From mechanism to vitalism in eighteenth century English physiology.

Abstract

One of the most striking features of English physiology in the forty years between 1730 and 1770 was the dramatic, indeed precipitous decline of varieties of mechanism and the rapid rise to preeminence of alternate varieties of vitalism. In 1733 Stephen Hales published his Haemastaticks. 1 This collection of twenty-five "statical experiments" about the functioning of animal bodies was dedicated to verifying and extending, with the help of precise, quantitative Newtonian investigative techniques, the hydraulic theory of the "animal oeconomy" that British medical writers from Archibald Pitcairne to Richard Mead had made widely popular between 1695 and 1715.2 Hales carefully measured blood pressure, determined the velocity of efflux from the heart, experimentally exhibited impedance caused by capillary ramification, and explored several corpuscular mechanisms for such phenomena as glandular secretion and animal heat.3 He thus quantitatively and conceptually elaborated the principal ideas English medical writers had previously introduced in the most recent phase of iatromechanism. Mechanistic physiology picked up where mechanistic medical theory ended, and now, early in the fourth decade of the eighteenth century, Newtonian methods and speculative suggestions served as the guidelines for the activity of the physiologists. But in the decade of the Haemastaticks and in the 1740's, physiological mechanism was already in serious decline. In the 1730's the only papers on physiological subjects to appear in the Philosophical Transactions were such diffuse and largely descriptive contributions as