The hollow spaces interposed between the muscles must not be of such
a character as that the skin should seem to cover two sticks laid
side by side like _c_, nor should they seem like two sticks somewhat
remote from such contact so that the skin hangs in an empty loose
curve as at _f_; but it should be like _i_, laid over the spongy fat
that lies in the angles as the angle _n m o_; which angle is formed
by the contact of the ends of the muscles and as the skin cannot
fold down into such an angle, nature has filled up such angles with
a small quantity of spongy and, as I may say, vesicular fat, with
minute bladders [in it] full of air, which is condensed or rarefied
in them according to the increase or the diminution of the substance
of the muscles; in which latter case the concavity _i_ always has a
larger curve than the muscle.
591.