The commander of the Continental Army realized that if he did not inoculate his army against smallpox, he might not have an army. Saving his men, he probably saved his country.

At a time when anti-vaxxer hysteria is colliding in the headlines with public alarm at the possibility of a global Ebola epidemic, it is bracing to read historian Tom Shachtman's account of another time in this nation's history when Founding Father George Washington kept his head (public hysteria was not invented yesterday) and insisted that his army be inoculated against smallpox, thus saving the lives of thousands of soldiers and in the process indirectly safeguarding the young nation he was charged with defending. Here's an excerpt, adapted by Shachtman for The Daily beast, from his latest book, Gentlemen Scientists and Revolutionaries: The Founding Fathers in the Age of Enlightenment.

In early January 1777, General George Washington decided to take an action that would later be deemed his most important strategic decision of the war, even though it had nothing to do with the positioning of his troops, and to take it on the basis of his scientific understanding of the situation: he was going to order the inoculation of all Continental troops and recruits against smallpox. For an agonizing 18 months he had been wrestling with the decision, knowing it would mean having to counter the express orders of the Continental Congress and the decrees of the legislatures of half the rebelling colonies.

It would be a daring, possibly dangerous move because, a quarter-century before the introduction of the Jenner "cowpox" vaccine that would make immunity to smallpox widely available, smallpox was still the biggest killer of the age. It had been so for the American colonies since the earliest days of European settlement: once or twice every decade, smallpox would sweep through cities and countryside, causing between 10 and 20 percent of all deaths in the years it appeared. 

In July 1775, when Washington had first taken command of the Continental Army, outside of Boston, smallpox was rampant in the city. Reporting to John Hancock, president of the Continental Congress, Washington wrote that he and his staff had been "particularly attentive to the least Symptoms of the Small Pox; hitherto we have been so fortunate as to have every Person removed so soon, as not only to prevent any Communication, but any Apprehension or Alarm it might give in the camp. We shall continue the utmost Vigilance against this most dangerous enemy." 

Vigilance, yes; but taking the most aggressive action—not so much. While Washington was acquainted with a technique for protecting people against smallpox, he would not then use it, partly because it was deemed illegal by the Continental Congress and colonial legislatures, and partly because many physicians believed the technique did more to spread the disease than to halt its progress.

The technique, called "variolation," was a form of inoculation in which pus from an infected person was inserted under the skin of an uninfected one; that gave the inoculee a mild case of the disease and, after the passing of a period of high communicability, lifetime immunity. But although championed by such scientific heroes as Benjamin Franklin, and undergone willingly by John Adams, Thomas Jefferson, and other leaders, variolation was castigated as unsafe for the community because the patient had to be isolated for a week prior to the inoculation and two weeks or more after it. Congress had forbidden military doctors to administer it and forbidden army officers to take variolation or have their subordinates do it, on pain of being cashiered.

During the first year of the Revolutionary War, Washington's tactic of isolating army patients of smallpox didn't stop the disease; that year, smallpox caused the deaths of more Continental troops than died on the battlefield.

Washington had his own immunity to smallpox, acquired in the "natural way," through having survived a case of smallpox when still a teenager; the pock marks on his face were its testament. When the British abandoned Boston in the spring of '76, Washington ordered that all the first Continental troops to enter the city have pock-marked faces, and that among their first tasks was the removal of any infected civilians. 

During the first year of the Revolutionary War, smallpox caused the deaths of more Continental troops than died on the battlefield.

After Washington's victory in Boston, the remaining nine months of 1776 were among the most difficult for the commander and the American cause, with significant losses in the New York area in the summer and fall. He and the troops then retreated across New Jersey to a winter redoubt. 

Meanwhile, Massachusetts had seen the light in regard to smallpox: after the military action had moved away from the area, and wanting to prevent a resurgence of the epidemic, the Massachusetts authorities lifted their ban on variolation and an orgy of it ensued—nearly 5,000 of the Boston area's 10,000 inhabitants were inoculated in a relatively short period of time. 

For Washington, the advent of winter meant fewer battles and more time for uninterrupted thought. During it, he reached two linked realizations that thereafter shaped his strategy: first, that preserving his forces was more important than controlling territory, and second, that to properly preserve those forces he would have to prevent them from dying of smallpox.

The scientific evidence on which he would base the decision was accumulating. The Massachusetts mass variolations proved it could be done. On a personal level, he had more evidence. He had his wife, Martha, inoculated in Philadelphia, and she came through the process healthy. But he also knew that the moment for ordering mass variolation would have to be opportune. Knowing that Congress would not be easily convinced, he softened them up by repeatedly petitioning for permission to allow troop detachments on their way to join the main army to skirt smallpox-prone Philadelphia. Each time, when he made these requests, Congress acceded to them, but still did not relent and issue a general order to inoculate the troops. Indeed, the idea of mass inoculation seems not to have occurred to the delegates, not even to the handful of physicians among them. 

Military victory always gives a field commander added clout with his civilian overseers. Washington's shocking success in the December 1776 raid across the Delaware River to seize Trenton had that effect—and he decided to seize the moment to unilaterally decree inoculation for smallpox as the policy of the army.

There then arose another roadblock in the path toward troop immunization, the result of intrigue among the fraternity of physicians in Philadelphia that led to a change in command of the medical services. Dr. John Morgan, perhaps the best-trained physician in the colonies, was then the leader. Dr. William Shippen Jr., Morgan's rival since the days when they had both been at prep school, successfully connived to replace Morgan by accusing him of poor management bordering on dereliction of duty. Washington did not like the change but accepted it. He knew Shippen, who had recently inoculated Martha, and he was on even more familiar terms with Shippen's brothers-in-law, the Lee family of Virginia. Partly to win Shippen to his position on mass variolation, Washington confided to him that he was going to petition Congress to raise the pay of surgeons willing to travel with the troops. But the main point of Washington's argument to the new chief medical officer was, as he would soon put it, "Necessity not only authorizes but seems to require the measure [inoculation against smallpox], for should the disorder infect the Army… and rage with its usual Virulence, we should have more to dread from it than from the sword of the enemy."

Shippen's initial answer to Washington's request on mass variolation was a surprising but logical no; the doctor objected to it on the grounds that provision for post-inoculation isolation was inadequate, which might spread rather than limit the disease. During the remainder of January, Washington deferred to Shippen's caution, but as February began and renewed outbreaks of the disease confronted the army, he overruled Shippen's caution. 

He had to inform Congress, but he decided to do so by burying the smallpox-prevention decision in the middle of a long letter to Hancock about other matters. Even so, the first draft of the paragraph about mass inoculation, written on February 5, contained a dollop of self-doubt: "The small Pox is making such Head in every quarter that I am fearful it will infect all the Troops that have not had it. I am divided in my opinion as to the expediency of innoculation, the Surgeons are for it, but if I could by any [other] means put a Stop to it, I would rather do it. However I hope I shall stand acquitted if I submit the Matter to the Judgment and determination of the medical Gentlemen."

Washington re-read the draft of the paragraph and judged the wording as too weak, that his "divided opinion" or his deference to the "surgeons" might provide Congress with reason to order him not to inoculate, or a way to use the doctors to gainsay him. That would not do. So aide-de-camp Tench Tilghman was instructed to cross out that wording and substitute a stronger one, making the tenth paragraph of Washington's February 5, 1777 letter to Hancock read: "The small pox has made such Head in every Quarter that I find it impossible to keep it from spreading thro' the whole Army in the natural way. I have therefore determined, not only to innoculate all the Troops now here, that have not had it, but shall order Docr Shippen to innoculate the Recruits as fast as they come in to Philadelphia. They will lose no time, because they will go thro' the disorder while their cloathing Arms and accoutrements are getting ready."

Not waiting for a reply from Congress, the next day Washington issued unequivocal instructions to Shippen to begin mass variolation for smallpox. 

The entire inoculation campaign was carried out in secret to prevent the British—and American Tories—from finding out about it and taking advantage. Small groups of Continental officers at a time were permitted to leave the Continental Army's main camp to go to Philadelphia for the inoculation process; and physicians were dispatched to Kingston, New York and to Bethlehem, Pennsylvania to set up facilities for inoculation, isolation, and recuperation. The isolation sites were mostly in private homes and churches.

Not all of Washington's field commanders immediately agreed to the procedures. When there were objections, Washington's aide-de-camp Alexander Hamilton, writing while the commander-in-chief was ill for a few days, reinstructed such officers as General Alexander McDougall and Major-General Adam Stephen on the unyielding nature of Washington's demands for inoculation. To Stephen, in answer to an objecting letter to headquarters from Colonel Andrew Ward, a Stephen subordinate, Hamilton penned the most complete articulation of Washington's reasoning:

His Excellency desires that this objection, with respect to Colonel Wards regiment, should cease; and that they may immediately be admitted to the benefit of innoculation, in the usual proportion. He begs also that the present opportunity, while the roads continue incommodious for any movements of the enemy, may be improved to the greatest advantage, as we do not know how long it may last; and shall have no time to spare, even if the utmost diligence is used …. Let this be urged upon the Doctors, and every thing else done which may be conducive to dispatch, in a matter of so great importance.

Washington also convinced Governor Patrick Henry to repeal Virginia's law against inoculation. Troops traveling north from the Carolinas were soon stopping in Virginia to be inoculated before continuing on.

In the spring of 1777, the Continental Congress, acknowledging Washington's success with mass variolation, at last issued a formal inoculation order. Before the end of 1777, nearly 40,000 troops had been inoculated. In the year following the start of mass inoculation, the infection rate from smallpox in the Continental Army fell from 17 percent to 1 percent.

Inoculating the American troops against smallpox effectively shielded Washington's army from being decimated by disease until the arrival of foreign arms made it possible for them to turn the tide of battle in America's favor. Nothing that Washington did had a greater impact on the outcome of the war than his actions to protect his troops from death by smallpox.

Adapted by Tom Shachtman from his book, Gentlemen Scientists and Revolutionaries: The Founding Fathers in the Age of Enlightenment, recently published by Palgrave Macmillan.