LAW OF VARIATION. 57 



where a farmer, from a distance purchased a two year 

 old heifer of the stamp referred to, for the purpose of 

 improving his polled cattle, and for this heifer he paid 

 fifty guineas." 



The knowledge of this law* gives us a clue to the 

 cause of many of the disappointments of which practical 

 breeders often complain and to the cause of many vari- 

 ations otherwise unaccountable, and it suggests par- 

 ticular caution as to the first male employed in the 

 coupling of animals, a matter which has often been 

 deemed of little consequence in regard to cattle, inas- 

 much as fewer heifers' first calves are reared, than of 

 such as are borne subsequently. 



Another faint ray of light touching the causes of 



» A very striking fact may be related in this connection, which 

 while it may or may not have a practical bearing on the breeding 

 of domestic animals, shows forcibly how mysterious are some of the . 

 laws of reproduction. It is stated by the celebrated traveler, Count 

 de Strzelecki, in his Physical Description of New South Wales and 

 Van Dieman's Land. " Whenever," he says, " a fruitful intercourse 

 has taken place between an aboriginal woman and an European male, 

 that aboriginal woman is forever after incapable of being impreg- 

 nated by a male of her own nation, although she may again be 

 fertile with a European. " The Count, whose means and powers of 

 observation are of the highest possible order, affirms that " hundreds 

 of instances of this extraordinary fact are on record in the writer's 

 memoranda all recurring invariably under the same circumstances, 

 all tending to prove that the sterility of the female, which is relative 

 only to one and not to the other male is not accidental, but follows 

 laws as cogent though as mysterious as the rest of those connected 

 with generation." The Count's statement is endorsed by Dr. Maun- 



