President William McKinley, reelected by even greater numbers thanks to the popularity of the Spanish-American War and Theodore Roosevelt as a running mate, took a trip through the West, ending in Buffalo, New York. His speech to the Pan-American Exposition on September 5 had attracted 50,000 people, and on the next day, September 6, 1901, McKinley made his way through the exposition crowds to the Temple of Music. In spite of the Secret Service, throngs of people approached the president, who patted men on the shoulder, shook hands and greeted bystanders. One, named Leon Czolgosz, pushed his way through the crowd. The Secret Service noticed a handkerchief in his hand, but by then, Czolgosz was within two feet of the president. McKinley smiled at the man and reached out his hand just in time to receive two revolver shots, one in his chest, and one in his abdomen. McKinley reeled from the shots, took a few steps backward and sat down in a chair before he was rushed to a hospital, and later, to the private home of John Milburn. Doctors operated on the president, but one week later, on September 14, he died from infection.

The doctors present that day were distracted by the death of President McKinley, but important matters were at hand, and focus quickly shifted to a discussion of Walter Reed’s yellow fever study.

“I wish briefly to add my words of congratulation to those of the whole scientific world in praise of Dr. Reed and his colleagues, who, in my opinion, have given us a work which has not been equaled, as far as its benefits to the public health are concerned, since Jenner gave us vaccinia,” gushed one doctor.

Still, there were those present who opposed the success of the Reed Commission, as it was becoming known. Eugene Wasdin, a longtime champion of Sanarelli bacteria, was also present. Having been on the board appointed by the president to confirm the Sanarelli bacteria in Havana, he had been incensed by the contradictoryfindings of Agramonte, then by the very public discovery of Reed’s Yellow Fever Board. Wasdin must have felt strongly about the subject for he arrived from the bedside of McKinley; he had been the anesthesiologist and an attending physician for the president. Worse, rumors of dissension among McKinley’s doctors now arose. Wasdin believed undoubtedly that the president’s infection was the result of a poisoned bullet, and he said as much in a New York Times article. His theory would prove to be the wrong one. Amid this very public stress, he attended the annual meeting for the Public Health Association, primarily to dispute Walter Reed.

“The fact that Dr. Reed states that the organism has not yet been discovered does not make that true. The organism has been discovered, and it is not inconsistent with Dr. Reed’s demonstration of the transmission of the disease by the mosquito, to accept the organism of Sanarelli as the cause of yellow fever . . . although Dr. Reed has demonstrated to my mind that the disease may thus be transmitted, it is not the only way by which we can contract the disease, and when contracted from the mosquito I deem it but an artificial infection such as we produce in animals in our laboratories . . .”

Reed rebuffed, “Will Dr. Wasdin please tell me in the transmission of malaria by the bite of the mosquito, whether that is also simply a laboratory disease?”

The familiar issue of quarantine battles ensued, especially among Wasdin and doctors from New Orleans, who had a hard time letting go of the theory that yellow fever could also be spread by infected clothing or bedding. With the New Orleans doctors, Reed was understanding. A city so threatened by yellow fever would approach any new study with some skepticism. For Wasdin, Reed had less patience.

“I was going to reach Dr. Wasdin’s objections in a little while, but perhaps I had better answer him now . . . It seems to me a waste of time, with all due respect to Dr. Wasdin, who has labored so hard over this problem, to longer consider this bacillus as the cause of yellow fever.”

In the coming months, Wasdin began showing signs of mental illness and was eventually committed to an asylum where he died.

Guitéras hoped that by infecting people with mild, nonfatal cases of yellow fever, they would be inoculated against it for life. As human cells fall under possession of a virus, the human body mounts a defense, building antibodies. Cells encounter a strange virus and its jagged edges in the bloodstream and create antibodies to attack the virus—the same way we shave and carve a metal key to fit a corresponding lock. But in this case, the lock of the antibody fits neatly against the key of the virus. As the human body struggles to create enough antibodies to lock onto and conquer the virus, the illness takes its course. The host may survive or it may die in the meantime, either from the symptoms of the virus or the body’s own immune response. In many viruses, one encounter with the disease produces a lifelong immunity. Those antibodies are always present, and if the person comes in contact with the virus again, the antibodies render the virus useless before it can do any damage.

Guitéras also believed that the success Walter Reed enjoyed was the result of mild cases of the fever, which could be produced by only one bite from a mosquito rather than a series of bites. Reed didn’t believe that to be the case and wrote to a friend: “I see that Finlay and Guitéras continue to harp on the harmlessness of a single mosquito’s bite, drawing the conclusion that ordinarily Y.F. is due to multiple bites. After some poor devil dies, they may change their minds.”

In what was known as “Guitéras Block” in the Las Animas Hospital, Guitéras inoculated ten volunteers using the same procedures Reed had used at Camp Lazear. As usual, yellow fever took on a life of its own. Guitéras’s cases were not as lucky as Reed’s and three of the volunteers died. One, a young American nurse named Clara Maass, died of yellow fever on August 24, exactly one year since Carroll and Lazear had started their ill-fated experiments with mosquitoes. Maass had volunteered for the experiments in hopes that she would develop immunity, which would enable her to be a more effective nurse. Though she was bitten on four different occasions, the fifth proved fatal.

Reed wrote of their failure, “I was very, very sorry to hear of Guitéras’ bad luck and can appreciate fully his mental distress over his loss of life—Perhaps, after all, the sacrifice of a few will lead to the more effectual protection of the many.”

While Guitéras failed to inoculate successfully against yellow fever, he did inadvertently prove one thing: The virulency of one case of yellow fever is determined by the virulency of another. In other words, strains of yellow fever vary in their deadliness. Clara Maass had been bitten a number of times in the months prior to August 1901. But that month, she and the other two fatal cases received blood from one source labeled Alvarez. The strain from patient Alvarez was apparently more virulent than others. That fact would come as little surprise to doctors who had served during Philadelphia, New Orleans and Memphis epidemics of yellow fever in decades past. Throughout history, yellow fever had swept through cities sometimes causing mild cases, other times killing thousands. For the virus, it was just a matter of fine-tuning.

Up to this point, a virus was an unknown entity. The actual word virus is Latin for venom, and that was the general definition. Science recognized that some poison was attacking the body; they just couldn’t find it. Vigilant microbe hunters studied blood smears of ill patients looking for the germ that caused a particular illness. Bacteria of all shapes and sizes had been discovered and named. Malarial parasites had been seen. It made it hard to imagine something even smaller that could be even more deadly.

There was also talk that Reed might receive the new, prestigious award called the Nobel Prize; but, in 1902, it went to Sir Ronald Ross, who demonstrated the link between malaria and mosquitoes. Most people felt certain Reed would be awarded the prize in the future, but that was never to be the case. The Nobel Prize could not be given posthumously.

Strain began to show on Walter Reed; lines etched into his face and his hair grew ashen. He was only fifty-one years old, but seemed to be aging rapidly. Reed spent the summer of 1902 with his family in their summer home, Keewaydin, in Blue Ridge Summit, Pennsylvania. Keewaydin, which had been built by Reed, had windows and balconies that afforded views in every direction. The wooden shingle house had sprawling porches, white columns and a beautiful garden. It was a place he cherished with the inscription: Love ever at my fireside, And peace within my door.

A friend who visited him there that summer remarked, “He was very much worn by his scientific labours, but it was also evident that he felt most keenly the attempts which were being made by persons high in authority to rob him of his just fame for the work which he had done.”

Reed had even written in a letter to his wife, shortly after his success in Cuba, predicting that Sternberg would attempt to take credit. “Of course,” Reed wrote, “he will, at once, write an article and say that for 20 years he has considered the mosquito as the most probable cause of yellow fever. That would be just in order for him to do so.” Reed was right. Sternberg published an article in Popular Science Monthly in which he claimed credit for the idea of the intermediary host. Reed wrote in a letter to a friend that “You might tell Dr. Finlay, too, with my best compliments, that he had better look to his laurels as the prosper of the Mosquito Theory, since Dr. Sternberg, in an article in the July Popular Science Monthly, puts forward his name very conspicuously for the credit for our work in Cuba.” Reed added, “This is the reward for our work in Cuba! He knows, as well as I do, that he only mentioned Finlay’s theory to condemn it!”

Sternberg could not bear to see another great medical discovery made without his name stamped upon it. He continually attempted to take credit for the discovery, and in 1905, when applying for a promotion in rank, Sternberg wrote: “I beg leave to call attention to the fact that the important discovery that yellow fever is transmitted by mosquitoes was due to my initiative. Withoutdetracting in the least from the honor due Major Walter Reed and his assistants, who demonstrated this fact by a masterly series of experiments, the official records will show that this investigation was made upon my recommendation, and that the members of the Board were selected by me. I, also, gave personal instructions to the President of the Board, and pointed out to him the direction this experimental investigation should take.”

By fall of that year, Walter Reed described himself as “a sick man.” He returned home on November 12, in pain, telling Emilie that he must have eaten something disagreeable. His abdomen was tender, and he began to think it was appendicitis. Although he requested his favorite breakfast, waffles, Emilie took the advice of his doctors and refused him heavy foods. Reed spent the morning in bed reading the paper and planning the garden for Keewaydin. But that night, his temperature rose, and his friends, William Borden and Jefferson Randolph Kean, decided to operate. The next morning, he was sent to the Army Hospital at Washington Barracks, but even as he left his bedroom, he refused a stretcher and insisted on walking. He even stopped at his desk on the way out to write a check.

Major Borden, an expert on appendicitis, would perform the surgery, but Reed’s longtime friend, Kean, would be there as well. In the operating room, an intern assembled the inhaler, a tank of nitrous oxide and an ether can. He asked Reed if he had any false teeth. “No,” he said emphatically. As the ether began to pull at his consciousness, Reed turned to his friend Kean and said, “I am not afraid of the knife but if anything should happen, I am leaving my wife and daughter so little. So little, so little,” he repeated.

The surgery, which took an hour and a half, revealed an enlarged and partially perforated appendix. It also showed signs of previous inflammation. Reed did not recover well from the operation and suffered from nausea and nervousness; his temperature stayed around 101 degrees, and his pulse began to rise, leveling out at 128. A junior medical officer was assigned each night to stay with Reed—Albert Truby was one of them—and Kean was there every day. In an attempt to lift his spirits, Kean told Reed that he would soon be promoted. “I care nothing for that now,” replied Reed. “It was the reply of Lancelot to the Lake,” Kean later said, Prize me no prizes, for my prize is death.

In spite of excellent medical care, the infection spread, peritonitis developed, and on November 23, 1902, Walter Reed died. All of the doctors present agreed that his health, weakened by the stress of his work in Cuba, had led to a fatal infection. Truby even believed that Reed unknowingly suffered from appendicitis during his work in Cuba, where Reed watched his diet vigilantly and suffered from stomach upsets.

It rained on Tuesday morning, November 25, when Reed was buried. The Potomac River blurred in the white haze, and the town houses of Dupont Circle and Georgetown cast tall shadows against the sidewalks. Clouds and rain cloaked the 100-foot spire of St. Thomas Episcopal Church. The Gothic stone building stood on Church Street, near Dupont Circle, and just a few blocks from the Reed’s home. The church was full of military men, all in uniform, including Albert Truby. Truby, who had been given his first professional opportunity by Reed, would one day rise in ranks to become brigadier general and the commander of the Walter Reed Army Institute. He watched as the guests filed in through the wrought-iron and glass doors of the church trailed by gusts of wind and golden leaves. Dr. William Welch, Reed’s mentor and professor, was there, as was Dr. William Osler, Dr. Simon Flexner and Secretary of War Elihu Root. William Randolph Kean was one of his pallbearers. Emilie was so distraught, she could not attend. And Reed’s son, Lawrence, was stationed in the Philippines at the time. Lawrence Reed received only a wire with the news: Your father died today. It was two months before he heard any more details; it would have cost additional money for the army to include more in the message.

Following the service, Reed was buried in Arlington National Cemetery, and his epitaph was taken from the recent remarks of the president of Harvard University: “He gave to man control over that dreadful scourge Yellow Fever.”

Theodore Roosevelt, then president of the United States, remarked: “Major Reed’s part in the experiments which resulted in teaching us how to cope with yellow fever was such as to render mankind his debtor, and this nation should in some proper fashion bear witness to this fact.”

Shortly after his death, a Walter Reed Memorial Association was established to raise funds for Emilie and Blossom Reed, as well as to finance a monument in Reed’s honor. Contributions were made by Alexander Graham Bell, John D. Rockefeller, John P. Morgan, George M. Sternberg, as well as William Welch, Carlos Finlay and William Gorgas.