elasticity of the lungs. 41 
which in ordinary cases, before the chest has been opened, is 
done with difficulty. As soon as the openings were made 
into the diaphragm, it became lax, flat, and corrugated. 
Frequent repetitions of these experiments, and much care 
and accuracy in conducting them, would be required, before 
the amount of the resilience of the lungs, in all the conditions 
in which it maybe supposed to exist, could be estimated. But 
defective as these experiments in many respects are, the ob- 
iect, for which they were instituted, seems to have been fully 
attained by them. In the Inquiry into the causes of the motion 
of the blood, it was contended, that the elastic substance of 
the lungs, in consequence of the degree to which that sub- 
stance was stretched in the living body, generated a perma- 
nent power of great extent, and that this power was employed 
by nature to circulate the blood, and to carry on the process 
of respiration. The existence of this power was inferred, 
from the elastic property of the substance of the lungs them- 
selves ; from the space which those organs must fill in the 
living body ; from the phenomena exhibited upon opening 
the chest and admitting the external air ; and from the ebul- 
lition on the surface of the water into which the inverted 
windpipe of an animal had been inserted, as soon as the lungs 
were allowed to collapse. In the various examinations which 
my opinions have undergone, the existence of this power has 
been admitted, and the claim to priority in the detection and 
application of it freely conceded to me ; but it has been con- 
tended, that the amount of it, in some instances, is incon- 
siderable, and consequently that the effects ascribed to it have 
been greatly over-rated. By these experiments, the power has 
been proved to be greater, than my anticipations even made 
MDCCCXX. G 
