Hence the story is almost always the same in the history of the insane; for weeks or months before the active indications of insanity appear, the patient has been more than usually anxious about some subject or other, and worried and wakeful, not sleeping more than four or five hours out of the twenty four. The trains of thought have been left too long moving on in certain channels of the brain, some experience has made too profound an impression, and the effects of what we call the will have been unable to control it; or there has been perhaps some source of eccentric irritation which has been reflected; or it may be that the blood, upon which every organ depends for nourishment and strength, has been poisoned, or its nutrient properties impaired; and the poor brain, unable to do its constant work under such influences, begins to waver, to show signs of weakness or aberration; hallucinations or delusions hover around like floating shadows in the air until, finally, disease comes and "Plants his siege Against the mind, the which he pricks and wounds With many legions of strange fantasies, Which, in their throng and press to that last hold, Confound themselves." CHAPTER XVI. CONCLUSION. It has been my aim to conduct the preceding discussion in so plain and direct a manner, that its lessons of instruction and warning, if it has any, shall be readily appreciated by the reader. It will not, therefore, be necessary to add chapters filled with specific directions how to avoid insanity. Some remarks, of a somewhat desultory character, concerning some branches of the subject will comprise this closing chapter. There are few diseases the conditions of whose existence are so clearly and fully understood that they can in every case be avoided, and in reference to the ultimate causes of many we know little or nothing. It is true that, within a few years, we have more clearly recognized the relations of hygiene to the prevalence of some forms of disease, and by this means have done much toward limiting their progress, thus achieving some of the grandest triumphs of medical science in recent times. In doing this, however, we have not always, or even generally, known the exact nature of the primary causes of these forms of disease, but have simply learned, from observation, their relations to hygienic conditions; but the knowledge of this relation has put society on vantage-ground in all efforts to maintain the public health, so far as it relates to certain forms of zymotic disease; and to the extent of our progress in understanding these relations to most other forms of disease, shall we be in a condition to avoid them.