ANIMAL PRODUCTION. 



265 



Laboratory studies of pepsin, pancreatin, and combinations of these fer- 

 ments, A. Zimmerman (Jour. Indus, and Engin. Cliem., 3 {1911), No. 10, pp. 

 150-153). — The iuvestigcitions have to do particularly with the influences of 

 pepsin upon pancreatin when these substances are administered together. 



Animal heat and bio-energetics, J. Lefevre {Chaleur Animale et Bio- 

 ^ncrgetique. Paris, 1011, pp. XV+1107+32, figs. 211 ) .—This exhaustive treatise 

 presents a historical and critical account of the development of the subject and 

 an extended discussion of topics concerned with the general question. The 

 main divisions include physiological calorimetry and the heat balance, thermo- 

 regulation and tbermo-genesis, general introduction to the study of bio-ener- 

 getics, and bio-energetics and general physiology. As a whole the volume con- 

 stitutes an important and exhaustive handbook and treatise. 



The numerous references to the investigations cited and the detailed index 

 are important features. 



Metabolism of plants and animals, E. Abderhalden {Internat. Hyg. Aus- 

 stellung, Dresden, 19 tl, Gruppe Emdhrung. Stofficechsel der Pfianze und des 

 Tieres. Berlin, 1911, pp. 2-'i. figs. 16). — An illustrated description of apparatus 

 exhibited at the International Exposition of Hygiene, Dresden. 1911, and a brief 

 account of the history of this line of investigation. 



ANIMAL PRODUCTION. 



The influence of maturity upon the value of timothy hay, H. J. Waters 

 (Proc. Soc. Prom. Agr. Sci., 31 {1910), pp. 71-98, figs. 8).— A report of a study 

 of the influence of time of harvest upon the yield, feeding value, keeping 

 quality, convenience of harvesting, selling value, and permanency of stand of 

 timothy hay. 



At the Missouri Experiment Station selected areas of pure timothy of uniform 

 development were harvested at 5 stages of growth, and the cured hays care- 

 fully weighed and analyzed, the average results being as follows : 



Average yield per acre of nutrients in timothy hay. 



There was no consistency in the yield of cured hay from year to year, because 

 of the variable amounts of water. There was but little difference in the yield 

 of dry matter between the second, third, and fourth stages, though the average 

 for 3 years was slightly higher in the third cutting. The decrease in yield 

 of dry matter toward maturity was thought to be due to rain, shedding of the 

 leaves, and transposition of the material to the bulb and seed. 



The results of 3 digestion trials with yearlings and 2-year-old steers on a 

 ration consisting entirely of hay, are summarized in the table following. 



