In 1843, Oliver Wendell Holmes (1809–1894) read a paper to the Boston Society for Medical Improvement entitled ‘‘The Contagiousness of Puerperal Fever.’’ The audience response ranged from indifference to hostility, although the paper is now generally regarded as a clear, convincing, and logical argument concerning the transmission and pre- vention of puerperal fever. Holmes, the father of U.S. Supreme Court justice Oliver Wendell Holmes Jr. (1841–1935), spent several years ‘‘yawning over law books’’ before taking up the study of medicine. After completing his medical studies in Europe, Holmes combined private practice with various academic positions, including professorships at Dartmouth and Harvard. He ﬁrst gained national attention with the publication of ‘‘Old Ironsides,’’ the poem that gave him a taste of the ‘‘intoxicating pleasure of authorship.’’ A report on a fatal case of childbed fever presented at a meeting of the Boston Society for Medical Improvement piqued Holmes’s curiosity about the disease. The physician who conducted the autopsy died of ‘‘pathologist’s pyemia’’ (septicemia) within a week. Before his own demise, the doctor attended several women in labor; all of these patients were stricken with puerperal fever. Such a pattern suggested to Holmes that puerperal fever was a form of contagion that could be transmitted from one patient to another by the attending physician. To conﬁrm this hypothesis, Holmes needed the kind of data that doctors were under- standably reluctant to share—a record of patients who had died under their care, perhaps because of their care. Ultimately, Holmes gathered evidence that should have been more than sufﬁcient to convince a ‘‘Committee of Husbands’’ to demand that a practitioner should be banished from obstetrics ‘‘after ﬁve or six funerals had marked the path of his daily visits.’’ Even a superﬁcial acquaintance with statistics and the laws of probability would suggest that Holmes had good circum- stantial evidence when he asserted: ‘‘It is not chance that accounts for a single practitioner having 16 fatal cases in a single month.’’ Nevertheless, Holmes was distressed to ﬁnd that America’s fore- most authorities on obstetrics consistently rejected the doctrine of the contagiousness of puerperal fever. Holmes’s critics defended the ‘‘value and dignity’’ of the medical profession and denied the possibility that a physician could become a ‘‘minister of evil’’ carrying disease to his patients. Rather than acknowledge a personal role in the transmission of puerperal fever, doctors attributed the disease to chance or to God. But, because the disease followed particular physicians and spared women attended by other practitioners, Holmes argued that childbed fever must be transmitted by contagion rather than miasma. Physicians used the term contagion to denote an agent that transmitted infectious disease through touch or direct contact. The term miasma referred to poisonous vapors that were thought to infect the air and cause disease. In other words, Holmes contended, puerperal fever was transmitted by a particular person, who obviously had a vested interest in ‘‘denying and disbelieving the facts.’’ Eventually, enraged by the intransigence of his colleagues, Holmes denounced them as self-righteous, ignorant men guilty of ‘‘professional homicide’’ and thundered a warning that for their voluntary blindness, interested oversight, and culpable negligence each of these pestilence carriers of the lying-in chamber ‘‘must look to God for pardon, for man will never forgive him.’’ For many and complex theoretical reasons, given the longstanding debate about the nature of the transmission of disease, physicians gen- erally rejected the possibility that puerperal fever could be transmitted by contagion. Still, it is difﬁcult to ignore Holmes’s charge that at least in part the learned debates about contagion could be reduced to a self- serving refusal to believe that a gentleman with apparently clean hands could be the agent of death. Steeped in prevailing miasmatic doctrine, doctors were a source of grave danger to their patients. This point is well illustrated by Holmes’s account of how Dr. Warrington performed ﬁve deliveries shortly after conducting an autopsy on a victim of puerperal fever in which he had scooped out the contents of the abdominal cavity with his bare hands. All ﬁve women were stricken with puerperal fever. Another example cited by Holmes involved an ardent opponent of the doctrine of contagion who participated in the autopsy of a victim of puer- peral fever. For the ediﬁcation of his students, Dr. Campbell ‘‘carried the pelvic viscera in his pocket to the class-room.’’ That evening, without changing his clothes, he attended a woman in labor. That patient died. The next day he delivered another patient with the obstetrical forceps. That patient also died, as did many others during the next few weeks. A few months later, after participating in another autopsy, Dr. Campbell attended two patients before he found time to wash his hands or change his clothes. Both of these patients died of puerperal fever. Having presented his case for the contagiousness of puerperal fever, Holmes outlined methods of prevention. He thought it best that obstetricians avoid active participation in all postmortems. If a physi- cian had been an observer at an autopsy, he should wash thoroughly, change every item of clothing, and allow 24 hours to pass before attend- ing women in labor. A physician who had two cases of puerperal fever among his patients should give up obstetrics for at least one month and try to rid himself of the contagion. Finally, when a ‘‘private pestilence’’ appeared in the practice of one physician, it should be seem as a crime rather than a misfortune. Professional interests, Holmes insisted, must then give way to the physician’s duty to society. Even admirers of Holmes’s ability to present a logical case in luminous prose have been dubious of his claim to the discovery of the cause and prevention of puerperal fever. His observations were not wholly original and his logic failed to compel the medical com- munity to accept his doctrine. Critics dismissed him as merely a poet-physician who had restated observations already made by Gordon and White, without coming any closer to an understanding the speciﬁc etiology of puerperal fever. Holmes fought the battle against puerperal fever with no weapons other than logic and his eloquent pen, but no one ever accused his Hungarian counterpart, Ignaz Philipp Semmelweis, of excessive eloquence. In contrast to Holmes, Semmelweis, a man apparently lacking even a rudimentary sense of tact and diplomacy, fought childbed fever with the blunt club of statistical and empirical evidence.