STOCK-BREEDING 377 



No one can, of course, at present say that these " simple 

 equations " will apply to the introduction of fresh blood into 

 a herd of cattle, but the time has come for more daring ex- 

 periment on Mendelian lines. It might obviously happen that 

 the " fresh blood " (B) introduced was quite incompatible with 

 the pure-bred (A), and the progeny was an undesirable freak. 

 But do not such casualties happen under the present instinctive 

 or empirical regime followed by most breeders ? 



A few Illustrations from Stock-breeding. — As everyone 

 knows, elaborate experiments on heredity have been carried on 

 for many years by breeders of horses and cattle, and increased 

 effort should be made to tap their valuable records. We cannot 

 attempt this here, but we give two or three illustrations, kindly 

 placed at our disposal by Mr. John Marr of Uppermill, Tarves, 

 and Mr. Duthie of Collynie, two well-known breeders. As the 

 facts were partly stated in conversation, we must bear the 

 responsibility of any inaccuracies. 



In answer to a question regarding the general origin of famous 

 breeds of cattle, Mr. Marr's statement is briefly as follows : 

 " As to the historical origin of recent breeds of cattle, it seems 

 to be generally true that men like Cruickshank, Booth, Bates, 

 CoUings, and McCombie began with a more or less random 

 selection of good specimens of the ordinary stock of the country. 

 A good pedigree was at first simply a pedigree built up of good 

 individual ancestors. The second step was to strengthen the 

 herd by elimination and to fix excellence by inbreeding and 

 selective breeding. In most cases, however, there seems to have 

 been a critical moment in the history of the herd when a par- 

 ticularly good' sire turned up, such as Champion of England 

 in the history of the Cruickshank Shorthorns. The breeders 

 then used the dominant sire and his male progeny on the different 

 families of cows composing the herd, until his most excellent 

 blood seemed to permeate the whole. Finally, there seems to 

 arise a limit of profitable inbreeding, when new blood has to be 



