320 Journal of Agricultural Research voi. xvii. no. 6 



with a law which may be stated in this way: The absolute amount of 

 milk produced per unit of time increases with the age of the cow until the 

 maximum is reached, but the rate of increase diminishes with advancing 

 age until the absolute maximum of production is reached. After the 

 time of maximum productivity, the absolute production per unit of time 

 decreases with advancing age at a continually increasing rate. 



(12) The mean fat percentage of the milk was found to decline with 

 advancing age until the tenth year of the cow's life is reached. From 

 that point on, the fat percentage remains about constant through the 

 remainder of the milking life of the cow. 



LITERATURE CITED 

 (i) Curtis, Maynie R. 



1914. A BIOMETRICAL STT.TDY OF EGG PRODUCTION IN THE DOMESTIC FOWL. 



IV. FACTORS INFLUENCING THE SIZE, SHAPE, AND PHYSICAL CONDI- 

 TION OF EGGS. In Arch. Entwicklungs-mech. Organ., Bd. 39, Heft 2/3, 

 p. 217-327, 18 fig. pi. 6-10. 



(2) Gavin, William. ^ 



1912. THE INTERPRETATION OF MILK RECORDS. In Jour. Roy. AgT. Soc, 



V. 73. P- 153-174. 



(3) 



1913. STUDIES IN MILK records: ON THE ACCURACY OP ESTIMATING A COW'S 

 MILKING CAPABILITY BY HER FIRST LACTATION YIELD. In Jour. Agr. 



Sci., V. 5, pt. 4, p. 377-390- 



(4) Greenwood, M., Jr. 



1904. A FIRST STUDY OF THE WEIGHT, VARIABILITY, AND CORRELATION OF THE 



HUMAN VISCERA, WITH SPECIAL REFERENCE TO THE HEALTHY AND 

 DISEASED HEART. In Biomctrika, v. 3, pt. i, p. 63-83. 



(5) Greenwood, M., Jr., and Brown, J. W. 



1913. A SECOND STUDY OF THE WEIGHT, VARIABILITY, AND CORRELATION OF 



THE HUMAN viscER.\. In Biometrika, v. 9, pt. 3/4, p. 473-485. 



(6) HowiE, John. 



I91O. REPORT ON MILK RECORDS FOR SEASON I909. RECORD OP 9,202 COWS. 



[Ayrshire Cattle Milk Records Committee.] 313 p. Kilmarnock. 



(7) MacdonELL, W. R. 



1904. A STUDY OP THE VARIATION AND CORRELATION OF THE HUMAN SKULL, 



WITH SPECIAL REFERENCE TO ENGLISH CRANIA. In Biometrika, V. 3, 

 pt. 3, p. 191-244, illus., 50 pi., 8 fold. tab. 



(8) Miner, John Rice. 



1915. fitting LOGARITHMIC CURVES BY THE METHOD OF MOMENTS. In JoUf. 



Agr. Research, v. 3, no. 5, p. 411-423. Literature cited, p. 422-423. 



(9) Pearl, Raymond. 



1905. BIOMETRICAL STUDIES ON MAN. I. VARIATION AND CORRELATION IN 



BRAIN-WEIGHT. In Biometrika, v. 4, pt. i, p. 13-104. 

 (10) 



19 13. CONSTANTS FOR NORMAL VARIATION IN THE PAT CONTENT OP MIXED MILK. 



In Maine Agr. Exp. Sta. Bui. 221, p. 299-305. 



1913. NOTE REGARDING THE RELATION OF AGE TO FECUNDITY, /n Science, n. s. 



V. 37, no. 945, p. 226-228. 



(12)— — 



19 14. ON THE LAW RELATING MILK FLOW TO AGE IN DAIRY CATTLE. In PrOC. 



Soc. Exp. Biol, and Med., v. 12, no. i, p. 18-19. 



