Organs of the Animal Body : their Forms and Uses. 33 
iFig. 20. — Bronchial Tiibc, with its Bronchules and ultimate Bamifica- 
tions (jiatural size). 
Fig. 21. — Postero-latcral view of the Larynx. 
means. As people understand the process, breathing consists 
in drawing air into the chest and driving it out again so many 
times in a minute ; but without going too far into the science 
of the matter, it is necessary to get beyond this very bald view. 
First, as to the number of breathings in a given time, there is 
much to be noted. A man at rest is said to breathe, that is, to 
take in (inspire) and drive out (expire) air, the double action 
VOL. XXII. — S. S. D 
