Galen's Humours
Galen's view of human anatomy became the framework for all further consideration of the body and its brain for the next 1500 years. Investigative inquiry into the anatomy didn't begin until Nicholas Copernicus challenged the prevailing Church backed view of the world as the centre of the universe by showing that the earth and the planets moved around the sun; and William Harvey demonstrated that the blood was pumped in circulation around the body. But the concept of "pneuma" still held sway in any discussion of the brain. Rene Descartes wrote, in the mid 17th century, in reference to the ventricles:
"The cavities of the brain are central reservoirs...animal spirits enter these cavities. They pass into the pores of its substance and from these pores into the nerves. The nerves may be compared to the tubes of a waterworks; breathing or other actions depend on the flow of animal spirits into the nerves. The rational soul (the pineal) takes place of the engineer, living in that part of the reservoir that connects all of the various tubes. These spirits are like the wind. When they flow into a muscle they cause it to become stiff and harden, just as air in a balloon makes it hard." [Bergland, p61]
Robert Burton in The Anatomy of Melancholy (first published in London in 1652) represents the "humours" view based on Galen. His book is possibly the first major treatise on a psychological problem, namely depression, ever published. In it Burton summarises the state of physiology with discussion of the humours.
 Title page from Robert Burton's The Anatomy of Melancholy, 1651. |
The four humors were:"blood
[sanguine] a hot, sweet,
temperate humour whose office is to nourish the
whole body, to give it strength and colour. |
He then goes on to describe the brain as a device for distilling the animal spirits:
"...the brain...is a soft, marrowish, and white substance, engendered of the purest part of seeds and spirits, included by many skins, and seated within the skull or brain pan; and it is the most noble organ under heaven, the dwelling-house and seat of the soul, the habitation of wisdom, memory, judgement, reason and in which man is most like unto God; and therefore nature hath covered it with a skull of hard bone, and two skins or membranes, whereof the one is called dura mater, or meninx, the other pia mater. The dura mater is next to the skull, above the other, which includes and protects the brain. When this is taken away, the pia mater is to be seen, a thin membrane, the next and immediate cover of the brain, and not covering only, but entering into it.
The brain itself is divided into two parts, the fore and hinder part; the fore part is much bigger than the other, which is called the little brain in respect of it. This fore part hath many concavities distinguished by certain ventricles, which are the receptacles of the spirits, brought hither by the arteries of the heart, and are there refined to a more heavenly nature, to perform the actions of the soul. Of these ventricles there are three - right, left, and middle. The right and left answer to their site and beget animal spirits; if they be in any way hurt, sense and motion ceaseth. These ventricles, moreover, are held to be the seat of the common sense. The middle ventricle is a common concourse and cavity of them both, and hath two passages - the one to receive pituita, and the other extends itself to the fourth creek; in this they place imagination and cogitation, and so the three ventricles of the fore part of the brain are used. The fourth creek behind the head is common to the cerebral or little brain, and marrow of the back bone, the last and most solid of all the rest, which receives the animal spirits from the other ventricles, and conveys them to the marrow in the back, and is the place where they say the memory is seated." [Burton, p97]
And so in referring to the cause of disease and paricularly mental dis-ease he says:
"...as the body works upon the mind by his bad humours, troubling the spirits, sending gross fumes into the brain, and so per consequens the faculties of it, with fear, sorrow, &c., which are ordinary symptoms of this disease [melancholy]: so on the other side, the mind most effectualy works upon the body, producing by his passions and perturbations miraculous alterations, as melancholy, despair, cruel diseases, and sometimes death itself." [Burton, p164]
To revue Burton: The rational soul was seated in the brain, and received sensations and controlled movement via the action of the fluid 'animal spirit'.