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268 ANATOMY
tlie structure of the nodes and passes along the axis-
cvlinder, disclosing transverse markings named lines
of Froiiimann. The action of osmic acid will cause
the nodes to become almost colorless, while the me-
didlarv or white substance, except close to the nodes,
Avill be stained a very dark color.
The Size of the S\'n-e-fibres varies, both in the
thickness of the medullated sheath and the diameter
of the axis-cylinder. This is dependent up(m the
distance which it extends from the centre of its
origination : the greater the distance covered, the
thicker will be the medullated sheath, though to
this there are numerous exceptions. As the fibre
approaclies its termination the medullary sheath be-
comes gradually thinner, diminishing until lost
altogether, leaving only the covering of the neuri-
lemma with the nerve-corpuscles between the axis-
cylinder and the membrane, thus producing a non-
medidlafed nerve-fibre.
The Non-ineduU((fed or Pale Fibres (fibres of Be-
mak) (Fig. 12(3) are made up of axis-cylinder, neu-
rilemma, and the nerve-corpuscles, which are situ-
ated at certain distances between the other two struc-
tures, the axis-cylinder being faintly striated. These
fibres are principally found in,
and compose the greater part of,
the sympathetic nerves, and are
the termination of the medullary
fibres. The olfactory nerve-fila-
ments are non-medullated, though
they cannot be classed as pale fi-
bres, as thoy have a distinct nu-
cleated sheath of their owji. These
fibres (pale fibres) differ also from
the medullary fibres by branching
and joining offshoots from other
fibres, thus forming a fine net-
work. Triangular nuclei are
fi)nnd at the nodal points, this
!)eing the situation at which
these connections occur.
Portions of two Nerve-
Fibres staiiiL'il with Os- Before the final distribution
mic Acid, from a Young Nerve-libre from the
Rabbit ( til diameters) of the nerve-fibre it loses its
Sciatic Nerve of the
7?, Ji, nodes of Kanvier, neuril'mma, leaving nothing but Rabbit, after the ac-
witli axi-^-cylinder pass- of
tion nitrate of
ing tliroiigh ; tive sheath of tlie nerve ed by thickened mem-
c, opposite the middle of The Division of Nerves and brane of Schwann ; m,
the s gment, indicates Nerve-fibres. — As white substance of
the nucleus and proto- the nerve- Schwann rendered
plasm lying between tlie trunks extend from transpirent by glyce-
Tirimitive sheatli and the the centres rin ; ri/, cylinder-axis,
medulbiry sheath. 1 ii A toward the })eri]ihery, thev di- which just iibove and
the nodes are wider, and below the leve' of the
the intersegmental sub- vide and s u b d v d e ; some annular constriction
i
i
stance more apparent presents the striae of
branches unite with those of
than in I>. Frommann.
268 ANATOMY
tlie structure of the nodes and passes along the axis-
cvlinder, disclosing transverse markings named lines
of Froiiimann. The action of osmic acid will cause
the nodes to become almost colorless, while the me-
didlarv or white substance, except close to the nodes,
Avill be stained a very dark color.
The Size of the S\'n-e-fibres varies, both in the
thickness of the medullated sheath and the diameter
of the axis-cylinder. This is dependent up(m the
distance which it extends from the centre of its
origination : the greater the distance covered, the
thicker will be the medullated sheath, though to
this there are numerous exceptions. As the fibre
approaclies its termination the medullary sheath be-
comes gradually thinner, diminishing until lost
altogether, leaving only the covering of the neuri-
lemma with the nerve-corpuscles between the axis-
cylinder and the membrane, thus producing a non-
medidlafed nerve-fibre.
The Non-ineduU((fed or Pale Fibres (fibres of Be-
mak) (Fig. 12(3) are made up of axis-cylinder, neu-
rilemma, and the nerve-corpuscles, which are situ-
ated at certain distances between the other two struc-
tures, the axis-cylinder being faintly striated. These
fibres are principally found in,
and compose the greater part of,
the sympathetic nerves, and are
the termination of the medullary
fibres. The olfactory nerve-fila-
ments are non-medullated, though
they cannot be classed as pale fi-
bres, as thoy have a distinct nu-
cleated sheath of their owji. These
fibres (pale fibres) differ also from
the medullary fibres by branching
and joining offshoots from other
fibres, thus forming a fine net-
work. Triangular nuclei are
fi)nnd at the nodal points, this
!)eing the situation at which
these connections occur.
Portions of two Nerve-
Fibres staiiiL'il with Os- Before the final distribution
mic Acid, from a Young Nerve-libre from the
Rabbit ( til diameters) of the nerve-fibre it loses its
Sciatic Nerve of the
7?, Ji, nodes of Kanvier, neuril'mma, leaving nothing but Rabbit, after the ac-
witli axi-^-cylinder pass- of
tion nitrate of
ing tliroiigh ;
c, opposite the middle of The Division of Nerves and brane of Schwann ; m,
the s gment, indicates Nerve-fibres. — As white substance of
the nucleus and proto- the nerve- Schwann rendered
plasm lying between tlie trunks extend from transpirent by glyce-
Tirimitive sheatli and the the centres rin ; ri/, cylinder-axis,
medulbiry sheath. 1 ii A toward the })eri]ihery, thev di- which just iibove and
the nodes are wider, and below the leve' of the
the intersegmental sub- vide and s u b d v d e ; some annular constriction
i
i
stance more apparent presents the striae of
branches unite with those of
than in I>. Frommann.
