Page:The Works of William Harvey (part 1 of 2).djvu/491

 marasmus, a considerable quantity of blood is still found after death in the veins. And farther, in youthful subjects still growing, and in aged individuals declining and falling away, the relative quantity of blood continues the same, and is in the ratio of the flesh that is present, as if the blood were a part of the body, but not destined solely for its nourishment ; for if it were so, no one would die of hunger so long as he had any blood left in his veins, just as the lamp is not ex- tinguished whilst there is a drop of inflammable oil left in the cruise.

Now when I maintain that the living principle resides pri- marily and principally in the blood, I would not have it inferred from thence that I hold all bloodletting in discredit, as dan- gerous and injurious ; or that I believe with the vulgar that in the same measure as blood is lost, is life abridged, because the sacred writings tell us that the life is in the blood ; for daily experience satisfies us that bloodletting has a most salutary effect in many diseases, and is indeed the foremost among all the general remedial means : vitiated states and plethora of the blood, are causes of a whole host of diseases ; and the timely evacuation of a certain quantity of the fluid frequently delivers patients from, very dangerous diseases, and even from imminent death. In the same measure as blood is detracted, therefore, under certain circumstances, it may be said that life and health are added.

This indeed nature teaches, and physicians at all events pro- pose to themselves to imitate nature ; for copious critical dis- charges of blood from the nostrils, from hemorrhoids, and in the shape of the menstrual flux, often deliver us from very serious diseases. Young persons, therefore, who live fully and lead indolent lives, unless between their eighteenth and twentieth year they have a spontaneous hemorrhage from the nose or lower parts of the body, or have a vein opened, by which they are relieved of the load of blood that oppresses them, are apt to be seized with fever or smallpox, or they suffer from headache and other morbid symptoms of various degrees of severity and dan- ger. Veterinary surgeons are in the habit of beginning the treatment of almost all the diseases of cattle with blood- letting.