It is now several years since I first proposed the operation of trephining the skull in general paralysis of the insane, at about the same time that Dr. Batty Tuke independently operated for the same disease. Others have also performed similar operations, but the results have not been publicly recorded or collected. Sufficient time has not elapsed, nor have the cases been sufficiently numerous to determine the future of the operation, whether it is of sufficient service to justify its frequent employment or whether it must be dismissed to the limbo of useless remedies. I have published cases where considerable temporary improvement has resulted, where life has been prolonged, and distressing symptoms alleviated, and I propose to give to the Association the short details of a hitherto unpublished case where no candid critic could, I think, deny the improvement that I claim for him. This much may be said for the operation—that it seems harmless when carefully performed, no fatal result having, as far as I am aware, ever resulted. The apprehended after-results, as regards local tenderness, liability to injury at the trephined spot, bulging of the contents of the cranium, are phantoms which have no basis of fact. I fear, indeed, that we have not been bold enough in our measures. Mr. Harrison Cripps, who performed the earlier operations for me, recommends the removal of a much greater extent of bone, of a piece indeed about three inches square, and he would do it on both sides of the skull. Of the after results of removing so large a piece of bone I should have no more fear than I have of the present comparatively small area; the great objection I have to the removal of so much bone is the long time required for the operation. Another point is with reference to the time chosen for the operation. I think it should be done earlier, it seems hopeless to do it in the later stages, after there is much thickening of the membranes and destruction of tissue—as far, at least, as any hope of cure is expected, anything, indeed, beyond relief.