94 THE MENDEL JOURNAL 



last number, carry with them a large measure of 

 utility to those who propose actually working along 

 Mendelian lines and will be of use to others interested 

 in the general problems, as showing how important 

 and widespread are the evidences of segregation in 

 the mechanism of inheritance. 



I shall in the few remarks I am about to make, 

 endeavour to show the suggestiveness of some of 

 the facts in Mr. Robertson's paper. They have not 

 only a bearing on horses but on sociological problems 

 that touch human life at many points. 



In considering Mr. Robertson's figures on page 

 55, which show that horses and colts have on the 

 whole a greater staying power than mares and fillies, 

 it is desirable to bear in mind that more horses from 

 three years of age upwards are in training for a race 

 than mares, in the proportion of 1 mare : 1*6 horses. f 

 But the proportion of mares to horses which actually 

 start in a race is as 1 : 2. This specific fact does 

 not of course invalidate the more general fact, as 

 manifested by the figures shown on page 55, that the 

 horses win more races than the mares. For not- 

 withstanding the smaller numbers entering a race, 

 if mares had more staying powers than horses, it 

 should still be manifested in a higher percentage of 



t This fact and the followmg explanation ^\•e^e kindh' supplied to me 

 by Mr. Robertson upon my enquir^y. Mr. Robertson tells me that " The 

 reason there are fewer mares than horses in training at three years old 

 and up\\ ards and still iewer which start in a race, is because during training 

 a large number of mares are found to be useless for racing after two years 

 of age ; the principal factor determining their uselessness is want of staying 

 power." 



