ANIMAL. PRODUCTION. 77 



ployed In these outlines are (1) a study of the living embryo, (2) a study of 

 the entire embryo as an opaque object with a dissecting microscope and witli 

 the coiupouud microscope, after killing, hardening, staining, clearing and 

 mounting. (3) a study of embryos by dissection, and (4) studies of serial 

 sections by the microscope. 



The transformations in the fats in the hen's egg' during development, 

 Elizabeth C. Eaves (Jour. rinjsioL, .'lO (WIO), Xo. 6, pp. Jfol-'tB-i) .—The 

 increase of fat in a chicif was not as rapid as the decrease of fat in the yolk. 

 The iodin values showed that there was a change in the composition of the 

 fat, and presumably the oxidized fat was used to furnish energy for the 

 growing embryo. 



" During the first 10 days the iodin value of the yolk fat did not vary much ; 

 it decreased from 70 to 64. After this there was a marked decrease, the value 

 fell from (J4 to 4o.7. The ifxlin value of the chicken fat was at first low, 59.4 

 (<) 01.1. This may be due to the presence of other substances in the fat ob- 

 tained; in the early stages the amount of fat extracted was very small, and it 

 contained a relatively large proportion of the brown substance which is very 

 soluble in water and insoluble in water-free ether, but soluble in wet ether; 

 this brown substance is probably glycerol and glycerophosphoric acid. As 

 devolopniont proceeds the iodin value rose and after the fifteenth day was 

 considerably higher than that of the fat from a fi-esh yolk. Just as in the 

 case of the phos])horus compounds the most marked changes occur between 

 the thirteenth and twentieth diiys, the maximum being reached just before the 

 chick is hatched. The decrease in the iodin value in the yolk fat is suggestive 

 of a primary absorption of the less saturated fats with a subsequent equal 

 absorption of saturated and unsaturated fat. The increase in the iodin value 

 of the chicken fat ])oints to a desaturation of the absorbed fat." 



The action of X-rays on the developing chick, J. F. Gaskell (Proc. Roy. 

 ^oc. [London]. Her. B, 85 {1911), No. B JoV/, pp. 305-310).— When incubating 

 eggs were exjjosed to the action of X-rays the mitotic activity of the growing 

 tissue was lowered, an effect which was very evident in embryos exposed to 

 long doses, as no mitotic figures could be found in an embryo of 3 days when 

 exposed for 4 hours. Diminution was progressive even with small doses, but 

 if not too great complete recovery occurred. The critical dose which prevents 

 recovery varied with the stage of the development of the embryo, decreasing 

 as the mitotic figures decreased. No other microscopic nor macroscopic changes 

 were observed. 



Data on the relative conspicuousness of barred and self-colored fowls, 

 R. Peakl {Amer. Xat., .'lO {1911), No. 530, pp. 107-117, figs. .}).— Statistics are 

 presented which cover the hatching season of 1909 at the poultry plant of the 

 Maine Station. These show that though barred birds were relatively much 

 less conspicuous than birds of one color, the relative inconspicuousness of the 

 barred color pattern did not afford its possessors any great protection against 

 elimination by natural enemies. 



The White Orpington color problem, G. D. Black (Rcl. Poultry Jour., 18 

 (1911), No. 2, pp. 232, 269). — Some possible causes of brassiness (fading of the 

 feathers) in white breeds are suggested. The author does not think that it 

 is induced by the nature of the feeds, but on the other hand supposes it to be 

 some physiological condition that may be bred out. 



Forcing egg yield by use of artifi.cial light, W. H. Reynolds {Rel. Poultry 

 Jour., 18 {1911). No. 2. pp. 2-'i0, 2-'fl, 262-264. figs. 4).— A report of an experi- 

 ment in lengthening the " working hours " of hens in the winter season by turn- 

 ing on an electric light an hour before daylight and after dark. The egg yield 



