both in structure and capacity."[20]

One of the most noted writers on the subject, after stating that a number of scientific men had spent thirty years in measuring and weighing the heads of idiots, sums up their conclusions as follows:—

1st. There is no constant relation between the development of the cranium and the degree of intelligence.

2nd. The dimensions of the anterior part of the cranium, and especially of the forehead, are, at least, as great among idiots as others.[21]

3rd. Three-fifths of idiots have larger heads than men of ordinary intelligence.

4th. There is no constant relation between the degree of intelligence and the weight of the brain.[22]

5th. Sometimes the brain of idiots presents no deviation in form, colour, and density from the normal standard; it is, in fact, perfectly normal.

After such a statement as this, I can readily imagine that some of you may say, it seems to us that you doctors really know but little about the genesis of idiocy. I am afraid this is, to some extent, true. We are only on the threshold of inquiry, and science of to-day is unable to bridge over the gulf that separates matter from mind.

Modern investigation, however, does not quite bear out the above sweeping statements in their integrity, although the most conflicting theories have been enunciated. Doubtless, attention has been too much concentrated on the gross morphology of the brain, without taking into account microscopical appearances. Dr. Shuttleworth, in giving the result of his long experience at the Royal Albert Asylum says, "We have occasionally found, when least expected, extraordinary defects in brain conformation;... microscopic examination will discover in many instances some abnormality of structure, such as the preponderance of simply formed braincells devoid of processes, denoting persistence of fœtal structures; or, on the other hand, degenerative changes resulting from inflammatory atrophy."[23]

Professor Luys, of Paris,[24] gives the result of the examination of the brain of 14 idiots, the anomalies observed being want of symmetry in the frontal lobes, and partial atrophy of the cortical folds especially of the frontal convolutions.[25]

Quite recently, Dr. Andriessen, at a meeting of the Leeds and West Riding Medico-Chirurgical Society, exhibited specimens of the brains of epileptic idiots, which showed conditions of microgyria with atrophy and sclerosis of the convolutions.

In considering the pathology of idiocy, I think sufficient attention has not been given to the chemical constitution of the cerebral substance. The most extravagant notions were at one time prevalent as to the rôle played by phosphorus in the animal economy; the Dutch naturalist, Moleschott, maintaining that "without phosphorus there was no thought." A celebrated chemist, Couerbe, also considered phosphorus to be the exciting principle of the brain, and according to him, the brain of ordinary men contained 2½ per cent. of phosphorus, that of the idiot 1½, and that of the madman 4 to 4½; from these data he concluded, "that the absence of phosphorus in the brain reduced man to the condition of the brute; that a great excess of this element irritated the nervous system and plunged the individual into the frightful delirium which we call madness; and that a medium proportion re-established the equilibrium and produced the admirable harmony which is none else than the soul of the spiritualists."[26] Professor Janet, in criticising the above theory, remarks that the brain of fishes, who do not pass for great thinkers, contains a large amount of phosphorus, also that the statistics of M. Lassaigne have shown that the brain of madmen does not contain more phosphorus than that of sane individuals.[27]

The late Bishop of Carlisle, in rebutting this phosphorus theory, remarks, "Why should we not go further and assert that there could be no thought without carbon or without any other element of which the human body is composed; for you can have no actual thought without a living creature, and no living creature without a body, and no body without carbon."[28]

I have treated the subject of the Chemistry of the Brain at considerable length in my treatise on "Aphasia and the Localisation of Articulate Language," to which book I would refer those who desire further information in reference to the connection between the amount of phosphorus and intellectual vigour.

MATTER AND MIND.

"Quare frustra sudaverit, qui cœlestia religionis arcana nostræ rationi adaptare conabitur." Bacon, "De Augmentis Scientiarum."

I have already stated that the study of idiocy was of great interest to the theologian, for I can imagine no more powerful weapon for combating the materialistic tendencies of the day than is furnished by a consideration of the natural history of the idiot. This is neither the time nor the place for me to enter into the question of the mysterious connection between matter and mind, a subject which I have developed at some length in my published works.[29] In my various public appeals on behalf of the Asylum for Idiots, I have also usually taken the opportunity of pointing out how the experience afforded by the study of idiocy is utterly opposed to the extravagant dogmas of the materialistic school, and to the crude notions which pseudo-science has engendered; and I have also shown how the results of idiot training furnish a forcible demonstration of the dualistic theory of mind and matter, upon which science reposed till the times of Spinosa, Laplace, Haeckel, Huxley, and others.