The dissections on which the following account of the structure of the cerebral hemisphere is founded, have been described in detail in a communication to the Royal Society. The results will be here given, without regard to the order in which they are reached, and with a view simply to clearness and comprehensibility.

Might it not be possible greatly to extend our knowledge of the effects of medicines in insanity by treating similar classes of cases in all asylums in a similar way for a certain time? Might we not in this way arrive at a much greater degree of scientific accuracy in our treatment of certain forms of insanity than we are able to practise at present?

In the present paper I do not intend to deal with those graver affections, such as apoplexy or paralysis, which frequently occur in the aged, and which depend on gross lesions of tissue. Nor shall I mention the severe and intractable neuralgias of advanced life. I desire to direct attention to a class of neuroses, which more or less inevitably attend the decline of life, and which, though they do not involve any serious catastrophe, are the cause of so much suffering that it is surprising that they should have received little or no systematic notice from medical writers. The neglect of these complaints is not merely a negative evil; for, owing to the fact that their neurotic nature is ignored, certain superficial symptoms which they present are treated as if they depended on functional disturbance of the liver, or ordinary stomach catarrh, &c., and very often with depressing remedies, which greatly aggravate the existing evil.

The cases that I propose to relate belong to a group either entirely overlooked or rarely met with until lately, and, doubtless, confounded with other forms of infantile paralysis. Having through the kindness of Mr. William Adams had the opportunity of seeing an example of the affection in the Royal Orthopædic Hospital, I was enabled to recognise the nature of the two first of these cases when called to see them in October last. I may observe that in a practice of upwards of thirty years, including during several years the charge of a large parochial infirmary for children, I had never recognised the disease. The association of mental imbecility with muscular paralysis, which is peculiar in these cases, has induced me to bring them under the notice of the members of this Association. In order to complete their history and to endeavour to render them the more worthy of your attention, I have embodied in my remarks the principal points that I have been able to gather from the study of M. Duchenne's pamphlet.∗

Reviewing a large number of cases of idiocy and imbecility which have come under my observation, I am able to call prominently to mind three cases in which apparent hypertrophy of muscle, combined with motor paralysis, was present. As these occurred to me before Dr. Duchenne, of Bologne, had pointed out their significance, I did not take steps to verify their condition. So marked, however, was the apparent muscular development, that the muscular feebleness puzzled me much. Faradization was tried in one case without any good result.

In publishing the following cases, recently under my charge, of mental derangement dependent upon atheromatous deposit in the coats of the larger cerebral arteries, without any apparent disease of the brain substance, I desire, if possible, to define the symptoms of that condition during life, so as to enable them to be distinguished from those of general paralysis, with which I believe them often to be confused.