ANIMAL FORM AN INDEX OF QUALITIES. 355 



in the performance of labor, or in the production of 

 wool and milk must not be overlooked, and even 

 then a long experience will be required to train the 

 eye and the touch to make nice discriminations in 

 essential details. 



Admitting, then, that the thorough knowledge of 

 animals that enables a person to form a correct opinion 

 as to characteristics and quality cannot be gained 

 without practical training and experience, it is never- 

 theless true that the acquisition of such knowledge 

 may be facilitated by a study of the correlated struct- 

 ure of the animal organization, so that the relative 

 value of different parts, and the relations of one organ 

 or set of organs to another, and to the entire system, 

 may be clearly understood. 



The principles that are applied in the study of 

 comparative anatomy and physiology, in tracing the 

 harmonies of structure and function in allied groups, 

 which have been discussed in a preceding chapter, 

 must then be of practical interest to the breeder, as 

 they aid him in determining the relative value of the 

 various modifications of form observed in the animals 

 he is trying to improve. 



Moreover, the external form and proportions of an 

 animal, when studied from this point of view, cannot 

 fail to furnish the most satisfactory indications of the 

 structure and functional activity of the internal organs 

 concerned in the complex processes of nutrition, upon 

 which all forms of animal products depend. 



As the greatest excellence in the production of 

 meat, or milk, or wool, or labor, involves peculiarities 

 of structure and function that adapt the animal in 



