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orders the predominant part is played by mental causes has been steadily growing during the forty years which have elapsed since the work of Charcot, and has been very greatly strengthened by the experience given to us by the war. The war has brought into being a large number of cases of nervous disorder which have been grouped together under the misleading name of "shell shock." These cases are in every essential respect identical with the hysteria, neurasthenia, nervous breakdowns and so forth with which we have always been familiar, only differing from the latter in the colouring due to the particular circumstances of their origin. But the war has produced them in such numbers that in every country attention has been forced upon the problems of their causation and treatment, and the result of that attention has been a rapidly increasing consensus of opinion that the chief factors both in causation and treatment are of the mental order.
Now, if this is so, what are these mental causes that are responsible for the affections we are now considering? The popular idea is that they are worries, anxieties and emotional shocks, and this popular idea is true enough in the main, but it requires precision. The mind of the nervous patient differs in certain important respects from the mind of the healthy man, and we require to know exactly in what this difference consists.
Consider for a moment how we may conceive the ideal normal mind. It would constitute an harmonious whole, with all its constituent parts fitting perfectly one into the other, and all its forces pulling
