Losing Ground. The Disappearance of Attraction from the Kidneys

The Scientific Revolution—The Kidney and Nephrology in and about the Seventeenth Century (Part 1)

“…He argued that the arterial blood delivered to the kidneys is separated into urine at a sieve like arrangement formed at the junction of the renal artery and vein at their smallest subdividing branches where they meet the tubule, where the small components of blood and its excess fluid are collected in the tubules as urine, while the larger components of blood are returned to the renal vein. The connecting point of the Y‐shaped anatomical structure (artery, vein, tubule) proposed by Bellini would become the eponymous vascular corpuscles reported by Malpighi in his 1666 De Viscerum Structura Excertatio Anatomica .…”

“…Deservedly, by far the better known contributor to renal structure and function was Malpighi, who with his more powerful microscope observed and described the pulmonary capillaries predicted by Harvey, and in the kidney, the glomerular capillary tufts that he described as “ minimae glandulae ” (tiny glands) that form ‘corpuscles’, an anatomical term applied to the small circumscribed endings of vessels and nerves . He states that the glands “drain the urine” that is “excreted”; he does not use the term “secretion” or “filtration.” His De viscerum structura contains five chapters on the liver, brain, kidneys, spleen, and polyps of the heart.…”

“…In what can be considered a belittling statement that "The kidneys are not present for necessity in animals but have the function of perfecting the animal itself," Aristotle literally condemned the kidneys to a perfunctory role that would haunt their study well into the Early Modern Period (39). He considered the role of the kidneys as that of separating the surplus of fluidities of the blood inside the solid renal substance (parenchyma) and transforming it into urine, to which he refers as "residuum" (40). The term 'parenchyma' was actually introduced later by the Alexandrian Greek anatomist Erasistratus (304-250 BCE) as that part of an organ into which the blood vessels seem to disappear, and was initially conceived as a porous tissue jelled from the blood disgorged into it from the veins.…”

“…What was extracted from the arterial blood (?bile) is not clear. Galen rejected the possibility of filtration alluded to by Aristotle 500 years earlier, and dogmatically concluded that the kidneys "secrete" urine by their inherent "attractive force" (40). Where Aristotle had belittled the kidneys, Galen banned them to negligence.…”

A forgotten chapter in the history of the renal circulation: the Josep Trueta and Homer Smith intellectual conflict

“…Until then, the kidney was considered a tubular secretory organ that was an adjunct to the gastrointestinal tract in its vital process of nutrition. The kidneys continued to be viewed as secretory organs long after Marcello Malpighi (1628 -1694) had described the tiny globular glands that formed his eponymous "corpuscles" and implied their connection to the "canaliculi" and tubules described earlier by Lorenzo Bellini (1643-1704) in the 17th century (34). This notion of the kidney as a secretory gland continued well after William Bowman (1813-1892) demonstrated the actual continuity of Malpighi's corpuscle with the tubule in 1842 and shortly thereafter when Carl Ludwig (1816 -1892) argued convincingly for glomerular capillary ultrafiltration.…”