Vol, 6, 1920 
GENETICS: R. PEARL 
233 
qualities are consequently more inbred than the group of sires with superior 
transmitting quaUties. 
9. The analysis of the pedigrees for the amount of relationship that may 
exist between the sire and dam of the individual bulls in the superior group 
and in the inferior group shows that there is little or no difference in the 
amount of this relationship within the two groups. 
10. The resolution of the four generation pedigrees into the Island bred 
Jerseys and by difference into the American bred Jerseys showed the mean 
number of Island males in the pedigrees of the superior sires' group to be 
8.07 and the mean number of females 7.79. The mean number of Island 
bred males in the inferior sires' group were shown to be 6.94 and the mean 
number of females 6.55. The group of sires which increased the production 
of their daughters over that of their dams had, consequently, more Island 
bred stock in their pedigrees. The females in each group of the pedigrees 
had a smaller proportion of Island bred individuals than the males had in 
each of the groups. 
11. Study of the pedigrees of these two groups of sires discloses the fact 
that all the animals which appeared in the pedigrees of the superior sire 
on the male side of the pedigrees more than four times or on the female 
side of the pedigree more than three times also had appearances in the 
pedigrees of the sires inferior in their transmitting qualities. This fact 
alone makes it clear that the appearance of certain famous animals in 
pedigree of a given bull is no guarantee of that particular bull's worth. 
My former student and successor at the Maine Experiment Station, 
Dr. John W. Gowen, expects presently to publish similar investigations 
for the other chief dairy breeds. It is a great pleasure to acknowledge the 
faithful and painstaking help of my two assistants, Mr. John Rice Miner 
and Dr. John W. Gowen in bringing this investigation of the Jersey breed 
to completion. Without their aid it is doubtful if this would ever have 
been finished, particularly in view of the influences, which have operated 
on my own scientific work during the past three years. 
^ Pearl, R., and Surface, F. M., Studies on the Physiology of Reproduction in the 
Domestic Fowl II. Data on the Inheritance of Fecundity obtained from the Records 
of Egg Production of the Daughters of "200-Egg" Hens. Maine Agric. Expt. Stat. 
Ann. Rept., 1909, pp. 49-84. Also Pearl, R., and Surface, F. M., Is there a Cumulative 
Effect of Selection? Zs. Ind. Abst. Ver., 2, 1909 (257-275). 
2 Pearl, R., Breeding for Production in Dairy Cattle in the Light of Recent Advances 
in the Study of Inheritance, Eighth Ann. Rept. Comm. Agr. Maine, 1910, pp. 118-129. 
3 The complete paper will have the following bibliographic status: Pearl, R., Gowen, 
J. W., and Miner, J. R. Studies in Milk Secretion, VII. Transmitting Qualities of 
Jersey Sires for Milk Yield, Butter-fat Percentage and Butter Fat, Maine Agr. Expt. 
Stat. Ann. Rept. for 1919, pp. 89-204. 
4 Pearl, R., On the law Relating Milk Flow to Age in Dairy Cattle, Proc. Soc. Exp. 
Biol. Med., 12, 1914 (18-19). 
