498 
Proceedings of the Koyal Society of Edinburgh. [Sess. 
Coat Colour in Horses. 
This case may well be considered first, as the data are large and 
probably accurate. Stud books giving the colour and pedigree of the 
horse have been in existence for many years, while the value of the 
animals and the great interest which exists in breeding combine to give 
the facts authority. 
To find the correlation Professor Pearson has divided the parents and 
offspring into groups of Bay and Darker, and Chestnut and Lighter, and 
calculated the coefficients by the fourfold method ; the coefficients as 
determined by him are as follows : — 
Inheritance of Coat Colour in Horses. 
Parental .... ’5216 
Grandparental . . . - 2976 
Great-grandparental . . *1922 
Great-great-grandparental . -1469 
Now brown and bay seem both dominant over chestnut and white,* 
at least to all intents and purposes. Chestnut with chestnut breeds true, 
and brown or bay mating with chestnut breeds in the first instance dark. 
The relations of brown and bay do not concern us, being both dominant. 
The number of pale horses not chestnut is so small that it may be neglected 
as not affecting the result to any appreciable extent. The proportion of 
these colours present is roughly that of three dark horses to one chestnut, 
though it must be borne in mind that this has nothing directly to do with 
Mendelism, but represents simply the proportions which find favour at 
present among those who breed horses. 
It is worth while reproducing the fourfold tables. That of parent and 
offspring is as follows j* : — 
Bay or Darker. 
Chestnut or Lighter. 
Totals. 
Bay or darker . 
631 
125 
756 
Chestnut or lighter . 
147 
147 
294 
Totals . 
778 
272 
1000 
This table at once reminds us of that already found from Mendel’s theory, 
namely (pars. 6 and 7) : — 
* Bateson, MendeVs Principles of Heredity, p. 124. 
t Roy. Soc. Trans., vol. clxxv. p. 35. 
