SECT. XVII. PHYSIOLOGY. 145 
cccLx1. Harvey thought that the blood ceasing 
to flow by the ductus arteriosus, was the cause of 
inspiration ; this idea is to take the effect for the 
- Cause. 
ccecLxu. Dr. Bostock seems to have had 
more philosophical notions regarding the first 
inspiration. In utero, the foetus is rolled up on 
itself, and the lungs are collapsed, but quite 
ready to expand when the incumbent pressure 
is remoyed. The pressure of. the ribs upon the 
lung, is partly removed by the uncoiling of the 
foetus after birth; the diaphragm, in place of 
being pushed upon them by the abdominal vis- 
cera, is relieved, in some degree, from this force, 
by the body of the infant being placed in a 
straight position ; a partial expansion of the lungs, 
and the removal of pressure from them, is,. of 
course, synchronous. But, excepting this uncoiling 
of the foetus at birth, I can perceive no difference 
between the cause of the first inspiration and any 
other. Whenever the placenta is separated from 
the uterus, or the umbilical cord tied, why should 
not the venous blood of an infant operate on the 
muscles of inspiration in the same manner as 
in the adult? If the uncoiling of the foetus 
account fully for the first inspiration, why are the 
lungs of still-born infants not partially inflated by 
the developement of birth ? 
T 
