ON THE INHEKITANCE IN COAT-COLOUE OF 
THOROUGHBRED HORSES (GRANDSIRE AND 
GRANDCHILDREN). 
By N. BLANC hard, B.A., Caius College, Cambridge. 
Dr E. Warren's recent paper on inheritance in Aphis incidentally draws 
attention* to the need for determining further correlations between grandparent 
and offspring. At the suggestion of Professor Karl Pearson I have worked out two 
further cases for the inheritance of coat-colour in thoroughbred horses. Using his 
index of coat-colours for the chief sires I extracted from Weatherby's Studbooks 
the coat-colours of 1000 colts and their paternal grandsires, and of 1000 fillies and 
their paternal grandsires. The correlation Tables I. and II. were then formed in 
the manner described in Pearson and Bramley-Moore's memoirf on inheritance of 
coat-colour in thoroughbred race-horses. These tables were then reduced to the 
fourfold division : 
Paternal Grandsires 
Bay and 
darker 
Chestnut and 
lighter 
Totals 
Bay and darker 
Chestnut and lighter 
494 
143 
213 
150 
707 
293 
Totals 
637 
363 
1000 
Paternal Grandsires 
Bay and 
darker 
Chestnut and 
lighter 
Totals 
Bay and darker 
Chestnut and lighter 
485 
119 
237 
159 
722 
278 
Totals 
604 
396 
1000 
* Biometrika, Vol. i. p. 129, 
Biometrika i 
t Phil, Trans. Vol. 195, A, pp. 92 et seq. 
38 
