Concerns about Climate

Let us take for an example the year 1891, when diarrheal deaths in all three of our case-study cities were at a comparatively low point. In 1891, in Birmingham, the number of combined deaths due to diarrhea (320) and gastroenteritis (113) was roughly comparable to those in Liverpool (330) and Manchester (432). This relatively low point in disease mortality before a surge that would follow over the next decade gave Medical Officer of Health Alfred Hill the chance to reflect on why deaths were so low during the year. He concluded in his annual report that the absence of a “high summer temperature” must have been the cause.1Hill, Report on the Health of the City of Birmingham for the Year 1891, 16. What is of particular note here is that Hill’s point is representative of a frequent observation made by his fellow Medical Officers of Health: when temperatures rose, generally, so too did diarrheal deaths; when temperatures fell, as they did in 1891, so too did diarrheal deaths. The mild summer temperature in 1891 appeared to give Birmingham a brief reprieve from summer diarrhea, as compared to the previous years (since a high of 729 deaths in 1886), but the reprieve did not last long. In 1893, when the average summer temperature rose sharply, Hill reported a surge in diarrheal deaths (828, with 200 additional deaths due to gastroenteritis). Birmingham residents had not seen such a severe death toll (1.7 per 1,000 living) since 1875. In two districts, Duddeston and St. George’s, diarrhea death rates were even higher still at 2.6 and 2.2 per 1,000 living, respectively.2Hill, Report on the Health of the City of Birmingham for the Year 1893, 16. Many of these deaths occurred in July (329) and were most common among children under one year of age (630).3Hill, Report on the Health of the City of Birmingham for the Year 1893, 24, 30. The following year, though, diarrheal deaths in Birmingham dropped to their lowest on record, with only 256 deaths in a city with a population of nearly half a million. Hill attributed this improvement to favorable climatic conditions – an “absence of very hot or very cold weather” during the year – indicating how he saw a relationship between temperature and the severity of the summer diarrhea from year to year.4Hill, Report on the Health of the City of Birmingham for the Year 1894, 3.

The strikingly low deaths in 1894 were an exception, as Figure 2.2 shows.5In their annual reports, the Medical Officers of Health presented their data in text and tables. For ease of presenting the data, I have aggregated and reproduced their data in graphs. As average summer temperatures rose over the following two years, diarrhea mortality also increased – to 605 deaths in 1895 and 589 in 1896. In 1897 diarrhea mortality in Birmingham soared to a record high of 923 deaths, exacerbated by 521 deaths from gastroenteritis. These deaths accounted for nearly a seventh of the total mortality in the city for the year.6Hill, Report on the Health of the City of Birmingham for the Year 1897, 20. In 1898, the number of deaths from diarrhea and gastroenteritis combined dropped slightly, to 1,212, before rising again to 1,411 in the last year of the nineteenth century. These figures, Hill somberly noted in 1898, were “very unsatisfactory” from a public health perspective.7Hill, Report on the Health of the City of Birmingham for the Year 1898, 26.

Hill’s colleagues in Liverpool and Manchester also tracked cases of summer diarrhea relative to climatic conditions, especially mean summer temperature (as well as seasonal rainfall, although that relationship was not as direct). In 1891, when diarrhea caused only 330 deaths in Liverpool, which marked the lowest death rate in the last quarter-century, the mean summer temperature was a pleasant 58.4°F (Figure 2.3).8Taylor, Health of Liverpool during the Year 1891, 15. However, beginning in 1893 the downward trend in diarrheal deaths reversed as average summer temperatures warmed, claiming 866 lives during the deadliest year since 1880.9Taylor and Hope, Annual Report on the Health of Liverpool 1893, 6. E.W. Hope, who replaced J. Stopford Taylor as Liverpool’s Medical Officer of Health that year, partially attributed these excess deaths to the “dryness and high temperature of the Spring and Summer months” in his annual report.10Taylor and Hope, Annual Report on the Health of Liverpool 1893, 9. When deaths dropped from 866 to 503 in 1894, Hope attributed this in part to a cooler summer with a mean temperature of 55.96°F.

In the last decade of the nineteenth century, Liverpool experienced three surges in summer diarrhea in the years 1895, 1897, and 1899. In 1895, diarrheal deaths (1,108) contributed to an exceptionally poor year in terms of infant mortality in Liverpool (202 per 1,000 live births), and also across the country.11Hope, Report on the Health of Liverpool during 1895, 20. The highest number of deaths occurred in the most economically impoverished districts of the city: Everton (232), Scotland (162), and Kirkdale (153).12Hope, Report on the Health of Liverpool during 1895, 37. In his annual report for 1895, Hope noted that the city experienced an intense cold in the early months of the year, which gave rise to a high mortality rate due to pulmonary diseases. This cold winter was followed by a particularly hot and dry summer that gave rise to an abnormally high number of diarrheal deaths.

In addition to temperature, Hope also observed a relationship with rainfall. Comparing 1891 and 1895, Hope observed that when 16 inches of rain fell in 1891 between June and September only 203 diarrheal deaths occurred in the third quarter of the year, but when only 7.7 inches of rain fell in those same months in 1895 summer diarrheal deaths rose considerably, to 819.13Hope, Report on the Health of Liverpool during 1897, 41. Hill feared that the absence of rain allowed streets to become exceptionally dirty and that sewers were less frequently naturally “washed.” As a result, he worried that filth and refuse accumulated despite regular sweeping, and dry gullies and traps allowed “sewer gas” to escape more readily, spreading pathogens with it.14Hope, Report on the Health of Liverpool during 1895, 14. “Sewer gas” was a nuisance and hazard that emerged as a product of water-borne sewage systems developed in the Chadwickian sanitary vision. While water-borne sewage systems marked a significant sanitary improvement from decaying cesspools of standing waste, blockages, especially in brick-lined sewers with flat bottoms, made sewers little more than “elongated cesspools” that required the natural flushing of rainwater to cleanse. When this natural cleansing did not occur, however, historian Tom Crook argues that sewers created a hazard to public health that was just as dangerous as the cesspools, because the noxious odors from decaying waste carried pathogens, attracted flies, and poisoned the nearby air with expelled (and occasionally explosive) carbonic acid, methane, and ammonia. See Crook, “Danger in the Drains,” 108–13.

Two years later, in 1897, diarrheal deaths reached a new record high in Liverpool, claiming the lives of 1,482 people. Among these deaths, 1,039 occurred in just a six-week period between July 25 and September 4.15Hope, Report on the Health of Liverpool during 1897, 40. Once again, Hope partially attributed these deaths to the climatic conditions, reporting that a warm, dry summer had contributed to the abnormally high number of cases of summer diarrhea during the year.

Like Hill and Hope, Manchester’s Medical Medical Officer of Health, John Tatham, and even more so his successor James Niven, tracked cases of summer diarrhea relative to climate conditions annually and shared in the consensus that summer temperature and rainfall influenced the prevalence of the disease from year to year. Diarrheal deaths relative to climate conditions in Manchester are shown in Figure 2.4. Tatham argued in 1893 that he had found a close relationship between warm summers and diarrheal deaths and a “less close” relationship between diarrheal deaths and rainfall.16Tatham, Report on the Health of Greater Manchester, 1891–1893, 68. He reported that during a particularly warm summer in 1893 (with a mean temperature of 60.4°F for the months July–September, the highest on record since 1884) diarrheal deaths surged to 956, more than double those of the preceding two years (432 in 1891 and 418 in 1892). Many of these deaths occurred in the second (131) and third (688) quarters of the year.17Tatham, Report on the Health of Greater Manchester, 1891–1893, 67. When Niven replaced Tatham as Manchester’s Medical Officer of Health in 1894, he observed lower than average diarrheal death rates, which he attributed to “the radiant spring and cool summer and autumn.”18Niven, Report on the Health of Greater Manchester, 1894, 3. Niven also believed that favorable climatic conditions contributed to the noticeable drop in diarrheal deaths (375), as compared to the previous year. But as diarrheal deaths rose and fell from year to year, especially in years when climate conditions were ill-suited to the spread of the disease, Niven paid special attention to the ways in which human behaviors might also contribute to the prevalence of summer diarrhea in Manchester.

Of course, the Medical Officers of Health were careful to avoid attributing summer diarrhea solely to a climatic causation. Rather, they believed that climate conditions could be a useful indicator of a potentially deadly diarrheal season, but they were aware that it was not the only variable. Alfred Hill, for example, was especially aware that environmental factors alone could not explain the changes in summer diarrhea mortality after he compared the climatic conditions in Birmingham with other large cities, with quite different case rates of summer diarrhea despite comparable climatic conditions. In his 1893 report, Hill indicated that he believed it “quite indisputable” that “high temperature” was an important factor in the prevalence of diarrhea, but acknowledged that it was “not in itself the essential cause of the disease, but is rather a necessary condition to the operation of that cause.”19Hill, Report on the Health of the City of Birmingham for the Year 1893, 16. Hill understood that local ecological conditions, like the sanitation of his city, and the social conditions, must also have played a role. However, he believed that city-wide sanitary conditions were the “only one of the three factors over which a sanitary authority has any control.”20Hill, Report on the Health of the City of Birmingham for the Year 1893, 8; Hill, Report on the Health of the City of Birmingham for the Year 1897, 24. On this last point, I argue that Hill was wrong.

Meanwhile, in Manchester, James Niven concerned himself with several additional risk factors, including household sanitation. He observed that in the central districts, where midden privies or pail closets were commonly used into the early twentieth century, diarrheal mortality was often highest.21Niven, “Summer Diarrhea and Enteric Fever,” 134, 169. Beyond general sanitation, though, Niven believed that infant feeding practices played an even more significant role in the severity and frequency of summer diarrheal deaths.22Niven, Report on the Health of the City of Manchester, 1895, 5. Exposing milk supplies to fecal contaminants in the air and carried by flies, then given to an infant as their most important source of food, greatly increased the risk of illness and mortality.23Frazer, A History of English Public Health, 333. On this last point, Niven was entirely correct.