Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

degree, modify or disturb the due exercise of the offices of the brain and nerves; and it is very difficult often, and sometimes it is impossible, to determine whether, and how far, the disturb- ance is primary or secondary. But let us now attend to our creed : — First. The nervous centres consist of the cerebrum and cere- bellum, the medulla oblongata, and the medulla spinalis, while the ganglia are the centres of the great sympathetic system of nerves. The " nervous system " is thus made up of those masses of nervous matter called nervous centres, and of all the nerves of the organism therewith connected, " as a means to an end," upon which we are utterly depending in every department of our organism and being. (See pp. 222, 264.) Second. I include the cerebral hemispheres, together with the lobes of the cerebellum, under the common term, the brain. So shall I speak of the medulla oblongata and the spinal marrow in the single phrase, the spinal cord, or as the cranei-spinal axis, their endowments appearing to differ more in relation and degree than in kind. The office of all their proper functions may be included in three words — sensation, thought, motion. I am inclined to the belief that the gray portions of the ner- vous centres (which are much the more vascular) form the part in which their own peculiar powers reside, or are generated ; and that their white or fibrous portions are like the white and fibrous nerves, being merely proper conductors of the nervous influence. I incline, also, to the opinion that the influence which originates in the gray nerve matter, and is transmitted by the white, is analogous, but not identical, with some modifications of elec- tricity. We already know that some of the effects of this influ- ence may be very exactly imitated, by means of galvanism, in animals very recently dead ; that is, while there is yet a spark of vitality left to modify or cooperate with it, but never after. Third. I believe that the faculties of sensation, of thought, and of the dominion of the will, ■— i. e., volition, and the power of originating motion, — belong to the brain ; in all probability, to the cerebrum alone. The precise office of the cerebellum is still involved in obscurity and dispute.