Francis Glisson was an English physician who is known for, among other things, his medical work with infantile rickets, the liver and the mechanics of muscle contraction.
While the details of Glisson's childhood and upbringing are cloaked in obscurity, what is known is that he was born in 1597 in Rampisham, located in southwest England; he graduated with a Bachelors of Arts from the University of Cambridge in 1621 and obtained a Master of Arts in 1624. He was lecturer of Greek from 1625-1626 and he became a physician in 1634; that same year he was a candidate of the Royal College of Physicians of London. He was named regius professor of physics at Cambridge University in 1636 and he held this position until his death. In 1639 he was named anatomy reader at Cambridge University.
Glisson became involved with a group of physicians and scientists who began to meet on a regular basis in 1645. Out of this group, which became known as the Invisible College, emerged the Royal Society. It was while associated with this organization that Glisson, along with G. Bate and A. Regemorter, was appointed the task of writing a book on the disease rickets; this condition was becoming a noticeable affliction in England at the time. Glisson made such an impression on his collaborators that he became the primary contributor to the project. This work became one of the first books in English on a medical subject.
Titled Tractatus de rachitide, the document was concerned with the description and anatomy of the disease rickets which is a softening of the bones; Glisson wrote at that time that the condition was due primarily to a deficiency of nutrition. The bones become brittle and soft and deformities of the bones often result. Something else significant about this book, and other of Glisson's work, is that in them he tried to clearly lay out his empirical findings and arrange in them in a academic manner as well as argue his position and defend any questions or problems with his position. This manner of conveying scientific information in published form was to be a model for years to come.
Glisson's second book, Anatomie hepatitis, was concerned with the anatomy of the liver and in it he was the first to describe the layer of connective tissue that covers the liver now known as Glisson's Capsule. This book was chiefly the result of lectures he had made on the subject of the liver in 1640; the book was published in 1654.
It was in this same book that Glisson advanced a new and groundbreaking concept which he called irritability. Simply put, this idea was concerned with the stimulation of muscle and this phenomenon was independent of any external stimulus. Up to this point, the nervous system was poorly understood and muscle contraction had been explained in different ways. One prevailing idea was that on contraction the muscle was inflated much like a balloon only instead of air there was an unexplained "spirit" that inflated the muscle that emanated from the brain and spinal column.
Glisson's concept was more in line with a nervous stimulation, or irritability as he called it. He theorized that nerve signals were sent from the brain by way of a contraction which caused a vibration in the nerve that subsequently caused the "irritability" in the muscle resulting in contraction. It was later that the concept proposed by Glisson was carried on further to explain muscle contraction and the operation of the nervous system.
MICHAEL T. YANCEY