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which enter the ear, 5 to 7 in number, and their next 
branches, varying from ‘074 mm. to ‘018 mm. in diameter. 
The mode of division of these trunks is mainly dichotomous, 
but they are connected by several different kinds of anasto- 
moses; as, for instance, by decussation of two adjacent 
trunks, by transverse or oblique connecting branches, by 
plexuses, by loops, &c.; while branches also perforate the 
cartilage, and bring the nerves of the two halves of the ear 
into connection. ‘The general distribution agrees with that 
of the larger blood-vessels. The second stratum lies imme- 
diately over the first, and is connected with it by a multitude 
of small branches, and by a fine marginal plexus at the outer 
border of the ear, which may be regarded as common to 
both. The diameter of its nerves is from 0185 mm. to 
"0098 mm; it lies immediately under the capillary vascular 
network of the skin, and has a generally reticulated arrange- 
ment, forming plexuses of very various shapes. The third 
stratum of nerves, developed out of the very finest twigs of the 
second, lies at the level of the capillary network ; it is com- 
posed of branches ‘0098 mm. to ‘0037 mm. in thickness, 
which (like those of the other strata) contain medullated 
nerve-fibres. It forms an extremely delicate network, like 
the second layer, but its finest branches may terminate in 
two ways. Some of them, each containing two to four me- 
dullated fibres, run directly to the hair follicles, and form a 
nervous ring round the shaft of the hair, terminating below 
the follicle in a nervous knot. Others, again, consisting of 
not more than two medullated fibres, bend towards the sur- 
face where the fibres lose their double outline, and form, im- 
mediately under the Malpighian layer of the skin, a fine 
terminal network of pale fibres, which is the fourth and ulti- 
mate stratum of nervous structures. The terminal ‘ knots” 
or corpuscles, and the nervous rings, are inseparably con- 
nected with hairs, and their sebaceous glands, so that through 
the whole of the external ear no hair can be found without 
this nervous apparatus, and vice versd. The connection of 
the hair follicle with the nerve termination is as follows :— 
Under the bulb of the hair in each follicle is a more or less 
conical prolongation, composed of distinct nucleated cells, 
which runs vertically downwards, and is enclosed within the 
limiting membrane of the follicle. The nervous twig which, 
as has been said, runs to each hair follicle from the third 
stratum of nerves, makes several turns round the shaft of the 
hair, and from the ring thus formed two to four nerve-fibres 
run vertically downwards to the prolongation of the follicle, 
immediately beneath which they form a knot. These knots 
