266 GENETICS [BoT. Absts., Vol. X, 



1733. Morgan, T. H. The genetic and the operative evidence relating to secondary sexual 

 characters. Carnegie Inst. Washington Publ. 285. 108 p., 10 pi. (7 colored). 1919. — This is 

 a detailed account of the author's experiments in castrating hen-feathered males, (with resul- 

 tant assumption of cock feathering) and of crosses between hen-feathered and cock-feathered 

 races. Hen-feathering is dominant and segregation occurs in F2, according to the di-hybrid 

 scheme. A description of the complex colors of the various hybrid offspring is given. There 

 is an extended review and discussion of the literature dealing with secondary sexual char- 

 acters, especial attention being paid to endocrine cells, hermaphroditism in poultry, and 

 theories, notably Darwin's, that attempt to account for secondary sexual characters. — 

 H . D. Goodale. 



1734. Payne, Fernandus, and Martha Denny. The heredity of orange eye color in 

 Drosophila melanogaster. Amer. Nat. 55: 377-381. 1921. — The authors have worked out the 

 genetics of the eye color of orange-ej^ed males, which have arisen in the stock called "re- 

 duced." It occurs when 2 sex-linked genes, sahnon (later proved identical with garnet) 

 and salmon-modifier, are present. These genes are not closely linked, but salmon-modifier 

 is very close to reduced. Salmon-modifier has apparently become homozygous, though not 

 visible, in reduced stock, and does not modify the normal red eye color except in the presence 

 of salmon. — John S. Dexter. 



1735. Pearl, Raymond. On a single numerical index of the age distribution of a popu- 

 lation. Proc. Nation. Acad. Sci. [U. S. A.] 6: 427-431. 2 fig. 1920. — This paper presents a 

 formula for an arbitrary index of the age distribution of a population for use in such problems 

 as correlation, where only a single value can be used to represent the condition in each com- 

 munity. The suggested index is obtained by comparing the percentage age distribution of 

 the population of the community with the percentage age distribution of a standard popu- 

 lation. The population given by the Lx line of Glover's United States Life Table for 1910 

 is the standard chosen. The formula is: 



M 



<t> = S<jUM-Mp) 



where P is the percentage in a given age group in the standard population, a the deviation 

 of the percentage in the corresponding age group of the population of the community from 

 the percentage of the standard population, S the summation of these percentage squared 

 deviations for the different age groups, and M and Mp the mean ages of the population of 

 the community and of the standard population, respectively. As an illustration of the use 

 and reliability of the index the values for 34 American cities are presented and discussed. — 

 Sylvia L. Parker. 



1736. Pf;zARD, A. Loi du "tout ou rien" ou de Constance fonctionnelle, relative a Taction 

 du testicule considere comme glande endocrine. [Law of "all or nothing" or of functional 

 constancy relative to the action of the testis considered as an endocrine gland.] Compt. Rend. 

 Acad. Sci. Paris 172: 89-92. 1921. — The author presents data which indicate that a mass of 

 testicular tissue weighing approximately 0.5 gr. implanted in the peritoneum of a castrated 

 cock brings about the complete redevelopment of secondary sexual characters, both morph- 

 ologic and psychic. A smaller mass registers no noticeable effect, and increasing the mass 

 to as much as 42.0 gr. gives no greater effect than the 0.5 gr. mass. — William A. Lippincott. 



1737. Pezard, a. Temps de latence dans les experiences de transplantations testiculaire 

 et loi du "toutou rien." [Latent period in the experiments with testicular transplantation and 

 law of "all or nothing."] Compt. Rend. Acad. Sci. Paris 172: 176-178. 1921.— The author 

 implanted testicular tissue in cocks at the time of castration, after which there was a period 

 of regression in the secondary sexual characters followed by their rather rapid redevelopment. 

 The author thinks the period of regression, 2-6 weeks, represents the time necessary for the 

 implanted tissue to acquire a weight of 0.5 gram. — William A. Lippincott. 



