Glory in the Guts


Mary Roach, Grunt: The Curious Science of Humans at War (W.W. Norton, 2016).


Diarrhea kills. Until very recently, disease claimed more lives in war than bullets, bombs, bayonets, or bludgeoning, and it remains a chief concern of militaries. Today, troops are vaccinated against a gamut of biological threats like tetanus, typhoid fever, measles, smallpox, and anthrax. However, vaccines and the U.S. military go way back: George Washington’s decision to inoculate his troops against smallpox while they rode out the winter of 1777 to 1778 at Valley Forge slashed the smallpox death rate from four in 10 to one in 50. An 18th century smallpox inoculation was a far cry from the tidy regime of shots available today. Back then, a doctor would scratch pus from a donor with smallpox into the skin, offering the immune system enough Variola virus to train its defenses without killing the subject. Usually. Naturally occurring smallpox has since been eradicated, but a vaccine regimen against natural threats and biological weapons remains key to the military’s effort to guard its greatest asset: the health of its people.

Take diarrhea, a condition for which there is no vaccine. Nearly a hundred thousand soldiers died from diarrhea or dysentery over the course of the American Civil War. Soldiers in Vietnam were admitted to the hospital with diarrhea four times more often than malaria. Safe drinking water and food sanitation practices have come a long way, but diarrhea remains a burden on the modern soldier. These days, it tends to strike many eating and drinking on the local economy, where sanitation standards could be nonexistent. Diarrhea, often the result of cellular destruction wreaked by infections like shigella or E. coli, can cause victims to lose fluids much faster than they can replace them. For a deployed soldier, the best course of action is an antibiotic strike against the offending microorganisms before dehydration sets in, but misinformation abounds: Those stricken often believe it is best to just let diarrhea run its course. In fact, letting the digestive tract flush itself out usually means losing fluids but retaining the problematic bacteria. The military is wary of anything that can put a soldier out of commission for days at a time. Thus, military doctors conduct clinical studies and information campaigns on, yes, diarrhea. It is one of many ongoing struggles to keep American service members in fighting shape.

Military commanders must juggle the diametrically opposed problems of killing the enemy and keeping their own soldiers alive and in fighting condition. Military science is a celebrated, storied field, but the myth-making usually revolves around combat hardware and those who design and operate it: Chuck Yeager breaks the sound barrier in the Bell X-1. Ballistic missile submarines are a technical marvel, but what happens when their crews aren’t getting enough sleep? Sleep deprivation, after about 24 hours, is as dangerous as being intoxicated. An exhausted submariner might as well be manning the torpedo tubes drunk.

Some of the toughest vehicular challenges are borne by the homely workhorses. A Mine-Resistant Ambush Protected (MRAP) vehicle, for example, has to endure a shock that no civilian automotive engineer considers: upward explosive force. When an IED detonates directly underneath an MRAP, the passengers inside find themselves accelerated upward. This is such a unique circumstance that even modern crash test dummies are not designed to measure it (wired-up medical cadavers are used in tests). When subjected to upward force, a solider could experience spinal compression or what was known in World War II as “deck slap,” where the floor of a vehicle rapidly strikes and shatters the heel. The solution? Specially designed footrests to separate foot from floor.

The most important piece of military equipment, at the end of the day, is the soldier, sailor, airman, or marine. Humans at war undergo an immense amount of mental and physiological stress. The military’s scientists work at — excuse the turn of phrase — breakneck speed to keep up. This work usually happens in the background. If you don’t hear about it, that means things are going well. Still, it deserves recognition.

Mary Roach, the author of Grunt: The Curious Science of Humans at War is interested “not in the killing, but the keeping alive.” The only gun that interests her is the one that fires chicken carcasses at military aircraft to test their birdstrike resilience. Roach isn’t squeamish, though. She participated in a training simulation as a victim of smoke inhalation burns, experienced a live-fire demonstration of the importance of hearing protection, and endured a treadmill trip in the 104-degree “cook box” to witness just how easy it is to become dehydrated while lugging 80 pounds of gear. Military-science just-so stories abound: how the soldier got his camouflage and how the Army picked the nylon-cotton blend to print it on.

The wars in Iraq and Afghanistan have presented a slew of new medical challenges which require medical expertise and military know-how. IEDs kill with shrapnel, but they also produce a blast wave of air pressure that shreds organs. This might not be apparent until the victim is in surgery — or autopsy. Add to that the blunt force trauma of being thrown around inside a vehicle and wounds infected by bacteria kicked up from the ground. It is a laundry list of injuries occupying a cross-section of sciences: anatomy, physics, automotive design, and microbiology. These things are impossible to predict. Military scientists learn about a problem when the first victim comes in, sometimes alive but often severely injured or dead.

Medical examiners perform autopsies on those killed in combat at the Armed Forces Medical Examiner System morgue. From there, they teleconference with medics and surgeons throughout the military, discussing injuries, first-aid measures, and causes of death. Department of Defense policy is to leave all medical equipment on the body so that medical examiners can study how effective the emergency measures were. This “feedback from the dead” reveals surprising field medicine complications: The standard needle inserted into the chest to relieve pressure from a collapsed lung might not be long enough to penetrate the pectoral of a particularly buff marine. Longer needles are now available.

Both Roach and the military doctors she shadowed in writing this book maintain a delicate balance of gallows humor and reverence for the dead, who take on a certain nobility over the course of Grunt. Medical cadavers endure explosions and penile transplants with what Roach comes to see as a sort of quiet, respectable work ethic. They aren’t literally undergoing any suffering, but Roach notes that checking the box to volunteer one’s body “to science” could mean any number of unglamorous ends for one’s remains. Or, at least not glamourous in the traditional sense. But Roach equally admires the scientists and the cadavers they work on — both confront death and dismemberment head-on for the benefit of the still-living.

It is heavy stuff, lightened by Roach’s pervasive sense of humor. In one episode, she chases down an aloof special operator in a mess hall in Djibouti to interrogate him for tales of diarrhea in the field, asks if it’s ok for her to test drive a Stryker (it is not), and is amused by the idea of a SECRET printer. Roach exaggerates her ignorance, though. She excels at pushing her subjects, especially her public-relations minders, until they open up. The anecdotes they spill are compelling, gruesome, and often darkly hilarious. Roach is akin to the scientists she interviews — relentlessly curious and strong-stomached. She cuts adeptly through jargon: the Army Combat Uniform-Alternate? It’s the women’s-size uniform.

Roach has a genuine excitement for her subjects and their work. She presents a pleasingly gender-balanced roster of scientists and soldiers, including a mother/son duo who happen to be working together as researcher and subject. The elder, an expert in human thermoregulation, reminds her test subject, an Army Ranger School instructor, to eat enough before he undergoes heat tolerance testing. Translation:

“Josh, eat your snack before you go in.”

“Mom, stop.

Roach neatly packages anecdote, science, and history into this tight, compelling volume. Much of the book’s content comes from interviews and observation, but Roach layers in primary sources and historical context when they are needed. As much as the scientific establishment would like to eschew controversy and focus on the work, sometimes politics are unavoidable.

War is often an intersection of the technical and the political. Look no further than the F-35 for allegations that the military bureaucracy produced a substandard product. Or the Bradley fighting vehicle. Or the Universal Camouflage Pattern. Ethical considerations abound, too. The 1899 Hague Convention attempted to ban the use of chemical weapons before they were even employed in battle. Its signatories recognized a scientific development that might be used to kill and tried to head it off. Their efforts failed, and medicine had to adapt when casualties of World War I gas attacks came flooding in.

Understanding the science behind combat gives the policymaker and the citizen a new perspective for evaluating war. Scientists and bureaucrats operate in very different worlds, and the better they understand the other’s environment, the easier it is to find a harmonious middle ground where effective research is done — on schedule and under budget. Like in the case of those who return home from combat needing the cost of genital reconstructive surgery covered, sometimes big policy changes start on the operating table. It adds a human dimension, too. The stories of doctors and patients, and researchers and subjects shed light on what soldiers encounter in war and what they bring back.

The health of the soldier is often taken for granted. We tend to assume that the ailments of yesteryear have been defeated by modern medicine. Some service members return from war missing limbs or with cases of post-traumatic stress disorder, but trenchfoot and deck slap are things of the past, right? This thinking belies the work that doctors, surgeons, scientists, and everyday grunts do to tackle the deeply weird, monumentally important problems faced by the modern human at war.


Greg Mercer is a master’s student in Biodefense at George Mason University, a consultant, and a freelance writer. He writes about defense, health, climate, and space, and he sometimes tweets @gregleemercer.

Image: U.S. Naval Research Labratory