VARIATION THE. MLNDLL LAW. 19 



we cannot explain. It is perhaps not unnatural to suppose that what \vecannotexplain is clue 

 to causes we cannot appreciate or understand, but in this case 1 think we can see something of 

 the general method of variation even where we cannot trace every variation to its sources. 



We can control variation in just the same way, and to much the same degree as we can 

 heredity, of which variation is one manifestation. That is, strictly speaking, we cannot control 

 it at all, but relying on the general law on average results we generally secure likeness in the 

 features we prize most, and avoid variations except in conspicuous characters. Yet In many 

 <-ases, having once found that a fowl, or the fowls of a certain line are strongly prepotent in 

 any direction, either for impressing high excellence according to established standards or for 

 the development of new and better types that knowledge may be made of great practical and 

 commercial value. The ability to discover and to use prepotent fowls and types that are better 

 or more attractive than those prevailing is one of fhe best personal assets a breeder of fowls can 

 have. It depends very much upon a knowledge of the phenomena and the principles of breed- 

 ing. Most of our successful breeders have a pretty thorough practical understanding of the 

 MI bject, though few can be found who can give a good systematic presentation of what they 

 know about breeding, and nearly all cling to some ideas about breeding which I have little 

 doubt they would quickly discard if once they put all their knowledge and thoughts about 

 breeding together in such a way that the inconsistencies in them would be clear. 



To the novice in breeding the first use of a knowledge of the principles and phenomena of 

 heredity should be to give him a more correct view of the actual status of so-called pure bred 

 stock, and through this to make him slower to condem,n breeders for faults in stock bought of 

 them. When a novice buys breeding stock it is sometimes subjected to several conditions not 

 favorable to best breeding results. The change of climate and environment may or may not be 

 advantageous. The effects of such changes are different with different individual fowls. The 

 same change may be beneficial to one, indifferent to another, detrimental to another; and these 

 results may be directly reflected in their progeny. With such small lots of fowls as are usually 

 purchased for breeding, it may happen that all are affected alike, and if the change is in any 

 degree detrimental the breeding results may be disappointing. The tendency in such cases is 

 to go back to obsolete types and characters, ami quite a variety of these may reappear at the 

 same time. Sometimes these results occur at first, but after the fowls become accustomed to 

 the change they breed right. For this reason it is best not to condemn good fowls on the first 

 season's breeding under new conditions. 



Very often the care and feeding the novice gives bis breeding stock are not favorable to good 

 breeding condition and results. Add to this the fact that manv novices practice buying from 

 different breeders to avoid inbreeding, and mate the birds without any knowledge of them, and 

 we have a combination of causes for reversion to obsolete types and characters, and it is not 

 difficult to account for the skepticism with which after a season or two breeding this way, 

 many a novice regards the statements of older breeders as to the proportion of birds of good 

 breeding quality produced from their matings. 



The Mendel Law. 



For several years past breeders of live stock have been showing more and more interest in 

 some experiments made years ago by a German scientist named Mendel, which have only 

 recently began to get the attention they deserved, but which now seem in a fair way to be con- 

 sidered of more importance than is actually warranted. The "Mendel law" is very glibly 

 discussed and applied by not a few people who have not grasped the meaning of that law at all, 

 and are equally uninformed about many of the cases in which they attempt to apply it. 



Two years ago I gave in FARM-POULTRY a statement of Mendel's law, and some observa- 

 tions on its application to poultry breeding and practical value to poultrymen. The number in 

 which this appeared was almost immediately out of print. So many calls for the article have 

 been made that as It is right in line with the subject of this lesson, and as it seems advisable to 

 have it in permanent form, I reprint here that part of the article relating exclusively to the 

 Mendel law. 



