118 
Heredity in Production of Bidter Fat 
function is probably at least as large as the coefficient of mean parental inheritance 
of physical characters in man*. 
(e) Inheritance in production is more pronounced in mature than in immature 
cows. 
(/) A comparison of the results corrected for selection with the uncorrected 
values illustrated the great influence of selection in modifying the correlation 
coefficient. 
(11) Descri])tion of Tables. 
(a) Ages in Tables are expressed in years. 
(b) Pi'oduction is expressed in pounds of butter fat made in seven consecutive 
days. 
(c) In Table IL, about one-tenth of the variates are re-entries, where we mean 
by a re-entry that a cow has a previous record. In Table IV., one-half the variates 
are re-entries. In Tables IV., X.-XIIL, there are given only first records of 
offspring. 
(d) In some Tables, the class values are 10-75, 11-75, ... instead of integral 
values. This grouping arises out of the fact that we first grouped in ^ pound 
groups and found these groups narrower than desirable, 
(e) The terra " offspring " as used in Tables VI., VII., X., XI. means offspring 
of the second generation removed, that is, granddaughters. 
Illinois Agricultural Experiment Station. 
March 18, 1909. 
* [It is worth while noticing also that whereas the parental correlation for mature cows is about -63 
that for grandparents on the average = ?; (-38+ '2.5) = ^ (-63) or, within the limits indicated by the 
probable errors, maybe taken as 7inZ/the parental correlation. Considering the difficulties of correcting 
for selection pointed out by Dr Eietz, it is not unjustifiable to suppose these relationships are in close 
accordance with the values of inheritance found for man. Ed.] 
