A pioneer in the field of microscopic anatomy and pathology, Friedrich Gustav Jacob Henle (1809–1885) made signal contributions to elucidating the structure of both healthy and diseased tissues. His discovery of the ascending and descending loops of the uriniferous tubule is central to understanding renal function, but the "loop of Henle" is just one of many anatomical structures carrying his name. Henle's recognition that all inner and outer surfaces of the body are lined with epithelial tissue has been called "one of the most momentous generalizations of the century" (Robinson, 1921), while his three-volume Handbook of Human Anatomy (1855–1871) is "considered by many authorities to be the greatest of the modern systems of anatomy" (Morton, 1965).
Epidemiologists celebrate Henle for his publication, in 1840, of Von den Miasman und Kontagien (On miasmata and contagia), which set out, more convincingly than previously, the concept that microscopic living organisms (Henle called them contagia animata ) were the causative agents of many diseases, especially those that occurred in epidemic form. Henle argued that in communicable diseases morbid matter apparently increases in amount in the host, but only after a period of incubation, which must correspond to the period of reproduction of the agent. His work drew on the work of Agostino Bassi (1773–1856), who showed that the muscardine of silkworm was attributable to a specific fungus. He also drew on Schwann and Schleiden's discovery that all life had a cellular structure; Schwann and Cagniard-Latour's proof that fermentation by yeast was the work of a live organism; and the evident ability of certain morbid matters, such as vaccinia and variola lymph, to experimentally produce systemic effects in animals even when greatly diluted.
Henle's thinking, which provided a theoretical basis for germ theory, had affinities with earlier writings of Girolamo Fracastoro (1478–1553) and Athanasius Kircher (1601–1680), but was nevertheless resisted for decades. Yet he lived to see his student Robert Koch (1843–1910) demonstrate conclusively the role of specific bacteria in anthrax, tuberculosis, and cholera.
(see also: Epidemics; History of Public Health; Koch, Robert; Theories of Health and Illness )
Morton, L. (1965). Garrison and Morton's Medical Bibliography: An Annotated Check-List of Texts Illustrating the History of Medicine, 2nd edition, revised. London: Andre Deutsch.
HENLE, JACOB (Friedrich Gustav ; 1809–1885), German anatomist and pathologist. Henle, who is considered one of the outstanding histologists of his time, was a member of a well-known family in Bavaria and the grandson of the rabbi of Fuerth. He was baptized at the age of 11 by his parents. He studied medicine at Bonn, and was the outstanding pupil, and later assistant, of Johannes Mueller. He moved with the latter to Berlin, where he was appointed lecturer of anatomy in 1837. From 1840 he served as professor of anatomy and physiology at Zurich, from 1844 at Heidelberg, and from 1852 at Goettingen.
Henle was a great anatomist and one of the founders of modern medicine. The scope of his research work, from his first study of the cornea of the eye (1832) until the final one on the growth of man's nail and the horse's hoof (1884), was astonishing in its variety. His book, Allgemeine Anatomie (1841), was the first in which the study of the cell was presented as a professional branch, thus taking a definite step forward in medicine. While at Zurich, he founded the Zeitschrift fuer rationelle Medizin, in opposition to the obscure romantic medicine of his day.
His anatomical discoveries were numerous and at least a dozen microscopic structures in anatomy were named after him. He summed up his life's work on anatomy in his great book Handbuch der systematischen Anatomie (1855–71). He also made contributions to pathology. His book, Pathologische Untersuchungen (1840) included, among others, a chapter on miasmas and infections, in which he first expressed (long before ways were found to stain and identify microbes) the theory that infectious diseases were caused by specific microorganisms, a contention that was to be proved 40 years later by his pupil Robert Koch.
V. Robinson, Life of Jacob Henle (1921); S.R. Kagan, Jewish Medicine (1952), 147; R.H. Major, A History of Medicine (1954), 797–9.
[Joshua O. Leibowitz]