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

cord; so the cord is, in great part, according to him, no more than a bundle of nerve fibres, going to and from the brain, and these fibrils are specially for sensation and volition. And in addition to these, there is another class of nerve fibrils, ac- cording to Dr. Hall, proper to the spinal cord and its intra- cranial continuation, and which forms a connection with the gray matter of the cord. Of these fibres, some are afferent or " incident," while others are efferent or " reflex ; " and these two kinds of nerves have an immediate, but unknown, relation to each other, so that each afferent has its proper efferent one, the former being the excilor, and the latter the motor. Now, the aggregate of all these fibres, together with the gray matter, says Dr. Hall, constitutes the true spinal cord; which, however, is not limited to the spinal canal, but passes up into the cranium as far as the crura cerebri. Moreover, these excitor and motor fibres are quite independent of those of sensation and volition, and of the sensorium commune, using that term as indicating the centre of intellectual actions, (as put forth by Prochaska.) Although these are bound up with sensitive and motor fibrils, yet they are not directly affected by them; and they maintain their respective course in the nerve trunks as well as in the centres. But this hypothesis of Marshall Hall is not entirely accepted now as complete. Another grand hypothesis, as laid down by Miiller, Whytt, and other leading physiologists of the present day, is, that the nerve fibres of sensation and of volition, individually and imme- diately, proceed to and from some part, or parts, of the intra- cranial nervous mass, and that every nerve fibril in all the organism is precisely by itself continuous into the brain. Those which are distributed to the trunk, or extremities, pass along the spinal cord, and separate from it at the various roots of the nerves, as they leave the spine; and while in their course within the spine they mingle more or less with the vesicular matter of the cord. According to this hypothesis, there are no other nerve fibrils but these, (excepting the commissural,) and they are quite sufficient to manifest all the physical, as well as the mental, acts. Thus the nerves of sen-