In the 18th century there was probably a great deal of fatalism about sickness in the early months of life as deaths among infants were so common. Many deaths in the first two years of life were recorded in a category labeled “infancy” in the London Bills of Mortality. A major category within this was “convulsions,” a symptom of many untreated conditions among infants, particularly certain infectious diseases and dietary deficiency. Diarrhea in infants can terminate in convulsions, and many deaths would have been caused by unhygienic or inappropriate weaning foods, water or milk contaminated with fecal matter, and dehydration, as in developing countries today. The summer peaks in “convulsions” deaths probably reflect a seasonal increase in gastrointestinal diseases due to fecally contaminated food and fly-borne germs. Deaths recorded in the category “teething” may also include many deaths from infectious diseases and gastrointestinal infections due to use of contaminated weaning foods. As mentioned earlier, the categories “convulsions” and “fevers” are likely to have included some cases of smallpox among infants, as they could have fever or convulsions but no other distinctive symptoms. The strong correlation (r = +0.6) between “infancy” and smallpox death rates for London based on the Bills of Mortality between 1671–75 and 1831–35 and the broad similarity between the trends and major turning points (fig. 3.1) are consistent with this.

This chapter considers the possible causes of the decline in death rates from infant disorders and infectious diseases. Despite the limitations of classification, the simple arithmetic components of mortality change give some indication of the relative importance of the different categories of deaths considered here. The total death rate (for all ages) for London based on the Bills of Mortality declined by about 32% between 1751 and 1801, with “convulsions,” “teething,” and other “infancy” deaths contributing -0.40 to each unit of change. In the second half of the 19th century, when the death rate for England and Wales declined by 22%, the major contributions to a unit of change were from convulsions/ teething (-0.14) and scarlet fever/diphtheria (-0.12). Between 1901 and 1951, the total death rate declined by about 62%; prematurity and congenital and perinatal conditions made a much greater contribution to each unit of change (-0.12), along with convulsions/teething (-0.06), scarlet fever (-0.04), measles (-0.03), and whooping cough (-0.03) (see appendix C1).