PREFACE. 
TuE past two decades have not only witnessed great activity in 
the study of the various problems of animal nutrition, but they are 
especially distinguished by the new point of view from which these 
problems have come to be regarded. Speaking broadly, it may be 
said that to an increasing knowledge of the chemistry of nutrition 
has been added a clear and fairly definite general conception of the 
vital activities as transformations of energy and of the food as 
essentially the vehicle for supplying that energy to the organism. 
This conception of the function of nutrition has been a fruitful 
one, and in particular has tended to introduce greater simplicity and 
unity into thought and discussion. Much exceedingly valuable 
work has been done under its guidance, while it points the way 
toward even more important results in the future. The following 
pages are not a treatise upon stock-feeding, but are an attempt to 
present in systematic form to students of that subject a summary of 
our present knowledge of some of the fundamental principles of ani- 
mal nutrition, particularly from the standpoint of energy relations, 
with special reference to their bearings upon the nutrition of farm 
animals. Should the attempt at systematization appear in some 
instances premature or ill-advised, the writer can only plead that 
even a temporary or tentative system, if clearly recognized as such, 
may be preferable. to unorganized knowledge. The scaffolding 
has its uses, even though it form no part of the completed building. 
The attentive reader, should there be such, will not fail to note 
that the work is limited to those aspects of the subject included 
under the more technical term of ‘The Statistics of Nutrition,” 
and that even in this restricted field some important branches of 
the subject have been omitted on account of what has seemed to 
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