DAIRY FARMING DAIRYING. 173 



occurred in from 30 to 60 parts per 10.000, but as the amount rises above 150 

 parts tliere is a marl^ed decrease in the number of chiclvens hatched. 



It is concluded that in all incubators carbon dioxid will be found, and that 

 while its presence is not essential to successful incubation its occurrence up to 

 60 parts in 10,000 is not prejudicial to incubation. Factors influencing the 

 amount of carbon dioxid in the egg chamber of an incubator are rate of venti- 

 lation, number of embryos, period of incubation, size of egg chamber, tem- 

 perature, and carbon dioxid in the air of the incubator room. 



Natural and artificial incubation of hens' eggs, 11. M. Lamon ( XJ. S. Dept. 

 Agr., Farmer.^' Bitl. 585 {ISlIf), pp. J6, figs. 3).— This bulletin gives directions 

 for the incubation of eggs, both natural and artificial ; describes the several 

 types of incubators ; and discusses their selection and care. 



The problem of moisture and ventilation requirements in incubation is dis- 

 cussed and the methods of testing eggs described. 



Electro-cardiogram for embryo chicks, J. K. A. Wertheim-Salomonson 

 iPfliigcr's Arch. Physiol., 153 {1913), No. 11-12, pp. 55S-573, figs. 23).— This 

 article reports observations made of the electro-cardiogram of the embryo chick. 



DAIRY FARMING— DAIRYING. 



Dairying, J. P. Sheldon (London, New York, Toronto, and Mclhourne, 1912, 

 pp. Xn-\-Ji65, pis. 33, figs. 21). — A comprehensive book treating of the principal 

 breeds of dairy cattle and the feeding, care, and management of dairy animals, 

 and including chapters on soils and climates suitable for dairying, land and its 

 betterment, manuring and treatment of soils, butter making, cheese making, 

 and cooperative dairying in England. 



Dairying in Nova Scotia (Halifax. N. .<?., 1912, pp. 112, pis. 11, figs. 8). — This 

 is a reprint of the annual report of the Secretary of Agriculture of Nova Scotia 

 for 1908, revised to date, and is a compilation of articles on general dairying 

 topics, with sjiecial reference to Nova Scotian conditions. 



[Dairy husbandry] (Rpt. Dept. Agr. N. S. Wales, 1913, pp. 5, 7, 30->36).— 

 This report deals with the production and consumption of dairy products in 

 New Zealand, the qualit.y and price I'eceived for butter, oleomargarine com- 

 petition, the cheese industry, and general dairy statistics. 



[Dairy husbandry], T. L. Haeckeb (Minnesota Sin. Rpt. 1913, pp. 22-25, 

 SO). — From feeding trials conducted with dairy cows it appears that 11 lbs. of 

 mangels or 9 lbs. of ruta-bagas are equivalent to 1 lb. of mixed grain, carrying 

 about 10 per cent digestible protein with a nutritive ratio of 1:6 or such a 

 mixture as would result from using equal parts of wheat bran and corn meal. 



Studies made of the protein requirements of the animal body and for milk 

 production have demonstrated the importance of long-time experiments. " The 

 animal body can stand shortage of protein for several months, and then show 

 the bad effect only to the trained observer. It was found necessary to continue 

 the cows on low-protein diet for three years before it was possible to state the 

 effect with certainty. When the change does come, it comes quickly, and the 

 results are marked." 



Manuring of grass land for milk and meat, B. F. Davis (Field Expts. 

 Harper-Adams Agr. Col. and Staffordshire, Rpt. 1913, pp. 4-7, fig. l).—ln 1911, 

 three plats of 3i acres each were drained and treated with ground limestone 

 at the rate of 15 cwt. per acre. Manures were applied as follows: Plat 1, 

 superphosphate 2i cwt. per acre; plat 2, superphosphate 2* cwt. and sulphate 

 of potash i cwt. per acre ; and plat 3, no manure. During 1912 and 1913 the 

 manurings were repeated. 



