ANIMAL PRODUCTION, 671 



biometricians may make of this speculation I do not Ivnow, but the amount of 

 variations that may arise from it seems to me enormous. 



" The theory I advance does not clash with mutation." 



The variability of lower organisms, H. Pringsheim {Die VariaMlitdt 

 nicderer Organismea. Berlin, 1910, pp. VIII+216; rev. in Science, n. ser., 32 

 {1910), No. 832, pp. 837, 838; Nature [London], 85 {.1911), No. 2155, pp. 501, 

 502). — This book contains a summary of investigations of unicellular organisms 

 from the standpoint of the student of variation, heredity, and evolution. 



The introduction deals with variation and heredity in a general way. Special 

 topics such as variation in form and structure and breadth of variability relate 

 chiefly to bacteria. The author holds that in certain cases fluctuating varia- 

 tions have shown themselves heritable and give rise to new races. Cases are 

 cited which are thought to prove that direct adaptations have proved heritable. 

 An annotated bibliography of 74 pages is appended. 



The law of sex determination and its practical application, Laxtba A. Cal- 

 houn {New York, 1910, pp, 25-'t, pls. 2). — This book contains a review of many 

 theories of sex, with some additional experiences of the author. 



A reply to the note of W. E. Castle entitled " Russo on sex-determination 

 and artifi.cial modification of the Mendelian ratios," A. Russo {Biol. Centhl., 

 31 {1911), No. 1, pp. 29-32). — A reply to the criticism of Castle, previously 

 noted (E. S. R., 23, p. 472). 



A study of Bermuda grass, C. K, Francis and R. O. Baird {Oklahoma Sta. 

 Bui. 90, pp. 5-19, figs. 5). — This contains general information on the methods 

 of planting and uses of Bermuda grass, in part derived from previous publica- 

 tions (E. S. R., 14, p. 855; 17, p. 1062). 



Chemical analyses of Bermuda hay for 3 successive years after planting were 

 as follows: First year average, water 7.38, ash 9.13, protein 18.72, fiber 21.57, 

 nitrogen-free extract 40.71, fat 2.49 per cent, number of analyses 18; second year 

 average, water 6.52, ash 8.03, protein 11.91, fiber 24.85, nitrogen-free extract 

 46.60, fat 2.09 per cent, number of analyses 16 ; third year average, water 10.74, 

 ash 6.43, protein 11.95, fiber 24.15, nitrogen-free extract 44.84, fat 1.89 per cent, 

 number of analyses 13. The protein content was noticeably high, but there was 

 a gradual decrease toward the end of each season. The yield of hay for the 

 first season was 5,850 lbs. per acre, the second year 1,635 lbs., and the third 

 year 1,667 lbs. per acre. 



Digestion experiments were made with 3 sheep, in which Bermuda grass con- 

 stituted the sole ration, with the exception of water and a little salt. The 

 average digestibility was dry matter 54.92, protein 64.19, fat 39.69, nitrogen-free 

 extract 52.71, fiber 58.93, and ash 41.68 per cent. 



Investigations of the digestibility and food value of reindeer moss, H, 

 Isaachsen {Tidsskr. Norske Landhr., 17 {1910), No. 6, pp. 287-302).— The 

 digestibility of reindeer moss was determined in digestion trials with two young 

 goats* 



The composition of the feed was as follows: Water 16.32, protein 8.81, fat 

 2.15, nitrogen-free extract 41.94, fiber 25.27, and ash 5.53 per cent. The follow- 

 ing digestion coeflicients were obtained when hay of known digestibility was 

 fed with the reindeer moss: Dry substance 55.1, organic matter 55.3, protein 

 negative, fat 58.3, nitrogen-free extract 55.5, fiber 64.6, ash 43.4, and digestible 

 energy 48.3 per cent. In a maintenance ration, 77 per cent of the energy of the 

 total digestible matter and 42.4 per cent of the total energy of the hay fed was 

 utilized. For reindeer moss the corresponding figures obtained were 40.2 and 

 72.8 per cent, respectively. 



93315°— No. 7—11 6 



