* This paper is an expansion of an address read before the Med. Psych. Assoc. during the Presidency of Dr. Needham. I have not always kept to the style of speaking before an audience. I have divided the matter into Sections. Anyone who has read Herbert Spencer's works will find that I have borrowed largely from them. There is nothing in this article which I can imagine to be of any value which has not been inspired by him. I should, however, be sorry if any crudities of mine were imputed to Mr. Spencer. I strongly urge all neurologists to study his works, and also Fiske's very valuable book, “Cosmic Philosophy.” Google Scholar

* Herbert Spencer says: “The doctrine of evolution under its purely scientific form does not involve materialism, though its opponents persistently represent it as doing so.” He speaks of the materialistic hypothesis as being “utterly futile.” He frequently insists on the absolute difference between states of consciousness and nervous states. Here is a most explicit declaration. After a consideration of increasing complication of mental states and nervous states, he writes (“Psychology,” Vol. i., p. 403): “Of course, I do not mean that material actions thus become mental actions. As was said in Sections 41–51, 62, 63: ‘No effort enables us to assimilate’ mind and motion. I am merely showing a parallelism” (italics in original) “between a certain physical evolution and the correlative psychical evolution.”.Google Scholar

* Of coarse we cannot say that such super-positive phenomena as foot-clonus, passage of fæces, etc., after epileptic fits, are paralytic; but they signify exhaustion of “controlling” nervous elements are indirect evidences of paralysis (or of exhaustion of efferent nerves).Google Scholar

* “Phil. Trans.,” Vol. clxxviii. (1887), B. pp. 153–167, and Vol. clxxix., 1888.Google Scholar

* This is a complex illustration, but one worth giving as part of the evidence towards showing a series of inhibitions in the central nervous system. The nervi erigentes inhibit the arteries of the penis. But the part of the visceral column (Stilling's sacral nucleus) from which these nerves come is itself inhibited so that the penis is ordinarily flaccid. In cases of complete transverse lesion of the lower cervical cord or upper dorsal cord inhibition is subtracted from Stilling's inhibitory nucleus, whereupon it, being “let go,” inhibits the arteries of the penis, they become dilated, and then the organ is turgid.Google Scholar

* By the expression “parts of the body” is here meant all parts other than the Nervous System; they make up the Lowest Level of the whole organism.Google Scholar

† The Lowest Level is cerebro-cerebellar; it is the lowest level of both the cerebral and the cerebellar systems. I ignore the cerebellar system for the most part in this Address, so that by Highest Centres highest centres of the cerebral system are meant.Google Scholar

* It may be said that the vaso-motor centre does not represent a limited region of the body, but the whole arterial system, and therefore that the formula does not apply. It may, however, be that this great centre is a sort of mosaic of minor centres; there seems to be one part of it which especially represents the arterial system of the liver. Moreover, there are minor vaso-motor centres in the spinal cord. In the text I am only considering the Lowest Level passingly. In another article I shall try to show that in the fore part of the Lowest Level there is a rudimentary highest centre; I mean a centre co-ordinating all parts of this lowly evolved level in a simple way. This hypothetical highest centre will be very rudimentary in man. One would suppose that the amphioxus must have such a centre to give some degree of unity to its simple self. Evolution is not, as we state it in the text, an even process, not one to be symbolized by what is called Involution in algebra.Google Scholar

* There is an unfortunate misprint in the latter account. For “volition of the movement” (an expression mixing up the psychical and the physical) read “volition of the moment.” Google Scholar