By David J. Peck, D.O.
On the Fourth of July, 1804, near present-day Kansas City, Kansas, a potentially devastating medical incident occurred. Private Joseph Field was bitten on the ankle by what was probably a prairie rattlesnake (Crotalus viridis viridis). But Lady Luck was with Corps of Discovery and, instead of a fatal or even serious result, the victim escaped with just a few days with a sore and swollen ankle.
Rattlesnakes have very sensitive heat-sensing organs on their heads, which they use to find food. As Field walked along the bank of the Missouri River, the serpent sensed his body heat and struck, burying its hypodermic-like fangs in his ankle.
Since rattlesnakes can vary the amount of venom injected into their prey and, fortunately, very little venom was injected into Field's ankle.
Venom from that rattler contained a number of digestive enzymes that attacked the cell walls of the tiny blood vessels (capillaries) in Field's leg. The enzymes immediately caused serum inside the vascular spaces to leak into the intercellular spaces. Field's ankle quickly swelled. The venom also attacked red blood cell membranes, potentialIy causing bruising, clotting, pain, and life-threatening reactions within the victim's body. Fortunately for Field, the potency of the prairie rattler's venom falls into the intermediate toxicity range of all North American rattlesnakes, the worst being that of the Eastern diamondback, Crotalus adamateus.
Modern treatment is to administer special antibodies, called antivenin, which inactivate the venom.
But Lewis and Clark knew nothing of venom action and had only their frontier knowledge, common sense, and some folk remedies. Captain Lewis applied his poultice of Peruvian Bark to the bite. This herbal medication was effectively for malaria because it contains quinine, a chemical that kills the disease-causing parasite.
Lewis did not understand the nature of malaria or how Peruvian Bark worked. He likely believed that if it worked against one type of illness, it might work in this case of snakebite as well. We cannot fault his ignorance. He did the best he could, although the poultice probably had no beneficial effect at all.
David J. Peck, D.O., Or Perish in the Attempt: Wilderness Medicine in the Lewis & Clark Expedition (Farcountry Press, 2003).
Robert M. Corker, Snakes of the United States and Canada (Herndon, Virginia: Smithsonian Institution Press, 2003).