BREEDS AND THE PRINCIPLES OF BREEDING. 419 



&quot;Whether this is true or not, it is now impossible to determine, but the constancy of this 

 peculiarity, even in the produce of other breeds crossed with the Dorking, would seem to 

 indicate that it is a character which has been fixed by long-continued inheritance. In the 

 Houdan fowls, when first introduced into England from France, a fifth toe was rarely seen- 

 but at the present time it is nearly as constant in this breed as in the Dorkings. 



Herbert Spencer very justly remarks, in connection with the monetary aspect of breed 

 ing: &quot; Excluding those inductions that have been so fully verified as to rank with exact 

 science, there are no inductions so trustworthy as those which have undergone the mercan 

 tile test. When we have thousands of men whose profit or loss depends on the truth of the 

 inference they draw from simple and perpetually repeated observations; and when we find that 

 the inference arrived at and handed down from generation to generation of those deeply- 

 interested observers has become an unshakable conviction, we may accept it without hesita 

 tion. In breeders of animals we have such a class, led by such experiences and entertaining 

 such a conviction, the conviction that minor peculiarities are inherited, as well as major 

 peculiarities.&quot; 



A difference in conditions will frequently lead to different results, as is instanced by the 

 physical changes brought about in animals by a change of food, climate, etc. It is stated by 

 good English authority that none of the English breeds of sheep can be kept absolutely 

 pure in France, the lambs of even the first generation losing vigor as the heat of summer 

 comes on, and the breed soon becomes degenerate. Notwithstanding the changes brought 

 about by different conditions, there is a fixed law of heredity clearly recognized in breeding, 

 which is to a greater or less extent under the control of the breeder, hereditary powers being 

 capable of becoming increased or diminished, according to the course pursued. 



Variability. It sometimes happens that the offspring differ very materially from the 

 parents. In many instances this will be due to a reversion to the original type, the variation 

 being derived from some remote ancestor, the peculiar characteristics of which are occasion 

 ally seen cropping out in successive generations. Such cases will properly be classed with 

 those of reversion, and not of true variation, where external causes may produce some con 

 stitutional or other change in the parent, which being transmitted to the offspring becomes 

 correlated with some other change, which causes new characters to make their appearance. 

 Hence, in selecting a certain character many other peculiarities may become correlated with 

 the first or original one. It is a principle in breeding that all true changes or modifications 

 which occur influence subsequent developments of the same parts, and also of others with 

 which they are intimately connected. Dr. E. L. Sturtevant, in. referring to correlated varia 

 tions, says: 



&quot; In the correlations between bone and hair, we have different structures built up in part 

 from the action of the same forces, as is shown by the history of their development. &quot;VVe 

 therefore have a certain affinity between them, and a change impressed on one is apt to be 

 followed by corresponding changes in the other. Were we sufficiently acquainted with the 

 forces which go towards making up the animal, the numerous immediate forces could be 

 referred to successive intermediate forces, into which they could be grouped, until finally the 

 simple force would be reached, a conception expressed by vitality in the abstract. Correla 

 tion is consequently but another expression of persistence of force. It is a recognition of 

 the mutual dependence of all structures upon simple, harmonious law.&quot; 



Prof. Brewer, an authority previously referred to in this department, expresses his opin 

 ion on this subject as follows: 



&quot; Heredity is not the only influence or force at work in the production and growth of 

 the living plant. The seed is a marvelous thing; it is commonly very small, compared with 

 the mature plant, a seed of the giant Sequoia of California is no heavier than a mustard 

 seed, yet, stored in that little grain are all the powers derived from parents and ancestors 



