This instinct is founded upon the truth that the perfect temperament is that happily balanced one which holds all the organs in equilibrium,--in which no one rules, where all are developed in proportion. Nature ever strives to realize this ideal. She instills in the nervous temperament a preference for the lymphatic; in the sanguine, a liking for the bilious constitution. The offspring should combine the excellencies of both, the defects of neither. We do well to heed her admonitions here, and to bear in mind that those matches which combine opposite temperaments, are, as a rule, the most fortunate. THE MORAL AND MENTAL CHARACTER. Very few words are necessary here. We have already said we speak as physicians, not as moralists. But there are some false and dangerous ideas abroad, which it is our duty as physicians to combat. None is more false, none more dangerous, than that embodied in the proverb, 'A reformed rake makes the best husband.' What is a rake? A man who has deceived and destroyed trusting virtue,--a man who has entered the service of the devil to undermine and poison that happiness in marriage, which all religion and science are at such pains to cultivate. We know him well in our capacity as physicians. He comes to us constantly the prey to loathsome diseases, the results of his vicious life; which diseases he will communicate to his wife, for they are contagious, and to his children, for they are hereditary; and which no reform can purge from his system, for they are ineradicable. Is this the man a pure woman should take to her arms? Here repentance avails nothing. We have witnessed the agony unspeakable which overwhelmed a father when he saw his children suffering under horrible and disgusting diseases, the penalty of his early sins. Very few men of profligate lives escape these diseases. They are alarmingly prevalent among the 'fast' youths of our cities. And some forms of them are incurable by any effort of skill. Even the approach of such men should be shunned,--their company avoided. A physician in central Pennsylvania lately had this experience: A young lady of unblemished character asked his advice for a troublesome affection of the skin. He examined it, and to his horror recognised a form of one of the loathsome diseases which curse only the vilest or the most unfortunate of her sex. Yet he could not suspect this girl. On inquiry, he found that she had a small but painful sore on her lip, which she first noticed a few days after being at a picnic with a young man. Just as he was bidding her good-night, he had kissed her on the lips. At once everything was clear. This young man was a patient of the physician. He was a victim to this vile disease, and even his kiss was enough to convey it.