3.4: The Scientific Renaissance and Colonization

Along with the age of enlightenment came the scientific renaissance in Europe, including the invention of the microscope, and the expansion of knowledge of human anatomy. Increasingly doctors were more educated even though they often had conflicting theories of disease and treatment practices. The agricultural revolution brought more people into the cities, requiring innovations in plumbing and sanitation. At the same time, colonization efforts required long journeys overseas, which carried unfamiliar diseases to new continents.

In the late 16th century, parishes (villages or neighborhoods with their own church) began keeping records of births and deaths, which in England eventually became the Bills of Mortality. In 1629, this weekly publication and annual abstract began to include causes of death, which opened up the possibility of studying the most common causes of death from a population perspective. In 1662, John Graunt published the first such analysis, demonstrating that statistics of death rates for different diseases could be connected to living conditions - higher death rates from infectious disease were to be found in the poorest slums. Current epidemiological techniques still employ vital statistics (like the Bills of Mortality), to research things like average lifespan and common causes of death, and track them over time.

From the 15th through 18th centuries, several European countries were heavily involved in expanding their empires and economies through conquest in the Americas, Asia, Africa and the South Pacific. This was followed by the colonization of these lands, and the enslavement of Africans and the indigenous peoples. Long voyages by ship, often with scarce or spoiled food, also introduced a new disease: scurvy. Scurvy was so common on seafaring expeditions that it wasn’t unusual for ships to return from long voyages with less than half their crew alive. In what is considered the first experimental human study in 1747, James Lind, a doctor in the British Royal Navy, tested a hypothesis that scurvy was caused by a dietary deficiency. Lind isolated 12 sailors who had the condition and fed them different diets. The two sailors who consumed citrus recovered so quickly that Lind had to conclude that citrus fruits contained some sort of cure. The Royal Navy eventually provided a lemon or lime juice supplement to all sailors and eliminated scurvy from their fleet. Even though the reason for this cure wasn’t fully understood (vitamins wouldn’t be discovered for another 150 years), Lind’s experiment was exemplary of the development of a clinical research process.

Figure \(\PageIndex{1}\):James Lind, conqueror of scurvy. Image by Robert Alan - Parke, Davis & Company. (Copyright; CC BY-SA 4.0, via Wikimedia Commons)

The devastating effects of these colonizing voyages to Native American and African peoples cannot be overstated. Even after experiencing violent conquest, famine and displacement, many tribes were devastated once again by communicable diseases brought over by European armies and settlers. While Europeans whose ancestors (or they themselves) had survived epidemics of smallpox, cholera, and measles had already developed some immunity, indigenous peoples had never been exposed to these infectious diseases. It is estimated that epidemics of these infectious diseases killed 90-95% of the Native American population. Smallpox devastated South African, New Zealand, and Australian communities as well, such that these original peoples could do little to resist their conquest by Europeans (Guns Germs & Steel: Variables. Smallpox, 2005). Some of these disease were transmitted by vulnerable African slaves in the transatlantic slave trade, which had already devastated Africa’s economic and agricultural opportunities and perpetuated atrocities of physical and mental violence to enslaved individuals. Around 15-25% of enslaved Africans bound for the Americas perished aboard the ships due to both epidemics and violence from their captors (Transatlantic Slave Trade, n.d.).