1919] ANIMAL PRODUCTION. 179 



calendar year of 1918, classified by counties. As in previous reports (B. S. R., 

 39, p. 73) a statistical summary is included. During the year tliere were en- 

 rolled 2.231 pure-bred stallions, a decrease of 325 from the 1917 totals; 1,182 

 grade and scrub stallions, a decrease of 496; 775 pure-bred jacks, an increase 

 of 34 ; and 409 grade and scrub jacks, a decrease of 70, 



Internal factors influencing egg production in the Rhode Island Red 

 breed of domestic fowl, H. D. Goodale {Amer. Nat., 52 {1918), Nos. 614-615, 

 pp. 65-94; 616-617, pp. 209-232; 618-619, pp. 301-321, figs. 40).— This paper from 

 the Massachusetts Experiment Station is described as a survey of the prob- 

 lem of egg production and a preliminary analysis of an egg record into its 

 constituent elements. It is pointed out that the number of eggs laid in unit 

 time is not an adequate measure of a hen's production, is an unsafe basis for 

 breeding operations, and can not be used satisfactorily to study the effect of 

 selection, because it is a complex character dependent upon the interplay of 

 such internal factors as age at which the laying starts, rhythm and persist- 

 ence of production, tendency to broodiness, occurrence of seasonal egg cycles, 

 etc., each of which must be studied separately with respect to its influence on 

 the numerical record and as to its mode of inheritance. The illustrative data 

 are selected from the records of the Rhode Island Red pullets hatched at the 

 station in 1913 and 1915. 



Comparing his Rhode Island Red flock with the Maine Station Barred Plym- 

 outh Rock pullets studied by Pearl (E. S. R., 28, p. 576), the author finds 

 that in the former individual pullets show great variations in the age at 

 which they begin laying but that when once started they lay at a fairly 

 uniform rate throughout the winter, whereas in the Plymouth Rocks laying 

 begins at about the same age but continues at widely varying rates. For 

 Rhode Island Red pullets hatched in March and April, 1913, the average age 

 at first egg was 201.2 days, with a standard deviation of 24.3 days. For pul- 

 lets hatched in March, April, and May, 1915, the mean age was 263.2 days 

 and the standard deviation 37.7 days. 



The measure of an individual's rate of production is taken as the percentage 

 of days on v.hich an egg was secured between the date laying began and 

 March 1. The rate of the 1913 flock averaged 62.5, with a standard deviation 

 of 15.8 per cent. For the 1915 flock, the average rate was 54.6 and the stand- 

 ard deviation 18.5 per cent. For the 1915 flock, the average rate was 54.6 

 and the standard deviation 18.5. The precise figures for the Maine flock with 

 respect to age at first egg and rate of production are not available, but the 

 author has confirmed his interpretation of published statements by personal 

 conference with Pearl. The differences between the two flocks make it impos- 

 sible to classify the Rhode Island Red genetically into mediocre and high pro- 

 ducers by the size of the winter egg record as was done satisfactorily in the 

 case of the Plymouth Rocks. 



Suggestions as to the influence of growth, maturity, stamina, and molt on 

 the egg record are given. Seasonal cycles seem to be of no practical impor- 

 tance in Rhode Island Reds for, as the author has indicated (E. S. R., 38, 

 p. 876), the distinction between winter and spring production in this breed 

 is arbitrary. The number of broody periods and the age incidence of broodi- 

 ness are found to be highly important, but a complete discussion of these is 

 reserved for a future publication of which a preliminary note has been is- 

 sued (E. S. R,, 37, p, 869). 



Commercial preservation of eg'gs by cold storage, M. K. Jenkins {U. S. 

 Dcpt. Agr. Bui. 115 (1919), pp. 35, pis. 6, figs. 8).— This contribution from the 

 Bureau of Chemistry is based upon the systematic examination of 841 30-doz. 

 cases of eggs of varying grades (April, May, June, and July firsts, June and 



