h are normally set in action from this
particular region, and movements of the muscles follow in certain
definite parts and directions. This is an indication of the normal
function of the part of the brain which is stimulated.

Besides this method of procedure a new one, also by brain stimulation,
has recently been employed. It consists in stimulating a spot of the
brain as before, but instead of observing the character of the
movement which follows, the observer places galvanometers in
connection with various members of the body and observes in which of
the galvanometers the current comes out of the animal's body (the
galvanometer being a very delicate instrument for indicating the
presence of an electric current). In this way it is determined along
what pathways and to what organs the ordinary vital stimulation passes
from the brain, provided it be granted that the electric current takes
the same course.

3. _Method of Intoxication, called the "Toxic Method._"--The remarks
above may suffice for a description of this method. The results of the
administration of toxic or poisonous agents upon the mind are so
general and serious in their character, as readers of De Quincy know,
that very little precise knowledge has been acquired by their use.

4. _Method of Degeneration._--This consists in observing the progress
of natural or artificially produced disease or damage to the tissues,
mainly the nervous tissues, with a view to discovering the directions
of pathways and the locations of connected functions. The degeneration
or decay following disease or injury follows the path of normal
physiological action, and so discloses it to the observer. This method
is of importance to psychology as affording a means of locating and
following up the course of a brain injury which accompanies this or
that mental disease or defect.

_Results_--_Localization of Brain Functions._--The more detailed
results of this sort of study, when considered on the side of the
nervous organism, may be thrown together under the general head of
Localization. The greatest result of all is just the discovery that
there is such a thing as localization in the nervous system of the
different mental functions of sensation and movement. We find
particular parts of the nervous organism contributing each its share,
in a more or less independent way, to the whole flow of the mental
life; and in cases of injury or removal of this part or that, there
is a corre