deep sleep. For it is merely the minister of foreign affairs, as the ganglion system is the minister of the interior. The brain, with its function of knowing, is only a vedette established by the will for its external ends, which, up in the watch-tower of the head, looks round through the windows of the senses and marks where mischief threatens and where advantages are to be looked for, and in accordance with whose report the will decides. This vedette, like every one engaged on active service, is then in a condition of strain and effort, and therefore it is glad when, after its watch is completed, it is again withdrawn, as every watch gladly retires from its post. This withdrawal is going to sleep, which is therefore so sweet and agreeable, and to which we are so glad to yield; on the other hand, being roused from sleep is unwelcome, because it recalls the vedette suddenly to its post. One generally feels also after the beneficent systole the reappearance of the difficult diastole, the reseparation of the intellect from the will. A so-called soul, which was originally and radically a knowing being, would, on the contrary, necessarily feel on awaking like a fish put back into water. In sleep, when merely the vegetative life is carried on, the will works only according to its original and essential nature, undisturbed from without, with no diminution of its power through the activity of the brain and the exertion of knowing, which is the heaviest organic function, yet for the organism merely a means, not an end; therefore, in sleep the whole power of the will is directed to the maintenance and, where it is necessary, the improvement of the organism. Hence all healing, all favourable crises, take place in sleep; for the vis naturæ mcdicatrix has free play only when it is delivered from the burden of the function of knowledge. The embryo which has still to form the body therefore sleeps continuously, and the new-born child the greater part of its time. In this sense Burdach (Physiologie, vol. iii. p. 484) quite rightly declares sleep to be the original state.
