250 GENETICS [BoT. Absts., Vol. VII, 



London for 1779 contain a rather complete family history of color-blindness, of interest because 

 of its early date and because the facts as given fall in line with the interpretation of color- 

 blindness as a sex-linked character in man.— J. H. Beaumont. 



1737. Collins, G. N., and J. H. Kempton. Heritable characters of maize. I. Lineate 

 leaves. Jour. Heredity 11:3-6. Frontispiece. Jan., 1920.— The authors point out the 

 desirability of reporting characters of genetic value as they appear in such an economic crop 

 as maize in order to avoid needless duplication by the workers in the field. They discuss the 

 character "lineate" and show that it may take its place among the other chlorophyll variations 

 of maize. [See also Bot. Absts. 7, Entry 1680.]—/. H. Beaumont. 



1738. VAN Creveld, S. [Dutch rev. of: Harris, J. Arthur, and Francis G. Benedict. 

 A biometric study of basal metabolism in man. Carnegie Inst. Washington Publ. 279, v -\- 266 

 p., 28 diagrams. Washington, D. C, 1919.] Genetica 2 : 466-468. Sept., 1920. 



1739. Danforth, C. H. Resemblance and difference in twins. Jour. Heredity 10: 399- 

 409. Fig. 9-14. Dec, 1919. — A discussion of the answers to questionnaires received by the 

 American Genetic Association from a number of twins. The answers to questions of the gen- 

 eral headings: height, weight, hair and ej'e color, physical traits, physiological traits, mental 

 traits and stronger affection, indicate that in uniovular twins identical likenesses are the 

 rule, while in biovular twins differences of the same order as between children of different 

 ages may be expected though striking similarities do occur in biovular twins of the same 

 sex. The author discusses the extent of similarity in biovular twins and the reason for 

 expecting differences in uniovular twins. — •/. H. Beaumont. 



1740. Daniel, Lucien. Recherches sur la greffe des Solanum. [Studies on the graft of 

 Solanum.] Compt. Rend. Acad. Sci. Paris 171: 1074-1076. Nov. 29, 1920. 



1741. Davenport, Charles B. Heredity of constitutional mental disorders. Psychol. 

 Bull. 7: 300-310. Sept., 1920.— The author reports chiefly his own investigations, but also 

 cites the most significant findings of recent study by others.— Analyses of the pedigrees of 

 feeble-minded individuals yield results supporting the conclusion that there is a single Mende- 

 lian factor absent in the ordinary type of feeble-mindedness. If the germ defect results in 

 the insufficient production of some hormone upon which the higher functions depend, the 

 intellectual centers develop each with its own idiosyncrasies and cease development prema- 

 turely at a lov,' level. In the most extensive pedigrees the defect has been traced for nine or 

 more generations and it is suspected that if records were obtainable it would go back 2000 

 years or more. — Contrary to former assertion on the non-inheritance of Mongolian imbe- 

 cility, recent investigations reveal neurotic conditions in both lines of ancestry.— Amaurotic 

 idiocy is apparently confined to families of Russian Jews.— It is not yet possible to say that 

 every case of epilepsy is inherited, but it is certain that in a majority of instances there is 

 nervous defect on both sides of the family. The element of periodicity in epilepsy has a clear 

 inheritable basis and the tendency to fugues is evidently a sex-linked trait, i.e., a nomadic 

 male inherits it from his mother's close male relatives.— The method of inheritance of 

 dementia praecox has been investigated by several authors all of whom conclude that it is a 

 simple Mendelian recessive. On the other hand Huntington's chorea and the temperamental 

 tendency to more or less periodic outbursts of violence seems to be a Mendelian dominant. In 

 the manic-depressive group of psychoses the hyperkinetic tendency is inherited independently 

 of the hypokinetic. The author formulates the hypothesis that the presence or absence of 

 genetic factors determines an individual's reactability to exciting situations. The history 

 of changes of mood in identical tv/ins strikingly corroborates the view.— The question of 

 inheritance of crim.inality receives the author's negative judgment except in so far as the eti- 

 ology is found in the inheritable traits of feeble-mindedness, feeble inhibition, or defective 

 internal secretions.— The bearing of consanguinity upon mental disorders is confined to mat- 

 ings in which both parents carry some recessive defect.— yl/iria??i C. Gould. 



