Phrenology is a pseudo-science that relates the mental and temperamental characteristics of an individual to the bumps and hollows of his skull.
The idea originated with the work of Franz Joseph Gall (1758-1828), a German physician, who pointed out, quite correctly, that the gray matter of the brain is the active and essential part and that the white matter is supporting tissue. Gall also thought that the shape of the brain is related to mental capacity and that different parts of the brain are involved with different parts of the body. Many of these ideas proved true, and neurologists map certain parts of the brain. Gall however, also thought that abstract qualities and tendencies, such as pride, courage, greed, firmness, and artistic talent, have specific localizations in the brain, and that is where he erred. He believed that an enlargement of a particular portion of the brain shows that there is an excess of the property associated with that portion and—worst of all—that an enlarged portion of the brain causes a bump in the skull at that place.
Gall's vague suggestions were systematized by his disciple Johann Caspar Spurzheim (1776-1832), who was the real founder of phrenology. The "science" spread rapidly in France, Britain, and the United States and fascinated men and women who were ready to believe that amazing insights into an individual's personality could be gained by fingering the skull. Phrenological heads in ivory and enlarged drawings with portions of the skull marked off and labeled offered laymen the chance to read skulls and were common objects into the early 20th century. Andrew Combe, who published the Phrenological Journal in Edinburgh until his death in 1847, represented phrenology at its height.
In the later decades of the 19th century, increased knowledge about the nervous system and the brain revealed that Gall's original theories were without scientific foundation, and phrenology quickly lost any standing it may have had among scientists. It remained popular for a while as a kind of sideshow attraction, like fortune-telling, and it is now of historical interest only.