C. These effects arise sometimes also from a moral shock, such as the sudden communication of afflicting news-terror-detection in crime, or any other analogous cause, equally or indifferently whether the cause be moral or physical-the brain is either entirely spoiled, temporarily deranged, only slightly injured, or in gradation from one to the other-losing one or more of its functions, and one or more portions of acquired knowledge.

D. After such effects have lasted a considerable time, and have or have not been accompanied or followed by any of the usual forms of mental aberration, or of imbecility, the whole powers of the brain may be restored. either gradually or in an instant-the watch may resume its motion.

All these facts are so familiar to medical men, that for them it is unnecessary to cite cases; and other readers. would find them tedious and difficult to understand; but if any one wish to examine for himself, he will meet with many such recorded in every work on insanity.

1. If then my doctrine of the entire completeness and sufficiency of each brain as an instrument of mind be firmly established, it follows, so plausibly as to be almost certain, that any of the states, A, B, C, and D, and many intermediate modifications of them, may spontaneously occur in one brain, leaving the other entirely unaffected; we see an example of this in hemiplegia, or paralysis on one side only.

2. One brain may be subjected to one of these changes, and the other brain may have its powers and functions changed or modified in a different manner.

3. One brain may be reduced to the state of childhood (state A), and the other remain in its ordinary state.

4. One brain may be in the state A or B, and the other may have its functions suspended or modified by a greater or less degree of torpor, as in sleep, catalepsy, ecstasis, etc.

5. One brain may be in the state of childhood, and the other torpid and unconscious.

Now, any of the states here described, or any modification of one or more of them may co-exist, or they may alternate. We see phenomena more or less analogous in intermittent insanity, where definite periods of excitement, collapse, and mental health follow in uninterrupted succession; the examples are numerous.

Suppose the lady whose case is spoken of as the second form of the malady of alternate consciousness, to be placed in the state No. 5 (a modification of that described under letter A). The only brain she now has at her command, is the brain in the child state; and, while the other remains in its torpor and quasi extinct, she must pursue her education as a child.

Let us next suppose the child brain to be in its turn seized with torpor, and the other to resume its functions with the use of all its previously acquired knowledge. Here, then, is the second state of the patient satisfactorily explained.

Strange and arbitrary as this hypothesis may seem, it is not difficult to shew that any one of the separate states here described as existing in one brain, or in portions of one brain, may exist in the whole brain (in the sense the word is generally used). Such phenomena are established by abundant evidence as consequences of blows on the head, moral shocks, disorder, or positive disease.

If then the status can exist in both brains, whether the derangement of functions depend on vibration, undulation, or circulation, or any other cause, it is a very natural presumption that the same status may exist in one only of the cerebra, in one only of the two entire and perfect instruments of MIND, which would at once solve the difficulty.

The wonderful powers of the microscope in its present state of perfection shew that the ultimate structure of a nerve or nervous fibre, is a tube; that these nervous fibres contain a fluid, and it is asserted that it is to be seen in a state of congelation as well as in a state of fluidity; that this fluid circulates during life, and coagulates some time after death. How exceedingly minute are these nervous fibres or tubes can scarcely be conceived by the mind, although their diameter can be measured by the microscope as accurately as we can measure the threads in a piece of cloth. On the authority of Erasmus Wilson, I state the average size of the nervous fibres (which vary from fourteen to seven thousand according to their position) to be about ten thousand to the inch, which gives to a column of an inch square the amazing number of one hundred millions; and there are many square inches in the two brains.

We may conceive, then, that parts of the brain are in too active circulation or action, others too passive, modifications in the nervous fluid, spasm of certain portions, and other states for which we have no names; the mind in all its varieties may then be produced by the action of these fibres singly, or in determinate fasciculi, or in myriads of combinations, correct or erroneous, which so wonderful a structure may admit. Out of these combinations, the states I have endeavoured to explain may easily be accounted for in health, as well as all the phenomena of insanity.

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CHAPTER XXVIII.

REV. J. BARLOW ON THE CONNEXION BETWEEN PHYSIOLOGY AND INTELLECTUAL PHILOSOPHY.-STATE OF THE BRAIN WHEM ITS HIGHER FACULTIES ARE NOT CALLED INTO ACTION. REASON WHY THERE SHOULD BE TWO ORGANS OF THOUGHT.-MR. HEWITT WATSON'S ESSAY ON THE USE OF THE DOUBLE BRAIN.

THE neccessity of assiduously enltivating the higher faculties of the mind, as a means of establishing selfcontrol when the brain is in perfect health, and of enabling the healthy brain to exercise a pure tyranny over its brother when the latter is disordered or enfeebled, is the great duty of man-a duty he cannot neglect, without injury to his interests even in this world. It is this which makes the grand distinction between the civilized man and the savage, between the man of education and of virtue over the worse than

savage of society - the ferocious unprincipled brute who gives way to his immediate animal instincts, like the beasts that perish; while the other "makes the past, the distant and the future, predominate over the present."

The Rev. Mr. Barlow, in his little book on the "Connection between Physiology and Intellectual Philosophy," has stated this admirably. In his 31st section he remarks: "Every bodily fibre acquires strength by exercise. None need be told now much muscular power is acquired by a constant and moderate exertion. The practised eye will see, the practised ear will hear, what