Guest post by Harold D. Langley
Before considering medicine in the U.S. Navy during the War of 1812, it is necessary to understand the ideas that influenced the professional healers of that era. Long before the germ theory of disease was discovered, the medical practice of the time was based on the “humoral” theory, which dates back to the ancient Greeks. This theory stated that the human body was divided into four liquid elements, or “humors”: blood, phlegm (a thick mucus secreted by the throat and bronchi), yellow bile (secreted by the liver), and black bile (an imaginary fluid supposedly secreted by the pancreas that resulted in a disorder of the intellect and acts of fury). Good health depended on keeping all the humors in balance. Thus, a runny nose indicated that there was an excess of coldness or phlegm and the patient needed medicine and warmth to restore the balance in the body. Later discoveries, such as how the blood circulated, were grafted on to the humoral theory.
By the late 18th century, a new concept called “solidism” was used with the humoral theory as a means of interpreting symptoms. Solidism focused on the tone, elasticity, and strength of the solid portions of blood vessels and nerves. Arteries and nerves were considered to be hollow tubes that propelled their contents through the body with a force that was proportional to the strength of the fibers in the tube walls. In a healthy person, blood, urine, feces, sweat, and fluids that were believed to flow through nerves moved freely. Obstructions to the flow of body or nerve fluids, some of which were humors, were believed to represent imbalances in the tone of the passageway through which they flowed, resulting in illness.
Thus, physicians could interpret most illnesses simultaneously in terms of the humoral and solidist theories. For example, a prolonged constriction of the intestines resulted in constipation. Jaundice accompanied by fever might be interpreted as an obstruction of the ducts through which the bile passed from the liver to the duodenum, the first part of the intestinal canal. Doctors tried to make a correlation between the patient’s symptoms and physical signs with imbalances in their humors and tones. For example, the pulse was regarded as an index of the fibers of the cardiovascular system through which the blood flowed. If the pulse was slow or weak, the doctor concluded that the vascular fibers were weak or lax. Or, if the pulse was fast, the physician deduced that the vascular fibers were hyperactive and produced heat when fever was present.
Having diagnosed the ailment, the physician now proceeded to treat it. He had at his disposal approximately 225 drugs that were prepared from about 100 supposedly active ingredients. Research based on the therapeutic methods of New England doctors in the late 18th century, which were probably used throughout the country, indicates that the most commonly prescribed drugs were cathartics, used to stimulate the intestinal tract to evacuate disease-producing materials and abnormal humors. Calomel (mercurous chloride), castor oil, and jalapa (a South American plant) were commonly used for this purpose.
The second most commonly used remedies were tonics, or drugs that were thought to strengthen the body tissues weakened by disease. Peruvian bark, Virginia snakeroot, and several spices were among the widely used treatments. Peruvian bark (cinchona) was later known to contain quinine, and it was used extensively as a tonic to treat malaria and other types of fever.
If a patient had eaten something that resulted in an imbalance of the humors, the stomach might be emptied by use of emetics (a medicine that induces vomiting), especially ipecac (a dried root of a small shrub native to Brazil) and tartar emetic (antimony potassium tartare). Similarly, diuretic salt (potassium acetate) was used to increase the secretion and flow of urine. It was also used to promote the absorption of fluid by vessels throughout the body so that it could be eliminated by way of the kidney. Diaphoretics, such as antimony salts, were drugs that stimulated increased perspiration.
Opium was prescribed mainly for the control of diarrhea, for pain, or to induce sleep. It was administered in pill form or in alcohol solutions such as laudanum. Astringents, such as lime water, were thought to condense the solids of arteries and nerves and to reduce abnormal losses of heat, fluid, and other secretions.
Severely ill patients might be treated with blistering agents or by bleeding. To raise a blister the doctor applied an alcohol solution of cantharides (powdered Spanish flies) directly to the skin so that pus and other noxious materials, including foul humors, could escape from the body into the blister fluid. Cantharides were also thought to counter-irritate underlying tissues so as to neutralize the more serious induced irritation that was causing pain and putrefaction.
In the case of bleeding, the usual practice was to perform it only if the patient’s pulse was full and strong. The amount of blood removed at one time was between 8 and 20 ounces, the average being about 12 ounces. By this means harmful humors were understood to be removed from the body.
Harold D. Langley is curator emeritus of naval history at the Smithsonian Institution’s National Museum of American History and the author of A History of Medicine in the Early U.S. Navy.