; but, at the expiration of ten or twelve minutes, slight convulsive motions became evident, which were gradually converted into violent tetanic spasms. The animal threw himself backwards with his limbs extended, and died, after repeated convulsive attacks, an hour and a half after the last injection. _Post-mortem appearances._ On opening the body, _no unusual appearances were observed in the limb_ upon which the last experiment had been tried, but the opposite one was tumid and emphysematous, infiltrated with a greyish red frothy serum of a fetid odour. _The small vessels were obstructed by firm clots of blood._ The gall-bladder was greatly distended; and the intestinal canal contained a quantity of yellowish mucus. PART II. ON THE INTRODUCTION OF VITIATED FLUIDS INTO THE BLOOD; ITS CONSEQUENCES, AND TREATMENT, WITH CASES.