162 EXPERIMENT STATION RECORD. 



reliance of the past, is soon to be replaced by principles discovered tlirough 

 scientific researcb. 



Th.e genesis of animal species, L. Cuenot (Le Genese des Especes Animales. 

 Paris, 1911, pp. Jt96, figs. 123; rev. in Rev. G6n. 8ci., 22 (1911), No. IJj, pp. 585, 

 586). — The topics treated in this book are the study of individual adaptation, 

 variation, effective environment, adaptation of species, mutations, and the 

 evolution of species by preadaptation or prophetic characters. 



Memorandum for committee on pedagogics of breeding, W. M. Hays 

 (Amer. Breeders Assoc. [Proc.], 6 {1910), pp. 3-'i9-352). — This contains many 

 suggestions for teaching the principles of breeding, and in particular the use 

 of illustrative material. 



Intra-individual variation and heredity, R. Pearl (Advance print from 

 Proc. Inteniat. Zool. Cong., 7 (1901), pp. 3). — Intra-individual variation is de- 

 fined as the variation between the different members of a series of like parts of 

 the same organism. A preliminary report is made of a biometrical study of 

 like members in the hydroid Aglaophenia helleri to determine whether the cor- 

 relation there corresponds in magnitude to those observed for ancestral in- 

 heritance among individuals. 



The work so far indicates that the processes of production of like parts of a 

 series by an individual and the production of like individuals through the 

 activity of germ cells must be regarded as biological processes very closely akin, 

 if not fundamentally identical. " The only distinction between them which it 

 seems possible now to make is that in one case the products of cell division re- 

 main permanently in contact with one another to form a single system, whereas 

 in the other case the products of cell division at some step in the process of de- 

 velopment separate completely from the system which produced them and 

 thereafter lead independent existences. So far as the process of production is 

 concerned this distinction does not appear to be fundamental." 



An important principle in selecting for fancy points, W. J. Spillman 

 (Amer. Breeders Assoc. [Proc], 6 (1910), pp. 375-380, figs. 2).— The author 

 points out that because it is so much more difficult to breed for two character- 

 istics than for one, progress in improving the utility characters would be much 

 more rapid if the standard for esthetic characters was fixed at that normal for 

 the breed, than at present when both esthetic and utility characters must be 

 considered. 



Inheritance in " blood lines " in breeding animals for performance, with 

 special reference to the " 200-egg hen," R. Pearl (Amer. Breeders Assoc. 

 [Proc.], 6 (1910), pp. 317-326, fig. 1). — It is pointed out "that the performance 

 record is in itself a poor indication of the breeding value or prepotency of the 

 individual. 



From a study of individual pedigrees in egg production, the author suggests 

 the following as a working hypothesis regarding the methods of inheritance of 

 a group of highly variable characters in domesticated animals, denoted as 

 " performing ability " : " Inheritance of performing ability is in blood lines, ahd 

 is fundamentally in accordance with the jmre line idea of Johannsen ; a geno- 

 typic high degree of performing ability tends to be dominant over a genotypic 

 low degree of performing ability with phenomena of segregation in subsequent 

 generations." 



Selection and pathology, J. U. Duerst (Arl). Dent. Gescll. ZUchtungsIc, 1911, 

 No. 12, pp. 5.'i, pis. 12). — It is pointed out that the inheritance of malformations 

 and other pathological conditions, such as is exhibited in crested fowls, in the 

 legs of the dachshund, and in digital abnormalities gives rise to new species 

 and breeds if the environment, either artificial or natural, is favorable. 



A bibliography is appended. 



