ANIMAL PRODUCTION". 75 



The feeding and fertilizer value of feeding stuffs estimated mathemat- 

 ically, V. Brdlik (Monatsh. Landio., 3 {1910), No. 7, pp. 211-223). The use of 



the method of least squares is suggested for estimating the value of feeding 

 stuffs. Examples are given in the application of this method. 



Game farming, J. L. Cowman {ScL Amer., 103 {I'JIO), No. 12, p. 212). A 



popular article on the opportunities for rearing bison, elk. Angora goats, and 

 fur-bearing animals. 



The conformation of spayed cows, J. Tandleb and Keller {Zentbl. Physiol., 

 23 {1909), No. 26, pp. 1036, i 037). —Measurements were made on 11 mature 

 cows which had been spayed when 6 months of age. As compared with uu- 

 spayed animals they had a longer head and horns, less pronounced facial parts, 

 longer limbs, broader back, smaller rump, and narrower pelvis. 



On the deviation of the length of the gestation period according to the 

 season of the year, O. Wellmann {Landiv. Jcihrh., 39 {1910), No. 3, pp. 

 1,09-1/28). — With brood mares the average length of the gestation period in the 

 case of 5,437 births was 334.67 days. The periods were shortest in the births 

 which occurred in July, the average length for that month being 321.94 days. 

 From July there was a constant increase from month to month until May, when 

 it reached 346.11 days. With working mares the average length in 171 cases 

 was 325.03 days, with a seasonal variation as in the case of brood marcs. The 

 average gestation period of 228 Hungarian cows was 284.61 days, and of 291 

 Simmeutal cows 291.2 days. Apparently there was also a seasonal variation in 

 cows, but much less in amount than in the case of horses. 



Estimation of the live weight of animals by measuring, J. Frischauf 

 {Landw. Jahrh., 39 {1910), No. 3, pp. 373-396, figs. 2).— The author discusses a 

 number of systems of estimating the live weight of animals, and presents a 

 system of his own which is explained in detail. 



The significance of circulation of air in stalls, Ltjdewig {Arch. Wiss. u. 

 Prakt. Ticrheill;., 36 {1910), Sup., pp. 299-305). — Experiments in measuring the 

 resistance of wire screens to drafts of air are reported. 



Both the size of the wire and the size of the mesh were found to affect the 

 amount of resistance to air currents. It is thought that a double gauze screen 

 made of wire 0.6 mm. in diameter, with a mesh from 0.5 to 1 mm., will offer 

 enough resistance to air currents so that they may be placed on the windward 

 side of the stable. In this way an abundance of pure air may be supplied with- 

 out causing dangerous drafts. 



Animals of antiquity. — I, Mammals, O. Keller {Die Antike Tierwelt. I, 

 Sdugetiere. Lcipsic, 1909, pp. Xll+JtSJi; rev. in Nature [London'\, 81, {1910), 

 No. 2134, pp. 357, 358). — This is the first volume of a work containing tlie results 

 of an exhaustive investigation of the records left by ancient peoples concerning 

 the wild and domesticated animals known to them. The aim was to identify 

 the different species described or depicted and to work out their past history 

 and geographical distribution, particular attention being paid to the larger 

 domesticated mammals. 



Deficiencies of the chromosome theory of heredity, M. F. Guyer {Univ. 

 [Cincinnati] Studies, 2. ser., 5 {1909), No. 3, pp. 19).— The facts concerning 

 the theory that chromosomes are the exclusive vehicles of heredity are herein 

 summarized, the conclusion being drawn that a satisfactory case has not yet 

 been presented. The author believes that other germ cell constituents may also 

 stand in casual relationship to adult characters. "Heredity is a problem of 

 the handing on of metabolic energies already established, rather than of the 

 transmission of a series of determinative units which create a wholly new 

 organism." 



