A. Because they consume so little air; and without a plentiful supply of air, combustion is so slow, that very little animal heat is evolved.
Q. Why is a dead body cold?
A. Air is no longer conveyed to the lungs after respiration has ceased; and, therefore, animal heat is no longer evolved by combustion.
CHAPTER VII.
MECHANICAL ACTION.
1.—PERCUSSION.
Q. How is heat produced by mechanical action?
A. 1.—By Percussion. 2.—By Friction. 3.—By Condensation.
Q. What is meant by percussion?
A. The act of striking; as when a blacksmith strikes a piece of iron on his anvil with his hammer.