The Pineal Gland

Abstract

Although the pineal gland (epiphysis cerebri) has been noted in medical writings for at least 2,000 years its possible physiological role remains unresolved. Early Greek anatomists, including Herophilus and his disciples, believed that the cerebral ventricles were the seat of the mind and that the pineal body or conarium had a sphincteric function to regulate the flow of thought. This concept was refuted by Galen who concluded that the pineal was probably a gland, similar to the lymph glands. Belief in a thought sphincter persisted and Galen ascribed this function to the cerebellar vermis.

In the seventeenth century Descartes established the idea that this organ was the seat of the soul. It is an awe-inspiring reflection of the power of Cartesian authority that, three centuries later, this is still the first association in the minds of many when the pineal gland is mentioned. His opinions were not accepted by everyone. Thomas Gibson, for example, in his descriptions of the anatomy of the brain in 1763 returned to the genital analogies of the early anatomists with respect to the pineal body.

“The first is Glandula pinealis, or Penis; because it representeth the Pine-nut, or a Man’s Yard. It is seated in the beginning of that Pipe, by which the third and fourth Ventricles are united . . . This Gland des Cartes thinks to be the primary seat of the Soul, and that all animal operations draw their origine from it. But Bartholin has sufficiently confuted that opinion; for it seems to be but of the same use as other glands, and particularly the GlanduIa pituitaria placed near to it, viz. to separate the Lympha from the Arterial blood; which Lympha is resorbed by the Veins . . . Near to this on both sides of this third ventricle four round bodies appear. The two upper are lesser and are called Testes: the two greater are lower, and are called Nates. The chink between the Nates is called Anus” .