In the normal man the sexual instinct is inherited but the passion is submissive to the control of the will. The will is supreme and self-restraint is always possible. The immoral man has refused to exercise this restraining power, he has, in fact, by his immoral thoughts, lent his mind to the strengthening of the passion until it has gained an ascendancy. Continual sexual excitement has resulted in the nervous centres controlling the sexual organs becoming so powerfully developed as to act almost automatically, and independently of the will. In the normal man, sexual excitement results upon the mental vision; in the sensualist the excitement precedes the vision. Another effect is noticed in the physiognomy which changes in accordance with the development of the nerve centres and presents all the appearances of the typical sensualist or prostitute. In some cases the sensualist transmits this highly organised or disordered nervous system to his descendants, and consequently when they arrive at a certain age they find their bodies invaded by a passion over which they have small, and sometimes no, control. It is distinctly a case of functional insanity with them. Their will power is weak because of undue stress, but it has not been perverted. Perversion may follow; but may also be avoided, and even the will sufficiently strengthened so that it may re-assume control and subject the passion to control. The influence of heredity is here also confined to the nervous system. That is, the direct influence, the influence which was first felt and before it received any support which the mind of the victim may give it. The cases of hereditary suicides, murderers and assassins afford a very large field for investigation, and we cannot do more than suggest some causes which seem to give strong evidence of their existence. These causes if their existence be allowed, and we see every reason that it should, will restrict the influence of heredity to a much narrower sphere than is popularly supposed. The old story of the devil preaching upon the horrors of hell serves somewhat to illustrate our meaning. When the abbot enquired whether it was not contrary to his interests to draw so vivid and terrible a picture he replied in the negative and gave as his reason that the man who contemplated the horrors of hell was the man who was bound to find his way there.