670 



EXPERIMENT STATION KECOKD. 



the essential factors? concerued iu the determination of the degree of variation 

 in size and shape exhibited by birds' eggs are purely physiological and in no 

 direct or immediate way (if at all) related to the action of natural selection. 

 It does not appear from the evidence that it is essential to the survival of a 

 wild bird that its egg shall be less variable than those of the domestic fowl, in 

 which egg variation obviously has no survival value whatsoever. 



"A study of intraindividual variation indicates that the relative variability of 

 eggs is a definite characteristic of the individual, some birds characteristically 

 laying eggs which are extremely variable and other birds characteristically pro- 

 ducing eggs which are very uniform. There is on the avei-age a considerable 

 reduction in variability in passing from the race to the individual. This 

 amounts in the case of length to 32 per cent and iu the case of breadth to 41 per 

 cent. Some individuals may show a greater variability both absolute and rela- 

 tive than a random sample of the eggs of the race from which the individual 

 comes. The rule that length is more variable than breadth is reversed in the 

 eggs of some individuals. Seven per cent of the birds studied produce eggs 

 which are more variable iu breadth than in length. In general a hen which 

 characteristically lays an egg longer than the average also lays an egg which 

 tends to be wider than the average. The same sort of correlation holds in 

 regard to the variability of the product. A hen which characteristically lays an 

 egg which is unusually variable in length also exhibits an unusual degree of 

 variation in the breadth of her product." 



These " data are of value iu connection with all physiological and genetic 

 studies in regard to the production of eggs. They also have a significant rela- 

 tion to the economic problem of the improvement of eggs in I'espect to quality 

 and uniformity by breeding." 



Artificial hatching- of chicks, W. F. Schoppe (Montana Sta. Circ. 34 (1914). 

 pp. 169-189. figs. 5). — This circular gives general information on the care and 

 management of incubators, the type of eggs to use for hatching, etc. 



DAIRY FARMING— DAIRYING. 



Investigations in milk production, T. L. Hakcker (Minnesota .S'/o. BuJ. 140 

 (1914), PP- 'i/-'^^')- — This is a continuation of work previously noted (E. S. R.. 14, 

 p. 1003), a portion of the results of which are used in the general summary of 

 results in the present work. The studies herein reported covered seven 

 winters, 1902-1909. 



A summary of the average dry matter and digestible nutrients consumed and 

 dairy products yielded dally during nine winters of stall-feeding is given iu 

 the following table: 



Summary of average nutrient.<< consumed and dairy products yielded per cow 



in stall feeding. 



