1174 EXPERIMENT STATION EECORD. 



In general, the chicks were fed on cli-y rations scattered at first on boards, 

 later in straw, and then from hoppers. 



The author also discusses the symptoms and possible cause of white diarrhea 

 in chicks. 



The experiments on which the author's discussion is based in considerable 

 degree are noted below. 



Humidity in relation to incubation, W. H. Day (Ontario Dcpt. Agr. Bui. 

 163, pp. 29-50, figs. 5). — Experiments and methods followed in the study of 

 humidity in incubators and nests are described and experimental data re- 

 ported. 



With hens on earth nests the humidity as determined was 70.8 and the 

 eAaporation 9.7. With straw nests and ventilated nests the humidity was 52.8 

 and 35, respectively, and the evaporation 11.9 and 14.5. With buttermilk as 

 a source of moisture in the incubator the humidity was .54.4 and the evaporation 

 9.5, and when a sand tray wet with water was thus used the humidity was 

 46.2 and the evaporation 9.6. Similar values in a dry incubator were 21.3 and 

 14.5 on an average. 



In the author's opinion, these facts indicate that the circulation is greater 

 in the nests than in the incubators. " Perhaps proper circulation is the vitaliz- 

 ing power that must be combined with those already established to place arti- 

 ficial incubation abreast or possibly in advance of the natural process." 



Carbon dioxid in relation to incubation, C. C. Thom {Ontario Dept. Agr. Bui. 

 163, pp. 51-56, fig. 1). — ^As shown by the author's studies, the air under hens in 

 nests contained on an average 31.93 volumes of carbon dioxid per 10,000 volumes 

 of air, the highest value, 37.14, being noted in a flat nest and the lowest value, 

 24.08, in a ventilated nest. With incubators the values ranged from 5.86 in the 

 case of a dry incubator treated with disinfectant to 58.21 in a dry incubator 

 into which lamp fumes were conducted. In the incubator room the carbon 

 dioxid content was 7. 



"Although the work on carbon dioxid is not conclusive, the results so far 

 furnish much valuable data, and establish many useful relationships. Just 

 what function, if any, carbon dioxid performs in incubation, and to what ex- 

 tent it is essential, is a point on which we have not at present sufficient experi- 

 mental data to warrant conclusions." 



Chemical work in connection with, incubation problems, R. Harcoukt and 

 H. lu. FuLMER (Ontario Dept. Agr. Bui. 163, pp. 57-66). — Determinations were 

 made of the peix*entage weight of shell, white, and yolk and the phosphoric acid 

 and calcium oxid in each in a large number of samples of eggs. The results 

 show a variation in weight of 44.27 to 65.28 gm. in the average eggs from differ- 

 ent hens. On an average egg white and yolk together contained about 0.11 to 

 0.13 gm. phosphoric acid and about 0.03 to 0.04 gm. calcium oxid, " a very small 

 amount to supply all the lime necessary for the formation of bone in the young 

 chick." 



Studies were also made of the lime content of eggs during different periods of 

 incubation. 



" It was soon found that after 11 days of incubation there was practically 

 the same amount of lime in the partially developed chick as there was in the 

 contents of the original egg, but that at the end of the incubation period there 

 was a very decided increase." 



Studies were made of the appearance of chicks at hatching with reference to 

 the absorption of lime from the shell and analyses were made of the bodies of 

 chicks hatched in different ways. 



" While we do not wish to draw any definite conclusion on the comparatively 

 small amount of work which has as yet been done, still we think it worthy of 



