The most important single factor in insanity, not dependent on constitution or heredity but on conduct, is that degeneration of the brain which brings on paresis or general paralysis of the insane. Taken by and large throughout the world generally, nearly one in five of all {211} those who die in insane asylums die from this affection. It is the result of an infection usually consequent upon sexual immorality. The disease is inevitably fatal and once it begins it is steadily progressive from the delusions of grandeur so common at the beginning through various delusional states up to absolute dementia and death, which usually takes place in a little more than three years from the beginning of the disease; five years is a long time for a patient to survive. Nothing has done so much to limit the occurrence of this disease as religious influences, and it has increased to become the modern scourge that it is just in proportion as religion has lost its hold upon the mind of the rising generation. The disease is particularly infrequent among clergymen, and while _lues_ from which the disease develops may be contracted innocently, it is very evident that a regular moral life such as is led under the sway of religious principles is the best possible safeguard against the spread of the disease. After paresis the most serious form of acquired insanity in modern life is that known as alcoholic insanity, due to excess in the taking of spirituous liquors. It is not necessarily inevitable that a man who frequently indulges to excess in alcoholic liquors will become insane any more than that he will suffer from alcoholic neuritis, but a large number of individuals prove susceptible to the toxic effects of alcohol in these ways. There is an inherent liability in their brain and nervous system to degenerate under the influence of alcohol acting as a poison. This is an extremely common form of insanity, but almost needless to say it occurs much less frequently in those who have any religious principles than in those who are without them, because religion protects from the excesses that predispose to these conditions. Clergymen {212} very rarely suffer from them and though occasionally clerical patients have developed alcoholic insanity or alcoholic neuritis, these cases on careful investigation oftener proved to be due to certain patent medicines which contained alcohol in large percentage than to any direct consumption of spirituous liquor.