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LANCASHIRE VETERINARY MEDICAL ASSOCIATION. 
nature with the delicate wavy fibres of common areolar or cellular 
substance, and of fibres of elastic tissue, presenting their character¬ 
istically curved ends, and branching and anastomosing distribution. 
In the superficial strata of the corium the white fibres are collected 
into small fasciculi, and form an intricate interlacement, wdiich 
supports the papillae, and constitutes a nidus for the capillary rete 
of vessels and terminal plexus of nerves. In the middle strata, the 
fasciculi are larger, and flattened, and the areolar network coarse; 
while in the deep layer the fasciculi are broader, and the areolar 
spaces wider. These spaces are occupied by small masses of adipose 
tissue, while the fasciculi are continuous with the subcutaneous 
cellular membrane. The yellow elastic fibres are solitary in their 
arrangement; they are abundant in the superficial layers of the 
corium, but rare and scantily met with in the deeper strata. The 
areolae left by the interlacement of the fasciculi of the areolar fibrous 
tissue are the channels by which branches of vessels and nerves 
find a safe passage to the papillary layer, wherein and in the super¬ 
ficial strata of the corium ; they are principally distributed. The 
smooth or unstriped muscular fibre of the derma is distributed more 
abundantly in the deep stratum of the corium within the spaces, 
which give passage to the hair follicles, and especially in the areola 
of the nipple, and the dartos of the scrotum. Dr. Lister says there 
is one of these muscles to each hair follicle, and this on the slooino: 
side of the follicle, a position which is best adapted for erecting and 
protuding the hairs, an example of which may be seen in the dog or 
cat, when vexed. 
In the areola of the mammae the bundles of smooth muscular 
tissue have a circular arrangement. 
The papillary layer of the derma is raised into small prominences 
or prolongations, which are termed papillae. The general form of 
these papillae is cylindrical and conical, but some are club-shaped 
and slightly fiattened, and others spring from a short trunk in a 
tuft of two to four and five, and are termed compound; the other 
being simple papillae. 
Upon the general surface of the body the papillae are short, and 
exceedingly minute, but in other situations, as the palmar surface 
of the hands and fingers of man, they are long, of comparatively 
large size, and numerous. 
In structure the papillae are composed of homogeneous nucleated 
and fibriilated areolar tissue, bounded by a structureless limitary 
membrane, and containing either a capillary loop (vascular papilla) 
or a nerve fibre (nervous papilla). Modern researches have sliown 
that the papillae of the skin are properly divisible into vascular and 
nervous ; that in the vascular papillae a nerve is rarely found, while 
in the nervous papillae a capillary loop is equally absent. 
The arteries of the derma, which enter its structure through the 
areolar of the under surface of the corium, speedily divide into 
innumerable intermediate vessels, which form a capillary plexus in 
the texture of the superficial stratum of the derma and its papillary 
layer. 
