Dark Banquet (11 page)

As one would expect, the calcar varies in size and shape among the eleven hundred bat species. In
Noctilio,
the fishing bat, for example, the calcar is a huge, bladelike affair.
Noctilio
uses it to get its substantial tail membrane out of the way while the gafflike hind limb claws skim the water's surface for prey.

It's also no surprise that the calcar is absent in bats that do not have a tail membrane. At least that's what I thought until I started examining preserved specimens of
Diphylla
at the American Museum of Natural History where I was working as a postdoctoral research fellow.

After determining that differences in performance existed between
Desmodus
and
Diaemus
(
“Diaemus
doesn't jump!”), I had started looking to see if these behavioral differences might be reflected by variations in their anatomy. While comparing the hind limbs of the three vampires, I noticed that the calcar was absent in
Diaemus
and reduced to a flaplike tab in
Desmodus.
Like I said, no big deal, when you consider that all three vampires lacked a functional tail membrane.
^*42

The calcar of
Diphylla
was a completely different story. Not only was it present but it also stood out like a tiny finger. I immediately pulled out several additional specimens—just to make sure I wasn't just looking at one extremely weird individual. But in each instance, I saw the same digitiform structure. Next, I hit the literature, looking for any mention of
Diphylla
's calcar. “Small but well developed” ran the typical description—but nothing more. Finally, I called the vampire bat expert, Scott Altenbach, recalling that he had once maintained a colony of
Diaphylla ecaudata
in New Mexico. Scott had done the original work on quadrupedal locomotion in the common vampire bat in the 1970s and he'd joined us in Ithaca during our force platform project in 1993.

I remember a conversation something like what follows taking place over another crackling long distance phone line.

“Hey, Scott, did you ever take any photos of
Diphylla
climbing around the branches?”

“Yeah, but they weren't branches. We used wooden dowels.”

“Well, check it out and let me know if your bats were using their calcars to grip the dowels.”

“What?”

“I think
Diphylla
is using its calcar as a sixth digit during arboreal locomotion.”

(Long pause)

“Scott?”

“I'll go get the photos.”

(Sound of phone dropping)

Basically, what I'd proposed was similar to the story of the panda's thumb (popularized in an essay by Stephen J. Gould). The giant panda
(Ailuropoda)
feeds on bamboo leaves that it strips off branches, apparently with the aid of its opposable thumb (something not found in any other carnivores). Anatomists who examined the panda, however, found that things weren't quite as they seemed. The panda's thumb was actually a wrist bone (the radial sesemoid) that had become greatly enlarged. This allowed it to take on a new function—stripping off bamboo leaves.

Gould cited the panda's “thumb” as a beautiful example of how evolution doesn't create; it tinkers with what's already there (in this case, the panda's radial sesemoid bone), modifying it for a new function rather than creating a new structure from scratch.

Ailuropoda
's odd little digit also presented some rather daunting questions for those who support a creationist view of how we got here. Basically, if there
is
an intelligent designer, why did he (or she) give the panda a jury-rigged structure for stripping leaves off branches? Why not just give the
Ailuropoda
a real thumb?

Back in Ithaca (and several minutes later), I heard scrambling and the sound of the receiver being picked up. “You nailed it, Bill—I've got some great shots.”

“Excellent,” I replied. “Do me a favor and send them to me at once.”

Altenbach's black-and-white photos clearly showed a climbing
Diphylla
with its calcar tightly wrapped around a wooden dowel. I immediately put together a proposal to record this behavior in the field, setting my sights on a visit to central Brazil. Since
Diphylla
didn't live in Trinidad, I contacted Brazilian researcher Wilson Uieda, who had been studying the hairy-legged vampire for years with his colleague, Ivan Sazima.

Outside the capital city of Brasília, at a ranch where the cattle were commonly plagued with
Desmodus
bites, Wilson and I set up my infrared video camera at sunset. We certainly weren't interested in the cows or even in
Desmodus
for that matter. Instead, we aimed our camera upward, into the branches of a fig tree, for it was there that the resident guinea fowl went to roost at dusk.

Several hours after nightfall, as I stared bleary-eyed at the camera's viewfinder, a pair of dark shapes flew past the sleeping birds.

“Wilson, check this out,” I whispered.

My friend, who had been dozing on the chair next to mine, was instantly alert.

Less than a minute later, the aerial recon was performed for a second time.

Wilson whispered a single word.
“Diphylla.”

After that we saw nothing for several minutes—until a tiny pair of glowing spots appeared beneath one of the roosting birds. I hit the zoom on the camera, focusing in on the twin points of reflected light.

They were eyes!

Wilson traced a dark silhouette on the screen and I could just make out
Diphylla
's upside-down head peeking out from the guinea fowl's feathery breast.

“Dinnertime,” he said.

“This is different from
Diaemus,”
I responded.

Wilson replied with a smile.

Rather than feeding from below the branch,
Diphylla
was actually hanging from the bird—and photographs taken by Wilson Uieda and his colleagues at another site clearly indicated that
Diphylla
was using its opposable calcar to get a grip on the body of its avian prey. Unlike the white-winged vampire, which generally fed from bites it inflicted on the toes of perching birds, many of
Diphylla
's bites were made around the cloaca (the common opening for the digestive, urinary, and genital tracts found in many nonmammalian vertebrates, like birds).

Several days later, we visited a cave that was home to a small colony of
Diphylla.
Using the infrared camera again, we recorded three hairy-legged vampires as they moved across the stony ceiling. Not only were the bats walking upside down, they were moving backward (not really strange since bat knees face backward). What was unique was the way that they led with their hind limbs—carefully seeking a secure purchase before taking a step—and using their “sixth digits” like a rock climber would use his thumbs. After scrambling around the cave ceiling for a few minutes, the vampire bats tired of our intrusion and disappeared into a narrow crevice.

I left the cave elated that we'd been able to support my hypothesis with observations in the field. What had begun as a surprising observation back in New York City ended with the discovery that just like the panda's radial sesamoid bone, the hairy-legged vampire bat's calcar had been co-opted for a new role—as an opposable digit.

Even more important, although local scientists in places like Trinidad and Brazil had been aware of it for years, it wasn't until the very end of the twentieth century that the mainstream scientific community began looking at each of the three vampire bats as separate and quite unique. Thanks to researchers like Farouk Muradali, Wilson Uieda, and the late Arthur Greenhall, vampire bats are currently being studied with an eye toward variation rather than presumed similarity. By avoiding our tendency to lump things together, these scientists have increased our knowledge about these fascinating creatures and shifted the focus from flamethrowers and cave destruction to systematic control and, in the case of
Diaemus
and
Diphylla,
conservation efforts. Additionally, a better understanding of vampire bats has helped to dispel myths and misconceptions about the eleven hundred nonvampire bat species as well as blood feeders in general. We can now spend more time dealing intelligently with our attraction to nature's vampires as well as the unique substance that ultimately led to adaptations like razor-sharp teeth and salivary anticoagulants. That substance is, of course, blood—to many, the source of life. But considering our seemingly innate feelings of attraction and revulsion toward blood, until recently, our relative lack of knowledge about the red stuff made us look positively erudite about vampire bat biology.

I firmly believe that if the whole
material medica
as now used could be sunk to the bottom of the sea, it would be all the better for mankind—and all the worse for the fishes.

—Oliver Wendell Holmes

Nearly all men die of their remedies and not of their illnesses.

—Molière

Several hours before his death, after repeated efforts to be understood, [he] succeeded in expressing a desire that he might be permitted to die without further interruption.

—Drs. James Craik and Elisha Dick (December 31, 1799)

4.

EIGHTY OUNCES

O
n the morning of Friday, December 13, 1799, the first president of the United States woke up with a sore throat. He had been riding at his farm the day before and the weather had been cold and windy—snow giving way to hail and finally rain. To make things worse, although his clothes had gotten soaked, he refused to change out of them before dinner. That evening, George Washington stayed up late, reading newspapers and asking his private secretary, Tobias Lear, to read him an account of the Virginia Assembly's debates on the selection of a senator and governor. Washington, whose voice had become hoarse, took no treatment for what he perceived to be the start of a simple cold.

Later, Martha, who could tell that her husband was starting to come down with something, chided him for coming to bed so late. “It has been my unvaried rule never to put off till the morrow the duties which should be performed today,”
reportedly
came Washington's famous reply to his wife.

At around 3 a.m., on December 14, the Founding Father woke with a fever. He also found it hard to speak and was having difficulty breathing. A mixture of molasses, vinegar, and butter was prepared, but Washington began choking violently when he tried to swallow it.

The former president's longtime physician, Dr. James Craik, was called in, but before the doctor arrived Washington sent for his estate overseer, Albin Rawlins, who appeared just after sunrise. Rawlins's medical experience consisted of treating sick livestock, but that didn't stop Washington from ordering the man to bleed him. Although this would seem to be a bizarre request, in Washington's time bloodletting or “breathing a vein,” as it was called, was an extremely common treatment, comparable nowadays to popping a couple of aspirin. Still, after preparing the former president's arm, Rawlins hesitated.

“Don't be afraid,” Washington told the overseer, who suddenly appeared reluctant about slicing into his master's arm. Soon after, the incision was made, and according to Tobias Lear, “The blood ran pretty freely.”

A pint of blood was removed.

In Colonial America (as well as throughout Europe), a bladed instrument called a lancet was commonly used during bloodletting. Lancets were produced in huge numbers and often stored in ornate cases. Their importance can be demonstrated by the fact that England's premier medical journal took its name from the instrument. After tying off the arm at the elbow, the lancet was applied lengthwise to the now bulging vein, which prevented the vessel from being severed in two. A number of spring-loaded mechanical devices (called scarificators) were also concocted to facilitate the drawing of blood, which was often collected in specially designed bleeding bowls. Some of these were quite beautiful, and they were often marked with inner concentric rings arranged in one-ounce increments.

When Washington's wife, Martha, came upon the gory scene she begged that the procedure be stopped, but her husband insisted that the bleeding continue.

“More, more,” he said, hoarsely, after complaining that the cut Rawlins had made wasn't large enough.

After the bleeding, Washington's neck was wrapped in flannel soaked in hartshorn ammonia
^*43
and his feet were bathed in warm water.

Dr. James Craik had been treating George Washington for over thirty years, and when he arrived, at around 9 a.m., he knew immediately that he was dealing with a potentially fatal illness. He applied a blister of cantharides to Washington's throat,
^*44
then instructed his famous patient to gargle with yet another mixture—vinegar and sage tea this time. The results must have been terrifying to those standing by. The former president, who was already struggling to breathe, nearly suffocated on the concoction. Alarmed that Washington could not swallow and was having great difficulty breathing, Dr. Craik sent messengers calling for two additional physicians, Dr. Elisha Dick and Dr. Gustavus Brown. Following this, Craik bled the former president and repeated the procedure at eleven o'clock.

By the time the two additional doctors arrived later that afternoon, Washington had been bled a total of three times. Although Washington's skin was blue when they arrived, to the physicians of his time this would have indicated an improvement in their patient's condition (except for the fact that the man was unable to speak, swallow, or breathe without great effort). Medical men of the day often sought to reduce fever or a high pulse rate by decreasing the volume of body fluids. It appears that as far as a patient's condition was concerned, cool, calm, and cyanotic was preferable to feverish, frenetic, and flushed. Inflammation and fever were not yet recognized as the body's attempt to combat infection, and so patients were typically bled to alleviate the heat, redness, and pain that were thought to result from “abnormal vascular congestion.”

According to George Washington Custis (Martha's grandson from her first marriage), the three physicians held a brief consultation: “The medical gentlemen spared not their skill, and all the resources of their art were exhausted.”

What course of treatment had the three doctors agreed upon? Additional bloodletting, and their patient (who had no medical training) agreed with them.

Another full quart of blood was removed, so that by early evening George Washington had been drained of
eighty ounces
within a thirteen-hour period. Much to the dismay of everyone present, Washington's blood flow was so weak (and his blood so “thick”) that physicians were unable to induce him to faint, the long-sought end point for most bloodletting treatments.

Deeply distressed at his rapidly deteriorating condition (he was reportedly in great pain and having tremendous difficulty breathing), the doctors administered calomel, a strong laxative and emetic tartar.
^*45
These purges were as commonly administered as bloodletting in the eighteenth century, but in this instance, although they had their expected results—“a copious discharge from the bowels”—there was no improvement in the patient's condition.

Alarmed but undaunted, the three physicians kept trying. In an attempt to draw the poisonous humors away from Washington's throat, blisters were raised on his extremities. Additionally, a poultice of wheat bran was applied to his feet and legs, and he was asked to inhale a solution of ammonia and water. Still, the former president's condition continued to worsen. Unbeknownst to his doctors, not only had Washington lost a dangerous amount of blood but the “medications” they prescribed to purge him had, in all likelihood, left their patient
severely
dehydrated as well.

In desperation, Dr. Dick suggested a tracheotomy (or bronchotomy, as it was then referred to). This was a relatively new procedure that was sometimes employed to treat injuries in which the larynx (voice box) had been crushed.
^*46

Unfortunately, no one will ever know if this procedure could have saved George Washington's life. Apparently, the two elder attending physicians overruled Dr. Dick.

Back at Washington's bedside, it soon became apparent to all (including the great man himself) that the end was near. According to Tobias Lear, by this point, his master “spoke but seldom, and with great difficulty; and at so low & broken a voice as at times hardly to be understood.” Washington asked his wife to fetch two wills from his desk, then instructed her to burn one of them (since it had been superseded by the other). He called upon Lear and struggled to make certain that his letters and papers were in order and that his accounts would be settled upon his death.

At around 10 p.m., Lear bent in close as George Washington struggled to voice his final words. “I am going,” he said. “Have me decently buried; and do not let my body be put into the Vault in less than three days after I am dead.” This seemingly odd statement can perhaps be explained by a widespread fear of premature burial that existed at the time.

After Lear confirmed that he'd understood what Washington had said, the first president of the United States uttered his last words, “Tis well.”

Shortly after that, the most famous man on the planet expired, “without a struggle or a sigh.”

George Washington was sixty-seven years old.

Over two hundred years later there is still debate over the specific illness that had stricken the Founding Father. While some have suggested laryngeal diphtheria or a peritonsillar abscess, most experts now believe that Washington suffered from an acute case of bacterial epiglottitis (an inflammation of the leaf-shaped flap that covers the entrance to the trachea during swallowing). Although rare in these days of antibiotics, this malady is potentially fatal since it causes the epiglottis to swell, blocking the airway and rendering the sufferer (as in Washington's case) unable to breathe.

There is
no
debate that the loss of approximately
40 percent
of Washington's blood volume within a thirteen-hour period hastened the great man's demise. For comparative purposes, the American Red Cross generally requires an eight-week period between blood donations of
one-tenth
the volume drained from the former president on what was to be his last day alive.

Eighty ounces.

“What the hell were those guys thinking?” I asked myself, initially.

But as easy as it is to scoff at Washington's physicians and their chosen course of treatment, I know now that I was dead wrong in doing so. These men were, after all, simply trying to save their patient's life, and bloodletting had been the accepted treatment not only for sore throats but also for scores of other maladies since the time of the Mesopotamians, Egyptians, and ancient Greeks (as well as the Mayans and Aztecs).

There was, in fact, a storm of criticism following Washington's death and those comments are quite revealing. One physician claimed that Washington's tonsils should have been scarified, while another suggested that the former president's doctors should have bled him from under the tongue, since that location was anatomically closer to the problem. Other suggestions included rubbing Washington's throat with “warm laudanum” (a mixture of alcohol and opium) and, following this, the application of a bag of warm salt to his neck. Instead of calomel, some insisted that he should have been urged to drink small portions of hot whey, laudanum, or
spiritus volatilis aromaticus,
a mixture of ammonia, carbonate of potash, cinnamon, cloves, and lemon peel.

Rather than condemning Washington's attending physicians, these nineteenth-century armchair quarterbacks have actually exonerated them, for it is unlikely that
anyone
could have saved him using the medical practices of the day. What might be even more difficult to accept is that even if George Washington had lived a century later—in all likelihood his treatment and its outcome (in the absence of antibiotics) would have been
exactly
the same (the only difference being that his physicians probably would have used leeches to draw off his blood).

But why was this so? With tremendous advances in nearly every field of science, why were renowned physicians still bleeding their patients, often to fatal excess, right into the twentieth century? How did this practice of bloodletting come about? Does it ever work and if not, then why are thousands of leeches being used by physicians today around the world?

To answer these questions, we'll need to take a slight detour from blood-feeding creatures to examine our knowledge (or until recently, our lack of knowledge) concerning blood and the circulatory system.