42 1 
and functmis of the nerves. 
and of that muscle of the cheek which makes the dimple in 
smiling. It was then evident that the child could not recover; 
that all but the system of respiratory nerves had lost their 
powers ; that the features, as far as they were subject to the 
influence of the other nerves, had fallen. 
There are conditions of the lungs, when the patient is in 
great danger, and yet the inflammation is not marked by the 
usual signs of pain and difficult motion of the chest. We 
shall see nothing but the twitching of those muscles of the 
face, which are animated by the respiratory nerve. We see 
a certain unusual dilatation of the nostrils, and a constrained 
motion of the lips, which with the change of voice is just 
sufficient to give alarm, and indicate the patient's condition. 
This is a state of the lungs very often produced after severe 
accidents, as gun-shot wounds, and after great surgical opera- 
tions. 
These circumstances are stated to prove, that the subject 
of expression is not foreign to medical studies ; and certainly, 
by attention to the action of the muscles of the face, we 
shall find the views drawn here from the anatomy, farther 
countenanced. We learn that smiling is an affection of the 
nerve of respiration on the muscles of the face, and that 
when laughter shakes the sides, it is only an extended and 
more convulsive action of the muscles produced by the same 
class of nerves. When to the paleness and coldness and 
inanimation of grief, there is added the convulsive sob and 
the catching of the throat, and the twitching of the lips and 
nostrils, we discover the same class of nerves to be affected, 
which, in crying, are only more obviously in operation, pro- 
ducing more violent contractions. 
