# American Medical Biographies/Jackson, John Barnard Swett

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​Jackson, John Barnard Swett (1806–1879)
The medical career of this pioneer pathologist is of especial interest, as he studied in Paris at a time when modern medicine was just making its entry into the scientific world. The old theories of humors was giving place to the exact description of disease, based on pathologic anatomy, while by physical examination men were attempting to define, during life, the abnormal condition which was the cause of the disease under investigation. Jackson returned to Boston in 1831 and from the first devoted himself to pathology. His general practice was always limited and after 1850 he seldom saw patients except in consultation. His life was spent in the pathologic laboratory and the medical museum of the Harvard Medical School. His chief interest lay in the close study and exact description of the gross pathologic anatomy of diseased organs, not in the microscopic study of disease. The modern microscope was unknown to him, and he died before bacteriology made known to the world the etiology of most acute and many chronic diseases.
Dr. Jackson was born in Boston, June 5, 1806, being the fourth and youngest child of Henry and Hannah Swett Jackson. He was the grandson of Jonathan Jackson of Newburyport, Massachusetts, "an honored member of the Continental Congress who held several offices under Washington," of whom a contemporary wrote, "He was the beau ideal of a gentleman who retained the supremacy among that galaxy of worthies which formed the intellectual and social life of Newburyport." His uncle, James Jackson (q. v.), the noted physician, had great influence over his life in a social, personal and medical way, as his father, a sea captain, died the year of his birth.
John was educated at private schools, entered Harvard College in 1821 and was graduated in 1825, among his classmates being Charles Francis Adams, Admiral Davis, the Rev. Dr. Hedge, S. K. Lothrop and the librarian, John Langdon Sibley. Dr. Jackson went abroad in 1829 in a sailing vessel, reaching Havre after a tempestuous voyage of fifty-six days. At first he devoted himself to surgery, studying with Dupuytren, Roux and Lisfranc. After a winter in Paris he spent some time in Edinburgh, where he studied with Mr. Syme. In London he first turned his attention especially to medicine and pathology, working under Bright, Addison and Hodgkin. He sailed for home June 4, 1831, as surgeon of a packet of 350 tons, reaching New ​York after a stormy passage of forty-four days.
In 1853 he married Emily Jane Andrews, and had two sons, Henry and Robert Tracy. His freedom from the daily care of private practise afforded him much opportunity for association with his family and for journeys to Europe that gave him much pleasure and were of much value to his children. He was professor of pathologic anatomy from 1847 to 1854 and Shattuck professor of morbid anatomy from 1854 to 1879, the latter chair being endowed by Dr. Shattuck as a proof of his personal regard and esteem and for the medical ability of Dr. Jackson. He was a member of the local medical societies and was especially prominent as a member of the Medical Improvement Society.
All his writings of import are on questions of pathology, and include many articles, published largely in medical journals. His most valuable contribution to the medical profession is "The Warren Anatomical Museum" (1870), not, as its title might suggest, simply a catalogue, but a storehouse of the results of many of Dr. Jackson's studies in morbid anatomy.
In 1851 he made an extensive trip to Europe, especially with the object of studying the museums and meeting again his fellow medical students, many of whom had won important positions in the medical world. Aside from his medical studies he was always deeply interested in natural history, and especially in the anatomy of the lower animals as well as in their diseases. He was probably the first medical man in Boston to turn his attention to the study of the diseases of the lower animals.
He died Jan. 6, 1879, of pneumonia. Though never robust, he worked hard to the end of his life and was in his beloved laboratory the day his last illness seized upon him.
A biographical notice of Dr. Jackson by his life-long friend and kinsman, Dr. Oliver Wendell Holmes, was published Jan. 9, 1879, in the Boston Medical and Surgical Journal. In this notice Dr. Holmes says, "He was not a microscopist. What he knew he knew thoroughly, but he never pretended to have the slightest knowledge beyond what his honest, naked eyes could teach him," and later, "His look penetrated like an exploring needle, and many a tympanitic fancy of careless observers has collapsed under its searching scrutiny."