316 ANNUAL REPORT OF THE Off. Doc. 



environment so that the characteristics of that original stock have 

 been almost completely lost and new ones introduced either in 

 whole or in part through the influence of environment; and then 

 third, and I think most important of all, and of course involving 

 the other two to a certain extent, is selection. The purpose of 

 the breeder, the ideal of the breeder, the standard that he has had 

 in mind all through these different generations, during which he 

 has been moulding and creating new forms and types. 



Now I will show you two pictures a little later of representatives 

 of two breeds, and I think the whole difference between them can 

 be accounted for in that way, it is the main factor. They are practi- 

 cally identical in blood, so far as the foundation is concerned; there 

 has been no admixture in either breed of recent date and com- 

 paratively little difference in their environment, and yet to-day they 

 are as unlike as two different horses can be, and the reason for 

 that unlikeness is the fact that the breeders of one breed have had 

 one ideal of what a draft horse ought to be and the breeders of the 

 other breed, another idea; so these are the agencies that have 

 operated, and as we work with our breeds, let us bear this in 

 Qiind, let us remember that that horse is not an individual; that 

 is an important thing to remember. 



Wlien we study the individual, the first thing to take into con- 

 sideration is whether or not he is a representative of his race. The 

 man who says he would not breed to anything but a Percheron 

 horse, may find the only Perclieron horse available a very inferior 

 individual, while there may be available a Belgian horse that stands 

 away up as a representative of his breed, and yet a man will tell 

 me he would not go to that horse because he is a Belgian. The 

 first thing to consider is whether or not the individuals available 

 to us are representatives of their race, because the individual, male 

 or female, does not transmit merely his or her own characteristics 

 but all the characteristics of their ancestors. Now if they are 

 better than the average of their ancestors, you know what the effect 

 on the offspring will be — their colts won't be as good as they are. 

 Why? Because their ancestry is pulling them down, they have shot 

 ahead of their ancestry a little bit, and yet there is the drag of 

 the race pulling them back to this common level; the average of 

 the offspring always represents the average of the ancestors; if you 

 have just an average individual, he represents the average of his 

 race and you are safe in assuming that the average of his get 

 will be just about like him. If you have got an individual that 

 stands away hiirher than the average of his breed, then you can 

 hardly expect his colt to be as good as he is. If, on the other 

 hand, you have an indivirlual away below the average of his race 

 and he is pure bred and has strong limbed, fast ancestors behind 

 him, you may expect those ancestors to help boost his offspring 

 up to a little higher level than he himself is. 



A Member: Can you say a word about the Mendel Law. 



DR. GAY: Well now, Mendel's Law has not been demonstrated 

 very clearly yet on horses. Mendel's Law has thrown a lot more 

 light on the subject of plant breeding and the breeding of rabbits 

 and guinea pigs than on horses and cattle; they have demonstrated 

 that the color of horses comes under Mendel's Law and the horn and 

 whole character of cattle comes under Mendel's Law. 



