Provisionally, I should doubt the statement until incontrovertible evidence is produced.
"I am not perfectly clear what a silver is, but I take it that a silver fox is to a red fox what a silver tabby is to a common tabby, viz., the same thing devoid of the red or yellow element. It may be difficult to disentangle the relations of the colour when there is a series of gradational forms* and, in the first instance, I should try to get a family in which the distinction between the reds and the silvers was sharp. Then I should breed the silvers together—brother and sister if need be.
"From what you say, I infer that two silvers of opposite sexes cannot be gotten to start from. That being so, you must mate together the silvers produced which you will raise from the reds produced by mating red and silver—if only reds come. But, if silvers come, then mate them together or back with the silver parent.
"Apart from the great practical difficulties which there are in breeding foxes in domestication, I think you will easily fix a strain of silvers."
Professor Bateson outlined perfectly the fox-breeding experiences of ranchers. Those who have spent their time working with gradational forms like the cross or patched foxes do not know what they will get until mating tests are made. Those who have chosen two distinct colour types are able to breed out to the pure recessive type in two generations.
Dr. Eugene Davenport makes an explanation of the
Characters That action of Mendel's Law of Hybrids that will prove Do Not Blend
instructive to many breeders. He says:
"When diverse characters are thus brought together two very different results may follow. They may blend into a single new character, in which case our figures show the proportions within the blood, or they may remain distinct as two independent characters within the same individual. Stature and size as well as many colours blend freely, but not all characters behave in that simple way. For example, white and black blend freely in the human race, and the offspring of white and negro are mulattoes of various shades, according to the respective infusions; but colours do not blend in pigs, which are either black, white, or spotted, never roan or mulatto. Some colours blend in horses (roan) ; some do not. Some breeds of cattle have blended colours (Shorthorns) ; in others. the colours remain distinct (Holstein-Friesian).
* Such as cross foxes.