Page:Popular Science Monthly Volume 46.djvu/167

Rh liver; that one process illustrates just as forcibly the influence of a mysterious force or power as the other.

The product of the liver, the bile, will vary according to the size, quality, and condition of the organ and the forces acting upon it; and the same is true regarding the functional product of the brain, the mind. Without liver there is no bile, and without brain there is no mind. At least the physician only investigates mind, which is a functional product of brain. The analogy, however, between brain and liver does not hold throughout, because after birth, and from that period to maturity, and indeed while



life lasts, the brain is ordinarily exposed to impressions made by an ever-changing environment, while the environment of the liver remains practically uniform.

It may be conducive to a clear understanding of the medical view of mind, and therefore of responsibility, to examine objectively the organ itself, and briefly the manner in which its functions are studied by the physician. I need hardly remind you that the brain is a double organ, and therefore only one half of it need be shown.

Figs. 1 and 2 are exact representations of the outer and mesial surfaces of the human brain.