EXPRESSION. 63 
prominence to. It occurs also in attempts to see 
distinctly external objects, helping to shade from 
dazzling surroundings, and concentrates the at- 
tention on a limited field; and, in exercising the 
internal perceptions when a difficulty is encoun- 
tered, the forehead falls into the same condition 
as when a difficulty in distinguishing an object 
with the eye is met with. These explanations 
appear to me more satisfactory than to sup- 
pose that the frown is the relic of childhood’s 
screaming,' the more so as in the worst cases of 
screaming in childhood the eyes are not protected 
by a frown at all, but by the violent closure of the 
lids by means of the ordicularis, so that the infantile 
frown is rather derived from the same source as the 
frown of the adult than the parent of it. 
The formation of “rectangular furrows” on the 
forehead, with elevation of the inner part of the 
eyebrow, is more complex, and demands reference 
to the anatomy of the muscles. Undoubtedly we 
owe to Duchenne the knowledge, which anatomists 
ought to have perceived before, but did not, that the 
pyramidalis nasi is antagonistic to the central fibres 
of the frontals. It is attached to bone below, while 
the more fixed attachment of the frozta/is muscle is 
above. For a much longer time we have known the 
1Darwin, op. cit. p. 225. 
