Early Blood Chemistry in Britain and France (History‪)‬

The British Account: Blood and Other Body Fluids Throughout the eighteenth century, most physicians thought that diseases arose solely in organs and tissues, the solid parts of the body. By the last quarter of the century, solidism was firmly entrenched in medical theory. Body fluids were not thought capable of causing or harboring diseases, their possible involvement in pathology was largely ignored, and any changes in them that might be observed were regarded as symptoms, rather than causes of disease. According to ancient humoral doctrine, body fluids, or "humours", were maintained in an internal balance. Their relative quantities were considered important, and medical treatments aimed to restore the balance of these humours when it became disturbed by sickness. Thus, purging, vomiting, cupping, venesection, and leeches figured prominently in the armory of the eighteenth century physician.