ANIMAL. PRODUCTIOlSr. 771 



died sooner or later by a reduction in tlie quantity of food supplied or by an 

 increase in the amount of exercise." 



Heredity in the light of recent research, L. Doncasteb (Cambridge, 1910, 

 pp. X+IJ/O, figs. 12). — A brief popular work on variation, the statistical study 

 of heredity, Mendelian heredity, and the material basis of heredity. A glossary 

 of technical terms and a bibliography are appended. 



Hereditary characters and their modes of transmission, C. E. Walker 

 {London, 1910, pp. XII+239; rev. in Lancet [London], 1910, II, No. 23, p. 1611 ; 

 Nature [London], 85 {1911), No. 2156, p. 536). — A treatise which covers the 

 whole field of heredity, but in which is proposed a theory that attempts to har- 

 monize the views of Mendelists and the biometricians by assuming that some 

 elements of the cell are inherited in an alternative manner. These are called 

 individual characters and are contained in the chromosomes, while the racial 

 characters divide in bulli and are blended as transmitted. 



The relative inheritance of ear length in rabbits according to Castle, and 

 the problem of blending inheritance in the formation of hybrid races, A. 

 Lang {Ztsehr. InduJctive Abstani. n. Vcrerbtingslehre, 4 {1910), No. 1, pp. 1-23; 

 abs. in Arch. Rassen u. Gesell. Biol., 7 {1910), No. 6, pp. 752, 753). — A critical 

 discussion of Castle's work, previously noted (E. S. R., 21, p. 772). 



Are particular chromosomes sex determinants? T. H. Montgomeey, Jr. 

 {Biol. Bui. Mar. Biol. Lab. Woods Hole, 19 {1910), No. 1, pp. 1-17).— A review 

 and criticism of the sex-chromosome theory, which is considered a crude hy- 

 pothesis, although it is deemed probable that the activities of the chromosomes 

 may affect in some way the sex of the organism. The author insists that there 

 is no valid reason to interpret sex as an immutable unit character resident in or 

 presided over by particular chromosomes and sorted out and distributed by 

 Mendelian segregation with all the complex mechanisms of dominance and de- 

 terminers, but rather as a growth of the results of a labile process which may 

 be changed by a variety of influences. 



A bibliography is appended. 



[The identification of animals by means of modifications in the epidermis 

 about the muzzle], H. G. Boehme {Exterioristische Betrachtungen ilber die 

 Formationes parorales et paranaricae der Wiederkduer, Suiden und Car- 

 nivoren des Hausstandes in Bezug anf die Moglichkeit einer Benutzung zur 

 In,dividualcharakteristik u. Eennzeichnung der Tiere. Inaug. Diss., Univ. Bern., 

 1910, pp. 24, pi. 1, figs. 2). — From a study of the epidermal tissues about the 

 nose and mouth of animals, the author believes that impressions may be taken, 

 as in the Bertillon system of the identification of criminals, which may assist 

 materially iu the identification of individuals in cattle, sheep, goats, swine, and 

 dogs. The method is not applicable in the case of the cat and the horse. It 

 is thought that this means of identification, combined with measurements and 

 photographs, will be of service for veterinary inspectors, breeders, and in cases 

 at law where the ownership or identification of animals is necessary. Direc- 

 tions are given for making the impressions. 



A bibliography is appended. 



Investigations on the annual horn rings of cavicornia as an indication 

 of the age of the animal, with special reference to cattle, G. Schroeder 

 {UntersucJiungen iiher die Jahresringe als Alter smerkmal der Cavicornier unter 

 spezieller Beriicksichtigiing des lUndes. Inaug. Diss., Vnin). Bern, 1909, pp. 91, 

 pis. .5).— Investigations on the fetal growth of horny tissues are summarized, 

 and a report is made of a study on the growth of the rings on horns of mature 

 cattle and sheep. 



Measurements were made of a large number of animals. The age could not 

 be determined with any degree of accuracy by means of the rings iu the case of 



