Who was Adolphe Quetelet? Born in Belgium in 1796, Quetelet early revealed a talent for the sciences in combination with a deep interest in the humanities, including the performing arts, painting, and poetry. After receiving his doctorate in mathematics from the University of Ghent at age 23, he went to Paris to study probability theory with Laplace, Fourier, and Poisson. Returning to Brussels, he founded the Royal Astronomical Observatory in 1828, which he directed for several years. During his career, he made important contributions to a wide range of disciplines: meteorology, astronomy, mathematics, statistics, demography, sociology, criminology, and the history of science.1 Quetelet explored relationships not only among celestial bodies but within human and social bodies, ie, societies. He took many anthropometric measurements and pioneered the statistical investigation of social behaviors, studying their distributions and averages. He systematically collected data on births, deaths, and crimes and contributed to the methods of population censuses. In a famous 1835 essay,2 Quetelet introduced the notion of the homme moyen (“average man”), combining the social and physical characteristics of populations. Such patterns, he argued, could be explained by “the general causes for which society exists and maintains itself.” He believed that the “science of man” should investigate the “social body,” and not the “particularities distinguishing the individuals composing it.”2Lambert Adolphe Jacques Quetelet (1796–1874)Quetelet's influential work was amplified by the English school of social biometrics in the early 20th century.1 He believed that statistical laws explained social phenomena, and that as civilization developed, the “average man” would be ever more closely approximated. This vision ignited heated debates about free will versus social determinism in the new disciplines of sociology and political economy.3 A cosmopolitan citizen–scientist, Quetelet actively fostered cooperation across the scientific community. He organized the first international statistical meetings and journals1 and was active in several Belgian and Europe-wide scientific societies. He became a private tutor to Prince Albert, Queen Victoria's consort; his perspectives may have influenced Prince Albert's political views. He frequently gave lectures aimed at general audiences, and kept a roster of >2,500 correspondents. With Malthus, he discussed population trends; with Goethe, he debated philosophical issues; and with US President Garfield, he consulted about improving the US census.4 Quetelet died in 1874, 5 days shy of his 78th birthday. Despite Quetelet's numerous contributions to physical and social sciences—all relevant to public health and epidemiology—he is not generally considered among the founders of the field. He left his mark on public health, nonetheless. In proposing a body mass index (weight [kg]/height [m]2), Quetelet provided a way to quantify the relationship between a person's life course weight and height, starting from the premise that “the transverse growth of man is less than the vertical.”2 His measure was so insightful and practical that it endures to this day as the most widely used indicator of obesity, a leading cause of disease and death in human populations.

De Re Metallica by Georgius Agricula (1494–1555) is a remarkable book—and not just because US President Herbert Hoover (a mining engineer by training) and his wife translated it into English from the original Latin.1 The text provides a comprehensive description of the mining industry during the early Renaissance. The descriptions in De Re Metallica were based on personal observations as Agricola traveled and practiced medicine in German mining communities—some of which still contain active mines. In De Re Metallica, we have the first comprehensive look at the interactions between engineering and human health. Agricola presents his observations in 12 chapters, with more than a hundred woodcut illustrations (Figure). Published only after Agricola's death in 1555, the book remained the primary source of mining engineering for 200 years. With regard to ventilating machines (page VI-200), Agricola observed that: “…If a shaft is very deep and no tunnel reaches to it,…or, when a tunnel is of great length and no shaft reaches it,…, and burning lamps are also extinguished,…There is, …a need for machines… which…allow the workers to breathe easily and carry on their work.” “…Stagnant air which remains in a shaft…or tunnel, produces a difficulty in breathing; the remedy for this evil is the ventilating machines which I have explained above. …If by good fortune the injured ones escape…no one should descend into the mine or into the neighboring mines, or if he is in them he should come out quickly.” On the topic of miners' health, Agricola writes (page VI-214): “It remains for me to speak of the ailments and accidents of miners, and the methods by which they can guard against these, for we should always devote more care to maintaining our health, that we may freely perform our bodily functions, than to make profits. Of the illnesses, some affect the joints, others attack the lungs, some the eyes, and finally some are fatal to men.” As our news headlines attest, the dangers of mining remain as dramatic today as they were 450 years ago.Figure

On 14 August 1881, Dr. Carlos Juan Finlay stood before an audience at the Royal Academy of Medical, Physical and Natural Sciences in Havana and read a paper entitled, "The Mosquito Hypothetically Considered as the Agent of Transmission of Yellow Fever."1 His paper was summarily dismissed by the assemblage. Finlay based his conclusions on his extensive study of the anatomy, physiology, and biting practices of the Culex mosquito. Vindication of his yellow fever hypothesis came in 1900, through the exhaustive investigations of the Yellow Fever Commission under the direction of Walter Reed. Even though Reed acknowledged Finlay's important contribution to the understanding of yellow fever transmission, Finlay's role is often overlooked. Born in Cuba in 1833, Carlos Finlay grew up as a person of broad intellectual interests. He graduated from Jefferson Medical College of Philadelphia and went to France for further training. Although his main passion was yellow fever, his research interests were diverse. He proposed that a cholera epidemic in 1867 had been caused by sewage contamination of the public water supply—a suggestion greeted at the time with disdain. His published work included concerns about environmental hazards associated with manufacture of soap and the production of illuminating gas, the causes of high mortality from infantile tetanus in Cuba, and reflections on the law of gravity and the philosophy of science. As a hobby, he translated antique Latin manuscripts into Spanish. With the end of the Spanish-American War and the independence of Cuba in 1902, Finlay was appointed Cuba's Chief Sanitary Officer. His election in 1905 as president of the American Public Health Association indicates his international reputation. Carlos Finlay died in 1915 in Havana. William Gorgas, the Surgeon-General of the US Army (and the person who had led the eradication of Aedes aegypti from Cuba and the Panama Canal region) told the 43rd Annual Meeting of the American Public Health Association that "No country owes a greater debt of gratitude to Doctor Finlay than does the United States."2 Carlos Finlay was nominated 7 times for a Nobel Prize, but was never awarded the honor.Figure: Carlos Juan Finlay

Most epidemiologists are familiar with the Cochrane Collaboration, which provides critical and systematic reviews of randomized trials relevant to medical practice and health policy. The Cochrane Collaboration has so far enlisted 15,000 volunteers worldwide in the preparation of these reviews.1 Today, more people are familiar with the Cochrane Collaboration than with Cochrane himself. But the man is worth remembering—Archibald Leman Cochrane was one of the most colorful medical scientists of the 20th century. Archie, as he was known, came from a wealthy family, thereby enjoying lifelong financial security. As a young man, he suffered from a sexual dysfunction for which he could not find treatment in the United Kingdom.2 He underwent psychoanalysis in Germany. While there, he became fluent in German—and infuriated by the Nazis. When his Jewish analyst fled to Vienna and subsequently to Holland, Archie followed. On returning to England, he enlisted in the International Brigade to fight fascism in Spain. During World War II, he was held prisoner for 4 years. After the war, Archie studied the chest diseases of mining populations in Wales, launching a series of remarkable surveys that reached more than 90% of their target populations. His studies of lung diseases and his papers on quality of health and medical care services are characterized by innovation and even audacity. The Cochrane Collaboration grew from ideas Cochrane presented in a 93-page book titled Effectiveness and Efficiency: Random Reflections on Health Services,3 published in 1972. The gist of the book is that evaluation of clinical procedures should depend on the results of randomized clinical trials. In his words, “I concentrated mostly on one simple idea—the value of randomized controlled trials in improving the NHS [National Health Service].” About the actual writing, he said “… I ended up writing the book… between the hours of 10:00 pm and 1:00 am when I had finished everything else. I date the real beginnings of my love of whiskey to this period.” This slim volume got rave reviews. It was quickly translated into Spanish, French, Italian, and Polish, and reprinted in paperback. With one small book, Cochrane revolutionized the approach to evidence in medicine. Cochrane retired to his home, Rhoose Farm House, in the Vale of Glamorgan, Wales, where he created a prize-winning garden, hung an impressive art collection, and entertained epidemiologists from around the world. He died in 1988 at the age of 79.Figure: Archibald Leman Cochrane

Most epidemiologists are familiar with the Cochrane Collaborati n, which provides critical and systema ic reviews of randomized trials relevant to medical practice and health policy. The Cochrane Collaboration has so far enlisted 15,000 volunteers worldwide in the preparation of these reviews.1 Today, more people are familiar with the Cochrane Collaboration than with Cochrane himself. But the man is worth remembering?Archibald Leman Cochrane was one of the most colorful medical scientists of the 20th century. Archie, as he was known, came from a wealthy family, thereby enjoying lifelong financial security. As a young man, he suffered from a sexual dysfunction for which he could not find treatment in the United Kingdom.2 He underwent psy choanalysis in Germany. While there, he became fluent in German?and infuriated by the Nazis. When his Jewish analyst fled to Vienna and subsequently to Holland, Archie followed. On returning to England, he enlisted in the Inter national Brigade to fight fascism in Spain. During World War II, he was held prisoner for 4 years. After the war, Archie studied the chest diseases of mining populations in Wales, launching a series of remark able surveys that reached more than 90% of their target populations. His studies of lung diseases and his papers on quality of health and medical care services are characterized by innovation and even audacity. The Cochrane Collaboration grew from ideas Cochrane presented in a 93-page book titled Effectiveness and Effi ciency: Random Reflections on Health Services? published in 1972. The gist of the book is that evaluation of clinical procedures should depend on the results of randomized clin ical trials. In his words, "I concentrated mostly on one simple idea?the value of randomized controlled trials in improving the NHS [National Health Service]." About the actual writ ing, he said "... I ended up writing the book . . . between the hours of 10:00 pm and 1:00 am when I had finished everything Archibald Leman Cochrane

An Egyptian stele dating from c.1500 BC describes a flaccid paralysis characteristic of poliovirus infection. It was not until the 1800s, however, that polio emerged as an important infection. The German physician Jakob Heine provided the first modern description in 1840. By the late 19th century, sporadic outbreaks of poliomyelitis had begun to occur world-wide. In 1890, Swedish physician Oskar Medin described the contagious nature of poliomyelitis and its epidemic potential.1 The first large epidemic in the United States was in 1905, with more than 3000 cases. In 1910, more than 7000 US cases were recorded, and in 1916 the country was shocked by more than 29,000 cases (the most severe US epidemic of polio on record). Wade Hampton Frost provided the first comprehensive description of the epidemiology of poliomyelitis in 1913, in a classic monograph, Bulletin No. 90, “Epidemiologic Studies of Acute Anterior Poliomyelitis.”2 Frost began his studies of polio in 1910, and in the next 3 years personally investigated 6 outbreaks with a total of 475 paralytic cases and another 54 cases in which central nervous system problems failed to develop (“abortive poliomyelitis,” in the lexicon of the day). Two of these outbreaks were in large cities, 2 were in small towns, and 2 were in rural areas. This diversity of settings helped Frost to make epidemiologic inferences. His report provided 2 key observations. One, persons who are exposed to the virus have a low risk of contracting the disease (demonstrated by a secondary attack rate of less than 3% within the families of an affected person). Two, the infectious agent has a wide distribution (at least during epidemic periods), conferring immunity on most of the population while producing disease in only a few. Frost described his logic as follows: “The spontaneous decline of epidemics in localities where only a small percentage of the people have been attacked...suggests that a population may be immunized by an epidemic giving rise to only one recognized case of poliomyelitis among... several thousand inhabitants.”2 In this observation, Frost introduced the indispensible concept of the “passive (healthy) carrier.”Figure: Wade Hampton Frost

In 1927, there was no professional society for US epidemiologists. Inspired by the London Epidemiological Society (established in 1850), Edward S. Godfrey, Jr. and Haven Emerson invited 17 public health professionals to a meeting in New York City for the purpose of founding a new society. With the stated purpose of promoting “the study and discussion of epidemiological problems,” this group became the American Epidemiological Society, now in its 82nd year.1 Godfrey's father was a cavalry officer in the Indian Wars, credited in 1876 with rescuing the remnants of Custer's Seventh Cavalry after the massacre at Little Bighorn. Edward Jr. was born 2 years later. His mother died when he was five, and his father took Godfrey on postings from Cuba to the Philippines until sending him, at the age of 8, to be raised by an aunt in Ohio. Godfrey enrolled at West Point but left to study medicine at the University of Virginia. He developed tuberculosis during his postgraduate training, and moved to the drier climate of the US southwest, where he took a job in Bisbee, Arizona as physician for the Copper Queen Mining Company. His observations of the miserable living and working conditions for miners may have contributed to his broader interest in public health. At age 30 he was appointed Superintendent of Public Health for the Territory of Arizona. Godfrey joined the New York State Health Department in 1917, becoming Director of Communicable Disease Control and later its Commissioner. Godfrey regarded epidemiology as “… the scientific basis for sound health legislation and administration.” An example is his classic paper on herd immunity in the control of diphtheria. Drawing on extensive data from communities in upstate New York, Godfrey showed that immunizing 50% or more of children 5–19 years of age did not control epidemic diphtheria, but that immunizing 30% of children under 5 was enough to stop the epidemic.2 Godfrey was a founder of the Epidemiology Section of the American Public Health Association, and eventually became president of APHA. He was a recipient of the Sedgwick Memorial Award in 1950. A profile published in the American Journal of Public Health cited his “healthy skepticism” as key to his excellence as an epidemiologist.3 Godfrey died on 13 December 1960 at the age of 82.Figure: Edward S. Godfrey, Jr.

A t about 4:00 PM on May 31, 1889, a wall of water and debris more than 35 ft high roared through the western Pennsylvania mill town of Johnstown, population 30,000.1 In minutes the city was annihilated. Fires among the debris added to the carnage. An accurate death count was never possible-the number of dead exceeded 2200. Johnstown lies on a flood plain at the confluence of 2 small rivers. Although both rivers had been at flood stage for several days, the deadly deluge issued solely from the gorge of one, the Little Conemaugh. The cause was an earthen dam that had given way. The south fork of the Little Conemaugh had been dammed in the early 1850s to provide reserve water for the Pennsylvania Main Line Canal, built in 1836. Earthen dams were used to create supplemental water supplies for 19th century canal systems. Many of these dams can still be found in the hills along the routes of long-abandoned canals. The train whistle was the death knell for canals. In 1852 the Pennsylvania Railroad opened a link from Philadelphia to Pittsburgh, and the Main Line Canal became superfluous. The canal was abandoned and its properties and appurtenances sold to private interests. Eventually, the Little Conemaugh property came into the hands of a consortium of wealthy Pittsburgh industrialists calling themselves the "South Fork Fishing and Hunting Club." Members included Andrew Carnegie, Henry Frick, and Andrew Mellon. They repaired the dam, which had been breached during its years of neglect, and built palatial lake side cottages and a 40-room clubhouse. Unfortunately, the dam repairs were not enough to hold back waters from the record rains of May 29 to 31, 1889. An estimated 20 million tons of water was released on the afternoon of the 31st. Devastation in Jamestown was complete. Those who escaped drowning, fire, or trauma were left homeless. An accurate count of the dead was impossible; bodies were discovered years after the disaster. The cleanup took more than 5 years. Among others, Clara Barton arrived from Washington DC with a team of 50 doctors and nurses repre senting the newly organized American Red Cross. The dam failure was traced to shoddy repairs by the South Fork Fishing and Hunting Club. Its members were never held liable. More than a century later, the flood remains the deadliest US flood, and one of the dozen most lethal floods in human history.

At about 4:00 pm on May 31, 1889, a wall of water and debris more than 35 ft high roared through the western Pennsylvania mill town of Johnstown, population 30,000.1 In minutes the city was annihilated. Fires among the debris added to the carnage. An accurate death count was never possible—the number of dead exceeded 2200. Johnstown lies on a flood plain at the confluence of 2 small rivers. Although both rivers had been at flood stage for several days, the deadly deluge issued solely from the gorge of one, the Little Conemaugh. The cause was an earthen dam that had given way. The south fork of the Little Conemaugh had been dammed in the early 1850s to provide reserve water for the Pennsylvania Main Line Canal, built in 1836. Earthen dams were used to create supplemental water supplies for 19th century canal systems. Many of these dams can still be found in the hills along the routes of long-abandoned canals. The train whistle was the death knell for canals. In 1852 the Pennsylvania Railroad opened a link from Philadelphia to Pittsburgh, and the Main Line Canal became superfluous. The canal was abandoned and its properties and appurtenances sold to private interests. Eventually, the Little Conemaugh property came into the hands of a consortium of wealthy Pittsburgh industrialists calling themselves the “South Fork Fishing and Hunting Club.” Members included Andrew Carnegie, Henry Frick, and Andrew Mellon. They repaired the dam, which had been breached during its years of neglect, and built palatial lakeside cottages and a 40-room clubhouse. Unfortunately, the dam repairs were not enough to hold back waters from the record rains of May 29 to 31, 1889. An estimated 20 million tons of water was released on the afternoon of the 31st. Devastation in Jamestown was complete. Those who escaped drowning, fire, or trauma were left homeless. An accurate count of the dead was impossible; bodies were discovered years after the disaster. The cleanup took more than 5 years. Among others, Clara Barton arrived from Washington DC with a team of 50 doctors and nurses representing the newly organized American Red Cross. The dam failure was traced to shoddy repairs by the South Fork Fishing and Hunting Club. Its members were never held liable. More than a century later, the flood remains the deadliest US flood, and one of the dozen most lethal floods in human history.Figure: No Caption available.

An explosion occurred in the harbor of Halifax, Nova Scotia on 6 December 1917, killing more than 2000 persons and injuring another 10,000. The explosion leveled a large part of the city and left at least 20,000 people homeless. It was the largest man-made explosion in history to that date, not surpassed until an atomic bomb was dropped on Hiroshima 3 decades later. The cause of the explosion was the collision of a Belgian ship, the Imo, carrying relief supplies to Belgium, and a French ship, the Mont Blanc, carrying 2600 tons of high explosives bound for France. The harbor at Nova Scotia comprises an inner basin able to accommodate more than 100 ships, and invisible from the open ocean (and from enemy submarines). The narrow entry passage is flanked by industrial and cargo handling facilities. In the First World War (as well as the Second), Halifax Harbor was a major venue for assembling convoys from America to Europe. On the morning of the collision, the Imo was steaming out of the inner basin as the Mont Blanc was bound inward. The Imo was off-course, forcing the Mont Blanc toward shallow waters at the edge of the narrows. Caught between imminent collision with the Imo and running aground, the Mont Blanc tried to escape by crossing the bow of the Imo. The maneuver failed and the collision set the Mont Blanc on fire. The ship drifted across the narrows toward the center of the city. Twenty minutes later, the Mont Blanc exploded. The blast was powerful enough to transport a 1000-pound section of the Mont Blanc's anchor 2 miles away. Within and around the epicenter, the death rate was estimated to be 29 per 1000. Sixty percent of the deaths were male and 40% were female. Forty percent of deaths were under 20 years of age, 50% between 20 and 60, and 10% over 60. Data regarding injuries are limited; an estimated 20% of those permanently disabled were blinded by broken glass—they apparently had been behind windows watching the Mont Blanc in flames, when it exploded.Figure: Halifax, Nova Scotia, 6 December 1917.

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Mort Levin received the John Snow award from the American Public Health Association in 1978. A member of the selection committee remarked that, “… Mort Levin has had as much impact on public health in this country as anyone during the past quarter of a century.”1 Today, if Levin is remembered at all, it is probably for his introduction of the concept of “attributable risk.” Mort Levin was born in 1904 in prerevolutionary Russia, and after World War I migrated with his family to the United States. He graduated from Johns Hopkins University and took degrees in pharmacy and medicine from the University of Maryland. As a dispensary physician at the Johns Hopkins Hospital, Levin came under the influence of Wade Hampton Frost, gave up clinical medicine, and received a DrPH in 1934. His first job as a public-health physician was as Commissioner of Health for Ottawa County, Michigan. Shortly after taking up his position, he traced the source of a milk-borne outbreak and forced through an ordinance requiring pasteurization. The unpopular legislation led him to be fired. Mort Levin made three major contributions to public health. One was the recognition and derivation of “population attributable risk,” which provided public health practitioners with a powerful tool for evaluating the impact of a particular disease in a defined population. His second major contribution was in his role as the first Director of the Commission on Chronic Illness (1950)–a Commission created by the AMA, the APHA and other prominent health organizations. Under Levin's leadership, the Commission expanded the scope of public health from a narrowly-focused emphasis on the control of infectious diseases to a concern with the full spectrum of disease occurrence.3 His third contribution was the 1950 publication of his case-control study of smoking and lung cancer4 which, along with simultaneous studies by Wynder and Graham5 and Doll and Hill6 unleashed a torrent of investigations on the harmful effects of tobacco smoking on health.Figure: Mort Levin