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Smallpox Pioneer Edward Jenner’s Dear Friend, Celebrated Physician Caleb Hillier Parry

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This post was authored by Stephanie Marcus, Science Reference Librarian in the Science, Technology, and Business Division.

We’ve all heard of Edward Jenner and his work with smallpox, but I wonder if anyone reading this has heard of Caleb Hillier Parry?  When Jenner wrote his Inquiry into the Causes and Effects of the Variolae Vaccinae, first published in 1798, he dedicated it to “C.H. Parry, M.D., at Bath, My Dear Friend.”  The two had met in grammar school and remained friends for life.  They both became physicians who spoke, wrote or collaborated on some of the same topics, among them, vaccination and cardiology.  When Parry died six years after suffering a paralytic stroke, Jenner was one of the pall bearers.  Jenner died the following year, the day after suffering an apparent stroke.

Caleb Hillier Parry. From National Library of Medicine, Digital Collections.

I learned in an unusual way about Caleb Parry (1755-1822), born in Cirencester, England (near Gloucester), and like Jenner, he was the son of a minister.  Although reference librarians at the Library of Congress answer most of our queries by email through our Ask a Librarian service, we still receive and answer handwritten letters.  One of mine was from a prisoner who has no internet access, but had learned that Parry was the first to describe hyperthyroidism and one of his requests was a copy of that report, written in 1786.  I won’t go into any more details on the prisoner’s case, but I started researching Parry and found him to be fascinating.

At 18, Parry began his medical studies in Edinburgh, then moved to London for two years to study with a physician and finally returned to Edinburgh to graduate with an M.D.  He wrote his dissertation on rabies: Tentamen medicum inaugurale, de rabie contagiosa, vulgo canina, Edinburgh, 1778, and we have a copy in the Library’s Rare Book & Special Collections Reading Room.  He later wrote in depth on tetanus and rabies in a book published in 1814 and dedicated to Jenner: Cases of tetanus; and rabies contagiosa, or canine hydrophobia; with remarks, chiefly intended to ascertain the characteristic symptoms of the latter disease in man and certain brutes, and to point out the most effectual means of prevention, (also in the Rare Book Room).

Dr. Parry settled in Bath, the famous health resort, and married Sarah Rigby, with whom he had nine children.  One son was the English rear admiral and Arctic explorer, Sir William Edward Parry (1790-1855), who made expeditions in search of a Northwest Passage.  He’s yet another interesting character to explore, and we have an 1816 astronomy book written by him:  Nautical Astronomy by Night.

Cases of tetanus, and rabies contagiosa, or canine hydrophobia by Caleb Hillier Parry, 1814.

Over the years in his medical practice, Parry made detailed notes on all of his cases (as well as detailed autopsy notes), which he intended to publish in a comprehensive work, Elements of pathology and therapeutics; being the outlines of a work, intended to ascertain the nature, causes, and most efficacious modes of prevention and cure, of the greater number of the diseases incidental to the human frame; illustrated by numerous cases and dissections.  However, he only completed the first volume, General Pathology, which was published in 1815.  This is the book where I searched for the report on hyperthyroidism.  The book was extremely difficult to use, as it had no table of contents and no index.  There were 463 pages with 1,023 entries—observations, results of experiments, and cases, and I wasn’t able to locate what I needed.  Thumbing through, I read on page four in the section on the sanguiferous (circulatory) system, his conclusion: “of all the deviations from health incidental to the animal frame, the most obvious is a disordered state of the whole, or some part, of the Sanguiferous System.”   He did many experiments on animals on the arterial pulse, determining that it was generated by contractions of the left ventricle.  In 1816, an article on this was published:  An Experimental Inquiry into the Nature, Cause and Varieties of the Arterial Pulse. You can read about these experiments, courtesy of the National Library of Medicine at

Parry was the first to make the connection between angina and coronary heart disease.  He remarked in his case notes that angina most often occurred in obese males over 50 and his autopsies showed calcification in the coronary arteries. He read his paper on the topic before the Gloucester Medical Society in 1788 and it was published in 1799 as:  Inquiry into the Symptoms and Causes of the Syncope Anginosa, Called Angina Pectoris, illustrated by Dissections.  This is recognized as his major contribution to medicine, although it was ignored for more than a hundred years. A full text scan of the original reprinted in the Annals of Medicine 1800 is available from the National Library of Medicine.  Parry suggested that to prevent coronary artery disease, his patients should eat and drink in moderation (avoiding “flesh meats”) and exercise, but he doubted his advice would be heeded.

It turned out, however, that the report I sought is actually in a book that was the continuation of the description of his cases finalized by another son, Charles Henry Parry, who also became a doctor. He produced Collections from the unpublished medical writings of the late Caleb Hillier Parry, published in 1825. The Library of Congress does not have this book, but it is available through the Hathi Trust.  These notes described the first recorded cases of congenital idiopathic dilation of the colon (Hirschprung’s disease) and facial hemiatrophy (Parry-Romberg syndrome), as well as a 1786 description of exophthalmic goiter (Graves’ disease—the most common cause of hyperthyroidism)—at last!

In all, Parry described eight cases of hyperthyroidism.  The first was of a woman aged 37 who came to him complaining of palpitations and some breathing problems. Three months after she delivered a child, she developed a mass on the right side of her neck that grew to cover both sides of the neck and her eyes protruded from their sockets.  He assumed she had died when she stopped coming to him. With these descriptions, Parry is considered by many, including the famous physician William Osler, to be the first to describe hyperthyroidism.  Osler said Graves’ disease should be called Parry’s disease, since he described it before Flajani (1802) and Graves, who published in 1835.  However, according to a chapter in the book Thyroid Disorders (S. Imam and S. Ahmad, eds., Springer 2016), the first written description goes way back to Egypt, 1550 B.C.!  This chapter bears the title, “Autoimmune Thyroid Disease (Flajani-Parry-Graves-von Basedow Disease): Etiopathogenesis, Clinical Manifestations and Diagnosis. Another source listed the disease with nine names!  It’s probably a good thing that we just call it Graves’ disease.

Caleb Parry had many interests beyond his medical practice.  He was a geologist, had a collection of 20,000 fossils, and was a member of the Society of Natural History of Gottingen.  He was also a breeder of merino sheep and experimented to produce a better quality of wool, which led to his election as vice-president of the Merino Society of London.

Now when you feel your pulse or pains in your chest, suffer from hyperthyroidism, have to get a tetanus shot or have the misfortune of getting rabies vaccine, think of the amazing Dr. Caleb Parry.

Note: In the original post I inadvertently left out that this was a guest post.

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