the epilepsy. Figures equally strong are given by Martin, who, in 150 insane epileptics, found 83 with a marked history of paternal intemperance. Of the 126 Elwyn cases in which the family history of this point was carefully investigated, a definite statement was found in only 4 of the cases (Osler). Huntington's Chorea.-Huntington's chorea is frequently inherited. The disease is known as chronic hereditary chorea. It was described by Lyon in 1863, who traced the disease through five generations. Huntington in 1872 gave the three salient points in connection with the disease, viz.: (1) its hereditary nature; (2) association with psychical troubles; and (3) late onset between the thirtieth and fortieth year. Huntington's chorea is a typical dominant trait. The normal condition is recessive; in other words, the disease is due to some positive determiner. Persons with this dire disease should not have children, but the members of normal branches derived from the affected strain are immune from the disease. This disease forms a striking illustration of the principle that many of the rarer diseases of this country can be traced back to a few foci, even to a single focus; certainly in this case many of the older families with Huntington's chorea trace back to the New Haven colony and its dependencies and subsequent offshoots (Davenport). Friedreich's Disease-Hereditary Ataxia.-This disease resembles locomotor ataxia, although differing from it in several essential particulars. It begins in childhood and usually occurs in a family having other members of the family affected with the same disease. There are curious forms of incoördination and loss of knee-jerk, early talipes equinus, scoliosis, nystagmus, and scanning speech. The affection lasts for many years and is incurable. In 1861 Friedreich reported six cases of this form of ataxia in one family. Since then it has usually been observed to be a family disease, and is, therefore, assumed to be transmitted hereditarily. The eugenic teaching in this affection, according to Davenport, is that normally all the affected fraternities should marry only outside the strain. Whether all cases of ataxic offspring of one normal parent are derived from consanguineous marriage is still uncertain and warrants hesitation in advising the marriage of any ataxic person. Imbecility, Defectives, and Delinquents. -Davenport believes that imbecility is due to the absence of some definite simple factor, on account of the simplicity of its method of inheritance. Two imbecile. parents, whether related or not, have only imbecile offspring. Davenport states that there is no case on record where two imbecile parents have produced normal children. Dr. H. H. Goddard, of the Training School for Feeble-Minded, at Vineland, N. J., has studied the ancestry of children in the Vineland institution and has found almost without exception a history of feeblemindedness for several generations. Dr. Goddard's remarkable study of the Kallikak family has already been referred to. In this instance he traced the ancestry of a 22-year-old girl through about 1,100 individuals as far back as the Revolutionary War. Similar studies are being carried out in other institutions and always with similar results. Insanity.—Insanity is a general term comprising many different conditions. No general statement can, therefore, be made except that certain forms of insanity are undoubtedly transmitted through succes d.i. d.i. d. 6yr. d.i. FIG. 67.-FAMILY HISTORY SHOWING FEEBLE-MINDEDNESS. Data from Goddard. A, alcoholic; d. i., died in infancy; E, epi- sive generations. Mental diseases are rare in persons free from ances tral taint, except as the result of wounds or toxic influences. Practically all the statistics accumulated on insanity have limited value to the student of heredity, because they do not give numerical records of the sane members of the families of the insane (see page 295; REFERENCES Lock, R. H.: "Variation, Heredity, and Evolution," 1910. Lamarck, J. B.: "Philosophie Zoologique," 1809. Darwin, Chas.: "The Origin of Species," 6th Edition, 1872. Weismann, A.: "Essays Upon Heredity," 1889; "The Variation Theory," 1906; "The German Plasm: A Theory of Heredity" (translated by W. N. Parker and H. Rönnfeld, 1893). Galton, F.: "Natural Inheritance," 1889; "Hereditary Genius," 1869; "English Men of Science," 1874; "Inquiries Into Human Faculty and Its Development," 1883; "Natural Inheritance," 1889; "Eugenics: Its Definition, Scope, and Aims," 1905. Davenport: "Statistical Methods," 1904; "Heredity in Relation to Eugenics," 1911. Pearson, K.: "The Grammar of Science," 2d Edition, 1900. Bateson, W.: "Materials for the Study of Variation," 1894; "Mendel's Principles of Heredity," 1909. DeVries, H.: "Die Mutationstheorie," 1901; "Species and Varieties: Their Origin by Mutation," 1905. Wilson, E. B.: "The Cell in Development and Inheritance," 2d Edition, 1900. Thompson, J. A.: "Heredity," 1908. Castle, William E.: "Heredity," 1911. The Proceedings of the Roy. Soc. of Medicine, 1909, Vol. II: "The Influence of Heredity on Disease," with Special Reference to Tuberculosis, Cancer, and Diseases of the Nervous System. Punnett, R. C.: "Mendelism," 1911. SECTION III FOODS CHAPTER I GENERAL CONSIDERATIONS Foodstuffs fall naturally into two great divisions: (1) those derived from the animal kingdom, and (2) from the plant kingdom. The animal foods are much more apt to convey infections or to possess injurious properties than foods derived from plant life. Of the animal foods meat and milk are the chief offenders. Water ordinarily is not classed as a food, and is discussed in a separate chapter. The increase of food poisoning and the increase of diseases caused by infected foods are more apparent than real. The subject is better understood, and cases are now recognized and reported that were formerly misinterpreted. The hygienic conscience of the people has been aroused, and a demand has been established for clean, fresh, wholesome foodstuffs. The separation of the producer and the consumer and the demands of large cities have made these sanitary reforms eminently necessary. The pure food laws, the meat inspection act, the milk ordinances, and the local surveillance over markets, provision shops, dairies, etc., are all part of the general movement to obtain a reasonably decent and safe food supply. People should be educated to demand flesh from healthy animals, cut up and handled in a careful manner by butchers free from disease, and to demand garden truck grown in clean dirt and not in soil polluted with human excrement. Food must be guarded in transportation and purveyed in markets and shops so as to be protected from flies, rats, dust, and unnecessary human contact. The prophylactic and therapeutic uses of food are growing subjects. It is only necessary to point out the importance of diet in the prevention and treatment of tuberculosis, diabetes, nephritis, arteriosclerosis, gout, rheumatic affections, disorders of metabolism, dyspepsia, gastric ulcer, infantile diarrheas, and many other affections. The proper amount and quality of food is one of our important preventive measures. |