"It is a wide-spread and deadly error, that only outward acts are harmful; that only outward acts are harmful; that only physical transgression of the laws of chastity will produce disease. We have seen all the effects of beastly abuse result from mental sin alone. I have traced serious affections and very great suffering to this cause. The cases may occur at any period of life. We meet with them frequently among such as are usually called or think themselves, continent young men. There are large classes of persons who seem to think that they may, without moral guilt, excite their own feelings or those of others by loose or libidinous conversation in society, provided such impure thoughts or acts are not followed by masturbation or fornication. I have almost daily to tell such persons that physically, and in a sanitary point of view, they are ruining their constitutions. There are young men who almost pass their lives in making carnal acquaintances in the street, but just stop short of seducing girls; there are others who haunt the lower classes of places of public amusement for the purpose of sexual excitement, and live, in fact, a thoroughly immoral life in all respects except actually going home with prostitutes. When these men come to me, laboring under the various forms of impotence, they are surprised at my suggesting to them the possibility of the impairment of their powers being dependent upon these previous vicious habits.”"