Chapter Two of my dissertation, ‘The Nature of Blood’, analyses the changing perceptions of blood in the Dutch Republic, both by Boerhaave’s disciplines and by his rivals.
Historically, blood has been closely associated with a wide range of cultural ideas, from family relationships and loyalties to violence and bloodshed. Blood had, of course, already been one of the four cardinal humours that were thought to determine a person’s physical qualities and temperament. But this chapter shows how early modern Dutch physicians analysed the peculiar properties of blood in the chemical laboratory. This led Boerhaave and Gaubius to develop a new understanding of the physiology of the body.
Their approach also provoked criticism: the The Hague physician Thomas Schwencke (1694–1767) grew deeply sceptical about chemistry, convinced as he was that blood in vitro and blood in vivo were drastically different fluids. Schwencke preferred measuring the weight and temperature of blood for diagnostic purposes. Analysing these competing claims, I argue that the debate went beyond the problem of methodology, and was directly linked to the question of the essential yet disputed question surrounding blood: was blood alive?