65 
of the rib, perhaps from the compression of 
the air in the lungs by the action of the 
Diaphragm, then a downward fall for a 
space of about 0’2 in., and afterwards an 
almost horizontal in-drawing of the rib 
(Fig. 5) quite unlike anything that could 
be produced by the simple angular move- 
ment of the rib. 
5. That in sneezing the course of the 
rib is similar to that taken in the act 
of coughing, except that there is no for- 
ward bulging at the commencement of 
expiration (Fig. 6), and in the latter part 
of its course the rib only drops about 
0T5 in. for 0*8 in. of in-drawing. 
6. That in the dead subject, the 
movement of the end of the ribs, when 
simply raised and depressed (fig. 7), 
approximates to a segment of a circle. 
7 . That as age advances there is an approach to the form 
of curve traced by the unyielding rib, and the upward and 
downward strokes are more nearly alike. 
From the above facts it follows that the horizontal in- 
drawing of the rib, in the spasmodic actions of coughing and 
sneezing, is impossible without an inbending of the rib itself, 
and that the variations in healthy breathing are chiefly to be 
ascribed to the influence of the muscles of forced expiration, 
which produce more or less bending of the rib during their 
action. 
In disease a comparative feebleness of the respiratory track 
is to be noticed, and the want of elasticity of the chest is 
evidenced by the tendency to similarity in the upward 
and downward course of the ribs, 
