Clifton Wintringham opens his 1721 treatise by declaring his aim to deduce the causes and explain the phenomena of the most fatal diseases, particularly at a time when several rage with uncommon violence and a pestilence threatens. He promises to reduce these diseases to simplicity and speak intelligibly of them, using the principles of modern philosophy. The preface addresses a practical audience: physicians who may not trouble themselves to deduce these phenomena. Wintringham then proceeds to define contagious diseases as those communicated by air or effluvia from morbid bodies, distinguishing epidemic from pestilential forms. The first chapter immediately introduces a geometric style, with Proposition I stating that increased magnitude of blood particles causes obstructions in smaller vessels, demonstrated through a canal analogy.

Geometric Method and the Blood's Particles

Wintringham structures his argument like a mathematical treatise, beginning with propositions and demonstrations. Proposition I posits that increased particle size in the blood leads to obstructions in smaller vessels, with the timing depending on particle magnitude and vessel size. This mechanical approach is reinforced by references to experiments: the addition of an acid spirit to milk changes its texture, analogous to how contagious particles affect blood. Wintringham cites Jo. Bapt. Alprunus's distillation of pestilential bubo matter, which yielded a phlegm, oily matter, and a salt so acrid it equaled aqua regis. He does not definitively conclude that an acid salt is the immediate instrument, noting that spirit of wine can produce similar effects, and that putrefying animal bodies yield a volatile alkaline salt. The emphasis is on the dual action of contagious particles: coagulating and inspissating some parts while volatilizing and attenuating others.

The Scorbutic Connection and Saline Spiculae

Wintringham draws on Dr. Hodges's observation of an affinity between pestilential and scorbutic habits of body. Those with blood naturally abounding in saline particles, and with coagulated or inspissated blood, were more grievously affected by the pestilence. He adds that many who recovered from the late plague were subject to scorbutic diseases, and he has frequently observed the same in smallpox and measles patients with a scorbutic habit. The saline spiculae affect not only the blood but also the nervous fluid, rendering it extremely acrid and pungent, which leads to pain, sickness, and inflammations. This connection between constitutional predisposition and disease severity is a recurring theme, grounded in the chemical properties of the blood.

Symptoms as a Catalogue of the Fatal Enemy

Chapter V lists the symptoms accompanying a pestilential fever: yawning, stretching, coldness, shuddering, sudden pains in the head, giddiness, loathing, vomiting, a low unequal pulse, trembling, great inward heat, coldness of the extremities, uncertain sweats, inquietude, stupor, delirium, watching, convulsions, carbuncles, buboes, livid vesications, purple spots, and hemorrhages—the last three being certain forerunners of death. Wintringham notes that not all symptoms occur in every person; they differ in number and degree according to the infection's virulence, the season's heat, and the patient's constitution. The more the blood is stocked with acrid and pungent salts, the more violent the symptoms. This clinical catalog is presented without narrative, as a systematic enumeration of the disease's manifestations.

Analogies and Limits of Inference

Wintringham repeatedly uses analogies from chemistry and natural philosophy to explain disease mechanisms. The milk and egg experiments illustrate how a small quantity of acid can change a substance's texture. He references Boyle's History of Human Blood and Friend's Emmenologia to support his claims. However, he is cautious about overinterpretation: he will not pretend to determine that an acid salt is the immediate instrument, since the same changes can be wrought by other liquids. The excerpts show a writer who grounds his arguments in observable phenomena but acknowledges the limits of his evidence. The treatise's structure—propositions, demonstrations, and clinical observations—offers a methodical approach to understanding contagion, though the complete work may develop these ideas further.

Wintringham's essay rewards readers who attend to its dual structure: the geometric propositions that model disease mechanics and the clinical lists that ground theory in practice. The excerpts suggest a work that moves between abstract principles and concrete symptoms, always with an eye to the physician's need for intelligible explanations. Readers should note how Wintringham uses experiments and analogies to bridge the gap between invisible particles and visible disease, and how he qualifies his conclusions when evidence is incomplete.