Treatment of the diseases of the eye, by means of prussic acid vapour, and other medicinal agents — Reading Notes

A Method Presented Through Cases

Turnbull does not write a systematic treatise; he assembles a series of numbered cases, each a miniature narrative. In Case 3, a girl named Munro from Mount Pleasant arrives with “albugo of corneæ in both eyes” and vision “almost completely destroyed.” Turnbull applies prussic acid daily for six weeks. On the eleventh day, she “can see some objects”; by the end of another week, she can name objects and identify colours of flowers presented to test her progress. The case ends with her walking unassisted over a mile and a half. Such detail—specific days, distances, names of witnesses like Sir George Sinclair—gives the work the texture of a clinical log rather than a theoretical argument.

The cases share a common arc: a patient with a condition previously treated without benefit, a course of prussic acid vapour, and a measured improvement. Turnbull often quantifies the change: in Case 4, the staphylomatous eye’s corneal prominence “diminished at least one-half,” and the occluded pupil expands to “about four lines in diameter.” These concrete observations anchor the book’s claims.

The Role of Professional Witnesses

Turnbull repeatedly invokes other medical men to corroborate his results. The preface thanks “those Medical Gentlemen who so kindly, and so patiently watched several of the cases.” In the case of Sinclair Sutherland (Case 4), the patient’s improvement is recorded without a named observer, but elsewhere Turnbull includes letters from practitioners such as W. H. Newnham, Professor Forbes, J. C. Atkinson, Dr. Maclean, and G. K. H. Paterson. These letters, reproduced in the contents and presumably in the text, serve as external validation. The book thus becomes a collaborative document, not a solo pronouncement.

This reliance on witnesses reflects the period’s medical publishing conventions, where case reports often named attending physicians to bolster credibility. Turnbull’s method—reprinting his own journal articles and then adding cases observed by others—creates a layered argument: the initial claims, then the confirming evidence.

Patient Voices and the Limits of the Record

Although Turnbull writes as a physician, the patients occasionally emerge as agents. Mrs. M’Kenzie (Case 6) has capsular cataract of “three or four years’ duration”; Turnbull applies prussic acid “by way of experiment” for five weeks, and the cataract “entirely disappeared.” The phrase “by way of experiment” hints at a tentative approach, yet the patient’s consent is implied. In Case 3, the girl Munro makes an “urgent request” for treatment despite Turnbull’s warning that he held out “no prospect of her being benefited.” These moments reveal patients pushing for intervention, a dynamic that complicates the doctor’s narrative of control.

The excerpts do not include the patients’ own words beyond reported speech. The reader sees only Turnbull’s summary: “She states that she can see some objects.” The interior experience of illness and recovery remains opaque. This limitation is inherent in the genre—the clinical case study prioritizes observable signs over subjective testimony.

Therapeutic Specifics and Their Presentation

Turnbull’s treatment is remarkably uniform: prussic acid vapour applied daily for weeks or months. He does not vary the dose or method across cases, though the duration differs. In Case 5, Mr. Alexander Macdonald, a merchant with retinal symptoms, receives the vapour for six weeks; after one month “all the former distressing symptoms had totally disappeared,” but Turnbull continues treatment “for some time longer.” This consistency suggests a standardized protocol, but the book offers no formulary for the vapour’s preparation in the excerpts—only later, in Chapter II, do “Formulæ” appear.

The cases also reveal what Turnbull considers a failure: he includes no negative outcomes in the provided excerpts. Every case ends with improvement or cure. This selectivity is typical of early nineteenth-century therapeutic publications, where authors aimed to establish a remedy’s reputation. The reader must weigh the evidence against the absence of counterexamples.

Turnbull’s book is best approached as a period document of therapeutic optimism, not a modern clinical trial. The reader should note the structure: the reprinted journal articles, the case series, and the appended letters from other physicians. Pay attention to the specific language of improvement—“translucent,” “progressive,” “quite restored”—and the absence of standardized measurement. The work invites comparison with contemporary ophthalmic texts, but its value lies in the concrete details of individual cases, however partial the record.

The rain drummed against the window that afternoon, and Dr. Turnbull's hopeful case notes kept returning to those moments when vapour met inflamed tissue—secret, intimate transformations documented in careful prose. I found myself wondering about older remedies, older fumigations, and set his book aside. My hand drifted to The Plague of Lust, Vol. 2 (of 2) Being a History of Venereal Disease in Classical Antiquity — A Closer Reading, and the rain seemed to slow, as if to listen.