coccus disease, etc. The anaphylactic reaction is also used in diagnosis, and in forensic medicine in the identification of blood stains, and, finally, may be used as a scientific instrument for the detection of minute amounts of protein.

References. Many of the statements contained in this chapter have been taken from Emery's splendid book upon "Immunity and Specific Therapy," which is recommended to the reader who desires a more extended review upon the subject. Kolle and Wassermann's "Handbuch der Mikroorganismen" has also been consulted, as well as Kraus and Levaditi's "Handbuch der Technik und Methodik der Immunitätsforschung." These volumes also contain selected bibliographies.

The current literature upon immunity will be found in the Zeitschrift für Immunitätsforschungen.

For those who desire to dip deeper into the subject the original reference to many of the fundamental studies will be found in "Collected Studies on Immunity" by Ehrlich, translated by Bolduan; "Studies on Immunity" by Bordet, translated by Gay; "Studies in Immunization" by Wright, and "L'Immunité dans les Maladies Infectieuses" by Metchnikoff, translated by Binnie.

CHAPTER II

HEREDITY AND EUGENICS

Heredity may be defined as the genetic relation between successive generations. It is a condition of all organic evolution. Castle defines heredity as organic resemblance based on descent.

It is now perfectly evident that heredity is one of the fundamental factors in preventive medicine-which, after all, is the true sociology. It is well known to students of biology that education and environment have but a limited power to influence imperfect human protoplasm.

One of the best protections we have against diseases of body and mind is that which is inherited from our forebears. The whole problem of improving the human stock, not only from the medical view, but from the broader sociological standpoint, is based upon the breeding of the fit and elimination of the unfit. The science of eugenics (normal genesis), therefore, assumes especial importance in preventive medicine. The physician, as well as the sanitarian, stands impotent before many deplorable conditions both in the individual and in society at large, which are inherited from our ancestors and are, therefore, incurable-but largely preventable. We are interested in educating the present generation to the facts of eugenics so that future generations may have that best of all birthrights-good human protoplasm.

The discoveries of Mendel have made it quite clear how certain characters are inherited, why certain characters skip a generation and reappear in the grandchildren, and why it is that certain defects are carried from generation to generation through many centuries. The defects transmitted hereditarily are not all of equal practical importance. Thus, it makes comparatively little difference to the individual if he has a supernumerary spleen, an extra finger, or an anatomical anomaly of the liver. The defects which are of especial importance both to the individual and to succeeding generations are the defects

Mendel's work has not only made it possible for us to predict with precision whether good or bad traits will or will not appear in the future offspring, but also to foretell with mathematical precision in what proportion certain characters will appear and reappear.

of organization of the nervous system. These comprise the class known as defectives. A slight defect in the structure of the brain which would be unnoticed in the lung, bone, or musculature may render the individual vicious instead of useful. The principal factors which are believed to start a line of defectives are inbreeding, syphilis, and alcohol; also nervous or physical diseases, mental or nervous exhaustion, and excesses and poisons of all kinds.1

The defective individual is very easily recognized when the condition is well marked. The mental abnormality is usually accompanied by prominent physical defects known as the stigmata of degeneration (Lombroso and Weismann). An unfortunate side to this problem is that degenerates and defectives generally are not only irresponsible morally, but are very prolific. They lack self-control and have abnormal sexual appetites. Defectives beget defectives, and thus insanity, nervous diseases, moral and physical degeneracy are propagated. The typical degenerate is of poor bodily development; the brain is smaller than normal, with convolutions less abundant, and less fully formed. He has a degraded physiognomy, lacks capacity for sustained attention or for prolonged thought, is cunning rather than intelligent, deficient in moral sense-in all points resembling the stigmata of the lower, less developed races of our species. The whole gives the impression of a reversion to a lower type.

Prevention of Propagation of Defectives.-Four methods have been proposed to prevent the propagation of defectives: (1) education; (2) legislation; (3) segregation; (4) surgery.

EDUCATION.-Education directed toward the defective is a failure, for he is incapable of profiting by the lessons. The education of the better class of the community is indirectly helpful in calling attention to the situation as being largely preventable, and to the necessity and means for controlling it.

RESTRICTIVE LEGISLATION.-Restrictive legislation is a praiseworthy effort, but has signally failed as a preventive measure, for the evident reason that it only adds illegitimacy to degeneracy, and thus the children enter on life's battle doubly handicapped. Minnesota has a law providing that within the bounds of the state no marriage shall be permitted, either party to which is epileptic, imbecile, feeble-minded, or afflicted with insanity, unless the woman be over forty-five. Michigan, Delaware, Connecticut, Indiana, New Jersey, and, North Dakota have also passed laws for the purpose of preventing marriage among defectives.

SEGREGATION.-Segregation would be an ideal and humane method

1 The real cause or method of origin of defective characters that are transmitted hereditarily is no better understood than the origin of "sports" or muta

of eliminating those who are incapable of having normal offspring. The segregation of all degenerates and defectives would be an enormous and impractical task. Further, the great difficulty is to detect the unfit individual who starts a strain of defectives and degenerates. It is evidently a hopeless task to know where to draw the line between the fit and the unfit, so that for the present we must be satisfied to enforce restrictive measures upon only those who are evident and well-marked examples. Insane asylums, homes for epileptics, reformatory schools, as well as special hospitals and institutions for advanced cases must not be regarded as preventive measures in the true sense, for such segregation provides care and comfort as a terminal measure; that is, it is usually a last resort. Frequently defectives propagate their kind before and sometimes after they are segregated.

SURGERY.-Surgery has been proposed as a means of controlling the propagation of defectives. This is done either by severing the vas deferens or the Fallopian tube. At the Indiana Reformatory Dr. Sharp carries out the law of that state providing for the sterilization of defectives. The operation of vasectomy consists of ligation and resection of a small portion of the vas deferens. The operation is very simple and easy to perform. It may be done without an anesthetic, either local or general. As performed by Dr. Sharp it requires about three minutes, and the subject returns to his work immediately, suffering no inconvenience and in no way hampered in his pursuit of life, liberty, and happiness, but is effectively sterilized. In 456 cases Dr. Sharp has had no unfavorable symptoms. The operation is performed as follows: After cleansing the scrotum with soap and water, followed by alcohol, the spermatic cord is grasped between the thumb and index finger of the left hand. The vas deferens is detected, firmly held and fixed with a pair of bullet forceps. It is then exposed by a small incision and drawn through the scrotum wound by means of a tenaculum. It is stripped of all membranes and the accompanying ar tery ligated above and severed, care being taken to cut away any por

1 The Indiana law reads as follows:

Whereas, Heredity plays a most important part in the transmission of crime, idiocy, and imbecility;

Therefore, Be it enacted by the General Assembly of the State of Indiana, That on and after the passage of this act it shall be compulsory for each and every institution in the State, entrusted with the care of confirmed criminals, idiots, rapists, and imbeciles, to appoint upon its staff, in addition to the regular institutional physician, two (2) skilled surgeons of recognized ability, whose duty it shall be, in conjunction with the chief physician of the institution, to examine the mental and physical condition of such inmates as are recommended by the institutional physician and board of managers. If, in the judgment of this committee of experts and the board of managers, procreation is inadvisable and there is no probability of improvement of the mental and physical condition of the inmate, it shall be lawful for the surgeons to perform such operation for the prevention of procreation as shall be decided safest and most effective. But this operation shall not be performed except in cases that have been pronounced unimprovable.

tion of the vas deferens that may have been damaged in the manipulation. This is done in order that the end next to the testicle may not become closed. It is very important that the testicular end shall remain open, in order that the secretion of the testicle may be emptied. around the vessels of the pampiniform plexus and there be absorbed, for it is through this process that the body receives the tonic effect of the internal secretion. Further, if the testicular end of the vas deferens is closed, there is likely to be cystic degeneration of the testicle. The retraction of the muscle closes the skin wound and no stitch, collodion, or adhesive plaster is needed. There is no diminution of the sexual power or pleasure. The discharge at the orgasm is but slightly decreased.

The operation in the female is more difficult, but if carefully done. no more hazardous. The Fallopian tubes are reached through a median incision and ligated near the uterus and severed beyond the ligature.

Opinions vary greatly concerning the proper use of sterilizing criminals, insane, degenerates, and defectives generally. There is no doubt concerning its effectiveness.

Sterilization is a measure which contains great potential possibilities for abuse and injustice. It probably will never receive general acceptance on account of the difficulty of determining upon whom the operation shall be done. Even in perfectly clear cases, such as the insane, the epileptic, or the high grade degenerate, the harm has often been done before the operation is decided upon.

Statistics of Defectives.-The large number of defectives and unfit in our country may be gleaned from the following figures.

The last census report for the United States gives data relative to the dependents and defectives in institutions; the number not in institutions can only be guessed at. Kellicott gives the following approximate numbers in our country to-day:

The number of persons cared for in hospitals, dispensaries, "homes" of various kinds in the year 1904 was in excess of two million.

We have to support about half a million insane, feeble-minded, epileptic, blind, and deaf; 80,000 prisoners, and 100,000 paupers, at a cost of $100,000,000 per year. A new plague affecting 4 per cent. of the population and costing this vast treasure would instantly attract uni