Page:Popular Science Monthly Volume 46.djvu/741



T is evident to any one who has kept abreast with the recent progress in psychology that the advance in the knowledge of mental processes has been greatly aided of late by contributions from certain collateral branches of science. The older method of introspection had, indeed, resulted in establishing many facts and in formulating numerous laws of psychical action. But this method had many defects, and it must be admitted by any candid observer that the debt which psychology owes to more modern methods of research is a deep and lasting one. To these methods also we owe much of our present knowledge of what may be termed the mechanism of thinking.

It may not be without interest, therefore, to review some of the results which modern studies have reached, especially as such a review will bring before us some entertaining curiosities of thinking.

And, first, we must mention the remarkable discoveries in regard to the localization of brain functions which may be traced to physiological experimentation upon the lower animals. It was long ago determined by Fritsch and Hitzig, Ferrier, Munk, and Beevor and Horsley that in the lower animals certain districts upon the surface of the brain could be laid down, to each of which a definite sensory or motor function could be assigned. Within the past decade it has been absolutely proved by pathologists,