is the oxygen in the blood used up by the wants of the system, so the
supply of prana taken up by the nervous system is exhausted by our
thinking, willing, acting, etc., and in consequence constant
replenishing is necessary. Every thought, every act, every effort of
the will, every motion of a muscle, uses up a certain amount of what
we call nerve force, which is really a form of prana. To move a muscle
the brain sends out an impulse over the nerves, and the muscle
contracts, and so much prana is expended. When it is remembered that
the greater portion of prana acquired by man comes to him from the air
inhaled, the importance of proper breathing is readily understood.




CHAPTER V.


THE NERVOUS SYSTEM.

It will be noticed that the Western scientific theories regarding the
breath confine themselves to the effects of the absorption of oxygen,
and its use through the circulatory system, while the Yogi theory also
takes into consideration the absorption of Prana, and its
manifestation through the channels of the Nervous System. Before
proceeding further, it may be as well to take a hasty glance at the
Nervous System.

The Nervous System of man is divided into two great systems, viz., the
Cerebro-Spinal System and the Sympathetic System. The Cerebro-Spinal
System consists of all that part of the Nervous System contained