In the Blood

This is an article I wrote for The Chronicle of the Horse at least 20 years ago, though I’m not sure what issue it was in. At the time, I was working at a site administered by the Minnesota Historical Society, where the bloodletting of its human occupants was the norm. I wondered if it was used to treat animals as well, so I researched the subject. This is the results.

An 18th century book illustration showing a man preparing to bloodlet a grey horse.
Bloodletting a horse from an 18th century Hindi text
Credit: Wellcome Library, London.

Picture poking a hole in your horse’s neck to treat his ills. Imagine his blood coursing down his shoulder, down his foreleg, onto the ground. Lots of it, a gallon or two or more, perhaps until his knees buckle and he faints. And imagine repeating this gory process again and again, sometimes for days, until he gets better–or dies.

Insanity? Few twentieth century folks would disagree, yet as a medical procedure for man and beast, bloodletting, also called bleeding and venesection, persisted for a long, long time.

Hippocrates, writing and practicing medicine in the fourth century B.C.E., authored a comprehensive treatise on bloodletting. Building upon Hippocrates’ notes, the Greek physician Galan was first to stipulate exactly how much blood should be drained (for a human, from seven or eight ounces to as much as a pound and a half; in certain cases until the patient fainted).

And throughout the ‘civilized’ western world, for century upon century, the grisly practice persisted. Why? Because folks believed it worked.

A typical 19th century, veterinary-style bloodletting fleam.
A typical 19th century, veterinary-style bloodletting fleam.

For instance, the learned Dr. Henry Clutterbuck of the Royal College of Physicians wrote, in On the Proper Administration of Blood-Letting, for the Prevention and Cure of Disease (1840): “The importance of blood-letting, as a medicinal agent, in comparison with other means of cure…is the least equivocal of remedies; its good effects, when properly administered, are, in most cases, so immediate and striking as not to be mistaken…In short, blood-letting is a remedy which, when judiciously employed, is hardly possible to estimate too highly”.

Physicians believed blood became too thick, then existed, according to Dr. Clutterbuck “in a state of great confusion”, causing all manner of illness and debility. People had themselves bled (often by barbers; the red stripe on a barber pole symbolizes blood) “for the purpose of avoiding bad health consequent on over-eating and over-drinking”. And they bled their livestock too.

Horses were normally bloodlet from the jugular vein, through an incision punched by a sharp iron lancet called a fleam. In 1876, in The New System of Educating Horses, Including Instructions on Feeding, Stabling, Shoeing, Etc. with Practical Treatment for Diseases, famous horse tamer D. Magner explains how this was done: “For general bleeding the jugular vein is selected. The horse is blindfolded, or his head turned away; the hair is smoothed along the course of the vein with a moistened finger, then with the third and little fingers of the left hand, which holds the fleam, pressure is made on the vein sufficiently to bring it into view, but not to swell it too much. The point to be selected is about two inches below the union of the jugular vein at the angle of the jaw. The fleam is put in a direct line with the vein at the center, when it is to be hit sharply with a stick. See that the fleam is large, sharp, and clean, for if rusty or dull, inflammation of the vein might result. It is of great importance that the blood be drawn quickly. When sufficient blood has been taken, the edges of the wound should be brought closely together, and kept together by a small sharp pin being passed through them. Around this a little tow or a few hairs from the mane of the horse should be wrapped, so as to cover the whole of the incision, and the head of the horse should be tied up for several hours, to prevent his rubbing the part against the manger. When the bleeding is to be repeated, if more than three or four hours have elapsed, it will be more prudent to make a fresh incision, rather than to open the old wound.”

For which diseases and afflictions were horses bled? And how much blood was tapped? Of that, says Magner:

~ For tetanus: “Bleeding about four quarts daily for four or five days has cured several bad cases”.

~ For laminitis: “As soon as the disease has developed itself, bleed from the neck, according to the size and condition of the animal–from six to twelve quarts”.

~ For inflammation of the brain, or ‘staggers’: “The cause of staggers is an undue flow of blood to the brain, which rarely or never occurs in any animals except those in plethoric (fat) condition. There is but one cure for this disease, and that is, remove the cause. Bleed largely from the neck–ten, twelve, or fourteen quarts, or until symptoms of fainting”.

~ For inflammation of the bowels (whatever that is): “In order to suppress the inflammation it is necessary to bleed immediately from the neck vein from six to ten quarters of blood, according to the size and strength of the animal. In extreme cases bleeding may be repeated to the extent of four to six more quarters in three to four hours.

~ And for spasmodic colic: “Take from six to twelve quarts of blood from the neck vein, according to the size of the horse and the severity of the attack. Always in bleeding make the orifice large, and extract the blood as quickly as possible. As bleeding is the most powerful and reliable means of relaxing the system, it can always be relied upon in the cure of this form of colic. There will be no relapse after bleeding…Bleeding alone will give sure relief, but sticking a knife into the mouth is not the way to do this, there is liability to cut the palate artery and have trouble. Always bleed from the neck vein, which is one of the simplest and safest of operations”.

An illustration from an Italian book published in 1591, showing where to bloodlet a horse.
A late 16th century illustration from Opera di Mescalzia. (Rome: P. Blado, 1591) showing the proper locations for bloodletting a horse.

And so it goes. But did Magner consider bloodletting a universal panacea? Not quite. Regarding flatulent colic, he warns, “Do not commit the error of bleeding for this form of colic, as it would be almost sure death”.

During Magner’s time, horses (and humans) indeed sometimes expired after bleeding. The practice sapped already jaded systems, especially when patients were repeatedly tapped, sometimes day after day, week after week, until they improved—or died.

And when horses or people died, was excess blood loss blamed? Almost never.

Practitioners assumed not enough blood was tapped, or the timing was wrong. The horse was too young or too old or too far gone for bleeding to help. So for centuries the practice survived.

Then during the mid-to-late 1800’s, as other more effective practices evolved, bleeding gradually fell from favor. By century’s end, few veterinarians and even fewer physicians endorsed bloodletting, except…

Even today, selective bleeding is the treatment of choice for a rare blood disorder called polycythemia. Polycythemia is caused by an overproduction of red blood cells, which thicken and slow blood flow, thus delaying the delivery of oxygen (and energy) to muscle tissue. Polycythemia manifests spontaneously in some Standardbred bloodlines, mostly effecting stallions in hard training. It affects humans as well, and they, like polycythemic horses, are bloodlet to thin clogged blood. Two thousand years after Hippocrates, bloodletting endures.

Another illustration for an late 16th century Italian veterinary book.
Another illustration from Opera di Mescalzia. (Rome: P. Blado, 1591).


Leave a Reply

Your email address will not be published. Required fields are marked *