12 GENETICS IN RELATION TO AGRICULTURE 
ciples of genetics, therefore, are always subject to such modifications as 
may be determined by practical considerations. 
Genetics in Agriculture——Modern agriculturists, for the most part, 
appreciate fully the importance of producing only the best types of plants 
and animals; for in spite of the strange anomalies of economic conditions 
which at times appear to give actually a greater return for smaller total 
yields, the fact must remain that the larger view of the agriculturist’s 
place in society requires of him as of all its other members the fullest 
possible returns compatible with economic principles and the require- 
ments for a permanent agriculture. But although the desirability of 
high production and quality is very generally recognized, it is a fact that 
very often this ideal cannot be attained except by the most careful and 
intelligent efforts. This is more often the case with plants than with 
animals, for plants are on the whole less independent of environmental 
conditions and therefore more susceptible to differences in them. Pro- 
ducers of crops are always in need of varieties which are better adapted 
to local conditions, but except in rare cases they are not fitted to develop 
such varieties. Here genetics comes very definitely to the aid of the 
plant breeder for its principles provide a safe guide for him in attaining 
his ideal. Already breeders of plants have realized a great saving of 
time and expense as a result of the application of principles derived 
from scientific investigations in their work. 
The animal breeder on the other hand has faced a somewhat different 
problem. The far greater comparative value of the individual in live- 
stock operations has led in animal breeding to the establishment of pure 
breeds of domesticated animals of remarkable excellence. Long applica- 
tion of the method of trial and error has developed a body of empirical 
knowledge which has achieved results nothing short of the marvelous. 
But while the old empirical methods have served their purposes well, 
nevertheless they cannot from their very nature give complete satisfac- 
tion Knowledge is only secure when it rests upon a firm foundation of 
principle, and however excellent have been the results of empirical 
breeding from a utilitarian standpoint, they have not led to the discovery 
of fundamental principles. The principles of genetics provide a consist- 
ent interpretation of the results of breeding methods. To the novice a 
knowledge of such principles is an abundant aid in interpreting and organ- 
izing details of experience; by its help he can progress more safely and 
more surely in determining the methods of procedure which are es- 
sential to the fullest success in his breeding operations. The real service 
of genetics to animal breeding lies in the promotion of clarity of thought, 
and that is a thing of no little value. 
Although genetics thus far has contributed but little toward improve- 
ment of the existing methods of animal breeding, it is not a dream im- 
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