This principle in the animal economy has been acknowledged by the practice of occasionally stopping the discharge of water from a canula in tapping, and of blood from a vein, in order to prevent fainting. Child-birth induces fainting, and sometimes death, only by the _sudden_ abstraction of the stimulus of distention and pain. In all those cases where purging or bleeding have produced death in the yellow fever or plague, when they have been used on the first or second day of those diseases, I suspect that it was occasioned by the quantity of the stimulus abstracted being disproportioned to the degrees of depression in the system. The following facts will I hope throw light upon this subject. 1. Dr. Hodges informs us, that "although blood could not be drawn in the plague, even in the smallest quantity without danger, yet a _hundred_ times the quantity of fluids was discharged in pus from buboes without inconvenience[79]." [79] Page 114. 2. Pareus, after condemning bleeding in the plague, immediately adds an account of a patient, who was saved by a hæmorrhage from the nose, which continued _two_ days[80]. [80] Skenkius, lib. vi. p. 881. 3. I have before remarked that bleeding proved fatal in three cases in the yellow fever, in the month of August; but at that time I saw one, and heard of another case, in which death seemed to have been prevented by a bleeding at the nose. Perhaps the uniform good effects which were observed to follow a spontaneous hæmorrhage from an orifice in the arm, arose wholly from the _gradual_ manner in which the stimulus of the blood was in this way abstracted from the body. Dr. Williams relates a case of the recovery of a gentleman from the yellow fever, by means of small hæmorrhages, which continued three days, from wounds in his shoulders made by being cupped. He likewise mentions several other recoveries by hæmorrhages from the nose, after "a vomiting of black humours and a hiccup had taken place[81]." [81] Essay on the Bilious or Yellow Fever of Jamaica, p. 40. 4. There is a disease in North-Carolina, known among the common people by the name of the "pleurisy in the head." It occurs in the winter, after a sickly autumn, and seems to be an evanescent symptom of a bilious remitting fever. The cure of it has been attempted by bleeding, in the common way, but generally without success. It has, however, yielded to this remedy in another form, that is, to the discharge of a few ounces of blood obtained by thrusting a piece of quill up the nose.