92 PRINCIPLES OF ANIMAL NUTRITION. 
metabolism, and while contributing its quota towards maintaining 
the normal temperature of the body is not directly available for 
other purposes. In other words, the question is not one as to the 
total energy liberated, but as to its form and distribution. As 
regards the fasting animal itself, the question is of minor impor- 
tance; but, as will appear in subsequent chapters, it materially 
affects our views as to the relative values of the several nutrients 
of the food. 
