stead of throwing the labour intended for them upon the comparatively
weak and delicate muscles governing the outlet of the windpipe.

To make the way in which respiration is carried on clearer still, I
quote the following interesting and lucid account from Huxley's
"Elementary Physiology," fourth edition, p. 104. He compares the
breathing apparatus to "a sort of bellows without a valve," in which
the chest and the lungs represent the body of the bellows, while the
windpipe is the pipe; "and the effect of the respiratory movement is
just the same as that of the approximation and separation of the handles
of the bellows, which drive out and draw in the air through the pipe.
There is, however, one difference between the bellows and the
respiratory apparatus, of great importance in the theory of respiration,
though frequently overlooked, and that is, that the sides of the bellows
can be brought close together so as to force out all, or nearly all, the
air which they contain, while the walls of the chest, when approximated
as much as possible, still enclose a very considerable cavity; so that
even after the most violent expiratory effort, a very large quantity of
air is left in the lungs."

=Respiration=, consequently, consists of two acts--namely, inspiration and
expiration. Inspiration may be produced in three different ways--(1) By
pushing the chest forward and flattening the midriff, so as to compel
the lungs to _descend_ and to increase in volume in order to fill the
empty space created by this movement; (2) by extending the ribs
_sideways_; and (3) by _drawing up_ the upper parts of the
chest--namely, the collar bones (pl. III, C C) and the shoulder blades.
In scientific works the first is called diaphragmatic or abdominal,[B]
the second lateral or costal, and the third clavicular or scapular
breathing. As, however, these terms convey no meaning to the general
reader, I prefer to speak of--(1) Midriff Breathing; (2) Rib Breathing;
(3) Collar-bone Breathing. In taking a full, deep inspiration, midriff
breathing and rib breathing take place almost together and assist each
other--that is to say, the midriff contracts and flattens, and
immediately afterwards the ribs extend sideways; with this difference,
however, that in men the action of the midriff takes a larger share in
the work than the ribs, while in woman, on the contrary, the movement of
the ribs is greater than that of the midriff.

By way of illustrating