organs, it is probable that they are affected by substances which exist in the blood and act as poisons to all parts of the body-the germ cells in the sexual organs included. Thus, in the larger number of germ diseases of other origin, the suffering and damage inflicted is chiefly due to chemical poisons generated in the process. Hence, the child of an alcoholic father may be so poisoned by the effect of this substance on the parental germ cells that the union of the germ cell of the mother with one of the father will not offset its effect in causing deterioration in the offspring. Special poisons may have a weakening effect on special organs, so that the child may be peculiarly liable or predisposed to diseases of certain organs in consequence. Such is the theory advanced to account for known facts. It is weakness or lessened resistance to certain or general diseased conditions which are inherited and which we can combat-not, fortunately, actual inherited disease in the great preponderance of cases. When the parental system is poisoned by the products of disease, the nervous apparatus of the offspring is most apt to suffer, since it is a law that the more recently developed organs are the first to succumb to such injurious agencies, and the nervous system of man is the most recent product of bodily development. ' Not only may a predisposition to certain morbid acquirements be present in the offspring, but a characteristic is likely to appear at the same time of life at which it appeared in the parent.

Certain natural characteristics are similarly inherited, such as the tendency to longevity; so that the most promising chance of long life is offered to the children of the long-lived. The following diseases are those commonly agreed to be more frequently inherited, although as we have stated, there is transmitted in most cases only a tendency to, or lessened resistance against, these diseases: near-sightedness, astigmatism, color blindness, deafness, obesity, diabetes, some forms of Bright's disease of the kidneys, gout (more frequently in the male line), rheumatism, syphilis, tuberculosis, cancer, skin diseases of certain kinds, and many nervous disorders, as nervous exhaustion, epilepsy, hysteria, paralyses, and insanity. The occurrence of albinos and bleeders is apt to result from inheritance.

Since the same predispositions to disease may exist in those descended from a common ancestry, it follows that marriage between relatives is inadvisable when such tendencies may be doubled in intensity in their offspring. The likenesses existing between brothers and sisters is greater than between parent and child; while the relationship existing between first cousins is practically the same as that between great-grandparent and offspring. The children of early and late marriages are not apt to be so robust as those resulting from marriage occurring at the most favorable time, which is for man at the age of twenty-five; for woman at twenty years. There are many exceptions to this

rule, depending on the health of the parents, etc. It is said that the child inherits the features, shape of the head, sense organs, and constitution from the father; while the mental characteristics may be transmitted from either parent, the shape of the trunk and internal organs more closely resembling the mother. Such a statement is also subject to many exceptions.

Lest too great influence be attached to heredity, it may not be amiss here to recall the vast importance of environment. The tendency of the times, through our greater general enlightenment, is to lay less stress on the importance of heredity as compared to the influence of environment in shaping the development of the offspring. Thus, the children of consumptive parents are very likely to acquire the disease, not through heredity, but through direct exposure to the germs of the disease. Change of environment of the children will show the folly of attributing the disease in them to the curse of heredity.

When we compare certain children reared in the United States with their foreign-born parents we realize the wonderful effect of environment and education in overcoming degeneracy and degradation. The sins of the fathers need not necessarily be visited upon the children if they heed the warnings which such sins offer, and instead of neglecting to follow the simple laws of health, make an effort so to develop and train their bodies that any inherent weakness may be thus overcome. The children of parents possessing de

fective vision should be examined, before beginning school life, by a competent oculist (not an optician), in order that they may not suffer damage from eye strain (refer to p. 35). The offspring of the nervous and tuberculous need to be reared so as to strengthen their general resistance against disease by an outdoor life, good food, exercise, and proper mode of existence, with freedom from worry, nervous strain, and dissipation or excesses of any kind.

With the assistance of the advice of an intelligent physician it will usually be found that children may be so reared that the weak points or predispositions likely to be inherited by them from their parents can be in large measure combated by proper environment, training, and education. The subject of heredity is a vast, intricate, and little-understood matter, and we have herein merely touched on some of its more salient features. The view taken by those most conversant with the study is, however, much more hopeful than formerly, as regards the inevitable, or even probable, transmission of taints, predispositions, weaknesses, or disease to the offspring when these can receive intelligent care.

CHAPTER II

Menstruation

Causes and Symptoms-Age of Puberty-Change of Life-Dysmenorrhea-Amenorrhea-Cessation or Scanty Menstruation

-Excessive Hemorrhage-Leucorrhea.

MENSTRUATION is the term used for the flow of fluid from the private parts of women, occurring every twenty-eight days during the period of their sexual activity, from puberty to the "change of life." Several causes have been assigned for the appearance of this flow, such as Nature's effort to rid the body of alleged noxious humors, or the relief of a supposed full-blooded condition, or congestion of the uterus following activity of the ovaries, or a shedding of the mucous membrane lining the uterus, which had been prepared for a pregnancy that did not occur. All these explanations are open to argument, and the fact is, that it is not known why menstruation occurs. It is known only that a nerve influence, starting in the sympathetic nerve system in the pelvis, causes stimulation of the maternal organs periodically. It is probable that the flow would not appear at all, were it not for the erect position of human beings.

The accepted term for menstruation is "being