Twentieth-Century Human Biology—Hygiene

Perhaps just as important as increased calorie intake was the production and spread of medical knowledge and the creation of an infrastructure to ensure better hygienic conditions. All these processes sometimes developed in tandem; for instance, the introduction of vaccines in the eighteenth century, independent of economic changes increasing calorie intake (the nineteenth century) and the construction of sewage systems and waterworks in the nineteenth and twentieth centuries.² Yet as Rober Fogel has noted, they overlapped to create a synergy that bolstered their effects. Well-nourished bodies deal better with diseases, and protected from illness through vaccines they make better use of the energy nutrients provide.³

The result was a demographic shift—a drop in mortality, especially among infants, fewer births, and a greatly extended life span. In Spain, the overall mortality rate per 1,000 people dropped from 27.9 in 1900 to 17.2 in 1930. In 2001, it stood at 9.1.⁴ In the same period, the average life expectancy rose from 34.8 years to 50, finally reaching 79.3 years.⁵

In the United States, which was largely ahead of Europe in terms of nutrition and hygiene, in the early twentieth century one third of all deaths were children five years or younger.⁶ In Poland in 2006, children four years or younger accounted for slightly over one in every thousand fatalities.⁷

Apart from the purely material aspect of changes in living strategies—not so many children had to be born if the living had a better chance of survival⁸—they led to a profound re-imagining of customs and (perhaps) mindsets. As a prewar Polish sociologist put it: “In the countryside they adore children, they love them, but if they die, it is no great loss. A crop failure causes more sorrow than the death of a child.”⁹ This need not prove the peasants’ cruelty—denial of grief could have been a strategy for dealing with an unpredictable reality. In this context, economic development was an opportunity for deeper human emotional development, contrary, as it were, to the idealizations of a life close to nature.

One of the more important transformations was the introduction of sewer systems and waterworks. This change was both essential and laborious—in 1913 “only nine cities in Congress Poland had waterworks, and eight had sewer systems.”¹⁰ In Warsaw itself, this went for half of the buildings in the interwar period. Even by 1960, “only seventy per cent of Warsaw’s inhabitants lived in homes with running water and plumbing.”¹¹

Apart from these sorts of major infrastructure projects, which caused problems even for more developed countries,¹² decisions like the introduction of iodized table salt was of great importance to the population’s well-being. Introduced in Switzerland in 1922, it cut down on thyroid problems, which caused goiters.