The father's care over the health of his child should begin before its birth, nay, before its conception. Proper attention then may avert taints of the system which, once implanted, no medical skill can eradicate. The truth of this statement is recognized by breeders of animals. Mr. Youatt, one of the best authorities upon the breeding of horses, observes, " The' first axiom we would lay down is this, like will produce like; the progeny will inherit the qualities or the mingled qualities of the parents. We would refer to the subject of diseases, and state our perfect conviction that there is scarcely one by which either of the parents is affected that the foal will not inherit, or, at least, the predisposition to it; even the consequences of ill-usage or hard work will descend to the progeny. We have had proof upon proof that blindness, roaring, thick wind, broken wind, curbs, spavins, ring-bones, and founder have been bequeathed both by the sire and the dam to the offspring. It should likewise be recollected that, although these blemishes may not appear in the immediate progeny, they frequently will in the next generation. Hence the necessity of some knowledge of the parentage both of the sire and dam."

The influence of one parent upon the other in counter. acting or intensifying the degree and the certainty with which the physical qualities of one or both are transmitted must be borne in mind. If the same defects be possessed by each parent they will be quite certain to appear in the children. If only one parent be affected, some or all of the children may escape the inheritance. Take, in illustration, that most common of all diseases, consumption. If husband and wife both have this affection, all of the offspring will be quite certain to be consumptive or scrofulous. If one of the parents be healthy, it is possible that only some of the children will be scrofulous, and even that none of them will inherit the disease. It is most fortunate that the tendency of a disease to propagate itself by inheritance is often overpowered by the stronger tendency of a vigorous constitution to impress itself upon the offspring. If it were possible to apply this principle to its fullest extent in every individual case, by never mating a feeble constitution excepting with one of that healthful vigor best calculated to counteract its transmission, the heritage of disease would, doubtless, soon be unknown. While it is impossible to lay down any absolute rule of conduct, and useless to hope that any such rule would be generally followed, even if enunciated, it behooves every man to know, be he strong or weak, that, for the reason just mentioned, he may marry a woman who will bear him healthy children, whereas his children by another woman may be doomed. The responsibility and risk are his own. We can only indicate them.

We have also words of cheer to utter in regard to the descent of diseased conditions from generation to generation. It is a stern fact that " Our fathers have sinned, and are not; and we have borne their iniquities." But disease is not eternal. The offspring of sinning fathers are not without all hope. The counteracting influence of one parent over the other with transmission of life, of which we have just spoken, does much to maintain healthful vitality and beauty in spite of the degrading tendencies which may be present. In addition, however, there is a force resident in our nature by which the diseased organization tends to return to health. This benign healing force, this vix medicatrix, " Which hath an operation more divine Than breath or pen can give expression to," is ever influencing the effects of inheritance. Were it not for this beneficent law the human race would rapidly degene-rate. The results of its operation can be seen in the faces of the children of squalor and vice who throng the narrow streets and wretched houses of our crowded cities. If, happily, time had not purified the debased organization and restored health, we should look in vain there for that comeliness of features, grace of figure, and strength of limb which are now frequently to be observed. As has been truly said, " the effects of disease may be for a third or fourth generation, but the laws of health are for a thousand."

The law of inheritance is a certain but not an invariable one. Its force must not be over-estimated. For if it were always true that the child of a father tainted with insanity or consumption is born with these affections, then moral law would imperatively forbid marriage. It is known that the offspring of a father who has too many or two few fingers sometimes escapes the transmission, when both parents have not been similarly affected. As the child inherits from the mother as well as the father, many or all the members of the family of a tainted father may be born with only a slight taint of the system, or none at all.

We shall now point out a few of those diseases which are especially liable to be transmitted from parent to child, with the view of indicating special means of preventing, before and after birth, the effects of inheritance.

The most cruel of all the maladies which afflict us, pulmonary consumption, is the one which is most constantly seen in its hereditary form. Dr. Theophilus Thompson, an English physician of very large hospital experience, states, in his "Clinical Lectures on Pulmonary Consumption," that" you will learn, amongst a thousand patients questioned on the subject, above one-fourth will mention having lost a parent by it."

Again, M. Herard and M. V. Cornil, two of the latest and most prominent of the French authorities on this subject, mention as the result of their investigations, both in hospital and private practice, that out of one hundred cases carefully questioned, they find the disease hereditary in thirty-eight instances. American statistics tell the same story of the large proportion of consumptives born with the taint.

The mother more frequently transmits this disease to the child than the father. Her daughters are also more apt to be affected by it, through her, than are her sons. Indeed, in regard to all diseases, the morbid constitution of the mother tends to impress itself upon her daughters rather than her sons, while that of the father has a reverse hereditary tendency. "With reference to the inheritance of mental qualities and peculiarities, the opposite inclination seems to prevail, as we have seen, mothers most influencing their sons, fathers their daughters.

That terrible and invincible foe to human life, cancer, is a markedly hereditary affliction. Where the taint exists, medical art has few resources either to prevent its transmission or to antagonize its effects.

Gout, asthma, and disease of the heart are also trans* missible. They are not, of course, exclusively the result of inheritance. They are often developed during the lifetime of individuals whose family record is a clear one. But once having made their appearance in a family, they have a greater or less proneness to recur.

Of all the affections which are transmitted by inheritance, the various disorders of the nervous system are the most common. Hysteria, epilepsy, paralysis, and insanity descend from the unhappy parents to the more unhappy offspring. Physicians who have devoted themselves to the study of that many-sided malady, insanity, are, of late, disposed to lay more stress than formerly upon the influence of inheritance in its causation. They allege that a vast number of the cases commonly attributed to physical or moral shocks are really instances of the breaking out of an inherited tendency, which has lurked unheeded in the system until aroused by some unusual excitement. According to the best authorities, from one-third to one-half of all attacks of insanity owe their origin to hereditary causes.

It is a noteworthy peculiarity of nervous ailments, that they are not always transmitted in the same form. The child of a person subject to epilepsy, for example, is as liable to be paralyzed or insane as it is to be epileptic. This change in the character of the nervous affection, in passing from the one generation to the other, is constantly met with.

Insanity furnishes another illustration of the greater disease-transmitting power of the mother. It is transmitted about one-third times oftener by her than by the father Again, also, we have an illustration of the greater influence of the mother over the diseases of her daughters for when the mother is insane, it does not affect the sons any more than insanity in the father would, but, on the other hand, the danger of the daughters is double what it would be if the father, instead of the mother, were the affected parent.

The hereditary diseases of which we have been speaking do not always show themselves immediately after birth. It is more usual, in fact, for them to lie hidden until the period of adolescence or maturity is attained. Scrofulous complaints, however, manifest themselves in the offspring earlier. The time at which a disease will first make its appearance is frequently as much a matter of inheritance as its other characteristics. This is, above all, true of nervous disorders. For instance, that form of insanity which is developed only after a certain age is often 'inherited. A case is related of a noble family in Europe, all the male descendants of which became insane at forty years of age. Up to that epoch in their lives they all exhibited great military talent, and were entirely trustworthy in every respect. At last there remained but one son, a distinguished officer like his father. The critical age arrived, and he also lost his reason.

The immunity occasionally seen to the invasion of disease is capable of inheritance. Some individuals can never acquire, no matter how exposed, certain diseases, such, for example, as smallpox or intermittent fever. The happy security may be transmitted.