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

so also if a tumor is in its substance. It is by compression, probably, that congestion paralyzes ; but this latter cannot often be regarded as a true paralyzing lesion. " I would say here, that the centre of volition (the seat of the will) is of very great extent; for we know it reaches from the corpora striata in the brain, down the entire length of the ante- rior horns of the gray matter of the spinal cord, and includes the locus niger in the cms cerebri, as also much of the vesicular matter of the mesocephale and of the medulla oblongata. Dis- ease of or accident to any part of this nerve centre is capable of producing paralysis of voluntary motion ; but as the intra-crani- al portion of it exercises by far the greatest and most extended influence in the production of voluntary movements, so disease of this portion of nervous centre gives rise to the most extended and complete paralysis. " Another fact, to be borne in mind, which anatomy demon- strates and pathological research confirms, is, that the centre of volition for either side of the body is not altogether on the same side of the body. Of the nerve centre for the left side of the body, for instance, the intra-cranial portion is on the right side, while the intra-spinal portion is on the left side; and these two portions are brought into connection with each other through certain oblique fibres from the anterior pyramidal columns of the medulla oblongata which cross from right to left, decussating with similar fibres proceeding from left to right, and which be- long to the centre of volition for the right side of the body." Thus much is demonstrated. While studying and treating the diseases of the nervous sys- tem, we shall do well to keep definitely before our minds the sev- eral leading propositions of recent systematic writers. We know that Dr. Marshall Hall lays down the hypothesis of an " excito- motory system of nerves" and of a true spinal cord; that is, as the centre of all physical nervous action. The various muscles and sentient surfaces of the body are, according to him, con- nected with the brain directly by nerve fibres which pass com- pletely from one to the other. Those fibres destined for, or proceeding from, the trunk to the brain, pass along the spinal