But he did not in the least associate the loose, light, unclean way of looking at human relations, with the same careless uncleanness as applied to the body. And yet, in reality, the one kind of uncleanness corresponds precisely to the other. In the one case the dirt is on the inside and is what we may call living dirt, because it is kept alive by the soul to which it is allowed to cling. In the other case the dirt is on the outside, and can be washed off with soap and water. Very few so-called men or women of the world are willing to appear dirty and slovenly in their bodies,--but a great many are willing to be dirty and slovenly in their souls. A curious and significant fact it is, that often, when a man's nerves give way, even when his external habits have been most cleanly, or even fastidious, they may change entirely, and he may go about with spotted clothes, dirty hands, and a general slovenly appearance, whereas such external shiftlessness would have been impossible to him while his nerves were comparatively well and strong. When such a man's nerves give way, so that he loses to some extent the external use of his will, the dirty habits of his mind appear in slovenly and dirty habits of body, because he has no longer the will-power to confine them to his private thoughts and feelings. The habits of his body become then a true expression of his state of mind. We may prove the relation between sin and disease by tracing what might be called a mild sin to its logical extreme. Just as we may follow almost any disease in its development, until it causes the death of the body, if the body is not protected from its growth, so we may follow any sin in its development to the death of the soul, if the soul is not similarly protected. All sin, when allowed to increase according to its own laws, is the destruction of both soul and body. Macbeth's mind became diseased; and we may find many an Iago in our insane asylums to-day, for, with all his cleverness, no Iago can, in the long run, keep control of his mind if his selfish plans are frustrated. The loathsome diseases of the body which are liable to overtake a Don Juan may only be spoken of, or thought of, as a means of removing the blindness of those who, from dwelling upon the sensations of the body, come to think of sin as pleasant. When their blindness is removed, the least touch of the sensuality which causes the disease will fill them with wholesome horror. It is wonderfully provided by the Creator that any sensation, which is selfishly indulged in, any sensation that a man remains in for its own sake, must lead first to satiety,--and then to worse than satiety and death. This is true both of all selfish sensations of the body and of all useless emotions of the mind. Our sensations and our emotions must be obedient servants to a wholesome, vigorous love of usefulness, or they become infernal masters whose rule leads only to weakness and death.