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The eentFal eourse of the Nervus oetavus
and its influenee on motility,

.c- >?vt:ivk:l.eii.

Verhandelingen der Koninklijke Akademie nn Welenschappen le Amsterdam.

(TTinBlSI>E SECTIE.)

DEEL XIT, N*, 1.

(With 24 Plates).

AMSTERDAM,

JOHANNES MtJLLER.
1907.

BOSTON MEDICAL LIBRARY

IN THE

FRANCIS A. COUNTWAY

LIBRARY OF MEDICINE

[NTROIJUCTIOIN.

After so many admirable researches as have been made of late
about the mode of distribution of the N. octavus in the central
nervous system, after all that has been brought to our knowledge
from competent investigators, as to the influence exerted by this nerve
on the muscular system in animals and in man, it may be con-
sidered an almost preposterous enterprise to publish another treatise,
and moreover a monography, on the eighth cerebral nerve.

We may not expect — at least not if no new methods are
employed — that we will find much to be added to what has
been taught us by Ewald about the troubles of motion, observed
in pigeons whose labyrinths have been removed on one or on both
sides. Our knowledge of the function of the octavus-system has
been settled for a long time by this eminent experimental essay.

Such is also the case with our anatomical notions. The investi-
gations of Held, of vak Gehuchten, of von Monakow, Lewan-
DowsKY and others form likewise in a certain sense a finished whole ,
accordant in many leading features.

These researches have shown the distribution of the Nervus
octavus in the central system to be much more complicated than
was surmised before. Still, though the whole appears thus com-
plicated, the differences of opinion, on cardinal points have dimi-
nished. Our knowledge having reached this stage, I am perfectly
conscious of the impossibility that quite new views should be offered
by this monography , in which the anatomy and the physiology of
the nervus VIII are not studied by means of new methods.

Yet I believe that in a few points I have succeeded in obtaining
definite results, going farther than those of my predecessors.

This was made possible only , because the functional effects , conse-
quent on the isolated removal of the cochlea , or on the entire removal

4 C. WINKLER. THE CENTRAL CXDURSE

of the labyrinth , or on the section of the Nervus VIII , or on that
of the corpus trapezoides , or on that of the dorsal tract of the N. octa-
vus , have been controlled regularly and minutely by the degenerative
or atrophical changes, found after these operations in the central
organ, and demonstrated by means of the methods either of Marchi,
of VON GuDDEN , of NissL or of Cajal , as may best fit the case.
Though the experiments of Ewald deserve justly to be called
masterly, yet there remains an incertitude adhering to the results
they have produced. The anatomical control of his operations on
pigeon ?5, carried through in an admirable manner for the periferical-
organs — the end-organ of the eighth cerebral nerve — was not
attempted for its mode of distribution in the central system.

This is no imaginary objection. In some instances it becomes
very palpable. When f. i. Ewald , speaking about his experiments
on rabbits, writes: „Ira ganzen eignen sich diese Tiere nicht sehr
gut zur Untersuchung der Labyrinthstorungen" the importance of
this objection becomes evident.

The real meaning of this sentence is doubtless, that rabbits,
whose labyrinth has been removed, more especially if it has been
removed on one side, show certain symptoms (rollings round the
longitudinal axis , constraint-situation of the eyes) not shown plainly
in pigeons, whilst other symptoms, appearing beautifully in pigeons
(the progression of the paroxismally produced peculiar attitude of
head and neck , the atony of the extremities on one side) either are
shown differently, or else offer difficulties of demonstration in rabbits.

It would be just as right however to maintain, that for the
same reason pigeons are animals less suited for experiments upon
the labyrinth than rabbits.

Still both opinions would be inconsiderate. For the mode of
distribution of the nervus octavus in the central nerve-system is so
widely different in both species of animals, that we may not rea-
sonably expect a perfect conformity in the symptoms of both species,
when the labyrinth has been removed.

The more to be admired therefore is the perspicacity of Ewa!.d, who
apprehended how, in one respect, the functional loss , most conspicuous
after the destruction of the labyrinth, was found to be accordant.

In demonstrating that a very serious atony of the extremities
especially on one side is caused by removal of one labyrinth,
Ewald has put a clue into the hands of anatomists, who know
very well that in despite of all differences , there still exists a great
conformity in the structure of the nervus octavus in the different
animal species.

OF THE NERVUS OCTAYUS. 5

On the other hand, the anatomists who have studied after Ewald
the central distribution of the octavus-fibres and who in the course
of their labours , met with quite new views about the architecture
of the medulla oblongata, have either quite neglected the results
of the physiology of this nerve or else have taken these only into
partial consideration.

In my opinion, a monography trying to establish a relation
between the results of physiology (results that I dare say are settled
permanently as regards cardinal points since Ewald) and those of
anatomy, may vindicate a right to exist.

The task, enjoined on a complete monography about this subject,
would be not only to treat different animals, representative of all
the great families of the vertebrates, it should be written also for
closely connected species of one family. This task however would
exceed the power of one man.

Thus much I have learnt during my researches, that the course
of the octavus-fibres and their distrubution towards different centra
in the medulla oblongata , pons and mesencephalon is differing for
rabbit, pigeqn, dog, cat, mouse, horse and man, and that the
function-trouble , consequent on section of the octavus in rabbit ,
pigeon , dog and cat is different too.

Not in the cardinal points, but in so many of the details, that
the cardinal points are sometimes masked by them.

I will therefore take as basis for the description of the course
of the primary and secundary octavus-tracts, and equally for the
description of the function-troubles after their lesion, the nerve-
svstem of the rabbit.

Only in as much as I think it necessary for the elucidation of a
few important facts, I will also memorate details about this system
in pigeons.

I have chosen the rabbit, because the oblongata of this species
is best known. By far the greater number of investigators have
studied the oblongata in this animal. For it is not the least im-
portant part of my purpose to consider the series of new facts,
brought to our knowledge by the methods of Cajal and Marchi
in their relation to the Octavus-question and to rely them to the
physiologically proved disturbances in motion, consequent to the
lesion of this nerve.

The long tracts, descending from mesencephalon, metencephalon
and myelencephalon towards the medulla, ought to be exnmined
as to their connection with the N. octavus. The results, obtained
by Marchi, Thomas, Van Gehuchten, Probst, James Collier,

6 C. WINKLER. THE CENTEAL COUESE, ETC.

Lewandowski and others with the aid of Marchi's method, by Forel
and Onufrowicz, Baginski, Von Monakow, Mingazzini, Fbrrier,
a. o. with tlie method of Gudden, by Cajat., Held a. o. with Golgi's
method, by Flechsig, Bechterew, Held a. o. with the aid of the
myelinisation of the embryonic nervous system, have certainly great
importance in elucidating the question about the course of the N.
octavus, and its primary and secondary distributions. All these are
waiting for a connecting bond with the results of the physiologists,
who Iiave destroyed experimentally the N. octavus or its end-organs.
On the other hand the question ought to be put again before the
physiologists, whether the better knowledge of the mode of distri-
bution of the N. octavus in the central organ can enable us to under-
stand the influence exerted by the N. octavus on the muscular system.

If I am right in my surmise, that the mode of central distri-
bution of the N. octavus does not allow a severe distinction
between that of the N. cochlearis and that of the N. vestibularis,
then it will be necessary to put again the question whether the
N. cochlearis, whose end-organ is endowed with the function
of hearing, does not exert a certain influence upon the muscular
system, and whether the N. vestibularis, endowed with such an
important significance for the motor disturbances and whose influence
on the movements is universally acknowledged, does not contribute
something to the function of hearing.

If I am right in my surmise that by the octavus-fibres, centra
are innervated, whence originate long tracts towards the lateral
and anterior columns of the medulla providing the motor centra
of the cord with fibres, and that even primary octavus fibres,
though in a slight degree, trace the same path, which is followed
by the secundary, the prospect would be opened of obtaining a
clearer comprehension of the motion-troubles after the lesion of the
end-organs of the eighth nerve. The sensu-motor centrum of the
N. octavus might in that case have become a more anatomically defined
being, strictly separated from the psychical-system of it , but not by
means of strict separation of the end-organs. Therefore I have endc avou-
red to establish a connection between the anatomy and the physio-
logy of the N. octavus. In this manner I hope to contribute something
towards smoothing the path, traced first by Evvald, a labour to
wich Thomas, Makchi, Forel, Held, van Gehichten, Cajal,
VON Monakow, Probst, Lewandowsky, and so many others have
given and are still giving, all their energy.

Chapter I.

The removal of the rabbit-labyrinth. The section

of the N. octavus and of its prolongation in the central

nerve-system. The disturbances

of motion following on these operations.

I. A few technical remarks on the removal of the labyrinth in rabbits.

Before trying to remove the labyrinth of mbbits, it is advisable
to learn this operation on pigeons, all the while following strictly
the technical directions, described with so minute a preciseness
by EwALD, without neglecting any of the details given by him.

If the removal of the labyrinth is performed with the purpose
of investigating, after a more or less prolonged duration of life of
the animal , the secundary degenerations and atrophies in the central
nerve-system by means of the methods of Marchi or Gudden, it
is of the utmost importance to take care that no accessory lesion
may occur.

For the same reason , with pigeons likewise as with rabbits,
the most careful antisepsis in the preliminary stage of the operation
and the strictest asepsis during its course are necessary , and some
subordinate parts of it ought to be executed with great circum-
spection. On the one hand, it is of absolute necessity to avoid any
bleeding during the operation. On the other hand the method of
the cauterizing the blood-sinus offers a danger, even when following
strictly the rules prescribed by Ewald. This danger is that the
heat, passing through the bone, may have scorched at a distance
the surface of the cerebellum and may thus have created the origin
of a secundary degeneration. And a pigeon , having a superficial
lesion of the cerebellum even though this may not be betrayed

8 C. WINKLER. THE CENTRAL COURSE

in the post-mortem by loss of substance or by softening seen with
the naked eye, but only shown in microscopical investigation as
the origin of a Marchi degeneration , is no longer suited for follo-
wing the course of the Nervus VITI by means of the Marchi-
method. Such pigeons are moreover likewise useless for the physiology
of the Nervus VIII.

On pigeons the operation is more difficult than on rabbits, and
even therefore it is necessary to make preliminary trials in remo-
ving tlie labyrinth on these animals, before experimenting on rabbits.

However, Ewald has described this opemtion on pigeons so
minutely in all its subordinate parts, that, guided by him, it will
be easy to obtain the experience that will be useful in experimen-
ting on rabbits. Still, I am of opinion, like Ewald, that the suc-
cess of the experiment i. e. the appearing of the functional troubles
(that are always the same after extirpation of the labyrinth) depends,
next to the post mortal assertion of the fact that only a lesion of
the Nervus VIII has been produced, on asepsis and on the tech-
nics of the operation.

For my purpose five operations have been found necessary to
elucidate the central course of the nerons VIII.

1°. the isolated removal of the cochlea,

2°. the removal of the cochlea together with the contents of the
vestibulum,

3"^. the operation mentioned sub 2° -f- the section of the N. octa-
vus in the meatus auditorius intern us,

4°. the section of the ventral octavus-tract (the corpus trapezoides),

5°. the amotion of the tuberculum acusticum and the nucleus
ventralis N. VIII together with the dorsal octavus-tmct (Monakow's
stria meduUaris in the rabbit).

The first four of these operations were perfoimed through the
buUea ossea, the last one from the 4*^ ventricle.

I will therefore begin with the description of the operations at
the bulla ossea, before proceeding to that from the 4** ventricle.

It must be remarked previously, that all animals destined to be
operated, are prepared the day before.

The skin over the region of the operation is shaven and carefully
cleansed with soap, alcohol and sublimate. I hold a repeated dis-
infection of the skin on the day before the operation and imme-
diately before operating, to be necessary. The great difficulty in these
operations is the disinfection of the skin. It is to the minute skin-
disinfection that I attribute the favorable results ^nd the absolute
aseptic woundhealing.

OF THE NERVUS OCTAVUS.

2. T/ie operations through the bulla ossea.

If the bulla ossea is to be laid bare, a rather large area of
operation must be prepared, having the shape of a rectangular
trapezium, whose upright rectangle-side is in the cervical part of
the mid-ventral line of the animal.

Cranial wards the boundary of this area is a line, starting from
the lateral canthus of the eye and crossing the cheek, standing
vertically on the mid-ventral line. It is the basis of the trapezium.

The dorsal boundary, is a line, drawn from the lateral canthus
of the eye along the auricular root towards the mid-dorsal line.

The caudal boundary, the oblique side of the rectangular trape-
zium, is indicated by a line, starting from the mid-dorsal line a
little way behind the ear and reaching the mid-ventral line at the
manubrium stemi.

Nearly in the centre of this trapezium is found the angulus
maxillae inferioris, serving as „ point de repere".

Especial care is given to the disinfection of the roots of the ear
and of the external auditory meatus, that after having been cleansed,
are filled with Bruns's wadding.

Thus prepared, the animal is stretched with its back turned
upward; and the head, retained in Czermak's trap, is placed in
such a manner that 'the area of operation is turned upward.

After carefal re-disinfection of the area of operation, the stret-
ched animal with its surroundings is wrapped up in sterile gauze,
only the area of operation remaining visible and accessible to the
operator.

The operator finds his way by the aid of the angulus maxillae
inferioris, that may be felt through the skin.

The incision of the skin commences somewhat laterally from the
lateral eye-canthus, passes midway between underjaw and ear, des-
cending at first parallel to the ascending branch of the undej-jaw,
till it has reached the angulus maxillae inferioris and until then
it continues standing nearly vertically on the mid-ventral line.

It then commences to deviate slowly caudalward, forms a right
angle with its original direction, courses parallel to the mid-ventral
line, and terminates about 2 cM. from its bend. In this manner
the skin-incision describes part of a circular line around the bony
and the membranous auditory meatus, or, if one likes, above and
over the bulla ossea lying in the depth.

This incision having been made, we meet in the caudal part of

C. WINKLER. THE CENlllAL COUESE

the wound, the vena jugularis externa, that is generally much
swollen by the turning of the head. (See fig. 1). This vena is sup-
plied with blood by several venae from the face and from the
auricle of the ear. Inconvenient among these may be the venae reaching
the vena jugularis along the underjaw and also the venae auricu-
lares, especially the vena auricularis posterior.

In the cranial part of the operative lesion is found the Nervus
facialis, crossing the area of operation (See fig. 1).

First of all the vena jugularis has to be put aside. With a
small blunt hook it is detached so far that it may be pushed
behind the angulus maxillae inferioris. The venae auriculares poste-

riores are stretched by this
proceeding , and it is there-
fore advisable to cut them
between two ligatures , be-
cause rupture and bleeding
in a later stage of the ope-
ration are to be avoided.
With a blunt wound-hook
the vena jugularis is now
kept behind the ascending
branch of the underjaw
and both together are drawn
aside 'by an assistant. Du-
ring the further course of
the operation this vena is
seen no more.

Next the N. facialis has
to be taken care of. This
nerve, after having been
isolated on the surface, is
lifted upward by an assistant
cautiously by means of a
blunt wound-holder.

I don't hold it necessary
to section the nerve in
order to avoid degeneration
in central direction, as has been done by van Gehuchten.
If carefully treated , there need not arise a degeneration. If the
nerve be sufficiently protected , this does not occur , and the impor-
tant advantage gained in this way is that no post-operative para-
lysis of the muscles of the face has to be combated. Once the

Fig. 1.

The skin and the soperflcial fascia being cleft, the
situation of the venae appears.
A maxilla inferior .B vena niaxillaris, C vena ju^. ext.,
D vena auric, lat. , E N. facialis, F r. auric. N. facialis,
G vena auric, ant., // vena facialis, / r. zygoin. N.facirlis.

OF THE NERYUS OCTAYUS.

vena jugularis and the N. facialis having been preserved, the fascia
is sectioned along the anterior border of the glandula parotis, that
is pushed backward, under the root of the ear, by means of a
third blunt wound-holder.

The operator now seeks his direction by the aid of the mem-
branous auditory meatus, and determines the place where it passes
into the bony part of it.

The periosteum lying on its surface is sectioned by means of
a small, solid and sharp bone-knife and is pushed aside. Before
proceeding directly to the bulla ossea, the periosteum along the
anterior border of the processus mastoideus is removed, continually
staying proximal to the place where the N. facialis leaves the bone ,
until the insertion of the
m. bi venter may be
plainly seen. This inser-
tion is lifted upward and
is sectioned close to
where it is affixed to the
bone, (See fig. 2 and
fig. 3). In this way a
large sptice is obtained
and the bony auditory
meatus may be seen pas-
sing into the bulla ossea,
this latter appearing as
a smooth hemisphere of
glossy white colour. (See
fig. 3).

Next it is ascertained
again that the vena jugu-
laris and the N. facialis
are not endangered. One
must make likewise sure
that nothing becomes
visible, either of the
arteria carotis or of the
nerves leaving the bony
skull at the posterior wall of the bulla ossea.

This latter point is of the utmost importance. For the sectio-
ning of the m. biventer in order to obtain more space, simple though
it may be for an experienced operater, may become an obstacle.
If, in lying bare the processus mastoideus , the knife of the operator has

— D

Fig. 2.
The vena jugularis is kept under the ascendent branch of tl»o
mnxilla.
The m. biventer crosses the flebl of the operation. The
N. facialis also croKses it.
A maxilla inferior, /? bulla ossea, CmuBc biventer, /JProcesiU'*
mastoideus, E Pars masloidea F meat, audit, mombranaceus, G
meat, audit, osseus, 7/ vena auric, ant., I N. facialis.

C. WINKLER. THE CENTRAL CX3URSE

A-^

deviated too much towards the foramen of the occiput, after the section
^ of the m. biventer, not

only the bony audi-
tory meatus with the
anterior surface of the
bulla ossea, but also
the inedio-distal wall
of it becomes visible.
Next to this latter is
situated the foramen
jugulare, and the ope-
rator will state to his
dismay that as soon
as the m. biventer is
sectioned , the arteria
carotis and the four
nerves appear within
the area of operation
(See fig. 4).

Beginning from the
centre, these are the
N. laryngeus supe-
rior, the N. hypo-
glossus, the N. sym-
pathicus and the N.
vagus. All these ought not to be seen, neiher in this stage of the
operation nor afterwards, when the bulla ossea is opened. For if
the bulla ossea is opened too far distalward, and the mediodistal
wall does not remain firm , but is ruptured and has too be
removed , the nerves will appear again. The danger of their being
injured is even very great in the latter case, as well as that of
injuring the well-protected N. facialis.

If one or several of these nerves are injured, the danger arises
again of occasioning uncontrollabe retrograde degenerations. In a
faultless operation however neither the artei-ia carotis nor one of
the afore-said nerves may have been seen by the operator.

The anterior wall of the bulla ossea and the passage of the
bony auditory meatus into the bulla ossea are now lying before the
operator, who supports the bulla by wadding and either punctions
the top of its hemisphere with a pair of small crooked nibling
pincers or else opens it with a sharp chisel. The supporting of
the bulla is necessary in order to prevent eventual fissures exten-

Fig. 3.

The position of the meatus auditoreus osseus, of the processus

maRtoideus and of the bulla ossea ,

after the cleaving of the m. biventer.

A maxilla iiiferior. D bulla ossea, C proc. mastoid., D meat,
audit, osseus. K meat. aud. mcmbranaceus , F n. facialis.

OF THE NERYUS OCTAVUS.

care is
a large

-■ D

ding themselves unto the basis cranii and occasioning uncontrollable
venal bleedings in the interior of the skull.

The aperture is widened further by means of a pair of small
nibling pincers, whilst
the utmost
taken that
part of the bulla
towards the basis cra-
nii may remain unin-
jured , until at last a
full view is obtained
in the cavum tympani.

Here the way is
easily to be found.

In the very first
place the operator's
attention is drawn to
the large triangular
orifice of the tuba
Eustachii in the ca-
vum tympani. From
this orifice rises in
a gentle declivity the
triangular pyramid of
the promontory, its
apex being turned
towards the orifice.
On the basis of the
pjTamid and turned towards the- operator is lying the foramen
rotundum, whilst the foramen ovale, turned more backward, is
not yet visible.

This latter becomes visible only if the passage from the bulla
ossea to the bony auditory meatus is destroyed and the ossicles of
the ear are removed. The glossy white sinew of the m. stapedium,
lying enclosed in a spacious bony hole on the dorso-medial side of
the promontorium is not seen if the bony auditory meatus remains
uninjured and its bony hole is left unopened. The cavum tympani
may now be surveyed.

Fig. 4.

The position of the arteria carotis, of the N. laryngeus superior,

of the N. hypoglossus of the N. vagus and of the N. sympa-

thicus in relation to the bulla ossea.

A art. carotis, B N. sympathicus, C N. vngus, D Gangl. supreni.
colli N. cympathici, E Gangl. N. vagi, Fr. auric. N. facialis, G meat,
audit, osseus, H N. facialis, / bulla ossea, J N. laryng. sup.,
K N. hypoglossus.

a. The removal of the cochlea.

From the orifice of the tuba Eustachii towards the foramen
rotundum runs the line, along which may be opened the thin

C. WINKLER. THE CENTRAL COUBSE

lamina of bone, constituting the promontory and covering the
cochlea.

If the promontory be opened by means of the chisel , this instru-
ment, that ought to be exceedingly sharp, is put on along this
line, i.e. along the lateral and posterior border of the pyramid,
and with a single, soft blow of the hammer the lamina of bone,
covering the cochlea, is sectioned.

Next the chisel is put on along the most anterior nervure of
the pyramid (partly along the border of the bony hole enclosing
the m. stapedius), and the thin lamina of bone is sectioned again.

1
1

F G

Fig. 5.

The bulla ossea is opened. The aditus ad tubam Eustachii, the promontorium,
the foramen rotundum, the foramen>vale are seen.

X N. cerv. H, B N. cerv. f, G N. Vagus, D for. rotundum, B N. symp., F N. hypogl.,
G promont., £f N. lar. sup., / tuba Kustachi, J for. ovale.

By a third stroke of the chisel both diverging lines of section
are united straight before the foramen rotundum.

A very narrow lamina of bone, lying before it, remains uninjured.

The thin lamina of bone covering the cochlea is now detached,
and may be removed with a pincet or an excavator.

If one does not dare to open the promontory with the chisel
— for there is some danger that the thin lamina, covering the

OP THE NERVUS OCTAVUS. 1 5

cochlea, may be either ruptured or pressed downward — then the
broad, flat edge of a small hook, having been bent vertically for
this purpose, is introduced through the foramen rotundum.

This edge is pushed under the thin lamina of bone, which is
then lifted up.

In most cases the lamina breaks off frontalward enough to offer
sufficient space, and the aperture may be widened with excavators.
Nevertheless a point de repere has been lost, because the foramen
rotundum forms now part of the breach in the bone.

The lamina of bone having been removed, the convolutions of
the cochlea are lying bare, and it offers no difficulty to extract
these by means of an excavator or of a small, sharp spoon. The three
convolutions being removed, we touch the petrous bone, forming the
posterior wall of the cavity containing the cochlea.

The operation is now terminated. The cochlea and therewith the
ganglion spirale N. cochlearis has been removed. The N. cochlearis
degenerates within a week.

Endolymph is flowing forth. Perhaps the peripherical organs in
the vestibulum may degenerate. Certainly the ganglia along the
N. vestibularis do not so immediately. They are certainly without
any lesion consequently of the cochlea-removal. It is therefore not
only possible, but it follows necessarily, that the degeneration is
confined to the N. cochlearis, if indeed this nerve does not exchange
fibres with the N. vestibularis.

b. The removal of the entire labyrinth and the section of the
N. octavus.

Generally however it is thought desirable to remove the entire
labyrinth.

To this purpose the operation is commenced in the same way
as described above. The bony lamella covering the cochlea is remo-
ved and the fenestrum rotundum is sought. After removing by
means of an excavator the anterior wall, that had remained stan-
ding, a breach is made between fenestrum rotundum and foramen
ovale in the bony wall covering the vestibulum. The stapes is
extracted from the foramen ovale, without injuring the tympanum.
The breach in the bone is enlarged as much as possible. Thus far the
operation may be made easily without the aid of a lens. At this
moment however it is preferable to examine the contents of the
vestibulum with a lens. The anterior ampulla is caught in an iris-
crotchet. The membranaceous anterior canal is cut through near
the ampulla and with slight tractions the membranous contents of

16 C. WINKLER. THE CENTKAL COURSE

the vestibulum are drawn out and removed. By this proceeding
the membranous wall of the semicircular canals, lying enclosed in
very hard bone, are stretched and ruptured above their ampullae ,
and it is advisable to help with a sharp excavator, and to section
them , as they present themselves , in order to obtain their easily
following the tractions. And yet it is very difficult to remove the
vestibulum whith maculae and cristae as a whole. Ordinarily the
anterior ampulla is breaking of. In that case the wall of the vesti-
bulum again is caught in the iris-pincet, and the tractions are
recommenced, until all ampullae are removed.

After the removal of the' cochlea, of the vestibulum with its
appendixes and of the ampullae, the trunk of the N. octavus is
lying bare. The trunk may be sectioned at the interior auditory
meatus, an operation that is often combined with the removal of
the vestibulum and the ampullae.

For the removal of the cochlea is, in its relation to the central
nerve-system , an operation very different from the removal of vesti-
bulum and ampullae. With the cochlea the ganglion spirale is remo-
ved, but if the vestibulum with the ampullae is extracted, it does
not follow necessarily that the ganglion vestibulare is totally extir-
pated. Therefore it is often thought desirable to destroy the trunk
of the N. octavus, that becomes visible directly after the removal
of the cochlea. For along this trunk in the meatus auditorius
internus are situated continuously the nerve-cells forming the ganglion
plexiforme Scarpae.

Only when the nerve has been sectioned between these cells
and the central nerve-system, the N. vestibularis is in the same
condition as that of the N. cochlearis after the removal of the
cochlea. Only then there are no longer anj^ cells between the lesion
of the nerve and the central nerve-system. It is even questionable
whether it be possible, in experimenting cm rabbits, to section
the N. vestibularis central ward from the ganglion vestibulare wit-
hout injuring the medulla oblongata and the N. facialis is mostly
injured in that case.

It is therefore rather easy to obtain isolated atrophy of the
N. cochlearis. On the contrary it is impossible to obtain atrophy
of the N. vestibularis, without injuring likewise the N. cochlearis.
As soon as the vestibulum is removed, necessarily the N. cochle-
aris is damaged too.

In the coiu^e of the operation neither the nerves, running in
the interior of the petrous bone, nor the N. facialis, nor the chorda
tympani, become visible.

OF THE NERVUS OCrTAVUS. 17

c. The sectioning of the corpus trapezoides.

Cochlea, vestibulum with ampullae having been removed and
the trunk of the N. octavus lying before us, it is very easy , guided
along by this trunk, to divide with a lanciform knife the dura
mater and to damage the medulla oblongata.

This lesion of the medulla oblongata is produced invariably dor-
sal from the ramus spinalis N. V, and if due care be taken that
the knife does not penetrate too far, the corpus trapezoides is cut
from the nucleus ventralis N. VIll, without many complications.
The knife enters the oblongata at the origin of the N. VIII, cuts
generally the dorsal part of the ramus spinalis N. V. , is intro-
duced between it and the oval area of the corpus restiforme in
the so-called interior part of this latter, and terminates more or
less far dorsalward in this interior part (the corpus juxta-restiforme).

The destruction caused by the knife may be controlled post
mortem when the medulla oblongata is examined in serial sections.

By this section the corpus trapezoides, at least in its distal
portion is divided from the nucleus ventralis N. VIII dorsal (lateral)
from the ramus spinalis N. V.

There is still another manner of sectioning the corpus trapezoides ,
without destroying the peripherical organs of the N. VIII and the
octavus-roots. The bulla ossea having been opened , the promon-
tory is left undamaged, but raedio-ventral from the promontory,
passing through the cavity (or next to it) that contains the M. stape-
rius (this latter being removed if necessary) , the posterior wall of
the bulla is punctured , and the glossy N. trigeminus does appear.
Directing the knife by the aid of this nerve, the dura mater is
cleft and the medulla oblongata is damaged, i.e. the corpus trape-
zoides medial from the ramus spinalis N. V. This lesion however
is of less importance than the former operation.

d. The section at the dorsal octavus-tract. (von Monakow's stria
meduUaris).

Next to the operations at the peripherical organs of the eighth
cerebral nerve and to the section of the ventral systems of the
root-fibres of this nerve, it may oflfer great importance to section
their dorsal systems.

The section of the dorsal octavus-tracts , simple though it may
be, must be attempted from the fourth ventricle. In operating on
rabbits, under strict asepsis, it does not offer any great difficulty
to lay bare in the mid-dorsal line the membrana atlantico-occipi-
talis, without any haemorrhage. This membrane being cleft , a view

Verfaand. der Kon. Akad. v. Wetenscb. (Tweede Sectie.) Dl. XIV. 2

18 C. WINKLEK. THE CENTRAL COURSE

is obtained of the interior of the 4^'' ventricle , bordered by the inferior
peduncle of the cerebellum. On both sides the interior part of the
corpus restifornie appears as protruding edges, that may be easily
recognized. The interior part of the corpus restiforme may now be
incised and with the corpus restiforme the stria acustica may be
sectioned transversally at different places.

This may be done:

V^ more distally. The thin knife is introduced through the most
lateral portion of the dorsal octavus-nucleus into the interior part
of the corpus restiforme, cutting this in latero-distal direction, pas-
sing farther thrdugh the oval area of the corpus restiforme and the
nucleus ventralis N. VIII and reaching the surface of the oblon-
gata dorsal from the place of entry of the octavus-roots. If the
operation is well done, the tuberculum acusticum and the nucleus
ventralis N. VIII are separated from the medulla, the oval area
of the corpus restiforme is sectioned but the two roots of the
nervus octavus are often very slightly injured.

If the attempt be made imperfectly, the point of the knife remains
within the juxtarestiform body.

2'^ more proximally. Again the knife is introduced in lateral
direction in the most lateral portion of the dorsal octavus-nucleus ;
but now it is turned somewhat more cranial , and is cleaving more
cranialward the ped. cerebelli superior, reaching the lateral surface
of the brain, a little above the pons in the lateral fillet.

Whilst by the former operation through the pedunculus cerebelli
inferior, the stria meduUaris was cut transversally in its more distal
part, the cranial rest of the stria did remain uninjured.

This cranial rest, to be sure, is cut transversally in the second
operation. But in the mean time this latter involves the section of
the pedunculus cerebelli superior.

Both these operations are likewise necessary, in order to obtain
orientation about the course of the secundary octavus-tracts. They
must be repeated several times before their influence upon secun-
dary degeneration may produce a uniform result.

2. T/ie acute motor-troubles arising after one-sided
removal of the labyrinth.

When, operating on rabbits in the above described manner, the
cavum tympani has been opened, the bony wall of the promon-
torium removed, the spiral convolutions of the (thus opened) cochlea
destroyed, the vestibulum having next been entered into and sac-

OF THE NERVUS OCTAVUS.

>j. ^^tt^^fO^m

Kig. 6.

cuius, utriculus and ampullae extracted (whilst, if necessary, the
N. octavus has been sectioned at the interior auditory meatus), —
then the one-sided destruction of the peripherical organ of this
nerve is followed by tempestuous troubles of motility.

The eye on that side is jerked violently towards the nas^d canthus
(hiterally) and remains fixed there, turned downward (ventrally)
as far as possible. The
slit of the eye is ex-
ceedingly narrowed ,
though there is pro-
trusio bulbi.

The opposite eye
on the contrary is
drawn towards the
middorsal line, devia-
ting likewise a little
in nasal direction , the
lateral edge of the
sclera becoming visi-
ble, the more so be-
cause the eye protru-
des from the widely
opened eye-slit.

This chamcteristic
position of the eyes,
appearing directly af-
ter the operation, is
maintained at its acme
for a few moments
only. After a few
moments it is some
what reduced, and
during the reduction
often the eyes are
continually brought
back into their first
position by jerks,
resembling those of
nystagmus. But after some minutes the characteristic position of the
eyes, not so intense however as immediately after the operation,
has become permanent and continues for weeks, months or some-
times even years after the operation with small loss of intensity.

Fig. 7.

Position of the eyes in a rabbit.
Three weeks after the removal of the left labyrinth .

20 C. WINKLER. THE CENTRAL COURSE

A glance on the subjoined photo may show better than any
description, how the characteristic attitude of the eyes (reaching
its uctne again when the head is kept straight) presents itself, the
head being put in a straight position, three weeksafter the operation.
(See Tig. 6 and fig. 7).

As it is said already, the attitude of the eyes is slowly amelio-
rating, and when it has been somewhat reduced, occasional shocks
of nystagmus recur continually, always in this manner that by an
active violent jerk the eyes are brought again into their maximal
deviati:)n, and return then gradually into a yet evident deviation
but of a less intense degree.

As soon as the animal (that hitherto was bound, and was there-
fore constrained to keep its head straight) has been loosened and
set on its legs , or laid down on the operated side , a new tempest
of involuntary movements does follow. The head is turned with
extreme vigour towards the operated side, in such a manner that
the cheek on that side is put down to the ground. Sometimes
even the turning of the head is so excessive, that the dorsal part
of the head — turning towards the operated side — touches the
ground. Simultaneously with this movement of the head, the upper
limb opposite to the operated side is extended and abduced as far as
possible from the body. With this limb the animal is scratching
the ground, as if trying to support itself by its leg in order to
prevent further turning.

Generally however it does not succeed in this.

The animal is beating the air desperately with the foreleg
opposite to the amoved labyrinth. This foreleg, still abduced
and extended as far as possible, rises and rises (fig. 8 A — C),
until at last it has got into a vertical stand. The dorsal part of
the head touches the ground, at this moment, for the turning
upward and the lifting of the opposite shoulder, subsequent to
the turning of the head , is the cause of the motion of the foreleg.
As soon as the foreleg has crossed the vertical level , another move-
ment appears. The animal cannot maintain the hind-part of the
body in the habitual attitude , now that the fore-part of the body is
so far turned. It has done so, until the fore-leg had reached the
vertical level, (or until the dorsal part of the head had touched
the ground), but the turning of the head still continues. Now at
once the animal subverts the hind-part of the body and also turns
it to the operated side.

Doing so — the animal has then rolled round its longitu-
dinal axis in the direction of the operated side, and it is not

OF THE NERVUS OCTAVTJS. 21

rare to see this movement repeated several times. (See fig. 8). ,

Fig. 8.
Diffei-ent attitudes during the revolutions of a rabbit, after removal of ihe left labyrinth.

Every revolution is accomplished in two tempo's, or rather it may
be decomposed into two semi-re voluticms. By the first of these, head,

22 C. WINKLER. THE CENTRAL COURSE

and neck are turned towards the operated side , the opposite shoulder
is turned upward , subsequently the crossed fore-leg is extended and
abduced and turned upward also (fig. A — C). The turning of head
and neck goes on until a position is attained, that does not allow of
maintaining the hindpart of the body in its original position towards
the distorted forepart. This fii*st part of the revolution apparently
does not depend on the will of the animal , but seems rather to
be involuntary, as an inevitable automatism. Head and neck (and
subsequently the opposite foreleg is rised) are forced in their position
to the side of the operation. But the second part of the revolution-
movement has another origine (fig. 8 D — E). It is impossible for the
animal with its fore-part so turned , to maintain the original position
of the hindpart , and it seems that this movement depends from the
animal's willing. Voluntarily the hindpart is thrown towards the ope-
rated side.

In order to obtain a just impression of the position of the
fore-part of the body, the best way is to lift up the animal
by the skin of the back. It may then be seen how the animal,
hanging free in the air, only supported by the hand in its back,
assumes, in consequence of the turning of head and neck, a very
peculiar position, not easily to be described.

When observing it from the ventral side, we see that the ope-
rated side of the head is pressed against the shoulder of the same
side , looking dorsalward and caudalward , whilst the now operated
cheek is looking frontal- ward and cranial ward.

This forced attitude of head and neck of the animal (even the
upper (anterior) part of the trunk participating in it) is orighiated
as suddenly as that of the eyes after the removal of the labyrinth.

To the purpose of giving a more minute description of the
characteristic attitude of head and neck , it is advisable to draw
mentally the mid-dorsal and mid-ventral lines of the animal, and
to take as a starting-point the stand of the medial plane of the
body brought through both lines.

The mid-dorsal line is running from the tail over the processi
spinosi of the chest-veriebrae (caudo-thoracic j)ortion of this line),
over those of the neck-vertebrae (cervical portion of this line) towards
the occiput, and thence passing between the eyes, over sagittal
suture and dorsum nasi towards the middle of the upperlip (cra-
nial part of this line).

The mid-ventral line goes from the middle of the underlip over
the cliin towards the larynx (cranial part of the mid- ventral line),
thence it descends opposite the trachea to the manubrium sterni

OF THE NERVUS OCTAVUS.

(cervical part), and reaches the symphysis along the linea alba over
the umbilic (caudo-thoracic part). The plane brought between both
lines, divides the animal into two halves, and is the median plane
of the body.

Now, if a normal rabbit is kept swinging free above the ground-
plane, its median plane is standing vertically on this ground-plane.
The caudo-thoracic and cervical portions of both median lines are
running vertically to the ground-plane and are one another's prolon-
gation. But their cranial portions, though lying in the same median

"3 V

^ e\a/^<kX ^oA^t

" \ Oia/u<<*aj6 ^Curvtr

^ CCuuifto

,iAor^C hi

CouJb. iAatAC^a^ '^

Fig. 9.

Scheme of the medial plane from a normal rabbit, swinging free above a
horizontal plane. Seen laterally from the right side.

plane with the other portions of both lines, are forming with these
latter an angle of 90^ or even more. Consequently, when viewed in
front the median part forms one line.

But viewed laterally, the median plane of the body appears as
is represented in the adjoining figure. The cranial portion of the
mid-dorsal line turning caudal ward is looking ventral ward, the cra-
nial portion of the mid-ventral line turned caudalward, nearly tou-
ching the cervical portion of that line.

Entirely diflferent is the position assumed by the rabbit whose
labyrinth has been removed on one side, when kept swinging free
in the air, as is shown in photo fig. 13.

In the caudo-thoracic portion both lines are still running straight
upward. The median plane through both lines is standing vertically
on the ground-plane, in the same w^ay as with the normal rabbit.

But at the 7**' cervical vertebra, in most cases even at more
distal vertebrae, another position commences. The cervical portion

C. WINKLER. THE CENTRAL COURSE

sometimes even also the thoraco-cervical portion of the median
plane is turning towards the operated side.

Consequently the cervical portion of the median plane of the
body is no longer lying in the prolongation of the caudo-thoracic
portion of this plane. It is forming writh this latter an angle of
90° , and runs therefore parallel again to the groimd-plane , on

^ 3 oiA^^^

CoA^Mc'tko^i k!^

rig. 10.

Scheme of the medial plane, if only its cervical part was turned 9(P, and if its cranial part bad
retained its original position relative to its cervical part. Seen from the right side.

which the caudo-thoracic portion of the median plane of the body
is standing vertically.

In the meantime however the cranial portion of the median
plane of the body has also taken a turning, as it would not main-
tain its original position towards the cervicnl portion because of
the changed position , assumed by this latter towards the caudo-
thoracic portion. If its original position had been maintained , then
the crnnial and cervical portions of the median plan of the body
would still form one plane, standing vertically on its thoraco-

OF THE NERVUS OCTA.VUS.

caudal portion , but now parallel to the groundplane in a level B. The
position would then be conform to the scheme, represented in fig. 10.
But such is not the actual position of the head. (See fig. 18).
Neither is the change in position, suflfered by the cranial portion
of the median plane towards its cervical portion a simple moving
parallel to itself, in such a manner that (as in fig. 11) the cranial
portion , though standing vertically on the cervical portion , runs

Fig H.

Scheme of the mpdial plane, if only Its cervical part wag turned 90^* and if its cranlel part bad
retained its original position relative to its caudo-thoracic part. Seen from the right side.

parallel to the thoraco-caudal portion that has retained its original
position in a plane C, parallel to A, where the latter is found. This
again is not the actual position of the head. (See fig. 13).

The cranial portion of the medial plane of the body has made
a turning on its cervical portion and this movement has been made
towards the operated side. The cranial poition is forming an angle
of 90° or more w^ith the cervical portion, and consequently a
position of the head is shown, as represented in the scheme of fig. 12.

The caudo-thoracic portion of the median plane is still lying in
A. The cervical portion is standing in a plane B perpendicular to
A. The cranial portion of the median plane is lying in a plane
C. standing vertically both on A and on B. Within this plane
it may assume different positions, as shown in a, /3 and 7.

Rarely however positions, surpassing that which is represented
in 7 are found, because in that case the rolling round the hori-
zontal axis becomes necessary.

C. WINKLER. THE CENTRAL COURSE

Of course a scheme as represented here, has no further signi-
ficance than that it may be of some aid to get a prompt orien-
tation in the position of the operated animal. In the photo (fig. 13)
the forced attitude, characteristic for the head and neck is repre-
sented, as shown when the animal is kept swinging free in the

♦5 OttJcJb. ^

Fig. 12

Scheme of the medial plane from a rabbit, swinging free above a horizontal plane after

removal of the left labvrinth. The cervical part is turned 90° upon the caudo-

thoracic part, and the cranial part has turned upon the cervical in

« 9^ 4n ^ 135°, in y 180. Seen laterally from the right side.

air. Neither does this position change when the animal is sitting
down on the ground. A comparison between fig. 13 and the posi-
tion, designed in fig. 14, A — B, will easily enable us to form
a just estinate of the attitude of head and neck, with the aid of
the scheme and its description. More-over the conformity between
the characteristic position of head and neck in rabbits and that
shown by pigeons (see fig. 14, C) is so striking, that it may be pre-
sumed a similar mechanism is working in both. These latter figures
however have been taken from animals, showing no longer any rol-
lings around their longitudinal axis towards the operated side , 3
or 4 weeks after the operation.

For , besides the forced position of head and neck , the position

OF THE NEEVUS OCTAVUS.

of the extremities directly after the operation is likewise characteristic.

When the animal is kept swinging free, the extremities on the
operated side are hanging helplessly down, those of the opposite
side are contracted. (See fig. 13).

Special description must be given of the opposite upper extre-

'%^

Fig. 13.

Copy of a photo from a rabbit swinging free above horizontal plane
after removal of the left labyrinth.

mity, because it assumes a very peculiar position, hyper-extended
and abduced from the body and in the meantime hypertonic.

During the first days after the operation the animal is beating
and scratching the ground with this leg, in order to prevent the
revolutions (fig. 8 A — D). Even in a period, when the turning
of head and neck has already been much reduced , this leg is still
kept extendend far from the body by the animal, partly because
the shoulder is lifted up, perhaps also to compensate the forced

C. WINKLER OP THE CENTRAL COUSRE

attitude of head and neck and to prevent rolling (fig. 14, A — B
and fig. 15 A).

For the extremities on the operated side remain inactive during

,.'/'■'. V

B C

Fig. 14.

Copies of photo's from rabbits and from a pigeon after removal of the left
(rabbits) and of the right (pigeon) labyrinth.

A. Rabbit's position a year after the removal of the left labyrinth.

B. Rabbit's position three weeks after the same opei-ation.

C Pigeon's position three weeks after the removal of the right labyrinth.

the revohition round the longitudinal axis. They are lax , and the
animal uses them far less than the opposite extremities, that are
continually kicking. The upper extremity has been shoven under
the body because of its laxity. It cannot bear the burden of the

OF THE NERVUS OCTAVUS 29

body and one of the phenomena, characterising the typical position
of the animal after the operation, is that this leg, having been
shoven involuntarily foreward and outward, gets under the head
and supports this latter (see fig. 14).

In this way the typical position of the rabbit after one-sided
removal of the labyrinth, reproduced as it is by the photo's fig.
14 A — B, fig. 15 A, occurs. The neck and head are turned to
the side of the operation, the opposite foreleg is extended and
abduced, the equilateral, relaxed, has given way for the burden
of the body and is shoven forward.

This position is permanent for a long time.

A summary of the phenomena, observed directly after the remo-
val of the labyrinth, runs therefore as follows:

1°. A peculiar forced attitude of the eyes. The eye on the
operated side is turned downward and inward.

2°. A peculiar forced attitude of head and neck. The cheek on
the operated side is turned in the direction of that side, and laid
on the ground.

3°. A peculiar abduced-extended position of the upper extremity
on the opposite side.

4°. Atony of the extremities on the operated side, the opposite
extremities on the contrary being more or less contracted.

5**. Rollings of the body towards the operated side round its
longitudinal axis.

These phenomena are gradually losing their intensity up to a
certain limit, but they never are entirely compensated.

3. Permanent disturbances of motion after the one-sided removal

of the labyrinth .

An investigation of the further course of the tempestuous motions,
following directly on the removal of the labyrinth on one side, is
of course indicated. Not only it is an interesting question whether they
are reduced at all afterwards, and if so in what measure, but besides
it is of great importance to investigate, to which extent all these
phenomena may be considered to be independent from one another,
or if we find this is not allowable, in what manner they may be
connected together.

We will therefore commence with:

a. The rolling of the body around its longitudinal axis in the
direction of the operated side.

I have demonstrated already , that neck and head , shortly after

30 C WINKLER. THE CENTRAL COURSE

the operation, have been turned round in such a manner that for
a normal animal it becomes impossible to remain seated on the
ground with its lower extremities, its forepart having assumed a
forced attitude , exceeding a certain degree. All the more so., because
of the fact that this position does not retain permanently the same
intensity, but is at intervals suddenly intensified.

If the rabbit, like the pigeon, did possess a long and easily
movable neck, that could be laid down on the ground and find
a support there, whilst the head was being turned upward, then
the turning might perhaps, as it is in pigeons, still be checked,
and the turning of the head only, might occur until 270° or even 360°.

Now this is impossible in rabbits. Therefore the animals roll. This
rolling of the body round its longitudinal axis is therefore always
accomplished in two tempo's. The first automatic tempo of the
rolling is the same as it is observed in pigeons. The head is thrown
vigorously towards the operated side, and turned so far, that its
dorsal cranial plane touches the ground. The head then turns IS 0^.
As is described already, at this moment the upper extremity
of the opposite side, drawn by the movement of head and neck,
is extended and abduced as far as possible from the body, and
by scratching the ground tries to prevent a further turning of the
head. But if once the head has been turned further, if its dorsal
plane touches the ground, if the turning surpasses 180"^, the aid
of the upper extremity becomes useless. The extremity is itself turned
upward, and at the moment when it does arrive in the vertical
plane, (the turning of the head then reaches 270"^) the second
tempo of the rolling sets in with a vigorous jerk, and the hind
part of the body is thrown round by the animal by an energetic
voluntary movement. The fact, that the rolling of the body round
its longitudinal axis is always preceded by a very intense turning
of head and neck, supports the probability that the mechanism of
the revolution may be a consequence of the automatic initial tur-
ning of neck and head.

After a few days however the rolling ceases. Then follows a
period after the. operation, wherein the rolling may be at any
moment provoked again by laying down the animal on its non-
operated side. The head is then jerked violently towards the
operated side and the revolution follows. After a week perhaps
this also ceases. It may still occur sporadically in the second week
after the operation , but after three or four weeks the animal does
no longer roll round its axis. Head and neck still are turned , but
this characteristic position has no longer the same intensity it

OF THE NERVUS OCTAYUS. 31

had shortly after the operation. The turning of head and neck
being thus gradually reduced, and at the same time the number
of fits diminishing, in which an acute and excessive turning of the
head called forth in periodical returns the acme, the rollings of the
animal have ceased likewise and do not return. A permanent
deviation of the head and neck of the animal remains, and in the
rabbit this is never entirely compensated. The turning of the head
on the cervical part of the body, towards the operated side, does
again allow the animal to be sitting on its four legs.

The fact , that the revolutions cease , when the deviation of the
anterior part of the body is corrected so far that sitting is made
possible again, offers a strong argument for. the presumption: that
the revolution is quite dependent on the intensity of the turning
of neck and head.

Still there is another, very important argument for this opinion.
The animal, though rolling with the utmost violence, can be relea-
sed immediately from these revolutions, if the other labyrinth is
also removed. By this second operation the turned position of head
and neck has likewise ceased as by enchantment , and also has the
deviation of the eyes disappeared in consequence of it.

As soon as by an operation , removing both labyrinths , the inner-
vation-defect has become nearly equal on both sides, the turning
of head and neck does not appear, neither the revolution round
the longitudinal axis of the body.

One of the phenomena described above, viz. the revolution round
the longitudinal axis of the body, may therefore be considered as
a consequence of the turning of head and neck; another, viz. the
hyperextended-abduced position of the opposite fore-leg, may be
necessitated partly by the changed upward position of the opposite
shoulder, on the operated side the shoulder being turned downward.

Both phenomena are therefore dependent on the turning of head
and neck, this latter may be said to belong to the primary distur-
bances of motion. Rolling and the characteristic position of the
foreleg are secundary to it.

Not so easy it is, to elucidate if there is connection between
the position of the head and neck and the deviation of the eyes.

b. Turning of head and neck and the deviation of the eyes.

After a complete removal of the labyrinth, head and neck are
never to regain their original position. All phenomena that did appear
directly after the operation, continue to exist in a lesser degree.
The neck is bent on the trunk, the head is generally turned so
fiar on the neck, that the cheek on the operated side is looking

32 C WINKLER. THE CEl^RAL COURSE

towards the ground , resting on the atonic foreleg of that side which
has been shoven forward, whilst the opposite fore-leg is hyper-
extended and abduced. Only the revolutions have ceased.

With its twisted head however the animal continues to provide
in all its habitual wants. It is eating, exerting coition, fighting
with other animals, and does not give the impression of being
dizzy, or of turning its head in order to compensate a sensation
of dizziness.

If eventually in periods of rest, when left entirely to itself the
animal is lifting its head, the orbital fissure on the operated side
is opened somewhat wider, and the eye is no longer turned so far
downward in the nasal corner as it was directly after the operation.
The eye on the opposite side is likewise turned less far doi'salward.

When an animal has got into this stage, and is able again so
sit on its four legs, we can try to put the head straight. A vigorous
exertion is needed to do this. The animal offers violent resistance,
but with some difficulty it may be done. If the head, after having
been kept straight in this manner, is suddenly left free, it falls
back with a vigorous jerk. It may even occur, that a single revo-
lution reappears by this experiment.

Of even more importance is the fact, that with an animal in
this stage, the deviation of the eyes, having also diminished some-
what already, at once become maximal, when the head is put straight.
This position of the eyes lasts as long as the head is kept straight,
sometimes the eyes relaxate, and in that case they are brought
back into maximal deviation by a sudden shock, nystagmus is seen.
These strokes of nystagmus often succeed one another with regular
intervals.

The deviation of the eyes is therefore doubtlessly connected
with the turned position of the head, in such a manner that the
head follows the position of the eyes, this latter showing itself
more plainly, if the head is prevented from following the eyes.

Evidently the eye on the operated side has assumed the most
evident deviation, the opposite eye rather following the former. The eye
on the operated side (see fig. 6 and 7) is drawn downward and
nasalward. The head is following exactly the movements of this eye.

The neck being turned into the frontal plane, and the head being
turned into a plane standing vertically on the former, the head
follows the direction indicated by the turning of the eye on the
operated side. Therefore the impression seems justified, that the
involuntarily assumed position of neck and head is a movement made
in compensation to the curious turning of the eye on the operated side.

OF THE NERVUS OCTAVUS. 33

Of course it would be very important if the deviation of the
eye could be counterfeited experimentally.

The analysis of the opposite eye shows the following phenomena^:

a, small orbital fissure.

h. protrusio bulbi.

c. maximal deviation in a direction downward (ventral) and in
the nasal canlhus (lateral) with a slight rolling of the eye.

All these phenomena may be the result of phenomena of paralysis,
whereas the antagonistic innervation has been preserved or is even
increased. In that case the paralytic phenomena must be:

a, paralysis of the m. levator palpebrae superioris.

b, paresis of several muscles of the eye with secundary exoph-
thalmus paralyticus.

c, paralysis of the m. rectus superior-drawing the eye frontalward-,
paresis of the m. rectus externus-drawing the eye lateralward- ,
paresis of the m. obliquus superior-drawing the eye downward

and rolling it.

In connection with these paralytic phenomena we must admit
a strong antagonistic action , exerted by the m. rectus internus and
the m. obliquus inferior to develop the deviation of the eye.

Basing on this analysis, I now sectioned in rabbits isolated or
in combination the m. rectus superior , the m. rectus extern us and
the m. trochlearis — all this being done easily by one single con-
junctival lesion — and extirpated pieces from these three muscles,
each piece being long at least 1 c.M.

After this operation however there is never observed any trace
of a deviation of the operated eye. Perhaps the muscles are not
rendered completely inactive, perhaps the antagonistic hyper-inner-
vation is not excited, probable because under these conditions such
an innervation would not serve to any purpose.

To conclude, 1 never did succeed in provoking any evident
deviation of the bulbus by means of sectioning the bulbus-muscles,
far less a position that might in any degree be compared to that,
observed after destruction of the labyiinth.

It remained therefore impossible to decide whether an experi-
mental deviation of the eyes was followed by a similar position of
head and neck in the same direction, because such a position of
the eyes could not be provoked experimentally.

Still the argument remains valid, that head and eyes compen-
sate one another mutually by the deviations they assume, and this
supports the opinion that the turning of head and neck may be a
corrective for the position of the eyes.

Verhand. Kon. Akad. v. Wetensch. (Twcede Sectie Dl. XIV). 3

C. WINKLER. THE CENTRAL COURSE

A farther support to this opinion is given by the fact that both
the deviation of neck and head, and that of the eyes, cease directly

after the removal of the
second labyrinth.

4. The disturba?ices of
motion in rabbits after
the extirpation of the
labyrinth on both sides.

No result of any ope-
ration can be more stri-
king than the result,
following immediately
on the removal of the
second labyrinth, when
this operation is made
some weeks or months
after the removal of the
first labyrinth.

The animal, l>efore
being operated , bears
its head obliquely, it
presents the involuntarily
assumed |)osition of the
eyes, the abduced-exten-
ded position of the oppo-
site fore-leg, the atony
of the homolateral extre-
mities, but after the
second operation it has
become (|uite another
animal (see fig. 15).

The oblique position

Fig. 15.

Copies of photo's.

A. A rabbit after removal of the left labyrinth.

B. The same rabbit after reaxoval of both labyrinths.

C. The same rabbit staggering.

of the head — the tur-
ning of head and neck — is suddenly changed. The animal bears
its head straight. Hut in order to do this, its forelegs are widely
extended (see fig. 15 B — C). The head is unsteady. It is hanging
downward (see fig. 15 B).

Besides now and then fits occur, in which the head is thrown
abruptly backward. The animal then staggers (see fig. 15 C).

The eyes are standing straight in the head. The orbital fissure

OF THE NERVUS OCTAYUS

on the opposite side is narrowed , that on the operated side is
widened by the second operation. There is no longer any devia-
tion of the eyes (see fig. 16 A before and B after the second
operation). On .both sides however there is distinctly protusio bulbi ,
and the movements of the eyes are performed by strokes of nystagmus.

Peculiarly striking is the position of the back, it presents no
longer a convex curve, as in the normal animal, on the contrary
it is sunken in, and cannot assume the former rounded position again
(see fig. 17).

Only with difficulty the animal is able to maintain itself on its
four legs, that are placed in a singular position under the body.

Fig. 16.

A. Position of the contra-lateral (left) eye after removal of the right labyrinths
B. Position of this eyo after removal of both labyrinlTis.

This latter is sunken in. At every moment it is slipping and there
exists a great laxity of all extremities. The rabbit does no longer
jump, it is creeping and faltering, and moves difficultly. Still it
does not roll. In the lower extremities the atony is very strong,
likewise in the fore-legs. The abduced-extended position has vanished.
In order to maintain its equilibrium, the animal keeps its forelegs
wide-extended. It does no longer react on sound-imprcsssions, and
I could never keep them alive for more than two or three weeks
after the second operation.

The results of the removal of the labyrinth on both sides are
apt to support the opinion, that the symptoms of one-sided extir-

pation

the turning of head and neck and the deviation of the

eyes-are connected symptoms, and that the rollings around the longi-
tudinal axis are dependent on the turning of head and neck. But
above all the results of the operation on both sides seem to prove
that after the removal of the labvrinth on one side a one-sided
spasm prevails, caused by destruction of innervations on the operated

36 C. WINKLEH. THE CENTRAL COURSE

side. If now these innervations are destroyed likewise on the oppo-
site side, as is the case after the second operation, there is no
longer any reason for the prevailing of tonic spasms on that side.
The normal position is regained. But all movements are feebler,
more unsteady, because they are supported by a reduced inner-
vation. Head, neck and eyes seem therefore to be recovered, the
extremities are atonic. The atony of the extremities exists on both
sides, it is strongest in the upper extremities, but is very marked
also in the lower ones.

5. The remits of destruction of the cochlea.

After the removal of the cochlea on one side, the animal, when
loosened from the operation-table, shows usually in both eyes some
nystagmus, by means of which is indicated the same deviation of
the eyes that is so conspicuous after destruction of the labyrinth,
and in the same direction. The head is also poised more or less
obliquely. The homo-lateral ear is often hanging downward and the
atony of the extremities on the operated side is plain.

A short time after the operation these phenomena have much
diminished. Still the experienced observer may easily distinguish
the operated side, because a somewhat oblique position of the head
is permanent, as is likewise a propensity to nystagmus or else to
a deviation of the eyes , and also is the atony of the extremities on
that side.

But all these phenomena are shown in a far lesser degree than
after destruction of the labyrinth. It occurs rather often, that one
or two weeks after the opei*ation the animal begins to roll, whilst
the involuntarily assumed position of the eyes, the turning of head
and neck, and the atony of the lower extremities increase. This
proves , that the discharge of endolymph — that will nearly always
complicate the removal of the cochlea — has brought a compli-
cation by altering the contents of the vestibulum. In this manner
the same complex of phenomena is brought about that appears after
one-sided removal of the labyrinth.

The removal of both cochleae has the following eflFects:

1. The animal does no longer react on the sound-impressions.

2. It walks with wide-stretched legs, head and ears are hanging
down, the back is sunken in. The head, though unsteady , is less
unsteady than after removal of the labyrinth. The eyes are stan-
ding straight, but nystagmus is easily provoked by moving the
head. Briefly, both after one-sided and after double-sided extir-

OP THE CENTEAL COURSE.

pation of the cochlea, all phenomena are shown that result from
extirpation of the labyrinth, but they are not so intense and are
much better restored?

In the first days after the removal of the cochlea on both sides ,
the animal is hardly to be
distinguished from one, in
which both labyrinths have
been removed. Trough in the
former case much more is
restored, 1 could not find a
great difterencc in the bearing
of rabbits after double-sided
removal either of the cochlea
or of the labyrinth during
the first week.

In both cases sound-impres-
sions are perceived very badly
or not at all. The disturban-
ces of motion resulting from
double removal of the co-
chlea offer at first no diffe-

i |i r». J xU '*• Position of a non-operated rabbit.

rence at all; aiterwaraS the B. position of this rabbit after removal of both cocWeae.

difference is great, for two

or three weeks afterwards, the atonic symptoms recover. Only the
double operation is dangerous and badly supported. The difference
seenjs to be a difference in degree. All that becomes atonic after
extirpation of the labyrinth, becomes so likewise after extirpation
of the cochlea. One-sided cochlea-operations are followed by fast
recovery. Rolling never is obtained.

Fig. 17.

5. The effects of the section of the dorsal secundary
tracts of the N, octavus.

As soon as in a rabbit the section in the IV^'' ventricle, des-
cribed in the preceding chapter is produced, great care should be
taken to keep the head fixed , in order to prevent the animal
from damaging itself. For the lateral eye is jerked violently towards
the lower nasal canthus and the opposite eye towards the dorsal
(upper) canthus, the head turning at the same time with equal violence.

The animal after being loosened from the operation-table, rolls,
the opposite upper extremity is hyper-abduced and extended and
the animal is kicking continually with this leg. The lateral fore-leg.

38 C. WINKLER, THE CENTRAL COURSE

and both lower extremities are atonic in the highest degree.

Gradually the rolling ceases. Permanently however the animal
bears its head obliquely, the eyes retain their deviated position,
changing with the position of the head. If this latter is put straight,
the deviation of the eyes attains again its maximal degree. Briefly,
an animal in wich has been produced a succesful dorsal section
is not greatly different from one in wich the labyrinth has been
removed in toto. Here also the diflference is only in degree. Yet
the atony is more evident. It exists on both sides and especially
in both lower extremities it is stronger than after removal of the
labyrinth. After this latter operation the atony of the lower
extremity on the operated side often has to be sought for. It can
only be demonstrated by comparing it carefully with the extre-
mity on the other side. After the dorsal section both lower extre-
mities, that on the opposite side also, are hanging helplessly down
like inert masses. Though the atony is strongest in the extremities
of the operated side, in the opposite legs it is still very important.
It prevails in the lower extremities, so much that during the first
days after the operation we might believe in paralysis of the hind-
|)art of the body. But if the animal is left to itself, we find that
it draws its hindlegs again under the body, though with some
difficulty. As soon as it is frightened and changes its place, the
lax lower extremities remain behind.

l^his appears to me being the cause that the rolling of the
animal is performed with less vigour than after removal of the
labyrinth. Generally it is confined to one single revolution , where-
as after extirpation of the labyrinth several revolutions may take
place, and do so as a rule.

This also seems the reason of a symptom, that rabbits present
sometimes as a permanent symptom after the sectioning of the
dorsal tracts.

It is the motion of the animal on the outline of a circle the
centre of which is found on the operated side. In rabbits with
one-sided removal of the labyrinth this manege-gait is not observed.
I believe the cause from this fact to be that after the latter opemtion
the atony in both lower extremities is never so much marked,
that the hind-part of the body does no longer follow the fore-part
of it. The fore-part during the gait , is deviating toward the side
of the operation. This is also the case after the removal of the
labvrinth. But after the sectioning; of the dorsal secundary tract of
the N. VIII, the weakness of the lower extremities is the cause
that they remain on their place (the animal then moves as the

OF THE NERVUS OCTAYUS. 39

hand of a watch-work) or proceed but very little (and in such a
case the animal moves with a manege-gait).

6. A comparison between pigeons after one-sided removal of the
labyrinth atid rabbits after the same operation.

In many respects the accordance is perfect between the distur-
bances of motion observed in rabbits after one-sided extirpation of
the labyrinth, and those found in pigeons. Those in pigeons
have been so carefully described by Ewald, that it is not necessary
to describe them again, for 1 have nothing to add to the magistral
picture, which that author has drawn.

Both animals present the peculiar turning of neck and head, the
atony of the extremities at the operated side. However , there remains
also an essential difference between the disturbances of motion
observed in both animals. The rabbit, immediatelv after the removal
of the labyrinth, shows the excessive deviation of the eyes and
the excessive turning of head and neck with hyperextended and
abduced position of the opposite upper extremity ; it is rolling
round its longitudinal axis in the direction of the operated side
and both extremities on that side are atonic. Gradually these symp-
toms are to some degree corrected, the rolling ceases, and the
animal contiiuies its customary life with its twisted head, as if
nothing had happened. The pigeon on the contrary offers but few
phenomena directly after the one-sided removal of the labyrinth.
It may walk somewhat unsteadily and with wide-extended legs,
its head is unsteady and tottering, but the animal does not roll
and shows no turning of neck and head. This turning does begin
only after a few days, and the symptom is complete only with the
2** and 3** week after the operation. Moreover it is there no per-
manent symptom. Only the turning of the neck appears on the
slightest occasion, though intervals occur during which the head is
kept straight.

The maximal deviation of the eyes however does not exist in
the pigeon, and rolling does never occur in uncomplicated cases.
Nevertheless, in my opinion, these difterences do not constitute an
essential difference.

The pigeon docs not roll round its longitudinal axis like the
rabbit. But the pigeon has a long and easily movable neck, that
may without any difficulty be laid down on the ground with its
middle-part and so offer a sup})ort there, whilst the head is tur-
ned so far that the beak is looking upward, or even farther (see

40 C. WINKLER. THE CENTOAL COURSE

fig. X). EwALD himself, thinks that the farther turning of the head is a
voluntarily accomplished movement. It is easier for the pigeon, to
have its head turned for 860"* than for 180°, and the length of
its movable neck permits it to do so.

That what the rabbit corrects by rolling round its longitudinal
axis, the pigeon does in bending round its neck till 360°.

Besides, the peculiar anatomical relations of the octavus-system
in the pigeon offer a clue to the behaviour of this animal shortly
after one-sided removal of the labyrinth.

When observing attentively the newly-operated pigeon after one-
sided removal of the labyrinth, we find that it presents a
slight resseniblance with the pigeon, in which the labyrinth has
been removed on both sides. At legist the ressemblance is far greater
than with itself after three weeks.

As a fact the one-sided extirpation of the labyrinth in a pigeon
does signify for the central nerve-system a very grave lesion in the
primary octavus-nuclei of the operated side and a less grave but impor-
tant lesion in the primary octavus-nuclei opposite to the side of the ope-
ration. The pigeon, whose labyrinth has been removed on one side, is
in the first days equivalent to an animal on which the removal of the
labyrinth on both sides has been incompletely performed. It is
only afterwards that gradually the preponderance of the one-sided
disturbances appear in such an animal. Esi)ecially under the influence
of emotions or other stimuli , the turning of head and neck occurs
suddenly. If the characteristic turning of head and neck are seen
they ressemble in all points that of the rabbit. But, and there
lies the difference, it only appears by intervals. However the pre-
vailing at the slightest occasion of the preponderance of the one-sided
head-and neck-inner vation is permanent in pigeons, as is likewise the
atony of the extremities at the operated side.

Tn the rabbit, where the N. octavus does not end into the
octavus-nuclei on both sides, as it does in the pigeon, the
post-operative results are different. Here the operation produces
a maximum of one-sided disturbance of innervation, not a double-
sided disturbance. Therefore this disturbance attains its maximum
directly after the operation, but gradually it diminishes. To a
certain degree only it is compensated. The characteristic turning of
head, neck and eyes remains for ever, though it also increases by
intervals.

The pigeon has another anatomy of the VHP*" nerve as the rab-
bit. The one-sided removal of tlie labyrinth repercutes on both
sides of the central system. Therefore in the first days there is a

OF THE NERVUS OCTAVUS. 41

slight loss of tonus in all extremities. But the animal , as the opera-
tive shock is gone, is not always able to compensate totally the prepon-
derate disturbance of innervation at the operated side, and then
the turning of the neck and head begins. Only when all around is
quiet, the pigeon is able to master the turning of head and neck.
Still ever and anon it is recurring by fits.

EwALD has even pointed out the memorable fact , that a pigeon ,
presenling the phenomena of a turning of head and neck recur-
ring by fits, may lose again this involuntarily assumed position,
if the labyrinth is again sought for, and the trunk of the N. octa-
vus, whose terminal organ has once already been removed, is laid
bare and a new lesion produced in It. Tn so doing, the Octavus-
nuclei on both sides are damaged again by operative shock, and
the results are once more the same as those of an imperfect double-
sided openition. In all these cases however the turning of head
and neck by fits returns gradually again.

For the rabbit things stand otherwise. Here we find in the
first place the strong deviation of the eyes, that does not exist in
pigeons, whose eyes are used for quite other purposes. Therefore
in pigeons the eyes have a great influence on the correction of the
deviation of the head. That also rabbits have not. So the turning
of the head and neck and its consequence the rolling round the
longitudinal axis, are the first symptoms of the rabbit.

Gradually the grave one-sided disturbance of innervation in the
rabbit is corrected, but never to such a degree that the head may
be borne erect, though it were only for a moment. From the very
first the disturbance has too much prevailed on one side to allow
this. The rabbit likewise is showing fits, in which all phenomena
are aggmvated , equivalent to the fits of turning of head and neck ,
observed in the pigeon.

But that, what in the pigeon is from the beginning a double-
sided disturbance of innervation, changing gradually to a partial
loss of innervation on each side, prevailing on that, where is operated,
becomes unperceivable w^hen the animal is perfectly quiet. In the
rabbit, from the very first, a one-sided total loss of innervation exists,
and though slightly diminishing afterwards, an always perceivable
disturbance on one side remains.

The pigeon therefore, whose labyrinth has been removed on
one side, is originally equivalent to an animal operated imperfectly
on both sides, in which gradually \^ prevailing the one-sided distur-
bance — the turning of neck and head and the atony of the extre-
mities — which is permanent.

42 C. WINKLER. THE CENTRAL COURSE

The rabbit, whose labyrinth has been removed on one side, is
an animal with a one-sided disturbance of innervation , a disturbance
being at its maximum at the onset, and up to a certain degree
compensated and corrected afterwards.

7. Conclusions concerning the disturbances of motion found after
extirpations of the labyrinth.

The disturbances of motion, observed after extirpation of the
labyrinth, may without any exception be considered as phenomena
of „loss of function." It is not at all necessary to presume symp-
toms of irritation in order to explain them. In this respect I have
nothing to add to the conceptions of Ewald. This opinion is proved
irrefutably by the eflTect of the double-sided operation, that of all
apparent symptoms of irritation, of all the spasms and forcibly
assumed attitudes does leave nothing but only a most extensive
nmscular atony. All this may be demonstrated on the rabbit with
still greater evidence than on the pigeon.

The identical disturbances of motion are shown further, though
in a far feebler degree, after removal of the cochlea. They are
then of the same kind as after removal of the entire labyrinth , and
there is such a striking accordance between both cases, that we may
only speak of a difference in degree, not of an essential difference.
This fact may be explained in two different ways.

In the tii-st place we may believe that the N. cochlearis, servhig
for the perception of sound, does not exert any influence on the
muscular system. As in removing the cochlea, to all probability
the contents of the vestibulum will be damaged in some measure
by discharge of endolymph , it is to be expected that some slight
disturbance of motion will occur. In that case the motion-symptoms
would be dependent on the peripherical endings of the N. vestibu-
laris. The Nervus cochlearis should have no influence on motion;
the two nerves would be quite different nerves.

It is indeed not rare to find that, without any obvious cause,
the far graver disturbances of motion, peculiar to destruction of
tlie whole labyrinth , are gradually developing likewise after remo-
val of the cochlea, and as in such cases the possibility of infection
is excluded, this degeneration must originate in a slow secundary
destruction of the vestibular endings.

This conception would be in accordance with the current opinions
concerning the physiological signification of the cochlea for hearing and
of the ampullae and maculae acusticac for the perception of equilibmtion.

OF THE NERVUS OCTAVUS. 43

But there may be given still another possible explanation of this
fact. Leaving aside the specific perceptive functions belonging hypothe-
tically to both terminal organs , it may still be imagined that both the
N. cochlearis and the N. vestibularis should extend their fibres into the
central nerve-system in a similar way , and are distributed in the same
manner in relation to the motor nuclei situated there. Such being
the case, the same disturbances of motion, that are manifested
completely when the entire terminal organ is extirpated, would
likewise be occasioned in a lesser degree (but still in quite the
same way) by the incomplete removal of the terminal organ , as is
done by destruction of the cochlea. As to the influence on motility ,
this conception is only seeing a quantitative difference between the
two nerves. The N. cochlearis has an influence on motility in the
same way, but not so intense as the N. vestibularis.

This conception may be argumented by the course of both
nerves, because both are degenerating centralwards as a result of
the lesion, and it is greatly supported in that way; but still it is
not quite in accordance with the current opinion, that N. cochlearis
and N. vestibularis are two nerves of entirely separate functions.
A discussion about these opinions here however would lead me
far beyond the limits put to this treatise , besides its being useless
for my purpose.

For I think it is not proved, either that the vestibular-endings
does not participate in the perception of sound, or that the cochlea
may be neglected as being without any signification when investi-
gating the causes of the spasms, the forced attitudes and the rol-
lings. I doubt if a decisive argument may be given that hearing
is not supported by the N. vestibularis, or that the N. cochlearis
should have no influence on motion.

The animal, in which the cochlea has been destroyed on both
sides, does not react on the violent sound-impressions of a Galton-
whistle, blown above its head, as it did before the operation. It
does not roll, but it always has in a slight degree the charac-
teric deviations of head, neck and eyes.

But as soon as the experiments are made to aim directly at the
solution of the question whether a remnant of sound-perception may
still exist after removal of the cochlea, there arise such enormous
difficulties, that I dare not draw any conclusion whatever from
those experiments.

I will only just recall to mind that after the opinion of Ewald ,
pigeons whose labyrinth has been destroyed on both sides, still
hear, i. e. that they reacted on sound-impressions, brought to act

44 C. WINKLER. THE CENTRAL (JOURSE ETC.

upon these animals, whilst every precaution had been taken to
prevent air-shakes. Without doubting in the least degree the cor-
rectness of the observations of such an investigator as Ewald, I
believe that such observations go beyond the limits assigned to
our judgment on the sense-perception of animals. I have believed
to observe that rabbits, whose cochlea was destroyed, still did
hear, but I wish expressly to leave this question undecided.

For the same reason I will only just recall the fact that the
animal, chosen preferably to all others for demonstrating the degene-
ration of the labyrinth as the cause of disturbances of motion , the
dancing Japanese mouse is at the same time deaf. I know of no
instance wherein dancing mice have been described that could hear
and I can assure that they have lost completely the primary nuclei
of the N. VIII. As to deaf- and dumb creatures, whether they
present disturbances of motion or not, it is my belief that the
question whether in their case it is only the cochlea or the whole
of the labyrinth that is damaged, is not yet resolved.

In this paper I carefully avoid to communicate anatomical investi-
gations on the periferical endings of the eighth nerve. I prefer main-
taining it between its proper limits. Therefore also I neglect experi-
ments on sound-perceptions. I only have to study the influence
that the N. octavus exerts on the motion of the animal.

ITiat, what I wish to state here, is that the disturbances of
functions, observed after removal of the cochlea and after extir-
pation of the labyrinth, show only a difference in degree, and
that they leave room for the conception that there need not be
assumed an essential difference in the mode of distribution in the
central organ of the N. cochlearis and the N. vestibularis. This
opinion is supported by the anatomical course of both nerves in
the central nerve-system.

Chapter II.

On the distribution of the nervus octaviis in the central
nervous svstem in rabbits.

1. Methods of investigation, Introditction.

In order to investigate the central distribution of the nervus
octavus it is necessary to use several methods of investigation.

From different species of animals the normal central nervous
system must be compared , before beginning the researches in rab-
bits. Though this method of comparative anatomy need not be
extended so far, as to apply it to nearly all vertebrates, it is neces-
sary to examine the medulla oblongata of men, dog, cat, horse,
mouse, rabbits, the amphibia and birds, which are common in our
laboratoria, before examining foetal or experimentally prepared
material of one species.

I even believe, that many questions, touched in this paper, will
ask for a solution from the comparative anatomy of special animals
or even of species, where an irregular differentiation of functions
may be supposed. So for instance the examining of the medulla
oblongata of the mole, the squirrel, the bat, of the cetacea, may
teach us much about the auditory nervous system. But for my
purpose the method of comparative anatomy is occupying only a
second plan. My purpose aims the study of the N. octavus in
rabbits. Therefore the method of comparative anatomy has the value
of an introductory method, but other methods are more necessary.
Absolutely necessary are embryological-investigations.

They may be applied in different ways, partly by studying the

46 C. WINKLEE. THE CENTRAL COURSE

myelinisation in foetal and young born animals, partly by studying
GoLGi preparations.

I must avow, that I cannot support in every respect, the views
of Flechsig, who sets too much value on the signification of the
myelinisation-process in nerve-fibres. This method , though offering
great advantages, offers great dangers too.

It may give evident results in some regards, as for instance,
that the vestibular-nerve receives the meduUated fibres at an earlier
period of development than the cochlear nerve. But it may be very
venturous to ascertain , that the vestibular nerve is myelinisated at
a time when the cochlear is still quite exempt of medullated fibres.

Investigators, who have worked exclusively with this method
will run a great chance to be induced into error, and it is my
opinion that Flechsig himself has not been very happy in his
description of the auditory tracts, especially in the separation of
the primary and secundary paths. The study of the development
of myelin may control other methods. Therefore it is of great value.
But it is restrained between strict limits and ought to be controlled
itself by the GoLGi-method and especially by the experimental
methods.

The methods of experimental anatomy have been chiefly used
in my investigations, either the method of von Guddbn or that
of Marcht.

Gudden's method of experimental secundary atrophy after lesions
in the young-born animal is, if exclusively used, dangerous, nearly
as dangerous as the myelinisation-method , but it cannot be totally
substituted by the methods of secundary degeneration , for instance
by the method of Marchi.

For an experimentally produced atrophy, once provoked, is
invariable. A nervous system sectioned in the young born animal
will be found totally atrophied after a lapse of three months or
longer.

But the dangers of von Gudden's atrophy are evident. The method
is giving too little and too much.

As soon as the atrophied fibres may be found distributed between
intact fibres, they are not recognised. The judgment on the par-
tially atrophied system is often a subjective judgment. In this respect
the method gives too little.

Moreover nobody can foretell the extension of the atrophy in secun-
dary and even in tertiary systems consequent to the atrophy of the
insulted one. Neighbouring systems, completely independent of the
one damaged, may, under circumstances, atrophy. In all these

OF THE NEKVUS OCTAVUS. 47

regards, the method is giving too much, and is dangerous espe-
cially if the atrophy existed for a long time.

These objections to Gudden's method have discredited it, and
in modern investigations the method of secundary degeneration , as
it was used by Marchi, is preferred. •

To be sure , Marchi's method is giving results in cases , wherein
that of VON GuDDEN is impracticable.

Degenerated fibres distributed between intact fibres are easily
found. When the method is used within a fortnight after the ope-
ration , the black granules in the degenerated fibres may be strictly
limited to the damaged and degenerated system. Nevertheless grave
objections are also to be made to the MARCHi-method.

V^. There must be certainty, that the experimental lesion, which
is studied with MARCHi-tinction , has passed without any complica-
tion. A slight infection, the most superficial meningitis, etc. may
be the cause of such an abundant overflowing of black granules
in the nervous system , that all the results of the experiment are
disturbed.

2^^. The black granules do not remain strictly limited to the
degenerated fibres, where they orinigated. The existence of neuro-
phj^ic cells transporting the myelin-globules into the lymph-channels
and the lymph-fissures is a grave complication. The black granules
therefore are often found in places, independent of the original
focus of degeneration. Such for instance is the case, in nearly all
the roots of periferical nerves. Their entrance in the medulla
oblongata is the favorite spot, where black granules are found.
For instance , black granules are nearly always found at the entrance
of the IIP nerve, consequently to every operation made in the
oblongata or in the pons Varoli.

The quantity of the transported granules is increased in reason
of the time that has passed after the operation.

3®. Every small incision made in the central system , is surrounded
by a (in MAUcm-tinction) white coloured mass , without black gra-
nules. The white-coloured mass in the neigbourhood of the wound
must be added to the extent of the lesion.

4®. The existence of the so called retrograde degeneration studied
by VAN Gehuchten and others. The retrograde degeneration (from
the body of the cell , which axon was sectioned towards the section)
begins after a fortnight.

5®. Three weeks (and even earlier) after the operation , the dege-
neration in the sectioned system is complete. The degenerated fibres,
though they may end in the nuclei by unfolding their terminal

48 C. WINKLER. THE CENTRAL COURSE

collaterals (Lewandowskt's Zersplitterung) or otherwise, can be traced
to them. But at the same time, degenerated fibres, originated in
the primary nuclei, are found. The question, whether those fibres
may be the fibres of secundary systems or not, is as yet an open
question. In respect of all these grave objections 1 believe that
Marchi's method must always be controlled as well by that of von
GuDDEN , as by the method of myelinisation. Exclusively used , none
of them is suflicient.

This is also the case with Nissl's method. It has to answer the
question to what extent degenerative changes have occurred in the
nerve-cells, but it is only adapted to the study of the relative
fresh disintegration in cells, whose eflTerent axons are sectioned. It
is nearly useless in the study of the changes in cells, receiving
the degenerated collaterals of damaged systems.

And yet those cells may atrophy, as is taught by preparations
treated with the carmin-method.

As we said before, the central course of the VHP** nerve can
only be elucidated by using all the different methods, and it is
only with the aid of their mutual controlling that many dubious
points may be ascertained.

There still is one important thing, that is often forgotten: The
central system should always be examined in uninterrupted series
of sections, and the direction of the sections should always be
varied.

The frontal sections usually studied, often in incomplete series,
are quite insufficient. Horizontal and sagittal series of sections are
just as necessary as frontal series. Questions of great importance,
that remain without solution in the frontal series, are immediately
resolved in the horizontal or sagittal series.

With the aid of these methods the nervous system of rabbits,
which had suffered different operations was studied and compared
with embryonic material, as well as with the normal medulla
oblongata of different animals, in order to form an opinion upon
the central distribution of the VIIF*" nerve.

2. The roots of the nervus octavus.

a. The actual views upon the signification of the N, cochlearis

and the N, vestibularis and their continuation in the

lateral and ventral root.

Generally the view is hold, that the centripetal prolongations of

OF THE NERVUS OCTAVUS. 49

the bipolar nerve-cells in the ganglion spirale cochleae are the
meduUated fibres composing the cochlear nerve and this nerve
may be continued in the lateral (dorsal or distal) root of the ner-
vus octavus.

Nevertheless it must be admitted that there exists a little ner-
vous branch, gathering the fibres from the macula sacculi in a
small proper ganglion. The central prolongations of the cells in
this ganglion may also be traced in the cochlear nerve (Retzii's,
SCHWALBE a. o.).

On the other hand the macula utriculi and the cristae ampullae
may receive the centrifugal prolongations of the bipolar cells
composing the ganglion plexiforme Scarpae. In rabbits these cells
are spread in the course of the vestibular nerve , and their centri-
petal prolongations pass through this nerve in the medial (ventral
or proximal) root of the nervus octavus.

Both nerves together therefore are forming the nervus octavus,
but, as is argued, cochlear and vestibular nerve are different ner-
ves, different in structure, as well as in function. Their structure
is different in many regards.

Firstly their relation to the periferical ganglia is not quite the same.

The ganglion spii'ale lies concealed in the lamina ossea of the
cochlea. Therefore the cochlear-nerve , in its traject through the
meatus auditorius internus, may be compared with a spinal root.

Not so the vestibular nerve. The cells are spread along this nerve
and the so called ganglion vestibulare nearly touches the medulla
oblongata. The vestibular nerve consequently may be partly com-
pared with a spinal root, but partly also with a periferical nerve.

The degenerations in the nervus octavus after removal of the
labyrinth may be influenced by this anatomical peculiarity.

For the removal of the cochlea includes necessarily the removal
of ihe ganglion spirale and it is directly comparable with a root-
section.

The removal of the contents of the vestibulum and even the
section of the vestibular nerve in the meatus auditorius is not
necessarily combined with a complete removal of the ganglion
vestibulare. To do this, the vestibular nerve should be torn out
and broken close to its entrance in the medulla oblongata, and it
is hardly possible to do so, without lesion of the medulla.

But only the latter operation may be compai-ed with a complete
root-section. The removal of the vestibulum and the section of the
vestibular nerve are operations partly comparable with a root-
section, partly with the section of a periferical nerve.

Verhand. Kon. Akad. v. Wetensch. (Tweede Sectie DI. \IV). 4

50 C. WINKLER. THE CENTRAL COURSE

This peculiarity influences the results of MARCHi-degeneration and
offers an advantage as well as a danger.

Besides the somewhat different behaviour of the two nerves
towards their periferical ganglia, they also show a certain difference
in structure, the vestibular being composed mostly of thick fibres,
the cochlear mostly of small ones. This difference is not caused by
the circumstance that the cochlear-nerve contains root-fibres and the
vestibular partly periferical and partly root-fibres , for then the same
difference should be found in the roots. The dorsal root should be
composed of small, the ventral of large fibres.

In this way the difference in the structure of the terminal organs
(cochlea and vestibulum) should be reproduced in the structure
of their centripetal nerves, as if a complete independency of the
two organs and their nerves existed.

Yet this difference must not be thought too important. Firstly
in rabbits the two nerves exchange many fibres. Consequently large
fibres are found in the cochlear and in the dorsal root, small
fibres in the vestibular and in the ventral root. In animals — for
instance horse and sheep — where the nerves do not exchange
fibres and where they run strictly separated, it is not otherwise,
Sections perpendicular to the longitudinal axis of the root demon-
strate with certainty, that there exists a certain prevailing of thick
fibres in the ventral root above those in the dorsal root, but this
difference in structure is only a relative difference.

Far more interesting than the supposed difference in structure
of the two component branches of the nervus octavus is the nearly
generally admitted opinion , that the cochlear and the vestibular
nerve, after entering the medulla oblongata, pui'sue a completely
different course in the central nervous system.

The cochlear nerve is continuated in the dorsal root and enters
in the latero-dorsal layer of the corpus restiforme. It turns in this
layer round the oval area of the rcstiform body , sending fibres during
this traject in the ventral nucleus, in the tuberculum acusticum ,
perhaps also in the lateral part of the dorsal nucleus of the N. VIII.

The vestibular nerve however, continuated in the ventral root,
finds its way between the restiform body and the spinal root of
the V**" nerve , goes straight to the internal part of the corpus resti-
forme and dividing itself into a descending and an ascending branch
ends in the nucleus dorsalis N. VIII, in the nucleus griseus rami
descendentis radicis ventralis and in the so-called nucleus of Bechtkrew.

In this way the cochlear and the vestibular nerves, being pur-
sued to different nuclei, originating out of different periferical

OF THE l^RVUS OCTAVUS. 51

endings, presenting each a special arrangement of their periferical
ganglia and showing a somewhat different structure in regard to
the thickness of their fibres , should betray themselves , anatomically
spoken , as complete independent nerves , though they compose
together the VIII^^ nerve.

But the distribution of the root-fibres in the central system is
not exactly so, as the generally admitted opinions, described above,
hold it to be. The greater part of my anatomical investigations will
be consecrated to demonstrating that the root-fibres of both nerves ,
may be pursued in all the primary nuclei and in all the secundary
systems of the nervus octavus. The difference in the central distri-
bution of the cochlear and the vestibular nerve is a difference
concerning the quantity of fibres thrown into the nuclei.

Therefore the complete independency of the two nerves, maybe
not so surely proved by their anatomy, as many investigators
believe.

But not only strictly anatomical data are brought forward to
prove that independency. The comparative anatomy also may fur-
nish some arguments to defend this opinion.

Indeed, the comparative anatomy allows the assertion that the
static organ is of a very old age in the phylogenetic history, for
it is nearly everywhere present in lower animals as an organ
bearing the otoliths.

Much later and gnidually the cochlea has been differentiated
from this static organ. In fishes scarcely existing, in birds repre-
sentated by the lagaena with- half a spiral convolution , it reaches
in the mammalia its total development with its three characteristic
convolutions. In the same series of ideas the embryonic argument
may be ranged, that in the ontogenetic development the fibres of
the phylogenetic much older nerve — the vestibular — begin their
myelinisation at an earlier period of foetal life , than the fibres of
the cochlear nerve.

This argument offers a support to the opinion that a certain
independence of the two organs of the labyrinth and of their nerves
exists, but nothing more.

My experiences are not at all in favour of the opinion , that the
cochlear and vestibular nerves are myelinisated as if they were inde-
pendent nerves.

Certainly the myelinisation begins at the radix medialis (ventralis)
at an earlier period than in the dorsal root , still hardly the myelini-
sation of the former has become evident but there also appear
medulla ted fibres in the cochlear.

52 C. WINKLER. THE CENTRAL COURSE

Far more demonstrative power than anatomical proofs, physio-
logical proofs may possess.

If it were demonstrated with certainty that the animal without
cochlea, was deaf and without disturbances of motility, and on
the other hand, that the animal without the static organ (contents
of the vestibulum) was hearing but presenting characteristic motor
symptoms — if this were surely demonstrated, the actual view
of the complete mutual independency of the two nerves might have
a firm base.

But, though this view is often defended, I hold it impossible
to realise the experiments tending to prove it.

Our experimental methods are too rough for this purpose.

As is shown in the preceeding chapter, the animal without
cochlea may present slight motor symptoms, not so grave as the
characteristic disturbances after the total removal of the labyrinth.

And as to the hearing of the animal , I repeat , that Ewald thought
pigeons were hearing, even after total removal of the labyrinth.

The enormous litterature on the functions of the otoliths demon-
strates the influence that the static organ has on motility. But all
this does not demonstrate , that the cochlea , after its differentiation
from the static organ, has no longer any such influence.

Only it is evident, that in quantity it*^ influence must differ
from that of the whole labyrinth. Cochlea and vestibulum may be
differentiated from a single more simple organisation — from a static
organ. Possibly the one — the cochlea — obtained the qualities to
prepare the psychical function of hearing. But there is not to be
seen any reason , why it should have lost the quality — originally
belonging to the whole organ — of acting automatically on a greater
part of the muscles.

Possibly the other part — the static organ strictiore sensu —
retained in a higher degree its original automatic influence upon the
muscles. But it is not proved , why it never should have pos-
sessed or why it totally should have lost a function for the per-
ception of shock and sound.

The experiences on dancing Japanese mice show, that those
animals, missing nearly completely the whole auditory system, have
motor disturbances (are dancing) and are deaf.

The experiences on deaf-mutes do not contradict the opinion
that both parts of the labyrinth or of their nervous system may be
damaged, and in consequence cause deafness and unsteadiness in
movements.

'J^lie anatomy of the auditory nervous system in rabbits now

OF THE NEKVUS OCTAVUS. 53

may prove that the course of the root-fibres of the dorsal and the
ventral root, is the same. Only the quantity of fibres, which are to
be traced from the root in a distinct central part, does vary. Both
roots innervate in larger or smaller quantity all the so-called primary
nuclei, both are searching in larger or smaHer quantity the same
so-called secundary paths.

An endeavour to demonstrate this, I intend to make in the
next paragraphs

3. The primary systems or the root-fibrj:s
of the nervus octavus

a. The freak degeneration in the root-fibres taking place after

the isolated removal of the cochlea and the initial course

of the dorsal {lateral) root i?i the central system.

We have seen that it is possible in rabbits to remove the cochlea
without damaging the vestibulum. We have seen that this operation
is equal to a section of the cochlear nerve between the spiral
ganglion and the medulla oblongata. A succesfully executed opera-
tion of this kind is always followed by a degeneration in the
cochlear-nerve , within a week.

Marchi's method then gives in those cases an evident result.

The lateral {dorsal) root of the VIIP^^ nerve is covered with
black grains, whereas the portion of the medial {vefitral) root , that is
found between ganglion vestibulare and medulla oblongata is totally
exempt of them. (See fig. \a on Plate I and fig. 2 on Plate 11).

This fact does not prove that the degeneration in the lateral root
is a complete one. There are reasons, as we will find, to admit
that this is not the case.

But in this fact we have an expedient to study the fibres,
Uiking their origin in the ganglion spirale, and to isolate them
from the rest. Unfortunately it is not possible to remove the con-
tents of the vestibulum without lesion of the cochlear nerve.

A comparison of the degeneration in the lateral root after remo-
val of the cochlea may therefore only be made with the degeneration
following the total section of the VHP** nerve.

The degenerated fibres of the ganglion spimle (the cochlear
root-fibres) throw themselves through the lateral root in the latero-
dorsal layer of fibres, that turns round the oval area of the restiform
body to reach the internal part of it. But after total section of the
VHP'' nerve the number of degenerated fibres in the latero-dorsal

54 C. WINKLEE. THE CENTRAL COURSE

layer of the corpus restiforme has increased and moreover they are lying
in the inner part of this layer close to the corpus restiforme , where
degenerated fibres are not found after the isolated removal of the
cochlea (see fig, 4 on Plate IV).

The common opinion that the stratum latero-dorsale of the corpus
restiforme is only formed by the root-fibres of the cochlear-nerve
is incomplete.

In fact the greater part of the lateral rootfibres continue their
course in this stratum latero-dorsale corporis restiformis — as frontal
sections through the medulla oblongata, touching the fibres of this
layer longitudinally , demonstrate easily — but this stratum receives a
considerable accres from fibres of the medial root. Lewandowsky is
right in this opinion.

With the Marchi-method it is easy enough , to follow the degene-
ration after the removal of the cochlea — the black granuled fibres
of the lateml root — not only in the stratum latero-dorsale but
also in other paths.

As soon as the degenerated dorsal root-fibres have reached in
that case the medulla oblongata they divide into three portions.

1®. Some fibres leave the dorsal (lateral) root rectangularly in a
ventral direction and passing directly in the corpus trapezoides may
be followed across the raphe (see fig. \a Plate I and Plate II fig. 2).

They are the root-fibres of the dorsal root, that are to partici-
pate in the formation of the „systema ventrale of the nervus octavus".

2® A few fibres — especially in the proximal region of the
entrance of the lateral root — enter between the oval area of the
corpus restiforme and the spinal root of the V^** nerve. They reach
the portio interna of the restiform body. They form the most
distally situated fibres among those, who are found between oval
area and spinal root of the N. V. and bear themselves as the greater
part of the root-fibres of the ventnil (medial) root do (see fig. 2 on
Plate II). They are the medial fibres of the dorsal root. This medial
trunk of dorsal rootfibres is not very important.

3®. The greater part of those fibres pursue their way in a dorsal
direction. Closely joined together, they penetrate through the nucleus
ventralis nervi VIII, dividing it into a smaller medio-ventral , and
a larger latero-dorsal part and reach the stratum latero-dorsale.

There they pursue their course, at first between nucleus ventralis
and the oval area of the restiform body, afterwards between the
tuberculum acusticum and the oval area. So they describe a cur-
vature round the oval area , closely adossed to it in its ventro-distal
part (see fig. \a on Plate I), but as they advance dorsally and

OP THE NERVUS OCTAVUS. 55

proximally (see fig. 2 on Plate II), there appear normal fibres
resting upon the lateral border of the oval area, which only may
be brought to degeneration after the section of the eight nerve
(see fig. 4 on Plate IV). On this traject the dorsal rootfibres enter
into the ventral nucleus and the tuberculum acusticum in a way
to be described further on and the remaining fibres reach also the
portio interna of the corpus restiforme in its latero-dorsal part.

These remaining fibres are the root-fibres of the lateral root,
which participate in the formation of the „systema dorsale nervi
octavi".

Each of the three portions of these lateral root-fibres has its own
adventures, and shall be separately described, as soon as the initial
distribution of the ventral root-fibres is known. In the description
of the initial ways of the lateral root-fibres here given I differ
essentially from the opinion of van Gehuchten, and approach to
that of Tricomi-Allegra, not only because the Marchi-degeneration
demonstmtes it, but also because it is concordant with the results
of other methods of investigation.

b. The fresh degeneration in the root-fibres taking place after

the section of the VIIP^"^ nerve and the initial traject

of the ventral {medial) root in the central system.

The ventral root may be brought to degeneration, together with
the dorsal root by sectioning the VIIP*^ nerve in the meatus audi-
torius internus.

The comparison of the degenerated fibres found after the removal
of the cochlea , with those found after the section of the VHP*" may
be used to study the course of the vestibular fibres and those of
the ventral root.

This study teaches us , that the ventral root-fibres divide in three
portions, exactly in the same manner as is done by the dorsal
root-fibres.

P. Some fibres, mostly thick fibres, leave the ventral root
rectangularly , bending in lateral direction in the corpus trapezoides
(see Plate VIII fig. 15 N°. 9, 10 and 11).

Those fibres incre^ise the number of degenerated fibres entering
there from the dorsal root, for after the section of the auditory
nerve the degeneration in the corpus trapezoides is nearly doubled
in intensity, as compared with that after removal of the cochlea.

Those fibres are the ventral root-fibres participating in the for-
mation of the „systema ventrale nervi octavi".

56 C. WINKLER. THE CENTRAL COURSE

2®. The principal portion of the degenerated fibres of the ventral
root passes straight forward between the oval area of the corpus
restifornie and the spinal root N. V to reach the portio interna
corporis restiformis (corpus juxta-restiforniis). There they occupy
the medio-ventral part , resting upon the dorsal surface of the spinal
root N. V. Immediately after their entrance they change abruptly
their direction. The larger number of fibres turns downward (dis-
tally) — the radix descendens nervi octavi (see Plate V fig. 9) —
and in a smaller quantity they turn upward (proximally) — the
radix ascendens nervi octavi (Plate IV fig. 8 , as well as Plate IX,
X, XI, fig. 16 A— N).

For this reason their course is better studied in horizontal series
of sections (Plate IX, X, XI fig. 16) than in frontal ones (Plate
VIII and IX, fig. 15).

These are the medial root-fibres of the ventral root, forming the
important medial trunk of the ventral root.

Many authors think that all the fibres found between area ovalis
and spinal quintus root are ventral rootfibres. Marchi-degencration
has shown us in the preceding paragraph , that in the distal region a
small portion of dorsal root-fibres take their course in the medial trunk.

Many authors also are of opinion , that all the ventral root-fibres
may be continued among the here described fibres and that none
of them take another way. But this certainly is not the case.

3®. Moreover an important number of ventral rootfibres passes in
the stratum latero-dorsale corporis restiformis.

The capital situated part of this layer is nearly totally formed
by ventral root-fibres. As we have seen in the preceding paragraph,
a large number of dorsal root-fibres are also found in this layer,
but in the dorsal and capital regions there always remain normal
fibres (after removal of the cochlea) lying closely to the area ovalis.
These fibres now degenerate after the section of the auditory nerve.

They turn in a curvature round the oval area of the restiform
body, always touching it (see fig. 4 on Plate IV). On this way a
part of them reaches the latero-dorsal pai-t of the portio interna cor-
poris restiformis, another part, perforating the oval area, and run-
ning transversally through it, also enters the portio interna. As
soon as (in series of frontal sections) the oval area enters the cere-
bellum as its pedunculus inferior — in the most proximal regions
of the octavus-entrance — the stratum latero-dorsale hiis disappeared
and the medial root-fibres are the only remaining fibres or better
the latero-dorsal and the medial trunk of root-fibres fall together,
and there are no longer two trunks.

OF THE NERVUS OCTAVUS. 57

The fibres mentioned here sub 3 are the ventral root-fibres par-
ticipating in the formation of the systema dorsale nervi octavi.

In this way the Marchi-degenemtion demonstrates that 1® in the
stratum latero-dorsale corporis restiforme root-fibres are to be tr-aced
as well from the cochlear, as from the vestibular nerve. They are
ranged there in such a manner , that distally the number of cochlear
fibres (dorsal root-fibres), proximally that of vestibular-fibres (ventral-
root-fibres) prevails.

2® that between the oval area and the radix spinalis N. V. prin-
cipally the fibres from the ventral may be traced. Only in the distal
regions there are found dorsal root-fibres.

3® that in the corpus trapezoides thick fibres — principally ventral
root-fibres — as well as small fibres, mostly dorsiU root-fibres, may
be pursued.

c. The supposition that both roots send their fibres , though in

different quantities , in the same paths , is confirmed by the

study of the myelinisaiion of the roots in the rabbit.

The Marchi-degeneration has shown us that the stratum latero-
dorsale is not only the continuation of the dorsal rootfibres, but
contains also ventral rootfibres (and as we shall see afterwards
many other secundary auditory fibres) , and that between oval area
and spinal quintus root enter root-fibres of both roots as well as
they do in the corpus trapezoides.

These conclusions are not accepted by the authors, who have
studied the central distribution of the auditory nerve by means of
the myelinisation-method.

So , for instance , the schema given by Bechterew is generally
accepted, and it is taught, that the ventral nucleus should be
an intervertebral nucleus, that the dorsal root may be continued
in the stratum latero-dorsale and the ventral root between the oval
area of the restiform body and the spinal root of the nervus trigeminus.

And, basing on Flechsig's investigations, it is usually taken for
granted that the corpus trapezoides only contains fibres of the
secundary auditory systems. Though thqse opinions are doubtless
in contradiction with many of the results, mentioned in the excel-
lent papers of Held , they are usually defended on the continent.

I must avow, that I fail to understand as yet, why the investi-
gators, who have studied the auditory system by means of the
myelinisation-method have not long ago stated the same conclu-
sions, that are defended here as the results of the Marchi-method.
For, as to my experience, the myelinisation of the root-fibres of

58 C. WINKLER. THE CENTRAL COURSE

the auditory-nerve gives a very decisive answer in favour of the
questions treated here.

Only it ought to be kept in mind that the ordinarily used fron-
tal series of sections are not very apt to demonstrate the course
of the root-fibres.

In a newborn rabbit it is nearly impossible (f. i. fig. 17. A
and B on Plate Xll, and fig. 5 on Plate I) to disentangle the fibres
mixed together at the entrance of the two auditory roots. There
the fibres of roots and of the corpus trapezoides are all medullated
and mixed together in an inextricable mass.

Much easier the question is in sagittal sections. There the rela-
tion between the two roots and the corpus trapezoides is very clear
(Plate VI fig. 19 A— B and Plate XIII fig. 18 A— D). Simpler
as it is given in Plate VI fig. 19 A and in fig. 18 A on Plate
XIII, the relation between the two roots may be hardly demon-
strated. In fig. 18 A the section touches the superficial layer of
the medulla oblongata. The entrance of the nervus trigeminus (N. V)
is found most proximally. The proximal (medial or ventral) root of
the VHP** nerve with its thick fibres is distinctly separated from
the distal (doi-sal or lateral) root of the VHP*" nerve , having small
fibres. But immediately it is seen that an intermedial rootlet passes
from the ventral towards the dorsal root (Plate VI fig. 19 A and
Plate XIII fig. 18 A r. interm).

By means of this intermedial rootlet fibres are passing from the
ventral root into the stratum latero-dorsale, as it is found between
the ventral auditory nucleus and tuberculum (Plate VI fig. 19 B
and Plate XIII fig. 18 B). And in Plate XIII fig. 18 C it is
clearly demonstrated that fibres of the ventral root, now found
between the spinal root of the N. V. and the restiform body,
perforate the latter (its oval area) to reach the stratum latero-dorsale.
Those fibres, penetrating the corpus restiforme, may be found in
all sagittal sections until the portio interna of the corpus restiforme
is reached, at that moment a new bundle is found, close to the
most medial limit of the oval area in the most lateral part of the
portio interna of the restiform body. This latter bundle (fig. 18 I)
on Plate XIII in h. or IIeld's interm. system) leaves the stratum
latero-dorsale, and crossing the forma tio gelatinosti of the spinal
trigeminus-root , finds its way as well to the systema intermedium
as even towards the corpus trapezoides. In a proximal situation to
this bundle — the bundle of Held — but medially from the oval
area, communicating fibres from the ventral root to the latero-
dorsal layer of the restiform body arc still always to be seen , and

OF THE NERVUS OCTAVUS. 59

always crossing queer this body. It is not necessary to study younger
foetus of rabbits in order to demonstrate, that fibres in important
quantity are going from the ventral towards the dorsal root , and from
the ventral root queer through the area ovalis towards the stratum
latero-dorsale of the restiform body. Therefore I can only conclude
that the fibres of the latero-dorsal layer, terminating as well in
the ventral auditory nucleus as in the tuberculum acusticum, are
originating of both roots of the VIIP^ nerve.

The myelinisation-method at the same time confirms the opinion
that rootfibres of the ventral root penetrate transversally through
the oval area to reach the stmtum latero-dorsale. Degenerate
fibres after sectioning the VHP*' nerve , demonstrated with Marchi-
niethod in the preceding paragraph (to compare Plate IV fig. 4,
Plate VIII fig. 15 N°. 7 and 8 with Plate XIII fig. 18 C and D)
may also be traced transversally through the oval area. There is
shown , that they are not found after the removal of the cochlea.

Therefore, I think it evident, that the myelinisation-method sup-
ports in every way the supposition that the stratum-latero-dorsale
and the ..ayaterna dorsale nervi octam' contain root-fibres of both
auditory roots.

But there is more. In the new-born rabbit and better still in
younger foetus, it may be seen, that the myelinisated corpus tm-
pezoides receives its fibres not only from the nucleus ventralis N.
VIII (Plate XIII fig. 18 B) but from both roots (Plate VI fig.
19 B). Rootfibres pass directly into it.

This is so evident, that I also think it demonstrated by the
myelinisation-method, that the „systema ventrale nervi octavV
contains root-fibres of both auditory roots as well as fibres of the
secundary system.

d. The supposition that both roots send their fibres in the corpus
trapezoides is also confirmed by Gudden's vie I hod. The tuberculum
acusticum and ventral auditory nucleus being removed in the youny born
aimal, without grave lesion of the auditory roots, the corpus trape-
zoides having lost its secundary only contains rootfibres.

Van Gehuchten, who hiis published many excellent articles on
the central course of the cerebral nerves , has in a recent paper revi-
ded the views previously originated in his laboratory as results of
the researches of his disciple Tricomi-Allegra.

The isolated removal of the cochlea in two guinea-pigs caused
MARCHi-degeneration only in the dorsal root, which was only to
be traced in the ventral auditory nucleus and the tuberculum

60 C. WINKLER. THE CENTRAL COURSE

acusticum. Van Gehuchten therefore thinks erroneous the differing
results of Tricomi-Allegra, who, experimenting principally on rab-
bits , assumes root-fibres entering the corpus trapezoides , and the
cause of his error is by van Gehuchten presumed to be a lesion
of the facial nerve.

This nerve indeed crosses the area of operation and if injured,
for instance by a slight traction , the lesion may be sufficient to
cause a degeneration of the transversal fibres of the corpus trapezoides.

Moreover , there are , with the Marchi-method , often found some
black stained granules at the entrance of the VIP** nerve and in
its root-fibres.

Therefore, as argues van Gehuchten, the slight tractions or
other lesions of the facial nerve during the operation are the cause
of the degenerated transversal fibres in the corpus trapezoides and
the passage of auditory root-fibres therein is not proved.

Now I have already mentioned that Marchi-method offers dan-
gers. One of these is, that the black granules — even within a
few days after their appearance — are aimed away by the lymph-
current and that the roots, leaving the central systems, may be
reckoned among the out-ways of the lymph-circulation. Indeed, black
granules are often found there , where roots leave the system , and
if a degeneration exists in the corpus trapezoides, they mmt be
found at the issue of the facial nerve.

But if the presence of some granules at the entrance of the
facial root-fibres is used — as is done by van Gehuchten — to
prove a lesion of the facial nerve I cannot entirely accept this
view. They necessarily must be found there after each degeneration
in the corp. trapezoides. And their presence in roots after degene-
rations in the central system only proves that Marchi-method is not
a sovereign method and needs to be controlled. But in the
preceding paragniph, I have established the fact that the myelini-
sation also gives arguments in favour of the opinion that root-fibres
of the Vlir^ nerve directly enter into the transversal fibres of the
corpus trapezoides (Plate XIII fig. 19 B). Another experiment
however may be taken , that demonstrates clearly the passage from
the rootfibies in the corpus trapezoides, as well from the dorsad
ar from the ventral root.

In a new-born rabbit, the atlanto-occipital membrane may be
opened in order to divide the lateral part of the medulla oblon-
gata in such a manner that the ventral auditory nucleus and the
tuberculum acusticum have lost all connections with the medulla.
This operation may be done with a single draught of the thin knife.

OF THE NERVUS OCTAVUS. 61

without damping the auditory root-fibres or with only a partial
lesion of them.

The operation may seem difficult , but as a fact it is much sim-
pler than it appears. In my possession are at least three series of
post-mortem verified specimina wherein such an operation has suc-
ceeded.

Now one of these relates to an animal killed six months after
such an operation. JVs I will show afterwards, in consequence of
it an important atrophy of the corpus l^rapezoides was produced ,
as indeed was our purpose. The latter is now reduced to the fibres
originating from the rootfibres, and to the fibres, originating from
the medio- ventral part of the ventral auditory nucleus , that cannot
he removed from the medulla oblongata, if the roots shall be spared.

Now the relations have become very transparent. Without any
difficulty , the normal fibres of the dorsal , as well as of the ven-
tral root, now may be followed in the transversal fibres of the
reduced corpus trapezoides (as fig. 12 on Plate XXI demonstrate,
where as fig. 28 A — E on Plate XXI show the extension of the
lesion, wich is found as a port-mortem defect).

Therefore, as to my experience, it cannot be doubted that
auditory root-fibres enter without ganglionic interruption between
the transvei-sal fibres of the trapezoid body. On the other hand
I must concede to van Gehuchten that in other animals — for
instance in dogs — I found the extirpation of the cochlea not
always followed by degenerations in the ventral systema, at least
within a fortnight. Indeed I believe, that the difference between
the root-systems and the secundary systems is not a very essential
one. Not only , I am convinced with HEiiD , that primary (root-)fibres
find their way in all the secundary systems , but I think even ,
that a primary system may be replaced by a secundary system and
vice vei'sa.

In rabbits however I argue that the Marchi-method of degene-
ration, the myelinisation and GuDm^.N's atrophy-method all are con-
cordant in the demonstration, t/ial root-fihres of both roots enter
directly into the corpus trapezoides or better in the so-called „systenia
ventrale nervi octam\

e. The systema ventrale nervi octavi. The situation of the
root-fibres in this system and their further course.

With a small variation from the nomenclature given by Edinger.
1 hence, forth will call the transversal fibres in the corpus trape-

62 C. WINKLER. THE CENTRAL COURSE

zoides, that pass along the ventral margin of the medulla oblon-
gata and belong to primary or aecundary auditory systems „the
systema ventrale nervi octavi". I have already mentioned that after
sectioning the eighth nerve , thick fibres as well as small fibres are
found degenerated among the transversal fibres of the corpus tra-
pezoides.

The thick fibres principally originate from the ventral root, but
they are also found after the removal of the cochlea in a smaller
quantity (Plate T, fig. la and U, Plate II fig. 2).

The degenerated t/iick fibres have their proper situation and are
found in the most ventral layers of the corpus trapezoides. At the
ventral margin of the medulla oblongata, ventrally only covered
by the free anterior pyramidal tract, they pass through the raphe
(see Plate VIII and IX fig. 15. N°. 11, 12, 18, 14) and end
in both nuclei trapezoides.

Only a small quantity ends in this nucleus of the same side in
its latero-dorsal edge. By far the greater part of them reaches,
after having crossed the raphe, the opposite trapezoid nucleus,
entering at its medial hilus (Plate II fig. 2, Plate VIII and IX
fig. 15, N°. 11, 12, 13, 14, fig. 16, A and B).

In frontal sections through the cjipital parts of the corpus trape-
zoides, those degenerated fibres, demonstrated with their black
granules by the MARCHi-method seem to form a garland (Plate VllI
and IX, fig. 15 N''. 11 — 14) thrown round the same-sided trapezoid
nucleus and held at its top by the opposite one.

In the systema ventrale nervi octavi therefore there may be
distinguished. 1 ^ thick root-fibres from both roots to the nuclei trape-
zoides , especially to the opposite nucleus , situated among the most
ventral transversal fibres of the corpus trapezoides and forming therein
the stratum ventrale or the stratum a of the corpus trapezoides.

But fibres of small calibre are also found degenerated among the
transverse fibres of the corpus trapezoides , as well after the removal
of the cochlea as after sectioning the eighth nerve (Plate I fig. la,
and U, Plate II fig. 2, Plate IX fig. 16 B and C).

They are found in deeper, more dorsal layers of it, pass close
to the lateral facies of the spinal root of the nervus V and along
to the facial nucleus. A few fibres terminate in the latter nucleus. I
certainly accord with Held in this regard (Plate I fig. la and
1/;, Plate IX fig. 16 C and D), but I will come back on this
question , when discussing the endings of the fibres of Held (of
the systema intermedium) in the VII*'' nucleus.

After their passage ventrally from the facial nucleus, the majority

OF THE NERVUS OCTAVUS. 63

of these degenerated fibres enters into the medullary capsula sur-
rounding the nuclei supra-olivares and para-olivaris of the same side
(Plate II fig. 2 str. dors. corp. trap, b, Plate IX fig. 16, B, C,
and D) at is lateral and ventral surface.

Notwithstanding the loss of fibres in the surrounding of the olivary
nuclei of the same side, still an important number of them trans-
gresses the raphe dorsally from the described thick fibres, reaches
the opposite nucleus para-olivaris and ends there in the medial
hilus of the medullary capsula of the opposite nucleus pam-olivaris ,
et supra-olivaris. h\ this veay these small fibres represent another
set of root-fibres, which also participate in the formation of the
systema ventrale nervi octavi.

In the „systema ventrale nervi octavi" therefore may be distin-
guished : 2*y. small root fibres from both roots to the ventral nuclei
of the tegmentum on both sides , especially to the nucleus supra-olivaris
and the nucleus pai*a-olivaris of the same side. They are situated
therein dorsally from the stmtum a , described before and form the
most ventral of the dorsal layers of the „systema ventrale", the
stratum b of this system.

Now, it must be kept in mind, that a well defined corpus
trapezoides is only present in its more distal parts. Especially its
limitation dorsally towards the tegmentum is difficult.

Together with the root-fibres, fibres from the ventral auditory
nucleus and from the tuberculum acusticum also participate in the
formation of the transversal medullary fibres.

These secundary fibres are mixed with the root-fibres , and even
when the most extensive degeneration after the section of the n.
octavus is found, normal fibres may always be demonstrated be-
tween them in the distal part of the corpus trapezoides.

As soon as the oliva superior appears, the ventral part of the
tegmentum, here characterised by the presence of a great number
of transversal fibres passing the raphe and crossing there the oppo-
site fibres, is no longer defined clearly towards the corpus trape-
zoides. But still always new fibres — now also originating from
the olivary nuclei — are tending to augment these transversal fibres,
and in sections through the middle of the olivary nucleus, the
ventral part of the tegmentum so far as it is intercalated between
them, is totally filled up with transverse fibres. The ventral teg-
mental transverse fibres between the olivary nuclei never degene-
rate after the section of the VHP** nerve.

In that case, however, sections touching the proximal half of
the olivary nuclei, demonstrate a new degeneration of root-fibres.

64 C. WINKLER. THE CENTRAX COURSE

which crossing the raphe , seem to unite the two dorsal borders of
the two nuclei. (Plate IX fig. 15 N". 13 and Plate IX fig. 16
1) in //). These fibres, also found in degeneration after removal of
the cochlea , may scarcely still be reckoned to the transversal fibres
of the corpus trapezoides. There will nevertheless exist a certain
arbitrariness in judging which of the transversal fibres may be recko-
ned still to the fibres of the corpus trapezoides , and which of them
deserve to be called ventral tegmental transverse fibres. In fact
the dorsal border of the corpus trapezoides is not precisely defined,
and therefore it is advantageous to reckon all transverse fibres in
the ventral part of the tegmentum to the „systema vcntrale nervi
octavi" and to use no longer the term of corpus trapezoides.

In that case, the last-described root-fibres, which we will meet
again when discussing on the „systema intermedium nervi octavi'*
and especially when their relation to the tracts of Held and to
the auditory fibres of von Monakow has to be settled, form the
utmost dorsal layer of the „systema ventrale nervi acustici".

In this way MARCHi-degeneration gives a special and very inte-
resting analysis of this system. As we have seen in the course of this
paragraph there are till now, demonstrated four portions in it.

Firstly, there are root-fibres to the trapezoid-nuclei (stratum a
systematis ventralis).

Secondly , there are root-fibres to the nuclei supra-olivaris (stratum
b systematis ventralis) and their surroundings. Both are degenerating
after the section of the n. octavus.

Thirdly there are fibres , though partly mixed among the former
two, forming a third , still more dorsal layer in the systema ven-
tralis (stratum c systematis ventralis) not degenerating after the
section of the N. octavus and consequently no rootfibres.

Fourthly , still more dorsally , a new small layer of rootfibres
appear (stratum c? systematis ventralis) , belonging only partially to the
systema vBntrale, deriving for the greater portion their origin from
the intermedial octavus-system. Their significance will be discussed,
when treating of this latter. (Plate IX fig. 15 N°. 13 and fig. 16 D).
They seem to unite the dorsal borders of the two nuclei olivares.

f. TIte myeUnimtwri'^method offers the same results as the Marchi-

method, as well in regard to the position of the transversal

root'Jihres in the systema ventrale 7iervi octauiy as to

the position of the secundary fibres.

The architecture of the systema ventnde N. octavi, as it has
been described in the precedent paragraph , is not such , as is

OP THE NERVUS OCTAVUS. 65

usually taught by the authors, controversing the existence of root'
fibres in the corporis trapezoides.

Ordinarily the opinion is defended, that the systema ventrale is
composed only by fibres of the secundary system originatuig in the
ventral auditory nucleus and in the nucleus olivaris superior.

However, the results of the myelinisation are in perfect concor-
dance with those taught by the Marchi-degeneration , demonstrating
different root-fibres in the systema ventrale.

Frontal sections through the oblongata of the rabbit, shortly
before it is born , and even still the first days after birth may
easily demonstrate this concordance. (Plate XII fig. 17 A, B and C).

And as the structure of the corpus trapezoides in the cat seems
the same as in rabbits, frontal sections through the medulla oblon-
gata of young born cat may be used likewise (Plate I fig. 5).
Sagittal sections may also serve to this demonstration (Plate XIII).

In new-born animals the two auditory roots are both provided
with raedullated fibres, though the ventral root more than the dorsal.
The systema ventrale is partly myelinisated , partly not. Intermittent
strata of raedullated and non medullated transversal fibres are found
in it. In frontal sections one may distinguish in ventro-dorsal direc-
tion four layers.

Most ventrally a mighty layer of thick medullated fibres appears
(Plate XII fig. 17 B, Plate I fig. 5, Plate XIII fig. 18 P the
str. ventr. a.), limited dorsally by a second layer of much smaller,
but also medullated and transversal fibres (the stratum h in the
figures), among which many non-medullated fibres are found. More
dorsally between the nuclei supm-olivares then comes a layer of
non-medullated fibres (the stratum c in the figures) and still more
dorsally at the boundary a fourth band of medullated small fibres
is seen (the stratum d or the fibres of Held in the figures). The
latter fibres seem to unite the dorsal borders of the two nuclei
supra-olivares.

In sagittal sections (Plate XIII fig. 18 F) again these four
layers may be seen , but here as strata of queer-sectioned fibres ,
and in such a vvay, that between the two ranks of supei-ficical
medullated queer-sections and those of Helu, the stratum of non
medullated fibres is present.

There exists a striking resemblance between the frontal section
through the oblongata of the new-born rabbit (Plate XII fig. 17 B)
and that through the oblongata of the rabbit, treated with Marchi-
niethod (Plate IX fig. 15 N°. 12 and N^ 13) within a fortnight
after the rootsection. The medullated fibres in the systema ventrale

Verhand. Kon. Akad. v. Wetensch. (Tweede Sectie Dl. XIV). 5

66 C. WINKLEK. THE CENTRAL COURSE

in the first case, are situated exactly at the same place, where the
degenerated fibres in the second case are found, and the non-
medullated fibres are corresponding with the non-degenerated. This
accordance does not only prove the existence of root-fibres in the
systema ventrale, but also puts it beyond doubt that they are
situated there in three layers.

Now , if it were proved , that the Marchi-method demonstrated
only root-fibres in degeneration within a fort-night after the root-
section; if it were proved that simultanous myelinisiition indeed
occurred only in fibres of the same system — then to be sure
the conclusion would be justified, that the quantity of root-fibres
in the systema-ventrale of the VHP'' nerve was very important.
But , because I believe , that even within a fortnight after the root-
section, a certain quantity of fibres in the secundary system may
degenerate and be demonstrated with Marchi-method , and that a
certain quantity of fibres in the secundary system myelinisate simul-
tanous with the root-fibres, I am not going so far as to declare
that all the medullated fibres in the systema ventrale of the new-
born rabbit are root-fibres.

As to the fibres of the secundary octavus-system* originating in
the ventral nucleus, the tuberculum acusticum and the nuclei
supra-olivares , they for the greater part, do certainly not degenerate
after root-section , and they have not all a myeline-sheath in the
new-born rabbit.

These fibres are partly mixed between the medullated fibres (in the
strata a, b and d) and partly they are collected in the stratum c.

The (juestion remains whether it is proved, how many medullated
fibres originate in the ventml nucleus and take their course in the
systema ventrale.

If this be the case, such fibres will not be shown by frontal
sections through the medulla of the not yet born or new-born rabbit.

In such sections there is only seen a field of medullated fibres
near the entrance of the auditory roots (Plate XII fig, 17, A,
B, C) which, medullated themselves, pass trough the myelinisated
corpus trapezoides, to reach the ventral nucleus and the portio
interna of the restiform body. I deem it impossible to decide here,
whether medullated fibres are root-fibres or fibres from the nucleus
ventralis. Even the argument, that there exists a disproportion be-
tween the quantity of medullated fibres in the auditory roots and
that in the corpus trapezoides, appears more decisive than it really
is, as it is not yet proved that the other roots (VII and V) do not
at all enter into it. But yet I believe, that a certain quantity of

OP THE NERVUS OCTAVUS. 67

secundary fibres from the ventral nucleus towards the corpus tra-
pezoides are myelinised in the new-bom rabbit, because in sagittal
sections indeed images may be seen (Plate XII fig. 18 B, Plate
VI fig. 19 B) allowing the interpretation of a direct transition
of medullated fibres from the ventral nucleus in the ventral system
on one side , as well as on the other side of a transit of root-fibres in it.
But the accordance between the results of the myelinisation of
the root-fibres, and their degeneration after root-section may be
sufficient, to elucidate the situation of the root-fibres in the systema
ventrale N. VIII, and to establish that, in rabbits their number
is more important, than is thought generally.

g. The secundary atrophy also confrms the existence of transvei'sal
root-fibres in the systema ventrale of the VIIF*' nerve.

If really the systema ventrale nervi octavi contains so many
rootfibres as is affirmed here, a long controversed question in the
central course of the nervus octavus ought to be settled. It is the
question , whether the corpus trapezoides does undergo an atrophy
or not, after the removal of the labyrinth in the young born
animal.

The first investigators on this subject, Forel and Onuprowicz,
supposed that the removal of the labyrinth in young rabbit was
not followed by any atrophy , worth mentioning , in the corpus
trapezoides. Baginsky, on the other hand , repeating the experiments,
defended the view that the atrophy of this body , after three months,
was important enough.

As to my experience , the opinion of Baginsky is right , and the
reason of the discordance between his results and those of Onufrowicz
may easily be understood.

For , it must be kept in mind , that the spiral and the vesti-
bular are intercalated between the perifical labyrinth and the roots,
that the spiral ganglion is necessarily removed with the cochlea,
and that the vestibular ganglion remains untouched (unless its
removal be intended for) when the contents of the vestibulum only
are withdrawn.

Now Onufrowicz has not completely removed the contents of the

vestibulum. He describes clearly enough, that the typical attitude

of the operated rabbits was not obtained immediately, but weeks

afther the operation , owing to a secundary lesion of the vestibulum.

His drawings also demonstrate, that the ventral root was very

little atrophied, instead of having disappeared.

68 C. WINKLER. OP THE CENTJBUa COUSRE

Consequently the atrophy in the corpus trapezoides that might
have been expected, was comparable to that, which follows the
section of the dorsal root and must have been very slight.

Baginsky who has probably removed completely the contents of
the vestibulum, did not intend to withdraw also the ganglion
vestibulare. Consequently he found a more important atrophy in
the corpus trapezoides, but not so intense as it ought to be after
total disparition of the two roots.

Now this only occurs after the total destruction of the vestibular
ganglion , an operation , hardly possible without lesion of the corpus
trapezoides itself.

These being the facts , I believe , that the cases of atrophy of
the corpus trapezoides observed months after labyrinth-lesions in
young born rabbits will oflFer very great individual differences.

Total atrophy never will be found, because powerful secundary
systems find a place in the corpus trapezoides. The different modus
operandi used by different investigators, will more or less have
exposed the vestibular nerve and its ganglion during the operation
and makes the lesion more or less equal to a ventral rootsection.
In the case that a true rootsection of both roots is made , both ,
the dorsal as well as the ventral root have completely lost their
fibres, and in those circumstances the corpus trapezoides, or better,
the systema ventrale nervi ocfaivi, is always atrophied. This atrophy
is chiefly confined to its distal part or at least it is rather easily
demonstrable there, as the proximal portions of it are enclosing a
larger quantity of fibres from secundary systems.

The figures Sa and Sb, 13« and I3d on Plate III are repro-
ductions of frontal sections through the oblongata of a rabbit , which
had lived one year after the removal of the labyrinth combined
with section of the VHP*" nerve made on the young born animal.

If the left side (fig. Sa and ISa) is compared with the drawings
(in fig. Sb and fig. }3b on Plate III) of sections at comparable
levels on the non-operated right side of the same animal, it is
immediately seen, that the distal part of the systema ventrale has
totally disappeared, not because there might have been a displace-
ment of the different parts in the central system, but because the
roots are completely atrophied.

More proximally the systema ventrale reappears and soon it is
no longer possible to give a judgment on its atrophy by comparing
the two sides. But the atroi)hy in the distal end of the systema
ventrale is not the only fact to be noticed in that case. There also
exists a considerable atrophy of the nucleus trapezoides at the oppo-

OF THE NERVUS OCTAYUS. 69

site side of the operation. It has lost nearly all its fibres. Consequently
the cells are lying closer together. The cells themselves have dimi-
nished in size, they are shrivelled, of irregulare shape, but none
of them has disappeared.

The other ventral nuclei in the tegmentum do not present such
intensive atrophy as the opposite trapezoid-nucleus. Yet the niedul-
lated surroundings of the nuclei olivares superiores and their acces-
sory nuclei have lost a great deal of their fibres on both sides,
but this loss is more apparent at the operated than at the oppo-
site side. Cellular changes also are present in the olivary bodies,
but in a slight degree.

Some cells may be diminished in size, perhaps some smaller
cells may have disappeared but the cellular change is by no means
so intensive as it is in the trapezoid nucleus. This nucleus has
suffered an atrophy nearly as intensive as that of the ventral nucleus
of the VHP** nerve, which afterwards in the discussion of the
„sy8tema dorsale nervi octavi" will be described.

So, as to my experience, Baginsky is right. After complete
root-section , the root-fibres disappear totally and with them the
systema ventrale atrophies nearly completely in its distal end. After
removal of the labyrinth the ventral root does not totally lose its
fibres , and the atrophy of the ventral system is less intensive , may
even be of small intensity , but in the distal end it is always present.

The atrophy of the systema ventrale is accompanied by a con-
siderable atrophy of the crossed trapezoid nucleus , whose fibres are
lost, whose cells are reduced in size, and with a remarkable loss
of fibres in the medullary capsule of both nuclei supra-olivares and
para-olivares , especially on the same side.

In this way the results of Gudden's method are accordant with
those given by Marchi's method and with those of the myelinisa-
tion-method.

h. The most dorsally situated root-fibres (the stratum d) in the

systema ventrale nervi octavi and their relation to the fibres r?/ Hei.d

or the y^systema intermedium nervi octav%\

As soon as, after section of the VHP** nerve the degenerated
transverse rootfibres of the ventral system, are studied in their
course with Marchi method on a series of horizontal sections of
the medulla oblongata, the origin of the most dorsally situated fibres
of this systema (the stratum d) may be settled with relative facility.

In fig. 16 A — I on plate IX reproductions are given of such a

70 C. WINKLEE. THE CENTRAL COUBSE

series of horizontal sections. In fig. 16 A the thick degenerated
fibres for the opposite nucleus trapezoides are found (the stratum a).

Somewhat more dorsally (in fig. 16 B) the degenerated smaller
fibres for the ventral tegmentum-nuclei (the stratum b). In the
figures 16 C and D the most dorsally situated degenerated root-
fibres (the stratum d) appear. Expecially fig. 1 6 I) is very demon-
strative. From the dorsal border of the olivary body opposite to
the rootsection part small degenerated fibres. They cross the raphe,
go towards the dorsal part of the medullary capsule of the same
sided oliva and reach from there the degenerated homolateral corpus
trapezoides. These are the rootfibres in the stratum d from the
systema ventrale nervi octavi.

But not all the, transverse fibres here described take that way.
A certain number of them do not enter into the corpus trapezoides,
but are united at the dorsal top of the same sided olivary body
into a separate bundle (^Plate IX fig. 16 E in //). This bundle of
now queer-sectioned degenerated nerves enters in the formatio gela-
tinosa of the V^** nerve (Plate X fig. 16 F in h). It passes the
spinal root in a. ventro-dorsal, and at the same time medio-lateral
direction (Plate X fig. 16 G, H and I in //) until the portio interna
of the restiform body is reached.

There, lying laterally from the radix descendens N. VIII, it is
found at the medial border of the oval area, confining it against
the portio interna and turning dorsally it disappears between the
degenerated fibres of the stratum latero-dorsale at the dorsal border
of the oval area of the restiform body (Plate XI fig. 16, K and L).
The study of the horizontal sections shows , that , after the auditory
root-section , the most doi'sal layer of rooffibres — the stratum d —
may not only be pursued in the corpus trapezoides (into the ven-
tral system) but also into the stratum latero-dorsale of the corpus
restiforme by means of an intermediary bundle of rootfibres.

This bundle, first discovered by Held, may be called the
systema intermedium nervi octavi, for it unites fibres of the dorsal
with fibres of the ventral system. This system contains partly root-
fibres of both roots, partly fibres of a secundary system.

This intermedial system may be very well demonstrated in frontal
sections of the normal animal, for instcince in fig. 13A on Plate
III , it is very well developed.

After removal of the cochlea, some fibres in this system are
brought to degeneration and frontal sections are better adopted
to demonstrate the course of the intermedial fibres in the latero-
dorsal stratum of the restiform body.

OF THE NERVUS OCTAVUS. 7 1

As soon as the dorsal rootfibres and their continuation in the
latero-dorsal layer are degenerated , a certain number of these fibres,
lying upon the lateral border of the oval area of the restiform
body , circle round it , first running dorsally , then turning round
its dorsal border, and returning in ventml direction through the
pars interna C. R. From here they perforate the grey matter of
the spinal V^^ root and reach the dorsal border of the oliva, and
taking a medial direction , participate with the transverse fibres in
the stratum d, (Plate I fig. U, Plate II fig. 2).

T3ut only a few fibres in this intermedial system are brought to
degeneration after the removal of the cochlea.

Much greater is the number of fibres degenerating in this system
after root-section. I have already mentioned, how in that case, the
number of degenerated fibres limiting the lateral border of the
area has increased. Also I have shown , that many of them are
seeking a shorter way to its medial border. They perforate the
oval area instead of making a curve around its dorsal border.

Apparently those fibres — as described , they are the fibres pas-
sing from the ventral root in the stratum latero-dorsale — being
themselves intermediary fibres between the roots, help in a consi-
derable manner to augment the intermediary bundle to the stmtum d,
(Plate VIII fig. 15 N°. 5—11, especially fig. 15 N^ 9 und U).
After all, this intermedial system contains fibres of both auditory
roots, and may be defined in the following way.

The root-fibres having entered the central system in dorsal direc-
tion, pass in the latero-dorsal layer, pass round or through the
oval area of the corpus restiforme to gain the ventral direction in
its pars interna. Penetrating there and through the spinal root of
the V^^ nerve, they reach the dorsal border of the facial nucleus
and of the medullary surroundings of oliva superior and accessory
nucleus on the same side. In these nuclei they send fibres, but
the greater part now take a ventral direction and become the trans
verse fibres of the stratum d in the systema ventrale.

This stratum d therefore will afterwards be reckoned to the
systema intermedium nervi octavi, a view, seeming perhaps arbi-
trary, as some of its fibres take their origin in the ventral system.
But a severe separation is impossible here. Por as we will soon
demonstrate the intermedial system gives also fibres to the super-
ficial (ventral) layers of the corpus trapezoides.

It has advantages to reckon all the dorsal root-fibres , the so-called
fibres of Held, to the inten»icdial system. But this system not
only contains root-fibres. There is also a secundary system and even

72 C. WINKLER. THE CENTOAL COURSE

an important one, represented in it. A total degeneration of its
fibres may only be brought about, after sectioning it at the dorsal -
border of the oval area. It is never found after root-section (to
compare fig. 25. H on Plate XX).

It has been controversed , for instance by Lewandowsky , that
the rootfibres here mentioned , should enter in the nucleus of the
Vir** nerve. I must, as regards this, be on the side of Hkld.
The fibres of the intermedial system enter in the dorsal border of
the facial nucleus of the same side, as well as those of the ven-
tral system enter it at the ventral border. But the greater number
of them ends in the dorsal border of the oliva superior at the same
side , and after having passed the Raphe in that of the opposite oliva.

In this w^ay, the intermedial system provides with fibres the
doi-sal bordei's of the ventral tegmentum-nuclei, whose ventral,
lateral and medial borders are provided by the ventral system of^
the Vlir'' nerve.

k. The longitudinal root-fibres of the ventral and intermedial systema

ascending towards the cerebellum and towards the mesencephalon.
Their situation in the lateral lemniscus. Their enditujs in the nuclei
tecti cerebelli and in the nucleus of the corpus quadrigeminum posticum.

As soon as the root-fibres of the intermedial system and those
of the ventral system have met in the medullary field between the
spinal quintus-root and the facial nucleus (respectively the superior
olivary body) -a small quantity of them deviate in longitudinal
direction to form ascending and descending tracts, which now ask
our attention. They contain rootfibres in a relative small quantity,
still enough to be demonstrable, but they have a great importance,
because they accompany important other secundary systems, taking
the same course.

It is since long known, that in the foetal medulla oblongata,
frontal sections may demonstrate between the spinal root of the
V^ nerve and the facial nucleus or the olivary body a triangular
field of queer-sectioned medullated nerve-fibres, that has obtained
several names. It chiefly contains 8j)inal fibres, which are situated
there in the fintero-lateral tract of Gowers, and so this name is
transferred to the field in the oblongata. Better it is to call it the
ventral and ascending spino-cerebellar tract (the dorsal ascending
spino-cerebellar tract being represented by Flechsig's Klein-IIirn-
Seitenstrangbahn). This triangular medullated field found for a short
time in the lemniscus lateralis, (Plate XII. fig. 17 A, B and C,

OF THE NERVUS OCTAVUS. 73

Plate I fig. 5 in 1.1.) is named the antero-lateral spinal tract, Gower's
tract or the fasciculus spino-cerebellaris ascendens ventralis, but it
must not be confounded with the more dorsally situated fibres
(MoNAKow's aberrirendes Seitenstrangbiindel with the so-called fas-
ciculus rubrospinalis) between formatio gelatinosa N. V and nucleus
N. VII or nucleus columnae lateralis aiul containing descending
fibres. This bundle afterwards shall be recalled to mind.

The farther path of the fibres of the antero-lateral tract is also
very well known.

Near the place, where the V^*" root leaves the medulla those
fibres bend in a dorsal direction (Plate XII. fig. 17 C, f. sp. c. v.)
into the lateral fillet , close to the fibres of the bracchia pontis here
embracing the medulla.

There they are somewhat dispersed by the appearance of the
nucleus ventralis lemnisci (Plate XIII. D and E fig. 18) but reunite
in the most lateral layer of the lemniscus lateralis, covering the
pedunculus superior cerebelli.

Now they lie free at the surface on the dorsal back of the
peduncle, only separated from the half-moon-shaped pendunculus
cerebelli superior by the deeper layers of the fillet and by the
nucleus dorsalis lemnisci, and their course till now having been
always a course in proximal direction changes abruptly.

They now turn distally and medially, cross the dorsal border
of the pedunculus cerebelli superior (Plate XV. fig. 14 D) and
end in the nuclei tecti cerebelli of the same side, or after having
transgressed the cerebellar medulla in those of the opposite side*

So the course of the antero-lateral spinal tract is described by
many authors for instance after the hemisection of the cervical
medulla.

But not all the fibres of this triangular field follow the here
described way. They all bend dorsally at the entrance of the tra-
geminus-root, but in the so-called lateral lemniscus a portion of
the fibres have another situation. They also surround the ventral
nucleus of the lemniscus, but in the medial medullar layers around
it. They also reach the lateral lenmiscus where it covers the cere-
bellar superior pedunculus but as the former tract turns distally,
the latter tract still pursues its course (Plate XIII fig. 18 1)) dor-
sally and slight proximally. They partly enter in the corpus quadri-
geminum posticum. These fibres participate to the sccundary audi-
tory-system as Flechsig and those who studied the auditory system
with the myelinisationmethod have taught.

Now indeed , rootsection of the nervus octavus within a fortnight

74 C. WINKLER. THE CENTRAL COURSE

or three weeks after the operation, brings degeneration in fibres
belonging to the two here described tracts.

In a frontal series after root«ection studied with Marchi method
it is easy to see (Plate VIII fig. 15 N^ 12andN^ 13) that on the
operated side, degenerated fibres detach themselves from the surroun-
dings of the oliva superior (from the place, where ventral and inter-
medial system are meeting) and seek their way between the sensible
and motor nucleur of the V^** nerve to the utmost lateral and super-
ficial layer of the lemniscus covering the pedunculus cerebelli superior.

From there, turning distally, they may be traced (Plate VIII
fig. 15 N^ 11, 10, 9 and 8) to the nuclei tecti mediales cere-
belli at the same and at the opposite side. But, it may also be
seen , that the root-fibres of the systema ventralis , having crossed
the raphe (and on their way remaining for the greater part in the
ventral tegmentum nuclei) still are present in the field between
oliva superior and spinal root of the V*^** nerve of the opposite side.
There they meet again fibres of the intermedial system, which also
have passed through the raphe. On this way also fibres are going
into the opposite antero-lateral tract (Plate VIII fig. 15 N*". 12
and 11), however in much smaller quantity as at the same side.

More easily the degeneration in this tract after root-section may
be traced in horizontal sections. (Plate X fig. 16 G, H and I,
plate X fig. 16 K, L, M, N, Plate XIV and XV fig. 14 A— E).
In fig. 16 at H, the entrance of the degenerated roots is found,
covered with black granules. But the degenerated fibres in the
lateral lemniscus have already appeared much more ventrally and
in Plate IX fig. 16 E they detach themselves from the oliva superior.

These are crossed fibres from the systema ventrale.

But a new increasing of the degenerated fibres in the lateral
fillet is found in Plate XI fig. 16 K. These homolateral fibres are
coming from the stratum latero-dorsale along the queer-sectioned
bracchium pontis. In a more dorsal section (Plate XI fig. 16 M
in 1.1.) the superficial layer of the lateral lemniscus, medially bor-
dered by the nucleus dorsalis lemnisci, begins to cross the superior
cerebellar peduncle and still more dorsally (Plate XI fig. 16 N).
These fibres enters in the same-sided and opposite nuclei tecti
n»ediales of the cerebellum.

In fig. 14 (Plate XIV and Plate XV) the direction of the hori-
zontal section is better fit for demonstration. The preparation (Plate
XIV fig. 14 A) at first touches the degenerated root-entrance, and
degenerated fibres (entered in more ventrally situated sections) are
already in the lateral lemniscus on both sides; lying close medial

OF THE NERVUS OCTAYUS 75

to the bracchium pontis. To these fibres new ones are joined from
the stmtum latero-dorsale , and together they form the degenerated
area, that may be traced (Plate XIV fig. 14 B and in Plate XIV
tig. 14 C in 1.1. and f. sp. c. v. a.) to the most lateral and super-
ficial stratum of the lemniscus, separated from the pedunculus
cerebelli superior by the nucleus dorsalis lemnisci. More dorsally
(Plate XV fig. 14 D and E in f. sp. c. v. a.) they leave the
lateral lemniscus, pass dorsally from the peduncle and reach the
nuclei tecti cerebelli mediales.

As it is demonstrated these fibres pass on their way the two
nuclei lemnisci, and it is not easy to say whether they enter in
those nuclei.

As for the nucleus ventralis lemnisci the fibres surround it at
its lateral, ventral and distal border, but as the number of dege-
nerated nerves here even after rootsection is always small, I dare
not say that they enter in this nucleus. I believe them to do so
because after sectioning the tuberculum acusticum (as well as after
hemisection of the lower part of the medulla oblongata) they cer-
tainly do.

As for the nucleus dorsalis lemnisci the question stands other-
wise. The fibres pass this nucleus at its lateral border, but send
no collaterals in this nucleus. In this way root-fibres of the ventral,
intermedial (but also from the dorsal systema) nervi octavi, reach
the nuclei tecti of the cerebellum, in the „fasciculus ascendens
ventralis spino-cerebellaris".

But after root-section other fibres in the lateral fillet are brought
to degeneration. They may be traced into the nucleus of the cor-
pus quadrigeminum posticum (Plate VIII fig. 15 N*". 12, Plate
IX fig. 15 N°. 13—16).

In frontal sections they also are found between the spinal root
of the V**" nerve and the oliva, they also bend dorsally into the
lateral lemniscus , near the departure of the V^^ nerve j (but in a
somewhat more proximal region as those , which enter in the cere-
bellar tract) and form there the medio-ventral surroundings, of the
nucleus ventralis lemnisci. Having left some fibres in this nucleus,
they continue their dorsal direction (Plate IX fig. 15 N°. 15). In
the lateral fillet they reach the nucleus of the corp. quadrigeminum
posticum , embracing it at its ventral pole.

Studied in horizontal sections these fibres may be likewise demon-
strated. As long as the ventral regions of the medulla are concer-
ned, they are not separated from the fibres going to the nuclei
tecti (Plate X fig. 16 E — I). In more dorsal sections they become

76 C. WINKIJIR. THE CENTRAL COURSE

separated from them (Plate XI fig. 16 K— N, Plate XIV and
Plate XV, fig. 14 A — E). They embrace the nucleus ventralis
leranisci, their number is augmented by root-fibres originating in
dorsal transverse fibres and as soon as the cerebellar fibres leave
the tegmentum to reach the nuclei tecti, (Plate XV fig. 14 D
and E) the fibres to the corp. quadrigeminum posticum remain.

Though degenerating on both sides after one-sided root-section
the greater quantity of these rootfibres is found on the opposite side.

After root-section of the VHP** nerve therefore also ascendent
tracts of root-fibres may be dedionstrated with Marchi method.
There are two.

Rootfibres of the N. octavus are found in the „ascending ventral
spino-cerebellar tracts" to the nuclei tecti mediales, especially in the
homolateral tract.

Rootfibres of the N. octavus are also found in the lateral fillet
to both corpora quadrigemina }>ostica but chiefly in the lateral
fillet of the opposite side. I repeat, that after rootsection, the
number of degenerated fibres in those tracts is not very considerable,
though they are evident.

After the removal of the cochlea the number is again diminished.
Then they must be sought for attentively , and I believe that
Marchi-method in such cases has nearly reached its utmost limits.
For, even in a fortnight, the black granules, characterizing the
degenerated fibres, are spread in the neighbourhood if there exists
a localised degeneration, and the number found in the two des-
cribed tracts after cochlea removal is very limited, especially in
the cerebellar tract. None the less I am convinced that even after
cochlea removal they may be demonstrated.

I therefore agree completely with Held, who has long since
defended the view , that primary fibres penetrate in all the secun-
dary systems and accompany them , but I also think that the num-
ber of root-fibres entering in secundary systems is very different in
different animals.

It is here perhaps the place to remark, how interesting it is,
that the very great number of root-fibres existing in the ventral
and intermedial system , is reduced to a very small quantity in the
lateral fillet to the corpus quadrigeminum. Indeed , if they were
not augmented considerably with rootfibres from the dorsal sj^stem,
rootfibres to the corpus quadrigeminum would be rare.

There fore I believe that the root-fibres in the ventral system
(the corpus trapezoides) have chiefly the significance to intercalate the
ventral tegmentum nuclei in the reflex-system of the nervus octavus.

OP THE NERVUS OCTAYUS 77

As I am convicted that fibres conducting sound must pass through
the corpus quadrigemiuum posticum, and as the greater part of
the root-fibres to this nucleus originate in the intermedial and
dorsal system, I believe that true auditory fibres must be sought
in transverse dorsal fibres. They chiefly are as we will see after-
wards MoNAKOw's transvei-se fibres, and Monakow is right to call
them the „auditory" fibres. And on the other hand , the views
of Flechsig and other authors after him, holding that the ventral
system is to be compared with the root-fibres in the chiasma ner-
vorum opticorum , and that the corpus trapezoides forms a kind of
semi-decussatio of the fibres towards the corp. quadr. posticum —
those views appear to me not sufficiently founded. The relations
of the primary auditory nuclei and the ventml tegmentum nuclei
with the lateral fillet are too complicated to allow such comparisons.

1. T'he rootfibres in the stratum latero-dorsale of the corpus restiforwe.

The nucleus ventralis nervi octavi, the tuberculum acusticum and

the systeina dorsale nervi octavi.

More complicated than the ventral system, is the dorsal system
of the eighth nerve.

As we have seen in the preceeding paragraphs, the important
layer of fibres curving round the area ovalis of the corpus resti-
forme as a stratum latero-doi-sale is not composed exclusively of
dorsal root-fibres.

Dorsal fibres of the ventral root also participate in its formation,
as is demonstrated equally by Marchi-method after rootsection and
by the myelinisation-method.

In sections through the medulla oblongata of the foetal rabbit
(Plate VI fig. 19 B, Plate XIII fig. 18 A and B) it is impos-
sible to determinate, from which of the two rootlets — from the
dorsal root or from the intermediary rootlet going from the ventral
to the dorsal root — originate the meduUated fibres, entering in
the ventral nucleus and in the tuberculum acusticum.

MARCHi-method may teach us more. After removal of the cochlea
there may be demonstrated an intense degeneration in the ventral
nucleus and in the tuberculum acusticum. After section of the nerve
there is a slight but strictly localisated increase of the degeneration
in the ventral nucleus , where as the degenemtion in the tuberculum
acusticum is nearly as intensive in both cases.

Therefore it may be established, that the greater part of the
dorsal root-fibres, degenerating after cochlea-removal are ending in

78 C. WII^LER. THE CENTRAL COURSE

the ventral nucleus and in the tuberculum acusticum. In reference
to this the ventral nucleus and the tuberculum acusticum may be
called the nuclei of the dorsal root.

But only thus far I can accept the common view. To admit
that these nuclei are exclusively the endings of the dorsal root,
and to deny that the ventral send a few fibres to them, would
be contrary to my experience. The study of the details of the
degeneration in the ventral nucleus after removal of the cochlea,
may establish that dorsal-root-fibres, then degenerating, enter it
in its distal and ventral pole , and , united together to a i-ather
sharply limited peduncle, penetrate it in a dorsal and slightly
proximal direction.

In this way the ventral nucleus is divided in two portions, a
distal and ventral one much smaller than the proximal and
dorsal portion.

The dorsal root, the peduncle crossing the nucleus, now sends
little bundles, containing 8 — 20 fibres each, like the radiation of
a fan in both portions. Therefore the nucleus is making the impres-
sion , as if round the root-peduncle were a great number of little
mcdullated nerve-bundles, and between these, the cells of the ven-
tral nucleus are found. The little bundles have different directions.
The more dorsally and proximally they are situated, the more their
direction tends to become longitudinal.

Now it may be demonstrated in frontal sections (for instance in
Plate II fig. 2 or Plate IV fig. 8) as well as in horizontal sections
(for instance Plate V fig. 9, fig. 10, Plate* XI fig. 16 K or Plate
XIV fig. 14 A) that in the disto-ventral portion of the nucleus
nearly all the little bundles are degenerated. Whether only the
cochlea be removed or the root-sectioned the result in both cases
is a very intense degeneration in the disto-ventral part of the nucleus.
And after removal of the cochlea the degenerated fibres therein are
so many, that an increase, even if it took place after octavus-
section , would not l)e betrayed to the observator.

The disto-ventnil portion of the nucleus surely seems to receive
none but dorsal-root-fibres.

With the doi-so-proximal portion of the nucleus it is otherwise.
Indeed in this portion also degenerated fibres are found among the
little bundles, which it contains.

But the farther distant the little bundles are from the root-|)eduncle,
according to their situation dorsally and proximally , the more the
number of degenemted fibres in them is reduced. (Plate IV fig. 8,
Plate V fig. 9 , Plate II fig. 2). In the dorso-proximal top of the

OF THE NERVUS OCTAVUS. 79

nucleus, there are always found normal fibres between the dege-
nerated bundles , whether the cochlea may be removed or the nerve
sectioned.

But in the latter case, the degeneration in the more dorsal and
proximal parts of the nucleus appears more intensive as the com-
parison of. f. i. fig. 2 on Plate II (cochlea-removal) with the fig.
8 on Plate IV or fig. 9 and fig. 10 on Plate V (octavus-sectioning)
may demonstrate.

But as in its dorso-proximal border in both cases the normal
fibres reappear in the ventral nucleus , it may be stated , that the
rootfibres chiefly enter at its disto-ventral pole , that the secundary
fibres chiefly leave it at its dorso-proximal border, but in this
manner that the entrance of root-fibres as well as the exit of secun-
dary fibres principally take place along the medial border of the
nucleus.

In fact the dorsal root meets^ the medulla somewhat distally from
the nucleus, and the disto-ventral portion of it, is so intimately
ioined at the root , that it forms a part of the stratum latero-dorsale,
which here, lying close to the area ovalis of the C. R. surely
contains exclusively dorsal root-fibres.

As soon as the fibres of the stratum latero-dorsale , in their cur-
vature round the area ovalis, have reached the dorsal border of
this area, they begin to diverge from it. They spread themselves
like a fan-radiation (see fig. \a Plate I) between the tuberculum
acusticum, the lateral portion of the dorsal nucleus of the eighth
nerve and the pars interna of the corpus restiforme. Even in distal
regions , but more easily distinguished in regions lying more proxi-
mally other fibres are running between the dorsal root-fibres in
the stratum latero-dorsale.

We have already demonstrated that a little more proximally
the dorsal root-fibres of the ventral root aid to increase the stratum
latero-dorsale. They remain intact after cochlea-removal, and dege-
nerate after section of the octavus (Plate VIII fig. 15 N°. 8, Plate
IV fig. 8). The greater part of them hold themselves close to the
oval area, and curving round its dorsal border or penetrating through
it, they help to compose the systema intermedium nervi octavi.

Being composed distally of dorsal root-fibres, proximally of ven-
tral rootfibres, this intermedial system originates from the most
internal fibres of the stratum latero-dorsale , which may be considered
as the beginning of the systema dorsale nervi octavi.

But a few fibres of the ventml root, may increase the rest of
the dorsal root-fibres, which, having passed the ventml nucleus,

80 C. WINKLER. THE CENTRAL COURSE

now are ranged in the lateral layer of the stratum latero-dorsale.
There between the latero-dorso-proximal portion of the ventral
nucleus (always providing this with fibres) and the oval area they
run dorsally from this area , but soon diverging from it , they form
the external radiation of the fan, radiating dorsally round the
oval area.

These fibres of the external layer of the stratum latero-dorsale,
bear as its stratum medullare profundum the tuberculum acnsticum.
They are degenerated in an intensive manner after removal of the
cochlea (fig. \a on Plajte I) perhaps still more intensive after nerve
section (Plate IV fig. 4) and in the distal regions of the stmtum-
latero dorsale, they a forming a second system of root-fibres.

Therefore now already two systems appear, j)articipating to the
systema doi'sale nervi octavi dorsally from the oval area , and both
being root-fibres.

Between the intermedial system curving closely round the oval
area , and the rootfibres , which in distal regions form the stratum
profundum medullare tuberculi acustici however new fibres make
their appearance.

They are fibres , which do not degenerate , even after the section
of the nerve (fig. \a on Plate I in /3).

They are found already in distal sections and increase in quantity
proximally.

They are secundary fibres emanating from the dorsal and proximal
border of the ventral nucleus and from the tnberculum acusticum.

They are mixed among the degenerated fibres of the' two des-
cribed layers but in the middle part of the radiation of the fan,
they form a layer of intact fibres where nearly no degenerated
fibres are found. But here no longer may be spoken of the stratum
latero-doi*salc , another portion of the systema dorsale nervi octavi
has begun , usually called Monakow's stria medullaris acustica. As
to its distal end, it is now composed of:

1* degenerated root-fibres of both roots, partly forming the
intermedial system, the internal layer;

2® intact fibres of a secundary system ;

3® degenerated root-fibres, chiefly belonging to the dorsal root,
the external layer.

The latter fibres form the basis, on which the tuberculum acus-
ticum is resting, and may be also called the stratum profundum
medullare of this ganglion. They are sectioned longitudinally in
frontal sections.

Perpendicular to the course of these fibres very small degenerated

OP THE NERVUS OCl'AVUS. 81

collaterals now detach themselves and penetrate into the tuberculuni.
In frontal sections they appear situated as the spakes in a wheel.
They are radial fibres to this ganglion which, sectioned frontally,
has the shape of a circle segment. Those radial fibres are only
traceable unto the level, where the great pyramide-shaped cells
of the ganglion are found.

Now on horizontal sections again the fibres of the stratum medul-
lare profundum are touched in a longitudinal direction and again
the collaterals leave them perpendiculary.

In this way their situation is the cause of a very peculiar aspect
of the degenerated ganglion, if coloured by Marchi-method.

It appeal^ to be divided into two rings, the outer is quite free
from degenerated fibres and extends to the layer of large cells.
The inner ring is thickly specked with very small black granules —
the degenerated collaterals — and radial fibres, also containing
these black granules, are easily to be distinguished. The two rings
are resting upon the deep medullary layer (fig. la Plate I, Plate
VIll fig. 15 N°. 6, Plate XI fig. 16 L and M, Plate XIV fig.
14 C) and bordering the outer (non degenerated) as well as the inner
(degenerated) ring the large pyramidal cells appear. In this way
Marchi-degencration divides the tuberculum acusticum into four or
five layers (Plate VI fig. 6). Named from its centrum towards the
periphery they are:

1®. The deep medulla or the stratum medullare profundum —
containing root-fibres chiefly of the dorsal root.
' 2^. The deep grey matter or the stratum griseum profundum —
containing degenerated collaterals of root fibres and small cells.

3*". The middle grey matter or the stratum griseum medium —
containing the large nerve cells.

4®. and 5®. The superficial grey matter and fibres or the stratum
griseum superficiale and the stratum medullare superficial, where
no degeneration is found after rootsection.

Moreover, in the same way as the nucleus ventralis, the tuber-
culum acusticum is receiving the greater part of the root-fibres at
the distal end. At its dorsal and proximal end the black globules
in the inner ring are less thickly spread and normal fibres mix
between the degenerated of the stratum profundum medullare,
seeking their way to the middle layer of the radiation found dor-
sally of the area ovalis.

Now , when following this radiation in proximal direction , the
aspect changes, because the tuberculum acusticum gradually takes
a more lateral instead of a dorsal situation. At the same place the

Verfaand. der Kon. Akad. v. Wetensch. (TweeUe Sectie.) Dl. XIV.

82 C. WINKLER. THE CENTEAL COURSE

dorsal nucleus of the VHP** nerve extends more laterally and the
portio interna of the C. R. has become more extended in such
a way, that the large cells of Deiters, which in distal sections
only were found at its latero-dorsal edge on the medial border of
the oval area, now make their apperance on its dorsal border.

In this way the radiation of the fan is enlarged. Laterally always
collaterals of the stratum meduUare profundum enter into the tuber-
culum , but dorsally the radiation is now opened towards the lateral
part of the dorsal nucleus n. VIII and towards the portio interna
corporis restiformis. After removal of the cochlea , there are always
found degenerated fibres here.

They are the dorsal root-fibres, remaining after the emission of the
trunk to the ventral nucleus and the collaterals to the tuberculum
acusticum.

Those fibres are tending for the greater part towards the lateral
part of the dorsal or triangular auditory nucleus. Their number,
is chiefly in proximal regions increased by root-section of the N. octavus.
If I have rightly understood Lewandowski, those fibres would be
represented in dogs by a contracted bundle , described by him
under the name of the fasciculus solitarius of the eighth nerve.
Apparently Lewandowski has had in mind a comparison with the
fasc. solitarius nervi vagi. But in rabbits this radiation of root-
fibres towards the lateral cells of the dorsal nucleus occurs conti-
nually and so there is no reason to speak of a fasciculus solitarius.
The dorsal nucleus in rabbits extends rather far proximally , even
so far, that when the fibres of the oval area have found their
way to the cerebellum and no longer belong to the medulla
(f. i. Plate VIII fig. 15 N°. 8—12), still the lateral part of the
nucleus dorsalis exists.

Now continually fibres are running to this part. In the more
distal part, they are chiefly rootfibres of the dorsal root, more
proximally they are merely dorsal fibres of the ventral root, and
as the corpus restiforme evades to the cerebellum the medial
fibres of the ventral root enter in it.

But the distal fibres, we have here in view are chiefly dorsal
rootfibres, degenerating after removal of the cochlea. They take
different ways.

P. They send collaterals in the lateral part of the dorsal nucleus
to its lateral group of cells.

2®. A few fibres go farther between the dorsal nucleus and the
portio interna corporis restiformis and become dorsal transverse fibres.

3*^. A few fibres penetrate into the portio interna and augmented

OF THE NERVUS OCTAVUS. 83

with a few fibres from the internal layer of rootfibres, which leave
the intermedial tract, they enter among the fibres of the descen-
ding ventral root.

The latter two systems will be studied afterwards , because they
may better be demonstrated after section of the nervus octavus.

But after removal of the cochlea there is found an important
degeneration in the dorsal systema , that in this way is composed of
the following layers.

1®. rootfibres to the ventral nucleus.

2®. rootfibres to the tuberculum acusticum.

3®. rootfibres which reach more proximally and go, « to the
lateral-cells of the dorsal nucleus, /3 between dorsal nucleus and
portio interna to become transverse dorsal fibres that will be des-
cribed afterwards, y penetrating into the portio interna to the
descending and ascending octavus-roots to be described afterwards.

4®. fibres, emanating from the ventral nucleus and the tuberculum
acusticum.

5®. rootfibres forming the already demonstrated intermedial system.

The three last named fibres form together the layer at the dorsal
border of the area ovalis, described by v. Monakow as stria acustica.
It is increased by new fibres originating in the cerebellum and
they all participate in the structure of the dorsal systema of the
nervus octavus.

m. The results of the secundary atrophy ^ as far as it may be applied
to this question, allow the same views as those, which are defen-
ded in the preceedent paragraph , and the myelinisatioti'method
also confirms the descriptio7i given there of the achitecture of the
systema dorsalis nervi octavi,

I have demonstrated, that MARcni-method allowed a division of
the stratum latero-dorsale in several layers. Degenerated rootfibres
formed an internal and an external layer, holding between them
the non degenerate fibres of a secundary system (fig. \a on Plate
I by /3). The secundary atrophy within the stratum latero-dorsale
some months after the root-section in a young borr» animal enables
to isolate therein all fibres that are no root-fibres.

For instance in fig. 3^ and in fig. 1 "ia on Plate Til the atrophy
in the distal end of the stratum latero-dorsale was drawn a year
after the root-section in the young-born animal. In this case the
two nerve-roots of the n. octavus have completely disappeared and
as the comparison wath the non-operated-side of the medulla demon-

84 C. WINKLER. THE CENTRAL COURSE

strates immediately (drawn in fig. 3^ and fig. 13A on Plate III),
there is found an intense atrophy in the stratum latero-dorsale.
At the non operated side , this layer may be found well developed
with the tuberculum acusticum resting upon it. The stratum medul-
lare profundum and the stratum griseum profundum of this nucleus
— the inner ring — is richly endowed with meduUated fibres.

At the operated side (fig. Sa) nearly all the fibres in the inner
ring have disappeared. The stratum griseum profundum does scar-
cely exist, and the stratum meduUare profundum also is much
reduced. Because the root-fibres have disappeared, the meduUated
fibres now found in the stratum meduUare profundum must belong
to the system of secundary fibres. And these secundary fibres now
form a small trunk of small fibres originating somewhat laterally
from the ventral nucleus.

Here is isolated the trunk of the secundary system from the tuber-
culum acusticum (fig. Sa on Plate III).

But at the same time the ventral nucleus is much reduced in size,
and especiaUy its ventro- distal portion. Here also in the first place the
fibres , constituting the rootbundles in this nucleus have completely
disappeared, at least in its distal end, but at the dorsal and proximal
border fibres reappear. Therefore at its medial border, increasing
towards the dorsal and capital end of the nucleus, a relative strong
bundle is found, a second trunk of secundary fibres.

Those two trunks meet each other at the dorsal border of the
area ovalis (see fig. 3^), the external from the tuberculum, the
intenial from the ventral nucleus. They form together the much
reduced stria acustica, but now a stria acustica, wherein no longer
any root-fibres are exsiting.

It is true that in normal frontal sections also the two trunks
of the secundary system may be demonstrated (compare fig. 13^)
but not so evidently, because there they are complicated by the
presence of the rootfibres.

However, from the atrophied radiation of the stria acustica, it is
now possible to trace several systems of fibres, in their farther course.

For instance its internal layer may be traced round the area
ovalis into the intermedial system. This system is much reduced ,
now that it has lost its rootfibres, but it contains a secundary
system. Its outer layer may be traced in the transverse (see fig.
ISa and fig. \Sd) dorsal fibres, passing between the dorsal nucleus
— which has lost many fibres — and portio interna. These fibres
also are reduced in quantity (see fig. \Sa and ISb str. doi^sale),
but enough of them are left to postulate an important secundary

OF THE NERVUS OCTAVUS. 85

system there. Between them many fibres still penetrate into the
portio interna towards the region where the radix descendens of
the n. VIII is found. They are less in number than at the other side.

Though the ventral root has completely lost its fibres, the des-
eendent root — though its atrophy may be called very important —
still contains many fibres. Therefore secundary fibres existing in
this area may be presumed.

The atrophy method therefore makes from the stria acustica the
exact reverse of what Marchi-method makes from it. The latter shows
degenerated fibres on both sides of a normal secundary layer, the
former shows the central layer without the rootfibres bordering it.

In the same way as the partial atrophy was formerly demonstrated
in the corpus trapezoides, it is now found in the stria acustica.
Indeed , between the stria acustica and the corpus trapezoides in
many regards a paralel may be drawn.

Both are atrophying partially, both are possessing an important
secundary system bordered on the two sides by root-fibres, both
obtain secundary fibres from the same ganglia — ventral nucleus and
tuberculum acusticum.

Frontal sections through the medulla of young born animals or
of elder foetus , also show very clearly the existence of the different
layers in the stratum latero-dorsale and in the stria acustica.

In the new-born cat (Plate I fig. 5 in /3) for instance, two layers
of medullated fibres , an internal and an external one are separated
by a layer of non medullated fibres.

In the elder foetus of a rabbit (Plate XII fig. 17 A in /8) the
medullated internal layer forming the intermedial system, and the
medullated external layer forming the stratum meduUare profundum
of the tuberculum are separated by a portion without medullated
fibres.

If compared with the stratum latero-dorsale, as Marchi-method
after cochlea-removal or root-sections shows it (fig. la on Plate I
in /3), the similitude is very striking.

The paralellism between the dorsal and the ventral systema again
appears very clearly.

Both possess an external border of root-fibres, a secundary system
and on their internal border the rootfibres of the intermedial system.

The atrophy in the primary nuclei , which accurs months after
the rootsection in the young animal, is now chiefly characterised
by an enormous loss of fibres, rootfibres as well as collatemls , but
it is remarkable that the loss or the changes in the nervous cells
of these nuclei is less evident. Firstly it may be called in mind,

86 C WINKLER THK CKNTRAL COURSE

that with Nissii's method used a fortnight after removal of the
cochlea or after root-section , were not shown any degenerative
changes in the cells of the nuclei , neither in the tuberculum , nor
in the nucleus ventmlis or in the olivae or nuclei trapezoides.

But in cases of atrophy the question stands otherwise. As regards
the tuberculum acusticum , for instance there certainly never occurs
any atrophy of the large cells.

A .preparation made on purpose to judge the cells in that nucleus,
for instance a Nissl preparation of the normal one (Plate VI fig. G)
may show , that 1® in the superficial medullated as well as in the
grey layers, small cells of spherical and pyramidal shape are scattered.

2® the large pyramidal-shaped cells are found in the middle grey layer.

S"" smaller pyramidal-shaped cells do appear in the deeper strata.

The more profoundly the layer is searched, the smaller the
cells are found to be , their prevailing shape becoming spherical or
elliptical, and their longest axis lying in the direction of the longi-
tudually sectioned fibres of the stratum medullare profundum. These
elliptical-shaped cells are increasing in number towards the distal
pole of the nucleus, and in its neighbourhood, somewhat laterally
situated between tuberculum and ventral nucleus, they are accu-
mulated in such a manner that a true nucleus is formed. This
accumulation is described as the „nucleus proprius rami dorsalis".
This nucleus continues towards the stratum profundum of the tuber-
culum, it also sends prolongations along the lateral and medial
bordei-s of the ventral nucleus, embracing it, and at the distal end
of this nucleus (Plate VII fig. 7 F and G) the number of the
small cells is again much augmented.

In the ventral nucleus cells of triangular and multipolar shape
are found, having nearly the same size of the larger pyramidal cells
in the tuberculum.

Now, for the tuberculum acusticum I agree with nearly all the
elder investigators, that in cases of atrophy after rootsection, I
never have seen any change in the large pyramidal cells, ranged
in radiar lines in the medial grey layer. On the contrary the small
cells in the deeper layers are disappearing in great number and in
the same time indeed nearly all cells of the nucleus proprius are gone.

In NissL-preparations however the large cells of the tuberculum are
not altered even months after rootsection. And yet after a section
through the dorsal system in four days all these large cells are swol-
len, their tigroid is desintegrated, briefly they show chromatolysis.

Now GoLGi-method shows easily that the large pyramidal cells
send their axones towards the stria acustica and von Monakow

OF THE NERVUS OCTAVUS. 87

has proved, that they disappear totally after a partial section of
the crossed lateral fillet.

For all these arguments it may be accepted as a certain fact,
that from the large pyramidal cells in the tubercuhim acusticum
originates a secundary system. Why then, those cells do they not
suffer any atrophy after root-section made long before? It appears
to me, that the cause of this behaviour after rootsection may be
found in the circumstance , that the collaterals of the rootfibres do
not terminate directly at the large pyramidal cells. I believe that
the small elliptical-cells in the deeper layers, the cells accumulated
along the root-fibres, the cells of the proper nucleus of the dorsal root,
are cells intercalated between the rootfibres and the secundary system.

And as for the ventral nucleus, it seems to me that the same
view may be defended.

This nucleus is reduced very much in cases of atrophy, to ^/^ of
its original size as compared with that of the other side. Its ventro-
distal end has suffered the greatest changes. The loss of fibres in
this nucleus is enormous, and according to it the cells are lying
close together. I cannot completely agree with Onufrowicz that
the cells disappear in the nucleus , or that they are found to have
diminished in size so very much as his drawings represents it.

This only is the case in its disto-ventral pole, where again the
small elliptical cells are found. In the dorso-capital regions there are
found a great many cells, which have degenerated not at all or very
slightly, but they are lying closer together, because the bundles of
root-fibres are gone. Here in this nucleus I believe that again the root-
fibres do not immediately terminate at the larger cells, from which
secundary systems originate, but by means of intercalated small cells.

And such may be also the case in the olivary bodies, where
again small cells may disappear, but the larger ones are found
unaltered. Only this is not the case in the cells of middle size
from the nucleus corporis trapezoides. Here as MARCHi-preparations
show, the degenerated collaterals of the rootfibres fill up the nucleus.
Moreover the peculiar terminations at the cells (the „Endfusschen"
of Held) in this nucleus is kwown. But in this nucleus — opposite
to the rootsection — the cells are not only lying closer one to
another than in the nucleus, corresponding to the undamaged root,
but they are considerably reduced in size.

I believe that the dorsal root entering at the distal end of the nucleus
ventralis, provides this nucleus with rootfibres, and afterwards entering
in the deep medullar layer also provides the tuberculum acusticum,
and that the ventral root only enters in these nuclei with a few dorsal

88 C. WINKLER. THE CENTRAL COURSE

fibres. Between the endings of the rootfibres and the origin of new
secundary systems however there must be intercalated small ceils.

n. The nucleus dor sails nervi octavi.

Before returning to the different root-fibres, which I left in the
radiation at the dorsal border of the area ovalis, it now will be
necessary to describe two very important parts of the auditory
system , viz : the nucleus dorsalis nervi octavi and the portio interna
of the corpus restiforme.

Else the nuclei situated therein, and the fibre-systems ending
in them or passing through them, may not easily be understood.

Now the dorsal nucleus is the most extensive of the auditory
nuclei. In frontal sections it begins already at a level with the
clear nucleus of the X^^ nerves and ends nearly at the entrance of
the pedunculus superior cerebelli (see for instance Plate VIII fig.
15 N°. 4 — 11) in the metencephalon.

At its largest extensity it takes nearly the whole bottom of the
4*^ ventricle, between the genu of the VIP** nerve and the portio
interna corporis rectiforme.

From the tuberculum acusticum, its lateral part is not always
disthictly separated. If it is separated from it, the radiation of the
dorsal systema at the dorsal border of the oval area confines laterally
the nucleus. The large number of transverse fibres originating from
this radiation and bending in medio-ventral direction, as transverse
dorsal fibres , distinctly separate the nucleus from the portio interna.

In this way, laterally limited by the descending VHP** root,
ventrally by the formatio gelatiuosa of the spinal V*** root, by the
formatio reticularis and the genu of the VIP**, the dorsal nucleus
obtains its triangular shape, its basis situated at the bottom of the
4^** ventricle its apex resting upon the descendent root of the radix
ventralis (f. i. Plate III, fig. lU).

In the ventricle it is making three pro-eminencies. The most
medial one, next to the raphe is in reality caused by the knee
of the VIP** nerve. More latemlly , the larger vault is made by the
principal mass of cells of the dorsal nucleus, and a smaller, most
laterally situated, is the expression of its lateral mass of cells (see
Plate VII fig. 7. F and G). Now if the limits of the doi-sal nucleus
are not precisely defined , especially its relations towards the portio
interna of the C. R. , it afterwards may offer difficulties to fix the
relations of the auditory root-fibres to it and to the nucleus of
Bechterew. And in order to avoid the confusion which very often

OF THE NEllVUS OCTAVUS. 89

has arisen amongst the authors concerning this region, 1 prefer
giving a description of the cellular structure of the nucleus dorsalis
N. octavi and its surroundings, before describing the entmnce of
root-fibres or the exit of the secundary fibres.

In a cell-preparation from the doi*saI nucleus at its greatest
extensity four groups of cells may be demonstrated (Plate III fig.
7A— H a—e).

a. a medial group (in a)

b. a principal, dorsal (in b) or central group

c. a lateral group (in c)

d. a ventral group (in d)

without reckoning to it a fifth group, the cells of the

e. nucleus nervi VI, which are closely allied to, and perhaps
are a ptirt of the doi*sal nucleus (in e).

From these four groups, the three first named have nearly the
same structure. Small cells are found in them, mostly elliptical or
polygonal cells. Occasionally a larger pyramidal cell is found among
the small ones. Together they allow the description as one single
larger cell-mass. The principal or dorsal cellgroup was already present
at the distal end of the nucleus, and as the nucleus exfoliated two
alae were adjoined to it, the one medially , the other laterally, which
again disappeared at the capital end. But as to the fourth group,
it is quite another case. Its structure differs very much from the
other three. The reason to distinguish the three former named one
from another, is chiefly their relation to the auditory root-fibres.

I'y. The medial group of cells (Plate VII fig. 7 A— H in a)
has nothing to do with rootfibres. Situated, in distal sections,
dorsally from the genu N. VII, in proximal sections, medially from
it, it never is found covered with black granules, neither after
cochlea-removal, nor after section of the nervus octavus.

2'y. The lateral group of cells (Plate VII fig. 7 A— II in c)
appears in the level of the tuberculum acusticum. It is laterally
bordered by the smaller cells in the deep grey layer of this nucleus
and medially by the cells of the principal group. But the separa-
tion between those cells is not very distinct.

As we have already seen, after removal of the cochlea, the
degenerated root-fibres enter in its distal regions, from the outer
layers of the radiation of the stratum latero-dorsale.

But as soon as the tuberculum acusticum does no longer cover
dorsally the C. R. and has retired laterally (Plate VII tig. 7 II in c)
this lateral group of cells is thrown more medially , because the portio
interna of the C. R. is penetrating between it and the tub. acusticum.

90 C. WINKLER. THE CENTRAL COURSE

For this portio interna has strongly increased in these regions. Partly
because the nucleus of Deiters has grown more extensive, partly because
more and more ventral root-fibres have entered, partly because more
and more fibres of the nuclei tecti cerebelli did find a place there.

Together with the portio intema the ventral group of cells in
the dorsal nucleus is also increased and retiring laterally. It does
no longer form the ventral border of the principal group only, as
it was the case in distal sections, but it begins to border it also
laterally. At the same time the lateral group has become smaller
and is flowing together with the principal group.

3^^. This dorsal or principal group (Plate VII fig. 7 A — H in b)
is very important. As soon as after rootsection, the ventral fibres
degenerate and with these the descending root of the ventral radix,
it is easily demonstrated that degenerated collaterals leaving per-
pendicularly the descending root-fibres penetrate into it (Plate V
fig. 9 and fig. 10). It is then very thickly specked with black granules.

The descending root however accompanies in its distal course,
the ventral apex of the dorsal nucleus, and though it is situated
in the medio-ventral part of the portio interna, it is surrounded
by cells, forming a cellular nucleus, situated dorso-medially from
the root-fibres.

The name of nucleus griseus radicis descendentis, given to it by
Lewansdowski , is a most fit one. These cells are of very different
size, but among them there are found many larger polygonal and
pyramidal ones , not so large as the cells in the nucleus of DErrERs,
a few of them reaching perhaps their size.

Those cells, now are hardly distinguishable from the cells in the
ventral group of the nucleus dorsalis N. VIII.

4'^ The ventral group of cells (Plate VII fig. 7 A— II in d) ,
though containing cells of different size, possess among smaller ones
many larger cells, a few of them also approaching the size of the
large cells of Deiteus.

The ventral apex of the dorsal nucleus truly has quite another
structure as its basis, rather the same structure as the nucleus
griseus rami descendentis. Both receive a great quantity of root-
fibres of the descending root, and both arc passed by root-fibres,
which must penetrate them, to reach the principal nucleus, as
well as the lateral nucleus.

As soon as the tuberculum acusticum is gone hiterally , and the
ventral root has entered , a part of its fibres are tending proximally
(as in Plate IV fig. 8 in a somewhat oblique frontal section is
seen). I have demonstrated that, in the same moment the ventral

OF THE NERVUS OCTAYUS. 91

group of the dorsal nucleus is forming the lateral border of its
principal and lateral cells. Here the nucleus griseus radicis descen-
dentis is not yet gone, and is joined to the ventral group. A little
more proximally the corpus restiforme (or its oval area) retires into
the cerebellum, and nearly at the same moment the nucleus of
Deiters disappears. But the nucleus griseus of the ventral root-fibres
together with the ventral group of the dorsal nucleus have remained,
and are situated still laterally of the latero-dorsal cells of the dorsal
imcleus. And on that plan cells of different, mostly of medial
size, are forming a larger area (Plate IV fig. 8), which has been
called since long the nucleus of Bechterew. It might have been
called also the nucleus giiseus of the ascending root.

It seems to me, that there exists some difficulty to define the
nucleus of Bechterew. I only wish to state , that this nucleus
certainly may not be identified with the proximal portion of the
lateral groop of cells in the dorsal nucleus, as is done by some
authors, f. i. Lewansdowski.

The relations of the ventral rootfibres to the nucleus griseus radicis
descendentis and to the cells of the ventral apex of the dorsal
auditory nucleus, during the whole course of the descending root
are clear enough. They become still more transparent, as the nucleus
of Deiters has disappeared and the ventral rootfibres instead of
forming a descending radix have a somewhat proximal direction
(the ascending root), but the relation of the root-fibres to this nucleus,
with its cells of midling size between small ones, has not altered.
Only its name is here no longer „a nucleus of the ascending ven-
tral rootfibres". This is the nucleus of Bechterew, lying between
the corpus restiforme, as it retires towards the cerebellum, and the
latero-dorsal cells of the dorsal nucleus, or between the nuclei
tecti cerebelli and the motor nucleus of the nerve V in the lateral
wall of the ventricle, characterized by cells of midling size scattered
between small cells (Plate IV fig. S and Plate V fig. 9).

Now still remains the nucleus of the W^ nerve, as the last of
the cell-groups entering into the surroundings of the nucleus dor-
salis nervi octavi. (Plate VII fig. 7 A — H). The cells of this nucleus,
scattered round the genu of the VIP*" nerve, bordered, but not
sharply, by the cells of the principal and the medial group of the
dorsal nucleus, are found latero-dorsiUly from the genu N. VII in
distal sections, latero-mcdially from it in proximal sections. In this
way, they force the leaving root-fibres of the VP^ nerve, to evade
the genu, before taking their straight dorso-vcntral direction.

The cells of this nucleus also receive rootfibres from the nervusoctavus.

92 - C. WINKLEK. THE CENTRAL COURSE.

o. The portio interna corporis restiformis {jiiwtu-restiform body)
and the root-fibres of the ventral root.

As the portio interna, lying between the oval area of the C. R.
and the dorsal auditory nucleus, is nearly everywhere passed by
or composed with auditory root-fibres, it is necessary to give a
minute description of its relations to these fibres.

In frontal sections, its distal end begins as soon as the nuclei of the
posterior spinal columns reach their proximal endings. As soon as
the dorsal ascending spino-cerebellar tract (Flechsig's Kleinhim-
Seitenstrangbundel), covering dorsally the spinal V^** root, attains
its place in the oval area , gre}' matter ajipears at the medio-doi-sal
side of this tract. (Plate VIII fig. 15 N°. 1 and N°. 2). There it
is situated laterally of the proximal ending of the nucleus of Burdach,
and as here the fibre-mass of the posterior spinal column soon has
found an end, there appears rather abruptly an area of transverse
sectioned nerve-fibres, united in little separate bundles, medio-
ventrally from this grely matter, (see fig. 15 N°. 3 on Plate VII).

The grey matter is the nucleus proprius of the restiform body,
the area with separated bundles contains the distal bundles of the
radix descendens nervi octavi. (Plate VII fig. 15 W . 3 in N. C. R.
and in r. desc. N. VIII;. Together they form the distal end of the
portio interna.

As soon as the nuclei from the posterior columns have ended,
at first laterally but soon dorsally of the nucleus of the X*** nerve
(Plate VIII fig. 15 N^ 4. n. d. N. VIII) the dorsal nucleus also
makes its appearance, and from that moment the difierent constituants
of the juxta-restiform body are present. Bordered at its medial side
by the dorsal nucleus and closely related to it, ventrally resting
upon the V* spinal root, laterally limited by the rapidly growing
oval area, it extends proximally unto the entrance of the superior
cerebellar peduncle.

Somewhat distally from the appearance of the tuberculum acus-
ticum the nucleus of Deiters is at first seen. The first large cells
of this nucleus are always found in the dorso-lateral edge of the
portio interna (Plate VII fig. 7 A — H) but as long Jis the tuber-
culum covers the oval area, those cells are not found dorsally from
this area. As soon as the stratum latero-dorsale and the tuberculum
are diverging from the area ovalis, Deiters' nucleus is dorsally
resting upon it and exfoliating laterally from it, it is crossed by
root- and secundary fibres curving in the systema dorsale nervi
octavi round the oval area.

OF THE NERVUS OCTAVUS. 93

The nucleus of Deiters disappears when the oval area leaves
the medulla and has become the inferior peduncle of the cere-
bellum, and as we will afterwards have much to do as well with
this nucleus as with its position in the latero-dorsal quadrant of the
portio interna, I memorate these long known facts here.

Rootsection of the nervus octavus now enables us to demonstrate
other fields in the portio interna and divides it in degenerating
and non degenerating portions.

After root-section, the medial octavus-trunk, the medial fibres of
the ventral root, nearly totally degenerate.

They enter between oval area and spinal root of the V^** nerve,
closely adossed dorsally to the latter (Plate VIII fig. 15 N°. 9)
and having reached the medio-ventral edge of the portio interna,
just there, where the ventral apex of the dorsal auditory nucleus,
the medial edge of the V*^ spinal root, and the portio interna meet,
a great many of them bend downward in an angle of 90°.

This is the descending octavus-root, the degeneration of which
after rootsection is shown very clearly in horizontal sections. (Plate V
fig. 9). Plate X fig. 16 I. Plate XIV fig. 14 A), but is also easily dis-
tinguished in frontal sections, as an area of degenerated fibres,
situated in the medio-ventral quadrant of the portio interna (Plate VIII
fig. 15 N^ 8, 7, 6, 5, 4).

This area, composed of separated nerve-bundles, showing many
degenerated fibres between non degenerated ones, may be traced
until the proximal end of the nuclei of the posterior columns.

Now, they are not exclusively medial root-fibres of the ventral root,
which compose this descendent tract, though they may form the
greater part of it.

After removal of the cochlea there are also seen some fibres
degenerating in it. These are firstly the few fibres running from
the doi'sal root into the medial trunk, but they mostly are belon-
ging to the fibres of the stratum latero-dorsale , which have curved
round the oval area, and passing obliquely through the nucleus of
Deiters also reach the medio-ventral edge of the portio interna.

These are the fibres, not very many, but yet demonstrable, which
from the dorsal root do enter in the radix descendens. They never
after cochlea-removal may be traced so far as to the nucleus of
the X^^ nerve.

But after root-section, the number of degenerate fibres in the
inner layer of the stratum latero-dorsale being increased, not only
the intermedial system is degenerated in a more important degree,
but also many of those fibres, penetrating through the area ovalis,

94 C. WINKLER. THE CENTRAL COURSE

go through the nucleus of Deiters to the medio-ventral part of the
portio interna in the descendent radix.

In this way the radix descendens contains different root-fibres.
For the greater part they are fibres of the medial trunk origina-
ting in the ventral root. Some fibres nevertheless, reach it through
the dorsal systema. They again are mostly fibres of the ventml root
passing through the oval area. But some fibres of the dorsal root
also attain the descendent radix by the two described paths, T^ as
medial fibres of the dorsal root. 2'^ round the oval area.

After rootsection however degenerated fibres are found not only
in the ventro-medial quadrant of the portio interna.

After rootsection the degenerate fibres in the stratum latero-
dorsale are augmented, most in the inner layer, but also in the
outer layer. They partly are ending in the lateral cells of the dor-
sal nucleus. But a rather important bundle goes on the latero-
ventral border of this nucleus, through the cells of Deiters, be-
tween this nucleus and the portio interna. As this bundle reaches
the ventral apex of the dorsal nucleus, there, where it touches the
nucleus griseus of the descendent root, it participates to the trans-
versal fibres of this region, changing its direction into a medial one
and going along the ventral border of the principal group and of
the nucleus N. VI, it reaches the raphe.'

These are the „transverse fibres of the systema dorsale n. octavi".
Their number is increased by fibres of the medial trunk, there
where it sends distally the greater mass of its fibres into the des-
cending root, but they are not only fibres of the ventral root.

For after removal of the cochlea there are also found degenera-
ted fibres in the transverse fibres of the dorsal systema.

Knowing now the degenerate fibres after root-section in the
portio interna I am enabled to reconstruct the systema dorsale nervi
octavi, where I left it.

This systema, by MARCHi-degeneration , has been divided in three
layers, whilst it was contained in the stratum latero-dorsale.

An outer layer of degenerate root-fibres, a middle layer of
normal fibres, and an inner layer again of degenerate root-fibres,
radiate together towards the stria acustica.

But this dorsal system contains at least five bundles.

P dorsal rootfibres (from the two roots) to the lateral cells of
the dorsal nucleus.

2*^ dorsal rootfibres (from the two roots) to form dorsal trans-
vei-se fibres.

3'' secundary dorsal transverse fibres.

OP THE NERVUS OCTAVUS. 95

4^ dorsal rootfibres (from the two roots) passing through the
portio interna towards the descending root.

5® dorsal rootfibres (from the two roots) forming the interme-
dial system.

Now, as soon as the corpus restiformis, deviates into the cere-
bellum the aspect of those fibres changes. The two slings of root-
fibres, between which the area ovalis was enclosed, mix together,
or rather the root-fibres penetrating through the oval area, found
in the proximal sections (Plate VIII fig. 15 N°. 8 and N*". U), are
the preliminaries of the union of the dorsal and medial sling of
root-fibres. And as the area leaves the medulla to become cerebel-
lar inferior peduncle, (Plate IV fig. 8) the combined root-fibres go
farther. They now have a somewhat proximal direction and may
be called ascendent root. But they are originating from the two
roots. The greater part may be medial fibres of the ventral root.
The proximal dorsal fibres however participate to it and a smaller
part of them may belong to the dorsal root.

As I have demonstrated, the nucleus of Deiters has now disap-
peared, but the surroundings of these fibres have remained unchanged.
They are surrounded by cells of the same shape and of medial
size, like those which in more disal sections characterized the
nucleus griseus round the descending root. But here the nucleus
griseus of this ascending root is called nucleus of Bechterew.

It is not difficult (Plate IV fig. 8, Plate V fig. 10) to demon-
strate the relations of the ascendent fibres to this nucleus. Many
of them remain there, but a few exceed this nucleus towards the
nuclei mediales tecti, from which the nucleus of Bechterew is less
sharply marked off*, as from the dorsal nucleus.

In this way the greater part of the root-fibres of the nervus
octavus entering in the medial trunk between area ovalis and spinal
V^^ root, join a smaller part that has sought a dorsal way in order to
reach the medio-ventral quadrant of the portio interna, forming a
long tract, an ascending and a descending root of the nervus octavus.

This tract is surrounded by a long stretched nucleus.

In proximal sections it is called the nucleus of Bechterew, more
distally the nucleus griseus of the descending root, still more distally
it confluates with the proper nucleus of the corpus restiformc,
and dorso-medially from this nucleus the dorsal nucleus of the
nervus octavus appeal's, extending in a similar way. In this way,
views closely allied to the elder views of Roller reappear.

Perpendicular collaterals part from this long tract during the
whole of its course. They perforate the nucleus griseus and the

96 C. WINKLER, THE CENTKAL CX)UIISE

nucleus of Dkiteus. They go at first ending tho the lateral and
principal cells of the dorsal nucleus, and to the nucleus of the VI"*
nerve (Plate XIV fig. 14 A). Those nuclei are thickly specked with
black granules after rootsection. Secondly an important number of
these fibres are ending in the nucleus griseus. Round the nucleus of
BEcmTEREW and in the whole long nucleus griseus of the descendent
root, ascending and descending rootfibres enter. They pass through the
nucleus of Deitrrs but they do not end among the large cells of it.

This nucleus is passed by all the rootfibres of the dorsal radia-
tion, but yet there is found not a single symptom that rootfibres
should be dissolved in collaterals or make any other contact with the
cells, which certainly are not in direct contact with the root-fibres.
Neither for the large cells of the tuberculum acusticum nor for the
larger cells in the dorsal-proximal pole of the ventral nucleus a
direct contact with rootfibres could be demonstrated, and in this regard
the cells of Deiters have not such a peculiar position among the
secundary systems of the nervus octavus as often has been presumed.
This however is a question, which afterwards will be discussed.

Until now the portio interna of the corpus restiforme contains
at least three regions.

I®, a dorso-lateral quadrant — the nucleus of Deiters.

2®. a ventro-medial quadrant — the descending root with its nucleus
griseus.

3®. The medio-dorsal border of transverse dorsal root-fibres. They
form part of the doi-sal rootfibres passing the portio interna in
every direction.

There still remain the non-degenerating fibres in the dorsal
radiation.

That a secundary system passed into the intermedial system and
into the descendent root I have already made probable. There
also passes one in the dorsal transverse fibres.

But Marchi-method after rootse(.*tion leaves two large quadrants
of the portio interna without degenerated fibres in the longitudinal
axis of the medulla (Plate IV fig. 4).

The dorso-niedial quadrant, where a great many secundary audi-
tory fibres will soon be recognised , mixed with fibres originating
from the cerebellum, and a ventro-lateral triangular area where again
(between oval area and spinal root of the V) non degenerated fibres
may be found.

The relations of the root-fibres to the dorsal nucleus n. octavi
and the portio interna being such as described here , the farther
coui-se of the dorsal system may be studied.

OP THE NERVUS OCTAYUS. 97

p. The portio interna in the embryo of the rabbit and its
atrophy after root-section in the young born animaL i

Till now the Marchi-method has shown degenerated fibres in the
intermediary and dorsal octavus-sy stems crossing the nucleus of
Deiters and in the descending root.

Now in the oblongata of the elder foetus of the rabbit (Plate

XII fig. 17, A, B and C) are found likerwise medullated fibres,
in the intermediary system (Plate XII, fig. 17 A, h = s,
interm), in the dorsal system (Plate XII (fig. 17 A, B and C,
fasc. doi^s. N. VIII) and in the descending root (Plate XII fig. 17
A r. desc. N. VIII), whereas in the area of Deiters itself only
a few medullated fibres, mostly passing through it, are seen.

In this way the portio interna appears to have medullated fibres
in all systems, wherein Marchi-method demonstrates degenerate
fibres after root-section.

And as in this still unborne young rabbit, the area ovalis, of
the C. R. , according to the medullated dorsal ascending spino-
cerebellar tract , is partly myelinisated , its portio interna is clearly
divided into four quadrants, among which the medio-dorsal and
the triangular latero- ventral area's are not yet provided with medul-
lated fibres.

Still more evident than in the mbbit (Plate XII fig. 1 7 A) this
division is in the young born cat (fig. 5 on Plate I). There again
the very powerful intermedial system, the very important system
of transverse dorsal fibres, and also the descending root-fibres are
medullated, the dorso-medial quadrant and the nucleus of Deiters
have only a few, the latero-ventral area between area ovalis and
the V**" spinal root is without myelinisation.

Sagittal sections through the medulla of the rabbit demonstrate
the same facts. Between the area ovalis and the V^** spinal root,
a long stret(!hed area is found (Plate XIII fig. 18 D), crossed
proximally by the medullated intermedial system (Plate XIII fig.
18 D in // (Held)). Medullated are also the medial (Plate XIII fig.
18 D) and the descending roots (Plate XIII fig. 18 E and V in
rad. desc. N; VIII), whereas the medio-dorsal quadrant (Plate

XIII fig. 18 E and P) dorsally from it is not.

The transverse dorsal fibres, also medullated (Plate VI 19 C)
are best demonstrated on horizontal sections, where their whole
course towards the fasciculus longitudinalis posterior may be seen.

Now if the frontal (Plate Xll fig. 17 A) or horizontal (Plate
VI fig. 19 C) sections thi'ough the medulla of the rabbit-foetus,

Verhand. der Kon. Akad. v. Wetenscb. (Tweede Sectie!) Dl. XIV. 7

98 C. WINKLER. THE CENTRAL COURSE

are compared with frontal (Plate I fig. la Plate II fig. 2) sections
after cochlea-removal or after root-section (Plate IV fig. 4) or with
horizontal sections after rootsection (Plate V fig. 9) treated with
Marchi, the similitude is striking.

Degenerated fibres are found situated at the place , where medul-
lafced fibres are seen, normal fibres there, where no myeliiiisation is
found. In this way the dorsal and ventral systems present the same
points of similitude.

Secundary octavus-fibres are not all medullated at birth. Some fibres
are not. in the dorsal system these are the middle layer (Plate XII
fig. 1 7 A in /3 , Plate I fig. 5 in /3) and the latero-dorsal part of
the portio interna. In the ventral system these are the stratum c
in the corpus trapezoides.

If it were an established fact, that all medullated fibres in the elder
foetus were only root-fibres, they should be present in the dorsal
as well as in the ventral system in a rather abundant number. In
regard to this question I at present only state, that MARCHi-method
indeed shows degenerate fibres after rootsection at the same places,
where medullated fibres are found, without more.

Now in the sections through the foetal medulla in this region
there still are seen medullated fibres in two not yet described
tracts, that may possibly contain rootfibres of the eighth nerve.

The first is the fasciculus longitudinalis posterior.

The second medullated bundle passes through or originates in
the nucleus of Deiters, and is known as the vestibulo-spinal tract,
or better called — with Lewandoski — the tractus Deiters des-
cendens. In frontal sections of rabbit (Plate XII fig. 17 A and B
f. Deit. desc.) and of cat (Plate I fig. 5 in f. Deit. desc.) it leaves
the nucleus of Deiters, crosses the rootfibres of the nucleus of the
VIP** nerve, which are forming the genu; afterwards, dorsally from
the nucleus of the VIP** nerve, it bends into the longitudinal axis of
the medulla, deviating slightly medialwards, but always situated
laterally from the root-bundles of the XIP** nerve, this tractus may
be traced into the spinal cord at the ventral border of the anterior
and lateral collumns.

In sagittal sections the tractus Deiters descendens (Plate XIII
fig. 18 F in f. Deit. desc), its bending distally into the longitudinal
axis of the oblongata, as is passes through the facial root-fibres is
demonstrated very clearly.

Whether rootfibres also may be found in those two tacts will be
discussed in the following paragraph. Here they are easily demon-
strated as medullated tracts.

OF THE NERVUS OCTAVUS. 99

Thus far we may hold it to be proved in a sufficient way , that
Marchi-method and myelinisation-method are tending to similar
results.

And Gudden's method also rather confirms these results. A year
after rootsection in the young rabbit it may be demonstrated that
a large quantity of fibres has been lost in the dorsal radiation
between tuberculum acusticum and oval area and that the inter-
medial system , the dorsal transverse fibres and the descending root
are atrophied to an important degree (see Plate III fig. \Sa and
3a compared with 13^ and Sb). Still an important quantity of
fibres have been left in these tracts — their secundary systems.

Fibres are lost also in the nucleus of Deiters, in the nucleus
of Bbchtekew, in the nucleus griseus of the descending root, in
the lateral and ventral parts of the nucleus dorsalis N. Vlll. And
from the medial trunk of rootfibres there is left nearly nothing.

In such cases also cells have disappeared.

As is demonstrated (Plate VII fig. 7 A — H) before, there are
found in the portio interna the large cells in the nucleus of Deiters,
the cells of small and midling size in the nucleus griseus, the
ventral apex of the dorsal nucleus and in the nucleus of Bechterew,
and the small cells along the fibres of the medial trunk between
area ovalis and spinal V nerve. In the dorsal nucleus (except in
the ventral apex and the nucleus of the sixth nerve) small cells
are found to prevail.

Now I agree, with all the elder investigators, that no change
is seen in the large cells of Deiters. As fig. ISa demonstrates
(if compared with fig. 13d, Plate III) clearly, those cells have
suffered not the slightest alteration nothwithstanding the important
atrophy of the fibres passing through the nucleus of Deiters.
Consequently they may lay more closely together than those of the
other side, but they do not alter, even not in a year after root-
section on a young animal.

But this also is the case with the cells of midling and larger
size, which are found in the nucleus of Bechterew, in the ventral
apex of the dorsal nucleus, in the nucleus griseus radicis descen-
dentis and in the nucleus N. VI.

Even a year after the operation, there may be found normal
cells in large quantity in these nuclei. Still cells have vanished, but
they are the small cells and among those of midling size, they are
also the smaller specimina.

Those along the medial trunk of rootfibres are all gone. Many
cells also have disappeared at the latero-ventral border of the dorsal

loo C. WINKLER. THE CENTRAL COURSE

nucleus touching the portio interna. Therefore this part of the
dorsal nucleus is found slightly atrophied, not only by loss of fibres
(collaterals) but also by loss of cells. Cells in the nucleus of
Bechterew, in the nucleus griseus radicis descendentis, in the ven-
tral apex of the dorsal nucleus also have disappeared.

But only smaller cells, the larger cells are not altered. Here the
same results reappear as were demonstrated in the nuclei of the
ventral system a year after rootsection.

There these results were: No alteration in the large cells of
the tuberculum acusticuni; loss or atrophy of small cells in the
deep grey matter. No alteration in the dorso-proximal pole of the
ventral nucleus. Loss or atrophy of cells in the proper nucleus
of the dorsal root of the smaller cells in the ventro-distal pole of
this nucleus.

No alteration in the cells of the facial nucleus or in the larger
cells of the olivary bodies. Loss or atrophy of cells in the small
cells in their medullary surroundings and in the opposite nucleus
trapezoides.

Here the results are : No alteration in the largest cells of Deiters,
or in cells of the large and middle-large size in the nucleus of
Bechterew, the nucleus griseus -|~ apex ventralis nuclei doi*salis,
and in the cells of the abducent Nerve.

Loss or atrophy of cells in the proper nucleus of the medial
trunk, in the ventral borders of the lateral and principal cell-groups
of the nucleus dorsalis, and among the smaller cells of the nucleus
of Bechterew, nucleus griseus -|~ apex ventralis nuclei dorsalis.

Here Jis before I conclude, that the contact between root-fibres
and cells, from which secundary systems originate is not a direct one.
Small cells are intercalated. Here the cells of the medial trunk
of rootfibres, the cells of the dorsal nucleus bordering the portio
interna, a certain part of the cells in the nucleus Bechterew
and in the nucleus of the descending roots.

And it is only through those intercalated cells, that the cells, in
which originate the secondary systems — here the large elements
in the nuclei of Deiters, of Bechterew, in the nucleus griseus
of the descending root and in the nucleus N. VI — are reached
by the root-fibres.

These results, following inevitably, as well from MARCHi-method,
as by Gudden's method, are not in contradiction with Golgi-
preparations.

OF THE NERVUS OCTAYUS. 101

q. The descending root and the transverse dorsal fibres.
The farther course of the systema dorsalis nervi octavi.

Its ascending tracts and its descending tracts.
Its relations with the nuclei of the VP^, IF^^, IIP nerve.

The degenerated descending root may now be traced in its distal
course as well in frontal as in horizontal sections. In frontal sections
this root is composed by a great many bundles of fibres, separated
by grey matter (Plate IV fig. 4). Near its origin it is resting
dorsally upon the spinal V^*^ root (Plate VIII fig, 15 N°. 7 and
N°. 8), and in its bundles the degenerated fibres are found. More
distally, as the spinal root of the V^*" nerve takes a more lateral
position, the descending radix, recognisable at its degenerate sepa-
rated bundles, has not followed the nervus trigeminus. It is now
resting upon the dorsal surface of the transparent nucleus nervi
vagi (Plate VIII fig. 1 5 N"". 5). But here some degenerated fibres
leave the radix descendens, to pursue their way in the fasciculus
solitarius N. X, and may be traced far distjiUy (Plate VIII fig. 15.
J!^^ 5— N^ 1). In horizontal sections (Plate XIV fig. 14 A,
Plate X fig. IGII) in the same way the continuation of degene-
rated fibres from the radix descendens after rootsection, into the
fasc. solitarius N. vagi may be seen.

In the transparent nucleus of the N. X, the fibres of the solitary
tract are sending scarcely degenerated collaterals, parting from them
in a i)erpendicular direction, in quite the same way as the descending
root is giving collaterals to the dorsal nucleus of the VHP*" nerve.

Not long ago van GEHUcn^rEN has emitted the view, that fibres
going from the descending root in the fasc. solitarius N. X, may
be fibres from the nervus intermedins Wrisbergii. Van Gehuc^hten
has torn out the facial nerve with its ganglion geniculi and has
concluded that the degenerations found after this lesion were caused
by the lesion of the nervus Wrisbergii.

I can only state that without the least lesion of the facial nerve,
the removal of the contents of the labyrinth and if necessary , root-
section is performed, and that, in cases of important degeneration
of the descending root, always fibres in the solitary tract of the
X^** nerve are found degenerated also. But the greater part of the
fibres of the descending root may be traced distally otherwise.

As it is seen on Plate XIV fig. 14 A , the degenerated root-fibres,
sending collaterals into the dorsal VlIP^ nucleus and even directly
to the nucleus of the VP^ nerve, appear as if ending all in the

102 C. WINKLER. THE CENTBAJ. COURSE

fasc. solitarius, but in frontal sections (Plate VIII fig. 15N^. 5 — 1)
there appears only a scanty number of them. As far as the field
of separated bundles may be traced, that is to the proximal
ends of the nucleus of Burdach-Monakow a few degenerated fibres
are seen. They probably provide the nucleus proprius of the resti-
form body till its most distal end.

Now the endings of the systema dorsale of the nervus octavus
still remain to describe.

From this I have already demonstrated the intermedial system and
found that it transported fibres from the dorsal system through the
ventral ascending spino-cerebellar tract into the nuclei tecti and
through the crossed lateral fillet to the corp. quadrig. postic. These
two ascending tracts need here no farther description.

It only must be kept in mhid, that in proximal sections, fibres
of the ventral root continue in the ascending root and go directly
to the nuclei tecti, without using the complicated way dictated by
the ventral ascending spino-cerebellar tract.

But after having lost the intermedial system and the fibres to
the descending root, the dorsal systema bends as transversal dorsal
fibres between the dorsal nucleus and the portio interna. Arrived
at the ventral apex of this nucleus or near to it, some dege-
nerate fibres leave the dorsal systema and enter the formatio
reticularis.

The most lateral of them following the edge between the V^**
spinalroot and the nucleus of the VIP** nerve , reach there the field
situated dorsally from the antero-lateral (Gowers) tract, bend distally
into the longitudinal axis of the medulla and give collaterals in
the direction of the VIP** nucleus, (see fig. \a on Plate I and fig.
15 N°. 11 on plate VIII). They reach a field, known as the „aber-
rirendes Seitenstrangbiindel, or as Monakow's bundle, or as fasciculus
rubrospinalis, or even as the dorsal descending spino-cerebellar (?) tract,
that soon will claim a discussion. As soon as distal ward the facial
nucleus has disappeared, there may be found in frontal sections some
black granules, more than usually (Plate VIII fig. 15 N°. 4) and
in horizontal sections very few degenerate fibres medially from the
spinal V^^ root between it and the facial nucleus. But here Marchi-
method reaches its limits. It only is interesting because afterwards
we will have to discuss the question to what extent secundary
fibres pass along this way towards the spinal cord.

More interesting are the fibres entering more medially into the
formatio reticularis, and seeking dorsally from the facial nucleus
the region, where the descending tract of Deiters or the fasciculus

OF THE NERVUS OCTAVUS. 103

vestibulo-spinalis is found. They also bend distally in longitudinal
direction and are represented by only a few fibres. In frontal
sections distally from this nucleus, a few black granules are scattered
here and there, within the area of this tract (Plate VIII fig. 15.
N°. 5 — N°. 1) and in horizontal sections (Plate X fig. 16 F) there
are found a few longitudinal fibres degenerated. These fibres
may become important, because they are found in the same area,
where a considerable secundary system (already myelinisated in the
elder foetus) will soon be demonstrated. Indeed I believe that a
small number. of rootfibres bends down, without interruption in
the . tract us Deiters descendens and may be traced towards the
beginning of the spinal cord.

But the few fibres, that in ventral direction deviate in the for-
matio reticularis, do not much enfeeble the transversal dorsal fibres.
Moreover these fibres have got a considerable increase in proximal
regions from the straight entering ventral fibres and from the
ascending root. They pursue their way, through the ventral apex
of the dorsal nucleus, along the ventral border of the nucleus of
the Vr*' nerve, giving collaterals to the principal and ventral cells
of the dorsal nucleus and to the sixth nucleus. They still form a
rather important bundle, as they reach the fasciculus longitudinalis
posterior, and pass the raphe to send fibres into the opposite sixth
nucleus, which is found blackened with globules, as well as that
of the same side.

But at their passing the raphe a sufficient quantity of degenerated
fibres, are bending in longitudinal direction to become ascending
as well as descending fibres in the fasciculus longitudinalis posterior
on both sides.

At first, more degenerate fibres are found in the opposite than
in the homolateral fasc. longit. post, they go distally and proxi-
mally, providing the nucleus of the sixth nerve on both sides.

In this way the two nuclei of the sixth nerve, receive fibres of
the dorsal systema. That of the same side recives them, 1® from
the descendent root (Plate XIV fig. 14 A), 2® from the fasc. long,
post. (Plate VIII tig. 15 N°. 8— N^ 11), that of the oppo-
site side only from the fasc. long, post., but, the number of
degenerate fibres in the opposite f. 1. p. being greater than in
that at the same side, the innervation of the two nuclei may. not
much differ.

Now a certain number of those fibres may be traced far more
distally than the nucleus of the VP^ (fig. 15 N^ 5— N". 1). They
are longitudinal fibres but have at the same time a slight inclination

104 C. WINKLER. THE CENTEAL COURSE

in ventral direction. In this way there may pass a few of them
in the so-called fasciculus praedorsalis.

The intermedial system however, at the moment of crossing the
raphe, also sends a few of its fibres distally in a longitudinal direction.

Therefore in distally situated frontal sections of the oblongata,
some degenerate fibres are found, in the region, that is called the area
or fasciculus praedorsalis. Mostly they appear at the same side but a few
in that of the opposite side of the root-section. In this area they
are found in frontal sections as black globules, dispersed near the
raphe, dorsally from the lemniscus medialis (principalis) and ven-
trally from the fasc. long. post. And in horizontal sections there
are found scarcely longitudinal fibres, degenerated in this region
near the raphe (Plate IX fig. 16 E, Plate X fig. 10 F and G).

Now it must be repeated that Marchi-method here has reached
its limits, that the distal degeneration of longitudinal fibres in the
fasc. long. post, and in the fasc. praedorsalis is not very im-
portant. But soon I will demonstrate, that a very important secun-
dary way may be traced through the fasc. praedorsalis into the
spinal cord.

In this way I believe root-fibres to be found as well in the
distal path of the tractus Deiters descendens, as in that of the
fasciculus longitudinalis posterior, tracts, which are both myelini-
sated in the elder foetus of rabbits.

A sufliciently large number of degenerate fibres however, enters
in proximal direction among the longitudinal fibres of the fasc.
long, posterior. These fibres are nearly all found homolaterally
and may be followed to the same-sided nucleus of the IV^*" and
that of the IIP*^ nerve, which in this way are connected w4th
direct root-fibres of the N. octavus. But not in this way only.

Better than in frontal sections, it is seen in horizontal sections
(Plate XIV fig. 14 B) of the normal, as well as of the young born
animal, that other fibres of the tranversal dorsal layer, are going
proximally towards the fasc. long. post.

In a slight ventrally curved proximal bundle, issued from the
dorsal transverse fibres and meduUated in the elder foetus of rabbit
(which in distal sections reached the fasc. long, posterior in the level
of the genu of the n. VII (Plate XII fig. 17, A, B and C))' somewhat
laterally from the fasc. long. post. (Plate XII fig. 17 A. Plate VI 19 C)
rootfibres reach the Nucleus N. IV and N. Ill, and provide in these
nuclei. In this proximal bundle of the transversal dorsal fibres a
slight but evident degeneration is found after root -section. The dege-
nerate fibres lying there may be traced into the IV^*" and IIP*^

OF THE NERVUS OCTAVUS. 105

nucleus (Plate XIV fig. 14 B, Plate XI fig. 16 K and L),
following the path of the ascending tract of Dkiters. I will soon
describe this bundle in a more minute way.

In this way the dorsal transverse root-fibres have relations with
the nucleus N. VI, the nucleus N, IV and the distal end of the
nucleus N. Ill of the same side and with the nucleus N. VI of
the opposite side.

In this way the dorsal system of transverse rootfibres may be
traced to its endings, towards all motor nuclei of the eye on the
same side, towards the opposite nucleus of the VP** nerve, in the
fasciculi longitudinal es posteriores and in the area of the descendent
tractus of Deiters.

It remains however a remarkable fact, that after rootsection
hardly any degenerated fibres or even none at all are found cros-
sing the raphe, between the layer of dorsal tmnsverse fibres and
the layer of intermedial transverse fibres.

The so called auditory fibres of Monakow appear free from dege-
neration after root-section as likewise they are not all myelinisated
in the elder foetal animal.

3. TUE SECUNDAllY SYSTEMS OP THE NERVUS OCTAVUS.

In using Marchi-method , after experimental lesions upon root-fibres,
it should always be kept in mind, that together with the enormous
advantages peculiar to this method, there also arise dangers, as
soon as single degenerated fibres are to be traced with its aid.

It is possible, even probable, that an experimentally produced
degeneration in a system of rootfibres, is not stopped by the first
nucleus, which is intercalated in its course.

As well as by Gudden's method — experimenting on young born
animals and studying their central system several months after the
lesion — may be demonstrated the loss or the atrophy in the
first nucleus and together with it the atrophy of the following
system, Marchi-method — used a fortnight after the experimental
lesion — may show a slight degeneration in the secundary
system.

As soon as scarcely degenerated fibres are found with Marchi-
method in a presumed secundary system, three possibilities exist to
account for their presence there.

The first is to suppose, that true root-fibres pass without any
interruption through the nucleus in the secundary system. I have
accepted this interpretation when an important number of fibres

106 C. WINKLEE. THE CENTRAL COURSE

were found within a fortnight after the lesion , and if the myelini-
sation-method or Golgi-niethod confirmed its possibility.

The second is to suppose, that rootfibres having been stopped
by a nucleus, where they find a preliminary end, (it may be indif-
ferent whether cells are intercalated between them and the cells
from which the secondary system originates, or not) damage the
cells of that nucleus, after a longer or shorter lapse of time, and
in this way cause a degeneration in the secundary system.

Or if the often controversed hypothesis of neurons coming into
contact with the cells should prove false, if this hypothesis ought
to be rejected and replaced by another , teaching an uninterrupted
continuity of nervous fibrils, — it still may be presumed , that dege-
nerated fibrils, degenemting through the cells of the nucleus reap-
pear in the fibres of the secundary system and cause the degeneration
of the fibre as a whole, made visible by Marchi-method.

In this way may be interpreted the fact, that the longer time
has elapsed after the lesion, the greater is the number of degene-
rated fibres found in secundary systems , according to the theoretical
views of the investigator and his defending the neuron-hypothesis
or the hypothesis of the continuity of the nervous fibrils.

Now this danger of MARcni-mcthod may under circumstances
become an advantage. For if, after a long lapse of time rootsection
can make visible degenerate fibres in secundary tracts, it may be,
that a few degenerate fibres in a defined tract furnish an indication,
a presumption that this tract might prove a secundary one.

Yet, this way may appear dangerous. The longer a degeneration
has existed, the more are the chances that the altered myelin
(the black globules) is spread and dislodged from the original to
other places, and so no longer corresponds to the sought degeneration.

Therefore this use of MARCHi-method was rejected.

I have preferred to study the degeneration or the atrophy, which
occur after lesions in the central organ and to compare them with
the degeneration or the atrophy after root-lesion.

I have destruated the nuclei to which the rootfibres go.

Such lesions however are always complicated, entailing more or
less extensive destruction in other systems. It may occur that diffe-
rent systems degenerate in many directions and that it appears
arbitrary to make a choice among them and to call the one or the
other system the secundary system of the injured nucleus sought
for. Yet if its results are interpreted with circumspection the method
may be useful, for it permits to demonstrate secundary degeneration
into a system, which otherwise can only degenerate indirectly.

OF THE NEKYUS OCTAVUS. 107

a. The secundary si/stem participating in the syatema ventrale nervi
octavi and in the sy sterna intermedium nervi octavi.

In order to study the secundary systems entering in the ventml
and intermedial system, it may be presumed, that they originate
in the nucleus ventralis N. octavi) in the tuberculura acusticum in
the nucleus of DErrERs and in the oliva superior with its adjoining
nuclei.

I therefore have made two operations, described in the former
chapter.

The first is the section of the corpus trapezoides or of the systema
ventrale, laterally from the issue of the facial nerve.

The second is the ablation of the tuberculum acusticum and the
nucleus ventralis.

As I have already described, each localised lesion in the central
system is followed by a surrounding area, where the nervous
elements are lost, not by means of simple degeneration, but (even
with the severest asepsis) by means of irritation. Therefore each
wound is surrounded by a more or less extensive area, not stained
black with Marchi-method , but characterised as a spot of white
colour, wherein here and there black globules are found.

The section of the lateral trunk of the systema ventrale is made
at the entrance of the two roots, with a very thin knife, following
the n. octavus through the meatus acusticus, and after some experience
this may be done without lesion of the facial root, distally from
the entrance of the nervus trigeminus, laterally from its spinal root.

Such a section is drawn in fig. 22 on Plate XVIII. The lesion
itself is represented in w (Plate XVIII fig. 22 A, B, C, D). The
incision enters (fig. 22 C) the medulla ventro-laterally and goes dorso-
medially. After cleaving the trunk of the corpus trapezoides, it
divides the oval area transversally, causing in this way a degene-
ration towards the cerebellum, that needs not be followed here. The
surrounding area extends into the dorso-lateral part of the fibres
(not into the formatio gelatinosa) of the V'** root, and causes a
descending degeneration of the dorso-lateral fibres of this root, the
ventro-medial fibres being normal (Plate XVIII (fig. 22 D — H).
The surrounding area also extends into the latero-distal part of the
portio interna, dividing the intermediary trunk, which is totally
degenerated.

The incision has also divided the two entering roots. And con-
sequently to this rootsection there exists a degeneration in the

108 C. WINKLER. THE CENTRAL COURSE

systema dorsale and in the descending and ascending roots, which
is nearly the same as after every rootsection. The nucleus of Deiters
(Plate XVIII fig. 22 D and E) is not sensibly injured.

A similar lesion was made in the case, from which the fig. 23
was taken.

Now in all cases, in which the lateral trunk of the ventral and
intermedial system is sectioned there is found an intense degene-
ration in these systems. If comi)ared with the degeneration after
rootsection, the difference is marked in scveml respects.

P. The degeneration in the systema ventrale and intermedium
is now found in alle the layers of the transverse ventral fibres.
In the layer of thick fibres (the stratum a) an enormous increase
of degenerated fibres is found as compared with those degenerated
in it after rootsection. (compare Plate XVIII fig. 22 li and Phite XXI
fig. 23 with Plate VJII fig. 15. N^ 11, 12 and 13).

In the layer of small fibres (the stratum b) the same is the case
there exists no longer a layer of normal fibres (the stratum c)
between the ventral and intermedial degenerated systems, but a large
quantity of degenerate fibres is found between the two olivary
bodies. It is evident, that the at contra-lateral side to the operation
this layer shows a more important degeneration than at the same
side. (Plate XVUI fig. 22 B and Plate XXI fig. 23). And it is
also evident, that the dorso-latero-ventral medullary surroundings of
the olivary body present a very intensive degeneration at the operated
side, where as on the contmry in the medial hilus of the nucleus
olivaris of the opposite side it is more important than in the
homo-lateral.

And the interpretation of these two facts is (a retrograde dege-
neration being excluded, because these degenerations are present
within a week) that in the olivary body originates a new system,
that leaves the nucleus at its medial hilus through the stratum c,
to seek the opposite side, whereas the degenerated ventral and
intermedial systems provide with fibres the homo-lateral oliva in its
dorso-latero-medial surroundings, and crossing the raphe provide
through the medial hilus the opposite one. The latter degenerated
part of the system covers the non degenerated one. Therefore it
has the appearance as if the medial hilus of the oi)posite oliva con-
tains nearly all degenerate transverse fibres and the homolateral nearly
all normal ones. Consequently there remains a layer of fibres in the
systema ventndis not degenerating if the ventral nucleus and the
systema intermedium be separated from the medulla.

The intermedial system (the stratum d) also presents a degene-

OF THE NERVUS OCTAVUS. 109

ration much more intensive than after root-section and therefore
contains a secundary system, as well as all the other layers. It is
however no longer differentiated from the ventral secnndary system.
The transverse fibres are so intermingled that it exists no longer as
a system separated from the systema ventrale.

In this way it may be demonstrated, that a very important number
of secundary fibres enters in the systema ventrale, from the ventral
nucleus, and along the intermedial system, and that there still are
found non-degenerate fibres originating in the oliva, leaving it through
the medial hilus and going to the opposite side (the lateral fillet).

2. There is also found now a degeneration more intensive than
after root-section in the region between the spinal root of the V**^
nerve and the oliva superior. Not only at the operated side but
also on the opposite side, and like the root-fibres (there are root-
fibres among them), the now degenerated fibres may be traced into
the two formerly described ascending tracts;

a, as to the ventral ascending spino-cerebellar tract, now also
the homolateral degeneration is more intensive (Plate XVIII fig.
22 B) than that in the opposite bundle;

b. as to the degenerated fibres to the corp. quadrigeminum posti-
cum through the lateral fillet, now again, like after root-section,
the degeneration in the opposite tract is more important than that
in the homolateral.

Though the number of degenerate fibres is now very (Plate
XVIII fig. 22 A) much increased I was not able to trace them
beyond the corp. quadr. posticum into its bracchium to the nucleus
geniculatus medialis.

But in the here described case, there was found a thin bundle
of degenerate fibres, forming a specimen of a commissural bundle
between the two degenerated lemnisci, passing ventrally from the
nucleus of the IV^** nerve.

These fibres are probably the same commissural fibres seen also
by Probst in fillet-degeneration and that have been described as
the bundle of Probst (Plate XVIII fig. 22 A).

3. In the dorsal systema there also is found a degeneration, which
as I have remarked, does not exceed very much that, found after
rootsection. Yet, the two roots and the ventral end of the stratum
latero-dorsale being sectioned, it may to a slight degree be increased.

In the fasciculus longitudinalis posterior therefore are found,
rootfibres from the degenerated transverse dorsal fibres, going 1®
to the motor nuclei of the eye 2® going distally.

These latter fibres do not remain there, but slightly deviating

110 C. WINKLER. THE CENTRAL COURSE

in ventral direction they reach the fasc. praedorsalis in their distal
course. They are found at both sides of the raphe.

At the same time, the intermedial transverse fibres, now inten-
sively degenerated, send, near their passage through the raphe, a
not unimportant number of fibres distally in the praedorsal tracts
on both sides, but more in the homolateral than in the opposite side.

At the level of the facial nucleus (Plate XVIII fig. 22 C and
I)) the degenerated fibres (root-fibres) in the fasc. long. post, are
separated from those (secundary fibres) in the fasc. praedorsalis.
The two separated tracts unite more distally and at the level of
the inferior olivary body, they have become one, along the raphe,
dorsally from the stratum intra-olivare (medial fillet). The tracts
may be traced dorso-laterally from the decussatio pyramidum, into
the anterior columns of the spinal cord, where we afterwards will
meet them again. But distal wards the degeneration in the opposite
tract is found gradually diminishing and in the most distal sections
(Plate XVIII fig. 22 F and H.) the homo-lateral tract is by far
the most degenerate one.

Here for the first time a degenerated tract descending to the
spinal cord is stated beyond doubt. It is composed , for the greater
part, of secundary fibres — from the transverse fibres of the
intermedio-ventral system — for the lesser part of rootfibres — from
the dorsal transverse fibres.

It is a medial or anterior descending spinal tract from the
octavus-system.

But it is also remarkable, that there now are found degenerate
fibres dorsally from the nucleus N. VII in the field, where the
tractus Deiters descendens is localised. As the degeneration in the
transverse dorsal fibres does not much exceed that after rootsection,
it is not very probable, that the degenerated fibres now found there
in a number, sufficient to exclude every doubt as to their forming
a slight tract, are all rootfibres. For, as is clearly shown by com-
parison with frontal sections after rootsection, the degenerate fibres
in the region of the so-called fasc. Deiters descendens (fasc. ves-
tibulo-spinalis) are now increased in an abundant manner.

The first presumption presenting itself, when we try to explain
this fact, may be: the nucleus of Deiters, lying close to the sur-
roundings of the incision, and being perhaps accidently injured,
is sending degenerated fibres to this region.

But this presumption seems to be erronous. Firstly there is seen
no lesion of the nucleus, and there are found no degenerated
fibres issuing from it in the direction of the degenerated field —

OP THE NERVUS OCTAVUS. Ill

yet it is very easy to trace these fibres to the nucleus of Deiters
when this nucleus is lesioned on purpose. Secondly the now dege-
nerated fibres are not the large ones with voluminous black glo-
bules, which are chamcterising the degenerated thick fibres from
the large cells of Deitkrs.

Thirdly, they appear abruptly distally from the degenerated corpus
trapezoides in the level of the nucleus of the VIP*' nerve dorsally
from it and fourthly they are found on both sides in the symme-
trical field, though in lesser quantity on the opposite side.

More-over the degeneration in the fasc. Deiters descendens being
moHB intensive, than after rootsection, I therefore believe that from
the intermedial and ventral systema a few degenerate fibres enter
in the region dorsally from the facial nucleus, and bend distally
in the formatio reticularis, to form a slight degeneration in a
descending fasciculus, taking its way in the descendent tract of
Deiters.

This tract, the existence of which, after rootsection alone, may
be doubtful, now appears clearly after section of th^ ventral -|- the
intermedial systema, (though far less extensive as I soon will
demonstrate it after section of the doreal system with injury of
Deitjirs nucleus).

And in this way a medial descending spinal tract composed of
a few rootfibres and a little more intermediary and ventral secun-
dary fibres, may be observed. It exists on both sides, but is
much more important at the side of the operation.

4 The most important descending degeneration however found
in this case , is a very marked degenerated area suddenly appearing
distally from the corpus trapezoides in the field between the spinal
V^** root and the facial nucleus. (Monakow's aberrirendes Seiten-
strangbundel).

A retrograde degeneration this cannot be, as it is found a
fortnight after the operation.

In frontal sections it is first seen laterally and ventrally from
the facial nucleus (see fig. 22 D and E). More distally it is retiring
in a dorsal direction (see fig, 22 F) having now the shape of an
equicrural triangle, one of its erect sides along the formatio gelati-
nosa , the other touching the lateral side of the nucleus of the
lateral column , and its base resting on the periphery of the medulla.
It leaves degenerate fibres into the nucleus funiculi lateralis.

During its further course, this tract maintains its situation
medially and ventrally from the formatio gelatinosa of the V^** root,
but the basis of the tract leaves the perifery as the ventral ascen-

112 C. WINKLEE. THE CENTRAL COURSE

ding spino-cerebellar tract (Gower's tract) covers it. Besides the
fibres of these two tracts intermingle. Arrived at the spinal cord
(Plate XVIII fig. 22 H) it has found its place, ventro-laterally
from the formatio gelatinosa of the cornu posterior, its top is found
in the formatio reticularis of the cornu lateralis , and it leaves fibres
in the lateral horn of the grey spinal substance.

Its degeneration is moderate , much more so than at the contra-
lateral side. There also however, this descendent tract is clearly
demonstrated by the black globules.

Now there is not the least doubt that this tract is the same,
that has been described under many names, as rubro-spinal tract
(Pawi.ow, van Grulchten), as aberrirendes Seitenstrangbundel (Mo-
NAKow) and others. As to its interpretation , it is allowed to presume
that the lesion made in a more proximal level , may have damaged,
the rubro-spinal tract in its course. But the most proximal end of
the lesion does not extend far enough to damage the issuing root
of the nervus trigeminus (Plate XVIII fig. 22 B) and neither the
incision, nor its w^hite surroundings (Plate XVIII fig. 22 C, D
and F) transgress the fibres of the V^** root. The non injured for-
matio gelatinosa and the nou injured ventro-medial fibres of the
Y^^ root are separating in all levels the lesion frgm the presumed
situation of the rubro-spinal tract. Therefore there is no reason to
suppose an accidental lesion of this tract in its more proximal
course. Moreover it is degenerated likewise, through in a less
intensive degree, at the contro-lateral side.

I therefore believe , we encounter here a third descendent tract,
that may be parallelised with the descendent tract of Deiters and
the descending praedorsal tract. Only this tract is more clearly
degenerated after the section of the lateral trunk of the ventral
system than after the dorsal section.

Besides I soon will have to discuss the further spinal course of
these three descending tracts, but before doing so there still remains to
be described another intermediary system that joins the ascendant
tract of the ventral system towards the corpus quadrigeminum pos-
terior after sectioning the dorsal system.

The section of the dorsal system is not so difficult as that of
the ventral system. I have made it some twenty times, at one side
and on both sides. If made aseptic, it is without danger for the
animal.

The incision made , after opening the membrana atlantico-occipitale,
has nearly always the same result. The tuberculum acusticum is
ablated, the radiation dorsally from the area ovalis is devided. The

OF THE NERVUS OCTAYUS. 113

incision goes through the portio interna, damages partially or
totally the nucleus of Deiters , divides the area ovalis , consequently
separates the intermediary bundle from its origin , cleaves often the
stratum latero-dorsale and may damage the ventral auditory nucleus ,
•running between its ventro-distal part and its latero-dorsal part. It
may* damage both roots , or one , or even none at all , this' depends
on its being made more or less deep. Only the beginner must take
care, not to incide too far proximally, otherwise the pedunculus
cerebelli superior may be lesioned, (which is not a great danger
and may be done on purpose) and the end of the incision may be
found in the lateral fillet.

Now in Plate XIX, XX, XXI fig. 25, Plate XVI and XVII
fig. 20 and Plate XXI, XXII fig. 28 such dorsal sections are
drawn. Plate XIX, XX, XXI fig. 25 represent the di-a wings of
an oblongata wherein this section was made on the two sides.

In cases that the nucleus ventralis is touched — even if its
ventro-distal end is not at all degenerated — the ventral system
degenerates nearly as intensely as after section of its lateral trunk.

In that case , the degeneration is less intensive in its distal part.
Even if the dorsal section be made on both sides a large number of
intact fibres is found between the two olivary bodies (Plate XIX
fig. 25 E, Plate XX fig. 25 E and G), probably those, which
are not yet medullated at the animal's birth and do not degenerate
or atrophy, unless the nucleus olivaris superior be lesioned.

Subsequent to this section, we meet for the first time with the
degeneration a system of transverse fibres , originating in the dorsal
system and joining the ventral system at its most proximal end.

They are the transverse fibres of Monakow, which leaving the
dorsal system at the level of the nucleus of the VP^ nerve, cross
the raphe, ventrally from the fasciculus longitudinalis posterior in a
dorso-venteil oblique direction in order to reach the dorsal top of
the cofttra-lateral oliva. In the medullary surroundings of this
nucleus they may leave a part of them.

But the greater part of those fibres continues in the lateral
layer of the olivary body and united with a part of the small transverse
fibres from the ventral and intermedial system, they reach the medul-
lary surroundings of the ventral nucleus lemnisci and bend upward.

In frontal sections this nucleus is seen as an acorn in a shell of
degenerate queer-sectioned fibres, surrounding it from three sides,
at the dorsal, ventral and lateral side (Plate XIX fig. 25 C, D, E).

The nucleus itself is filled up with degenerate fibres and dis-
persed black globules.

Verhand. Kon. Akad. v. Wetensch. (Tweede Sectie Dl. XFV). 8

114 C. WINKLER. THE CENTRAX COURSE

After a short longitudinal and proximal coiii'se those fibres bend
dorsally into the lateral fillet (Plate XIX fig. 25 A, B).

In frontal sections through this part of the pons, where the
pedunculus cerebelli superior begins leaving the cerebellum, the
situation is now characteristic enough.

Dorsally and laterally of this peduncle the lateral fillet lays free
at the surface (fig. 25, C) and its most superfcial layer is totally
degenerated. It here contains the ventral ascending spino-cerebellar
tract (GowRRS tract) , which has just entered in this place after its
ventro- loi-sal path through the lateral lemniscus, and leayes it soon
again to seek the nuclei tecti.

But in these levels the degenerate layer round the ventral nucleus
lemnisci begins to change its longitudinal into a dorsal direction.
Embracing the nucleus ventralis lemnisci, its fibres never form the
most lateral layer of the lateral fillet , even not after the disappearance
of the antero-lateral spinal tract, but coursing towards the ventral
pole of the nucleus of the corp. quad, postic, they end in this
nucleus and I cannot trace them with certainty into the corpus
geniculatuni mediale.

These Monakow fibres, do not form a so sharply defined bundle
crossing they raphe, as they seem to do in the dog. Between the
fasc. long. post, and the place where the intermedial^ system passes,
there are found many crossing degenerate fibres, uniting themselves
in the degenerated area dorsally from the nucleus olivaris superior ,
and in the surroundings of the nucleus ventralis lemnisci.

In this manner there may now be distinguished, besides Gowers'
tract, at least four different kinds of fibres in the contm-lateral fillet.

1*^ rootfibres — because some of them are degenerated after root-
section. They reach the fillet through the ventral and intermediary
system.

2"^ secundary fibres issued from the ventral nucleus — because
a greater number of fibres degenerate if rootsection is combined
with section of they lateral ventral trunk. Those fibres , of course ,
also pass through the ventral and intermediary system.

3® secundary fibres issued from the tuberculum acusticum —
because a still greater number of degenerate fibres is found there
if degeneration in Monakow's fibres occurs.

They pass through the stria medullaris as Monakow's bundle
and enter in the dorsal layer of the oliva superior and in the sur-
roundings of the ventral nucleus lemnisci.

V' secundary fibres non degenerating after these operations and
probably issued for the greater part from the contra-lateral oliva

OP THE NERVUS OCTAVUS. 1 1 5

from the same-sided nucleus trapezoides (?) and from the same-sided
nucleus lateralis lemnisci.

Now from the degenerated fibres composing here the fillet, by
far the larger portion is due to Monakow's fibres.

MoNAKow has proved evidently with Gudden's method, that, in
the dog, after a section of the lateral fillet at one side, fibres are
lost in the opposite stria acustica medullaris, together with a loss
of nearly all the large pyramidal cells in the tuberculum acusticum.

He also distinguishes several layers in the lateral fillet, according
to their origin from the opposite tuberc. acusticum, the dorsal
border of the same-sided oliva, the nucleus ventralis lemnisci and
the „aberrirendes Seitenstrangbundel."

Now it cannot be doubted that after a section through the
dorsal system — including the stria medullaris — in the neigh-
bourhood of the tuberculum acusticum, all the large cells in this
nucleus are found in chromatolysis 5 days afterwards, whereas in
the cells of the nucleus ventralis N. octavi (if it be spared) the
chromatolysis is not so intensive. Three months after ablation of the
tuberc. acusticum, there has remained nothing of it.

But it is very interesting to verify, to what extent Gudden's
atrophy six months after the ablation of this nucleus, confirms
the results of MARCHi-method. In the case here mentioned (Plate
XXI and Plate XXII fig. 28 A— F) the ablation of the tuber-
culum was nearly a total one (fig. 28 A, B, C, D) from the
ventral nucleus a ventro-distal end has been left (see fig. 28 B).

Consequently the same-sided corpus trapezoides has lost the
greater part of its fibres (see fig. 28 D) at the operated side,
only in the distal part fibres have remained.

The same-sided oliva has lost a large numbre of fibres in its
dorsal and ventral layer. At the contra-lateral side the dorsal layer
of the oliva superior has lost many fibres and on both sides the so
called trunk of the olivary bodies is very clearly to be seen, (see
Plate XXIT fig. 28 G). As it has already been memorated the
crossing fibres through the raphe do not form a very sharply
defined bundle. Nevertheless from the stria medullaris originates
(Plate XXII fig. 28 E) a large bundle and passes through the
issuing facial root, which does not exist on the operated side. It
enters into the formatio reticularis, where more transverse fibres
are found than on the operated side.

Now on the contra-lateral side, the dorsal surroundings of the
oliva superior are joined to the surroundings of the nucleus
ventralis lemnisci. These surroundings have lost a great many fibres

116 C. WINKLER. THE CENTRAL COURSE

and the „aberrirendes Seitenstmngbunder' (Plate XXII fig. 28 C)
also has. Those different layers are forming the lateral fillet.

As soon as the contact with the cerebellum is lost, and the
bracchia pontis surround the basis mesencephali (Plate XXII
fig. 28 F) a very interesting aspect is fonnd.

At the side of the operation, most superficially, laterally from
the pedunculus cerebelli superior, separated from it by the dorsal
nucleus lemnisci, the ventral ascending spino-cerebellar tract lays.
Only for a moment, for it distally retires to the cerebellum in the
nuclei tecti, and proximally (Plate XXII fig. 28 F) it gives its
fibres to the ventral part of the tegmentum. This tract has lost
here many fibres on the operated side, and is much smaller than
that on the contra-lateral side.

But more interesting is the loss of fibres found now in the ventral
parts of the lemniscus at the contra-lateral side (Plate XXII fig, 28 F).
The nucleus ventralis lemnisci is atrophied. It has not only lost many
fibres, but also a great many cells and they are much smaller than
at the operated side. Its surroundings, still adjacent to its lateral, dorsal
and ventral bordei-s have lost fibres and are intensely atrophied.

There is an absolute ressemblance with the drawings of the
MARCHi-degeneration, where these surroundings (the shell of the
acorn) are degenerated (fig. XIX, XX fig. 25 A — G fasc. later. 1. 1.)

But medially from the nucleus ventralis lemnisci there appears
another layer of fibres, on which the ventral end of the biucchium
conjunctivum cerebelli reposes. This layer a continuation of the
dorsal olivary surroundings has lost a great many fibres. If com-
pared with the MAKCHi-degeneration , the degenerate fibres found
medio-dorsally and dorsally from the contra-lateral nucleus ventralis
lemnisci are now intensely atrophied (on both sides in Plate XIX,
XX fig. 25 A— F fasc. med. 1. 1. y and Plate XXII fig. 28 F).

These two layers — the fasciculus medialis lemnisci and the fasci-
culus latemlis lemnisci — embrace the nucleus ventralis lemnisci,
They pass into the more internal layers of the lateral fillet, whose
lateral surface remains free from degeneration or atrophy. They
surround the distal pole of the corp. quadrigerainum. This part of
the ganglion is atrophied — with Gudden's method — to a consi-
derable degree. With MARCHi-method there also intense degene-
ration is found. A great many of the degenerate fibres however
remain in the nucleus ventralis lemnisci and (Plate XIX fig. 25
B — G) the lateral layers round this nucleus, entering in internal
layers of the fillet, are less intensely degenerated than those situated
medially from it.

OF THE NERVUS OCTAVUS. 1 1 7

Thus far the results of atrophy and degeneration are wholly
concordant as may be seen by comparing the figures given in fig. 28
and in fig. 25.

I believe with Monakow and contrary to the opinion of Bechterew,
Fi.ECHSiG and most modern authoi-s, that the stria meduUaris and
MoNAKOW*s transvei'se fibres, have more to do with the auditory
function, than the larger part of the ventral systema has, and that
Lewandowski has not set value enough on Monakow's system here
treated; There are reasons to think so.

For it seems probable to me, that the elder foetus or the new
born rabbit, may posess medullated fibres in the roots and in the
lower secundary reflex or automatic systems, but that medullated
fibres are still wanting in the higher secundary systems, which have
not yet functioned. Therefore I think we ought rather to seek the
true auditory systems among those of the secundary octavus-systems
which are not yet medullated at birth.

They are in the first place, a large part of the fibres in Monakows'
decussation corresponding to the nonmedullated central layer /3 in
the stria medullaris, those at the dorsal proximal end of the oliva
superior (fig. 17 and fig. 18 E.), the fibres in the stratum c of the
ventral system and many fibres in the lateral fillet.

The ventral nucleus lemnisci is covered with medullated fibres
at its disto-ventral pole, but sends only non medullated ones in
the lateral fillet.

I do not reckon the ventral system of no importance for hearing.
On the contrary I believe, that there are non medullated fibres
enough in that system issued from the olivae. The stratum c may
never be brought to total degeneration, even after sectioning the
dorsal system with the greater part of the nucleus ventralis, as long
as the olivary bodies remain intact.

MoNAKOw's fibres, the non degenerate fibres between the olivae
superiores in the stratum c and the non medullated fibres in the
lateral fillet, though their relations to this fillet are very difficult
to elucidate, probably form one system. Probably both nuclei olivares
send fibres into it. Monakow in sectioning the fillet states a loss
of cells in the medial leaf of the same-sided oliva. I, after sectioning
the stria, found a like result in the same-sided oliva but in its
lateral leaves. This part of the lateral lemniscus therefore seems a
very complicated mixtum of fibres.

A few words still on this „aberrirendesSeitenstrangbunder' which
here appears as a part of the fillet.

It hast lost a gi-eat many fibres as it enters into the opposite

118 C. WINKLER. THE CENTRAL COURSE

lateral fillet (Plate XXII fig. 28 F) of which it forms the greatly
atrophied most medial part.

More distally, where the V*^ spinal root leaves the cord, its
atrophy at the contra- lateral side also seems evident (fig. 28 E).
In still more distal sections this is no longer the case and the region
between the oliva superior and the fifth spinal root it even is smaller
at the operated side (fig. 28 C).

To interpfete the fact I remember that the ascending spino-
cerebellar tract has lost fibres. I have shown its atrophy at the mine
side of the operation , there where it is lying free at the surface of
the superior pedunculus cerebelli (fig. 28 F).

At the opposite side, there is again found atrophy of another
part of the lateral fillet and of the „aberrirendes Seitenstraugbundel.
This contra-lateral atrophy is found combined with an atrophy of
transverse ventral fibres crossing the raphe at the operated side.
(Plate XXIII fig. 28 F.) In this distal part of the decussatio ventralis
tegmenti (Forel) there is also found degeneration in transverse
fibres with Marchi. (Plate XIX fig. 25 A— D).

It is therefore doubtful whether this „aberrirendes Seitenstraug-
bundel" that MoNAKOW has isolated after transverse section of the
oblongata (the ventral ascending spino-cerebellar tract having totally
disappeared in such cases) contains only a rubro-spinal descending
tract. Tliere must still be found fibres of another origin.

The current view is that the rubro-spinal tract issued from the
nucleus ruber after crossing in the ventral decussatio ~ tegmenti
(Forel) runs downward. Without , contact . with the red nucleus,
there must still exist a crossed portion of thatj„aberrirendes Seiten-
strangbundel" ascending to the medial part of the lateral fillet, and
thence in the ventral fibres under the nucleus quadrigeminum
posticum passing upward.

After all, there are entering two important systems into the lateral
fillet — without reckoning the root-fibres — that accompany them.

The one, originating in the contra-lateral tuberculum acusticum,
both olivary nuclei, and the same sided nucleus ventralis Icmnisci
lateralis, are not yet all medullated in the elder foetus or at birth.
They go through the fibres of Monakow, the stratum c of the
systema ventrale et intermedium into the lateral fillet.

The other originates in the contralateral nucleus of Deiters, the
contralateral nucleus ventralis N. octavi, the contralateral nucleus
griseus nervi descendentis, perhaps in the same-sided nucleus trape-
zoides. It passes through the ventral, intermedial and dorsal system
of the nervus octavus and is medullated at birth.

OF THE NERVUS OCTAVUS. 1 19

In this way there may exist two systems, differentiated in the
centi'al secundary octavus-systems, the one to be used for the
higher psychical function of hearing, the other for the automatic
and reflex-functions, defining the influence upon movements, which
the N. octavus has.

b. The longitudinal secundary systems participatiny in the
systetna dorsale nervi octavi.

As may be seen best in an horizontal section of an elder foetus
of a rabbit (Plate VI fig. 19 C) the dorsal systema is forming
a powerful mass of meduUated fibres , spread over an extensive area.

A medullated bundle runs from it proximally (Plate VI fig. 19 C.
syst. dors. N. VIII).

After rootsection (Plate XIV fig. 14 B, Plate XI fig. 16 K) in
this tract, some degenerate rootfibres are found, which could be
traced towards the nucleus of the IV'^ nerve.

After section of the dorsal system, this tract degenerates nearly
totally.

Very instructive in this respect are here the results of the double-
sided ablation of the tub. acusticum (Plate XIX, XX fig. 25 X— A).

There on the right side, the incision falls not so far proximal-
ward as on the left side. The nucleus of Deiters, on the left, has
been totally destroyed. On the right its destruction is only complete
at its distal end and at its proximal end some very well developed,
normal cells are seen in it (Plate XIX, XX fig. 25 E, F at the
right side);

Now from the proximal end of the damaged nucleus Deitehs
on the left, there appears a large radiation of degenerated fibres
(Plate XIX fig. 25 E). They radiate in medial direction, at fii^st
doi^sally from the spinal fibres of the V^*'® root, which is just
preparing its issue from the central system. At its issue they pursue
their medial course, now situated dorsally from the sensible and
motor V^^ nucleus. (Plate XIX fig. 25 D). They now bend in
longitudinal direction, lying among the longitudinal fibres in the
dorsal part of the formatio reticularis half way between the fasc.
long. post, and the bracchium conjunctivum cerebelli (Plate XIX
fig. 25 G). Slightly approaching the fasc. long. post. , they touch
its lateral border, and as ari united bundle the (degenerated) fasc.
long. post, and that here described (Plate XIX fig. 25 B) pursue
their common proximal course. Those degenerated fibres at first
remain lateral from the fascic. long. post. , but as the nucleus of

120 C. WIJSKLEE. THE CENTKAL CX)UBSE

the IV^^ nerve appears, they surround this nucleus from its lateral
side, lying now nearly dorsal from this fasc. long. post. (Plate XIX
fig. 25 A).

Now on the right side, degenerate fibres taking the same way
are also found, though in a smaller quantity, and they also may
be followed through the proximal part of the stria medullaiis,
between the normal cells, which are left by the partial destruction
of the right Deiters nucleus.

This ascending tract in the dorsal system degenerating here on
both sides, may be called the tractus Deiters ascendens. Degene-
rating partially after rootsection , it does so totally within six days
after the section of the dorsal systema, as Deiters nucleus is
incised. The tract gives an important number of fibres between
the cells of the IV^** nucleus, also to the distal end of the third
nucleus and not only this, but within six days I found a very
intense degeneration of the roots of the N. trochlearis.

On horizontal sections (Plate XVI fig. 20 D) the degenerated
tract is also found after the division of the dorsal system. It is
found degeiiei-ated on the operated side and forms a powerful
bundle of fibres from the nucleus of Deiters towards the same-
sided motor nuclei of the eye.

However the tractus ascendens of Deiters is only one of the many
systems of fibres degenerating after the destruction of that nucleus.

In following (Plate XX fig. 25 P — L) the damaged nuclei
Deiters to their distal ends, there appears a new bundle of dege-
nerate fibres. Apparently it accompanies for a short moment the
descending root of the N. octavus, lying at its medial side (Plate XX
fig. 25 V tr. Deit. asc. -f- r. desc. N. VIII) but soon it leaves
the root and radiates in a medio-ventral direction crossing the facial
issuing root (fig. 25 F and G).

In horizontal sections this radiation is found as a field of dege-
nerated queer-sectioned fibres medially from the facial root and
surrounding it (fig. 20 E fasc. Deit. desc).

As the root is crossed it slightly bends distally until the root-
fibres leaving the VIP^ nucleus are reached (fig. 25 H). There
the bundle forming an angle of nearly 90°, abruptly takes a lon-
gitudinal and distal course (Plate XX fig. 25 I L).

It is the tractus Deiters descendens. Horizontal sections (Plate
XVII fig. 20 E and F. tr. Deit. desc.) are very useful to demon-
strate this part of this tract and it may likewise be plainly demon-
strated in the double-sided section of the dorsal svstema, even
better on the right, because the incision falling not very proxi-

OF THE NEKVUS OCTAVUS. 121

mally, has not lesioned there completely the ventral root at its
entrance and is consequently more or less isolating the tractus
Deiters descendens from the descending root (Plate XX fig. 25 G)
at the beginning of its course.

The degenerated fibres of this tract are very thick fibres and
may easily be followed towards the nucleus of Deiters in case of
partial destruction (in fig. 25 at the right side).

During its distal course this field of degenerate fibres is lying
in the middle of the formatio reticularis. In frontal sections it has
the form of a triangle, its top is directed dorsally and its base
resting upon the facial nucleus.

More distally, the facial nucleus having disappeared it tends to
take a more ventral position. In the level of the oliva inferior,
it reaches the nucleus para-olivaris resting upon its lateral border.
Medially the area is bordered by the issuing rootfibres of the
Xir** nerve. There it reaches nearly the peripherical margin of
medulla oblongata (Plate XX fig. 25 I and K).

At the distal end of the medulla oblongata it is found at the peri-
pherical margin, bordered medially by the roots of the V^ spinal
ventral root. Its form (Plate XX fig. 25 L) is still that ot a
triangle , with its basis at the ventral margin of the lateral column ,
its short side towards the formatio reticularis of the cornu lateralis,
to which it leaves collaterals.

At the entrance of the second spinal ventral root it has a posi-
tion still more at the peripherical antero-lateral margo of the cord
(Plate XXI fig. 25 M).

The diagram of the degenerated tract now has the form of a
spherical obtuse-angled triangle, the basis of which lays at the
antero-lateral margin of the cord, for its ventral edge now is no
longer bordered medially by the entering roots and reaches into
the columna anterior.

In this way the basis extends along the ventral third part of the
lateral margin. There the short side of the triangle leaves the mar-
gin under an obtuse angle, curving towards the lateral cornu in
a ventrally concave curvation. Its top now nearly reaches the
ventral portion of the formatio reticularis of the lateral horn, and
from there parts the long side of the triangle, sligtly arched and
concentric to the border of the cornu antero-lateralis and concave
towards the median line, it returns under a sharp angle, towards
the ventral end of the basis.

During its distal course through the cord, the diameter of this
degenerated area changes. In its way through the intunnjscentia

122 C. WINKLER. THE CENTRA.L COUK^SE

cervicalis it does suffer great alterations. (Plate XXI fig. 25 M — O).
The dorsal obtuse edge, tending towards the lateral horn disappears
and when the tract has reached the thoracie cord its much reduced
diagram (Plate XVII fig. 21 D^ Dg Djg) has the form of a seg-
ment, lying at the peripherical antero-lateral margin and the issuing
anterior roots pass between its degenerate fibres. In the lumbo-
sacral intumescentia the edge towards the lateral horn reappears,
now situated more medially and going along the roots. (Plate XVII
fig. 21L4,S2).

In this way the tract of Deiters may be traced (Plate XVII fig. 21,
Plate XVIII fig. 22 F. G. Plate XXI fig. 25 M— O) into the
sacral cord, providing the antero-lateral horn with degenerate col-
laterals, but leaving the greater part of its fibres in the cervical
cord, and giving more fibres to the intumescentiae than in the
thoracic part of the cord.

For tracing the two tracts of Deiters, MARCHi-method excels
above all other methods, but it remains in perfect accordance
with them.

The myelinisation-method in the new-born or elder foetus of
rabbit is very appropriate to demonstrate the beginning of the
descending tract, its relation to the facial root and the facial nucleus
and rootfibres, and its curvation into the longitudinal axis (Plate
I fig. 5. Plate XIII fig. 18 E and F).

In that stage it is meduUated there among other non medul-
lated fibres. But in the medulla it becomes more difficult to trace.

Gudden's method, as employed by von Moi«jakow, has demonstrated,
that after hemisection of the lower oblongata or in the cervical
part of the cord, all the large cells in the nucleus of Deiters
disappear. In this case , like in that of the fillet-section with loss of
the large cells in the tuberculum acusticum , there is demonstrated
a total retrograde atrophy from a system lesioned not too far from
its origin.

But by MARCHi-degeneration after the section of the dorsal
systema more is shown.

In the beginning of their course , the fibres of the ascending
and descending roots of the N. VllI are intermingled with those of
the tracts of Deiters in such a manner, that it is impossible to
judge, whether the transverse dorsal fibres, now degenerated in a
most intense degree take their origin in the nucleus of Deiters
or in other nuclei from the dorsal systema.

Some of those degenerate transverse dorsal fibres may be
traced through the raphe, through the fasc. longitud. posterior.

OF THE NEKVUS OOTAYUS. . 123

among the transverse dorsal fibres on the other side. There they
pass ventrally from the dorsal nucleus of the VIII^^ nerve towards
the opposite nucleus of Deiters and bending distally, they follow
in the contra-lateral half of the oblongata, a perfectly symmetrical
course, forming a contra-lateral descending Deiters tract, slightly
yet evidently degenerated, though not in such intensity as the same-
sided tract. (Plate XVII fig. 20 E and F). These transverse dorsal
fibres I believe to originate in the destroyed nucleus of Deiters
at the opposite side.

However from the two tracts of Deiters, as well from the
ascending, as from the descending, many other transverse fibres
originate. As is seen both in horizontal (Plate XVI fig. 20 D in
tr. Deit. asc.) and in frontal sections (Plate XIX fig. 25 A — E in
tr. Deit. asc.) the ascending tracts send transverse fibres crossing
the raphe just ventrally from the fasc. long, posterior. As soon as,
in frontal sections, this tract approaching the fasciculus longitudinalis
posterior at its lateral side, has touched the grey matter round
the aquaeductus Sylvii, there, are seen always fibres leaving it, pas-
sing the raphe. These fibres find their way to the lateral fillet.

It has already beeu described that the lateral fillet here is com-
posed of several layers, from which two were degenerated. The
one, lateral from the nucleus veutralis lemnisci was formed by the
decussatio of Monakow fibres in more distal regions, the other,
also originated by these fibres did reach the doi-sal layer of the
oliva superioi and increased with fibres arrived there from the
ventral and intermedial systems, formed the medial bundle in this
lateral fillet.

Into this medial bundle (Plate XIX fig. 25 C and D)the dege-
nerated fibres above mentioned may be traced and this bundle is
increasing in its proximal course. .

These fibres, without any doubt being fibres going from the
ascending tract of Deiters to the medial bundle of the contra-
lateral fillet, may be interpreted as more proximal situated Mona-
Kow's fibres and at the nucleus of the IV^** nerve , where the
ascending tract approaches its end, (it passes near to the nucleus
of Darkschewitsch , but gives only a few fibres into it) the most
proximal fibres of this system pass the raphe to the medial bundle
of the lateral fillet.

In this way the tract described by Probst as a commissure be-
tween the fillets , passing ventrally before the nucleus IV , may be
a part of this system.

The relations between the descending tract of Deiters and trans-

124 G. WINKLER. THE CENTRAL COURSK

verse fibres are naerly the same as the above mentioned. At their
origin from the degenerated mass of dorsal fibres, it cannot well
be judged whence Monakow's fibres come, but as the Deiters
tract has loosened itself from this mass and crossed the facial root,
a great many fibres issue from it in order to give an important
number of fibres in Monakow's system.

In horizontal sections (Plate XVII fig. 20 E) this is easily demon-
strated. Some of those fibres even bend proximally and , after having
crossed the raphe , may again reach the medial bundle of the lateral
fillet. The larger part follow the usual path of the Monakow fibres.

Therefore it appears, that the fibres issued from the large cells
of the tuberculum acusticum , do not only follow the direct way into
MoNAKOw's decussation to reach the dorsal layer of the oliva
superior and from there the medial layer of the fillet, but that
they also enter in both tracts of Deiters and remain there for a
longer or shorter extension till they find , by means of a decnssatio
ventral from the fasciculus longitudinalis posterior, a direct way
to this bundle. In this way the tub. acustic. may aid to the archi-
tecture of the Deiters tract, and the nucleus of Deiters, to that
of the Monakow system to the lateral fillet.

Now leaving those tracts, still other important layers of degene-
rate fibres after the section of the dorsal systema ask a description.

V^' in following the (degenerate) descending root, it appears that
the layer of normal longitudinal fibres found after rootsection
medially from the (degenerate) rootfibres (Plate V fig. 9 and fig. 10)
between this root and the nucleus dorsalis N. octavi shows also
degeneration (Plate XVI fig. 20 D). Subsequently this descendent
tract, accompanying the descending root, intensely degenerated,
may be traced very far distalward , constinuing with a part of its
fibres in the fasc. solitarius N. vagi (Plate XVII fig. 20 E) and
(Plate XX fig. 25 H) found there situated dorsally.

From this tract part an innumerable quantity of small collaterals
perpendicular to its direction (Plate XVI fig. 20 D) ending in
the nucleus N. VI, now totally blackened with black globules,
in the nucleus dorsalis N. VllI, in the nucleus N. X and in the
same-sided nucleus N. XII. The XIP*^ nucleus however is only very
slightly connected with the secundary octavus-fibres , at least in a
far less intensity than the upper part of the spinal cord. In this
way as till now is demonstrated , there is only one motor nucleus,
that of the V^^ nerve, having no relation with them. Only not
all are degenerated with the same intensity. The most interested
nuclei at the operated side are :

OF THE NERVUS OCTAVUS. 125

The IV^^ and the distal end of the IIP*^ nucleus and that of
the Vr** nerve; in a lesser degree the facial nucleus, the motor
nuclei N. X, and the nuclei funiculi lateralis; least that of the
Xir**. Uninterested surrounded at all sides by a large quantity of
degenerate fibres the motor quintus nucleus is lying.

2^-^ from the descending root and also from the descending tract
of Deiters, there however originate dorsal transverse fibres, not
ending in the described nuclei but passing the raphe.

They go ventrally and dorsally from the genu of the nervus VII ,
they even penetrate through it , pass the raphe , provide the contra-
lateral nucleus of the W'^ nerve withe a large quantity of fibres,
pursue their course in the contra-lat^ml layer of transverse fibres
and reaching there the portio interna, they accompany the descen-
ding rootfibres giving there again collaterals to the contra-lateral
nucleus nervi VI (Plate XVI fig. 20 D).

In this way> the descending root of the opposite side receives a
secundary system through the transverse dorsal fibres and in the
same way as the secundiiry system in the contra-lateral descending
Deiters tract, it is less important than that of the same side.

3^^ a great many degenerate fibres of the dorsal transverse layer
however , at their reaching the raphe bend in a longitudinal direction,
forming in the fasciculus longitudinalis posterior an ascending and
a descending tract.

After one-sided section of the systema dorsale it appears that the
contra-lateral f. L p. is degenerated more intensely. The same fact
I have stated after rootsection on one side.

The proximal part of this tract, giving fibres to the contra-lateral
nucleus N. VI diminishes rapidly. The contra-lateral Vr** nucleus,
as has been shown, now being provided from three sides, from
dorsal transverse fibres after their crossing the raphe , from the contra-
lateral fasciculus longitudinalis posterior and from the descending
root , is degenerated to such an intense degree , that its degeneration
hardly differs from that at the same side. The fasciculus longitu-
dinalis posterior however do not leave all its degenerate fibres in
this nucleus and in sections proximal ly from the levels of the Vr**
nucleus there are still found a few degenerate fibres in it. They
may be followed to the IV^*" nucleus causing there a very slight
degeneration (Plate XVI fig. 20 B). It is not quite clear however,
where the larger part of those degenerate fibres remains.

Now, as it may be seen in fig. 20 G, the bracchium conjunc-
tivum ped. cereb. sup. is divided. The subsequent degeneration is
seen (fig. 20 D) in this bracchium towards the contm-lateral red

126 C. WINKLER. THE CENTRAL COURSE

nucleus. It may be presumed, that the degenerated pedunculus
cerebelli superior , after passing the raphe sends fibres into the fasc.
longitudinalis posterior and in the fasc. praedorsalis backwards. My
experience in regard to this is conform to that of Van Gehuchten.
But this presumption does not enable us to interprete the prevailing
of degenerate fibres in the contra-lateral fasc. long. post, in sec-
tions falling proximally from the nucleusof the VP** nerve after root-
section. Even if (in the case drawn in fig. 20) fibres from the dege-
nerated bracchium conjunctivura pedunculi cerebelli superior might
have increased here the contra-lateral degeneration in the fasciculus
longitudinalis posterior, it still would be too intense, to be caused
by those fibres which only may exist in small number.

Therefore I believe that there exist fibres, issued from the nucleus
ventralis nervi octavi and from the nucleus Deiters of the opposite
side , which take temporary a place in the contra-lateral fasc. long,
post, to provide chiefly the nucleus VI of that side, in a far lesser
quantity the nucleus IV and X, but leaving it also to reach the
medial bundle of the lateral fillet.

All contra-lateral degenerated fibres in the fasc. long. post, remain
within the medulla oblongata.

At the proximal top of the XIV^ nerve, the degeneration prevails
in the fasc. long. post, of the operated side, but these fibres have
quite an other signification. Many transverse dorsal fibres namely
have remained at the same side in the fasciculus longitudinalis
))osterior and bending distally they have a slight ventral inclination,
in such a way that in proximal sextions being longitudinal fibres
of the fasc. long. post, they gradually pass distally into the fasc.
praedorsalis. Now from the degenerate transverse fibres in the
decussatio of Monakow and from that of Held, there also bend
fibres in the homo-lateral fasc. praedorsalis and take a longitudinal
course.

At the level of the XIP*^ nucleus (Plate XVIII fig. 22 F and G,
Plate XX fig, 25 L, Plate VIII fig. 15 N^ 5— N*. 1) the fasci-
culus longitudinalis posterior and the fasc. praedorsalis are no longer
differentiated. There now is in the medial field of the medulla
oblongata, between the stratum interolivare (Levandowski's lemniscus
principalis) and the dorsal nuclei an intense degeneration at the
same side and a much less intense, but still evident one, at the
contralateral side.

At the end of the oblongata this degenerated tract is found in
the anterior columna of the cord (Plate XXI fig. 25 M) at the
sides of the decussatio pyramidum, and at the exit of the 2^** ante-

OF THE NERVUS OCTAVUS. 127

rior root, it has a position in the columna anterior, between the
anterior horn and the fissura anterior inedullae. It rests upon the
commissura anterior, and following the medial border of the horn,
it is laterally limited by the most medial issuing rootlet.

This situation the degenerated field preserves in its course through
the cervical medulla, giving fibres into the anterior horn. (Plate XXI
fig. 25 N and 0).

If one-sided section through the dorsal systema is made it pre-
vails very much upon the operated side (Plate XVII fig. 21 C^).

As it reaches the cervical intumescentia, it retires from the com-
missura and from the horn, takes a position at the peripheric mar-
gin of the cord along the fissura anterior and at the anterior
margin. Extending more laterally, it soon touches the medial end
of the tractus Deiters descendens and together these two tracts
now form a long peripherically situated degenerate small band,
beginning at the commissura anterior, along the fissura anterior
and the antero-lateral margin, untill the middle of the lateral column
(Plate XVII fig. 21 C 7).

To reach the grey matter, their fibres often bend abruptly into
a medial direction, crossing obliquely the columna.

This is the second long descendent tract, which unites the pri-
mary octavus-nuclei with the motor columns of the spine. Together
they may be traced unto the sacral part of the cord (Plate XVII
fig. 21 S3). Thus it is found degenerated as w^ell after section of
the lateral trunk of the ventral system, (Plate XVIII fig. 22 H).
as after section of the dorsal system (Plate XVII fig. 20 and
fig. 21. Plate XXI fig. 25 M — O) and after section on both sides.

Through the existence of contra-lateral symmetrical tracts may
not be denied, those on the same side are much more volumi-
nous, as the intensy of their degeneration shows evidently.

There still remains to discuss the third long descendent path
towards the spinal cord.

I already described its degeneration after the section of the late-
ral trunk of the ventral systema.

I saw it very intensely degenerated after the section of the dorsal
systema (Plate XVII fig. 20 F and fig. 21 Cg— S3) and in a less
intense way after the double-section (fig. 25 M. N. O.)

It appears in the oblongata as soon as the voluminous degene-
ration of the corpus trapezoides has ended, as a degenerated area
between the fifth root and the facial nucleus, extending ventrally
of this nucleus at the peripherical margin. As Gowers tract, with
which its fibres are mixed, slightly bends medially and Flechsig's

128 C. WINKLER. THE CENTRAL COURSE

tract begins the formation of the restiforra body, the area must
leave the peripherical margin. At the end of the oblongata it has
the shape of an equal-sided spherical triangle. Its top is lying in the
formatio reticularis lateralis medullae, one of its sides borders the
formatio gelatinosa of the posterior cornu, the other borders the
nucleus funiculi lateralis. (Plate XVIII fig. 22 H).

In the medulla the degenerated field preserves ist place, with
the top in the formatio reticularis and resting upon the formatio
gelatinosa cornu posterioris,. bordered ventrally by the pyramidal
tract in the lateral column, and laterally by Flechsig's Kleinhirn-
Seitenstrangbahn (the dorsal ascending spino-cerebellar tract). This
position (Plate XVIT fig. 21 C 8) it retains, until the sacral part.
It also has a tendency to reach the peripherical margin of the
posterolateral column, and in the middle of the thoracic part of
the cord (Plate XVII fig. 2 1 D 4) the whole peripherical margin
of the columna laterales et anteriores, may be formed by a small
degenerated band, composed of fibres of our three descending tracts.

I believe this descendent tract for the greater part issued from
the ventral nucleus n. octavi, because I have not found it dege-
nerated in such an extensive degree after dorsal section as after
section of the ventral systema.

It is found chiefly degenerated at the operated side, but slightly
degenerated is also its contra-lateral partner in all cases.

But here a difficulty arises. The way traced out is the way of
the descendent path in Monakow's „aberrirendes Seitenstrangbundel,"
which according to Pawlow and van Gehuchten might be a
rubro-spinal path.

Certain it is, that in none of my cases the nucleus ruber is
lesioned. But it is questionable whether by the dorsal section, the
tract in its course from the contra-lateral nucleus ruber, crossing
in the ventral decussatio tegmenti and reaching in such a way the
„aberirrendes Seitenstrangsbiindel" may be divided.

This rubro-spinal path exists, I do not doubt it, but the aber-
rirende Seitenstrangbiindel reaches also the lateral fillet (Plate XXII
fig. 28 E and F). There, lying still more medial than the medial
bundle of this fillet, it is not only formed by the crossed fibres
of the rubro-spinal tract, but it reaches probably much farther.

In the section of the dorsal system of fig. 20 (Plate XVI fig. 20 D)
the lateral fillet in its dorsal regions has been touched, but in the
section of the lateral trunk of the ventral system (Plate XVIII
fig. 22 B) it is not, and in the double-sided lesion (Plate XX
fig. 25 C — H) equally the fillet is intact. In the dorsal section of

OF THE NERVUS OCTAVUS. 129

fig. 20 and in the ventral section of fig. 22 the samesided dege-
neration in the rubro-spinal tract was very intense, in the double-
sided it was only slight. I doubt, that the rubro-spinal path should
have been damaged, but if in the medio-dorsal parts of the lateral
fillet fibres are found, issuing from the c. quadr. posticum (or
through the ventral fibre-layers of this ganglion from the corpus
geniculatum or from the thalamus) and degenerating in descendent
direction, it might have been possible, that, in the extensive dorsal
section of fig. 20, a division of those fibres has been the cause of
the intensive degeneration found in the rubro-spinal path.

Now as I find without lesion of the fillet a slight (Plate XXI
fig. 25 M— O) or even a more intense (Plate XVIII fig. 22 G— H)
degeneration in this tract (doi^sally situated in the cord) according
to dorsal or ventral section of the secundary systemata, I conclude
that this tract also receives any fibres through the secundary octavus-
systems and chiefly from the ventral systema. Here also the dege-
neration is found on both sides, but chiefly homolateral.

In this way I believe that the secundary octavus-systems are
sending fibres to the medulla chiefly on the same side, along three
ways. There are to distinguish 1^^ a praedorsal system or in refe-
rence to the cord , a ventral octavo-spinal way , 2'^ a tractus Deiters
descendens, or in reference to the cord, a lat;eral octavo-spinal way,
3*y a smaller path in the „aberrirendes Seitenstrangbiindel" or in
reference to the cord a dorsal octavo-spinal way.

5. Summary ov resuli's.

I will close this chapter by giving the schemata, according to
the results of these anatomical researches.

After removal of the cochlea, there is found an important dege-
neration in the dorsal root, the extra-medullar part of the ventral
root however is found without degeneration.

After removal of the labyrinth, both roots are brought to dege-
neration, but a still more intense one takes place in the extra-
medullar part of the dorsal root than after cochlea-removal.

Both roots, after having entered the oblongata, divide in three
parts, a dorsal, a medial and a ventral trunk.

The dorsal root sends by far the larger part of its fibres into
the dorsal trunk (stratum latero-dorsale C. R.), only a few fibres
into the medial trunk, and also some fibres into the ventral trunk.

The ventral root sends the majority of its fibres into the medial
trunk between the spinal root of the V^^ nerve and the area oval is

Vdrband. Kon. Akad. v. Wetensch. (Tweede Sectle Dl. XIV). 9

130 C. WINKLER. THE CENTRAL COURSE

C. R. , some fibres into the ventml trunk , but an important number
of its fibres are by means of an intermediary bundle, directly or
through the corpus restiforme, introduced into the dorsal trunk. In this
way the course of the two roots does differ very much as to the
quantity of the fibres, directed into the different trunks, but there
are no paths, followed by one of them, wherein no fibres of the
other appear.

Their course may now be illustrated by the adjoined schemata.

THE FIBRES OF THE DORSAL ROOT (cochlear-fibres).

(Schema A).

Most fibres of the dorsal root enter in

I. THB DORSAL TRUNK (stratum latcro-dorsalc corporis restiformis).
Those fibres perforate the ventral nucleus N. VIII and leave

1. a great many fibres in the di^to-vetitral part of the ventral
nucleus.

Between the larger cells of this nucleus — from which secun-
dary systems originate — and the rootfibres, small cells are inter-
calated (the nucleus proprius radicis dorsalis) and also

2. 7nany fibres in the dorso-proximal part of the ventral nucleus,
After the perforation they form the external layer of the stratum

latero-dorsale C. R. the beginning of thr systema dorsale nervi
ocTAVi. They divide into many bundles, radiating dorsally from the
area ovalis C. R.

3. the dorsal rootfibres in the stratum medullare pro fundum tuber-
culi acustici.

From these rootfibres perpendicular collaterals enter in this nucleus
and with the aid of small intercalated cells (in the stratum profundum
griseum) the large radially situated cells are innervated — from
which secundary systems originate.

4. the dorsal rootfibres to the lateral part of the dorsal nucleus
N. VIII.

Collaterals end therein. The small cells therein may intercalate
them to the nucleus of Deiters.
Les3 in number but evident are:

5. the dorsal rootfibres among the system of dorsal transverse fibres.
They are much increased by ventral root-fibres. Only a few fibres go
OL ventrally from the dorsal eighth nucleus to the W^ nerve ^

remaining in those nuclei. On this way very few are going.
/3. to the formatio reticularis {desceudenl 1)eiteiis tract).

OF THE NERVUS OCl'AYUS.

131

Fig. 18.

Schema A.

Scheme of the central path of the root fibres of the donial eighth root

132 C. WINKLER. THE CENTKAL COUESE

y. to the fasc. long, posterior {descendent praedorsal tract) and
having crossed the raphe.

5. to the contra-lateral fasc. long, posterior and through it to the
contra-lateral nucleus VI.

6. the dorsal root fibres to the radix descendens and to the radix
ascendens N. Fill,

In distal regions these fibres penetrate through the portio interna
C. R. to reach the field of the descending root.

In proximal regions as the ped. c^rebelli inferior retires to the
cerebellum, dorsal and medial trunk fall together, and the most
proximal dorsal rootfibres even reach the nucleus of Bechtkrew and
the nuclei tecti. Their course will be schematised in the description
of the ventral (medial trunk) root-fibres.

A more important set of fibres however are

7 the dorsal rootfibres to the intermedial system. They curvate
around the area ovalis, perforate through the gelatinous substance
of the V^^ spinal root towards the field of the so-called aberrirendes
Seitenstrangbiindel.

They participate to the systema intermedium nervi octavi.

This system sends some fibres

a. in longitudinal direction.

oui Very few distally (beginning descendent tract), /3/8
more proximalward towards the nuclei tecti (ventral ascending
spino-cerebellar tract).

/3. in the facial nucleus.

y. in the systema ventralis N. octavi.

More fibres in the

5. dorsal medullar layers of the nucleus olivaris superior.

But the majority of its fibres become.

e. transverse intermediary fibres (Held) which are passing the
raphe, giving a few fibres in distal direction tho the praedorsal
tract and also a few fibres to

OL the medial hilu^ of the contra-lateral oliva and to it^

dorsal layer.
(2 in the contra-lateral ,,aberrirendes SeitenstrangbiindeV.

Together the latter fibres go proximally, to become
^. dorsal rootfibres reaching through the intermediary system, the
contra-lateral fillet and the corp, quadrigeminum posticum.

II. IN THE MEDIAL TRUNK Only a fcw fibres enter. They will be
schematised in the description of the ventral rootfibres.

OF THE NEKVUS OCTAYUS. 133

III. IN THE VENTRAL TRUNK.

The dorsal rootfibres entering there have the same course as the
ventral rootfibres. Therefore for this part the schema of dorsal and
ventral-rootfibres are nearly equal.

They participate to the systema ventrale nervi octavi.

They follow Several ways.

1. dorsal rootfibres to the contralateral nucleus trapezoides.
They are thick, superficial, transverse fibres, from which some

remain in the same-sided nucleus. The rest, after passing the raphe
enter into the contralateral.

2. dorsal root-fibres into the ventral system ^ to the nuclei veti-
trales tegmenti of the same side. They leave collaterals into their
lateral and ventral medullary layers and passing the raphe they are.

3. dorsal root-fibres to the contra-lateral nuclei ventrales teg-
menti. They leave a few fibres in the medial hilus of the contra-
lateral nucl. olivare superior, and the rest, united to the fibres of
the intermediary system coming there, pursue their way in proximal
direction as

4. dorsal root-fibres y reaching through the ventral system the
contralateral fillet and the corp. quadrigeminium porficum.

THE FIBRES OF THE VENTRAL ROOT
(Schema B).

A considerable number of fibres of this root enters in
I ITS dorsal trunk.

Directly or through the corp. restiforme the ventral rootfibres
pai-ticipate to the formation of the stratum latero-dorsale, forming
chiefly its internal layer. They therefore also take part in the systema

DORSALE nervi OCTAVI.

To the ventro-distal part of the ventral nucleus N. VIII they
give no fibres. They may give a few fibres to the ventral nucleus
in its dorsal and proximal part and to the tuberculum acusticum,
but they increase considerably the dorsal radiation upon the area
ovalis C. R. thus giving.

1 . the ventral root-fibres to all cells of the nucleus dorsalis N, VIII.

2. the ventral root-fibres reaching the descending root through the
area ovalis corporis restiformis. These perforating fibres participate to

3. the ventral root-fibres in the intermediary system. Consequently
to its increase by ventral rootfibres, the intermediary system of
THE N. ocTAVus is strengthened, and so are the ascending and
descending tracts.

134

C. W1NK1.ER. THE CENTRAL COUllSK

Fig. 19

Schema B.

Schema of the central path of the rootfibres of the ventral ligt root.

OF THE NERVUS OCTAVUS. 135

II ITS MEDIAL TRUNK howevcr leceives by far the larger portion
of its fibres. They enter doi'saliy from the spinal V^*" root, between
it and the oval area C. R., and dorsally resting upon its medial
end they bend distally (the descending root) and proximally (the
ascending root). These fibres unite with dorsal and ventral root-
fibres of the dorsal systema which have curvated round the corpus
restiforme. As the restiform body retires into the cerebellum dorsal
and medial trunk are no longer separated and form a single trunk.

In the ventral trunk small cells are intercalated (nucl. proprius
radio, ventr.).

The descending rootfibres are accompanied by smaller and larger
cells (the nucleus griseus radicis descendentis) united to the cells
of the medial apex of the nucleus dorsalis.

This nucleus continues to accompany the ascending root and is
called there 4;he nucleus of Bechterew. The ascending and the
descending root give rootfibres (far the greater part being ventral-
rootfibres, the smaller part dorsal rootfibres) to many nuclei.

1. ventral rootfibres to the nuclei tecti cerebelli.

2. ventral root-fibres to the nucleus of Bechterew and to the
nucleus griseus radicis descendentis.

3. ventral rootfibres to all the cells of the dorsal nucleus N. FIJI,
In all these nuclei small cells are found to intercalate rootfibres

with the large cells of Deiters nucleus, which have no direct
relations with any rootfibres.

4. ventral rootfibres among the dorsal transverse fibres, taking
the way described in the schema of the dorsal root-fibres but
providing now to a mere considerable degree the IIP*", the IV^^
and the VP*" same-sided nuclei, the contralateral VP nucleus and
the beginning of the tractus Deiters descendens and the tractus
praedorsalis.

III ITS VENTRAL TRUNK

receives fibres taking the course described by the dorsal root-fibres.

THE ASCENDING FIBRES OF THE SECUNDARY SYSTEMS
OF THE NERVtJS OCTAVUS.

(Schema C).

Degeneration and atrophy after sections through the central
system in rabbits and comparison with the foettil central system
have taught, that from the nucleus ventralis, the tubcrculum acus-
ticum and Deiters nucleus (-f- large cells of the nucleus griseus

136

C. WINKLER. THE CENTRAL COURSE

Fig. 20.
Scheme C.
Scheme of the ascending secundary octavus-lisres.

OF THE NERVUS OCTAVUS. 137

and Bechterew) and from the olivary bodies issue secundary
systems. Those systems (without those of the nuclei olivares supe-
riores, nuclei paraolivares and nuclei trapezoides have been schematised).
They augment all the systems of rootfibres, and participate to
the systema ventrale and intermedium, following the way traced
by the root-fibres.

1 . The secundary fibres in the systema ventrale are chiefly issuing
from the ventral nucleus and are situated among all its layers.
To this secundary system certainly is added an important one from
the nuclei olivares especially in the stratum c of this system, pro-
bably following afterwai^s paths as the first.

2. The secundary fibres in the systema intermedium are also
issuing from the ventral nucleus, but some of them may issue
from the nucleus of Deiters. To these secundary fibres the olivary
bodies again add many fibres, not yet meduUated at birth.

Those two systemata give now its origin to an ascendent, chiefly
same-sided (but also contralateml) tract, which together with spinal
fibres and octavus-rootfibres takes the way of the „vental ascending
spino-cerebellar tract". Going proximally in the „aberrirendes Sei-
tenstrangbunder' these primary and secundary octavus-fibres, they
reach with the lateral fillet the outer layer of the pedunculus superior
cerebelli, cross its bracchium conjunctivum and reach the nuclei
tecti. Therefore in the

3. ventral ascending spino-cerebellar tract secundary as well as
root-fibres of the n. octavus are found.

To this tract the olivary bodies, probably do not participate.

4. The secundary fibres in the systema dor sale issued from nucleus
ventrale, tuberculum acusticum and nucleus Deiters follow the
dorsjd way already traced by the root-fibres. But there parts from
the stria medullaris a new very important system

5. MoNAKOw's transverse and ascendant secundary fibres.

They cross the raphe ventrally from the fasc. long. post, reach
the dorsal layer of nucleus olivaris superior, and that of the nucleus
lemnisci ventralis.

This decussation of Monakow's fibres may be followed very far
proximally, but in proximal regions (between the motor nucleus
of the V^^ and the nucleus of the IV^^ nerve) they exit from the
tractus DErrERs ascendens. In distal regions Deitkh's descending
tract sends fibres among them.

Together with root-fibres and secundary fibres of the ventral and
intermediary system, they go proximally in the lateral fillet in two
distinct bundles. Thev unite there with

138 C. WINKLER. THE CENTRAL COURSE

d, the lateral bundle from the niicL ventr, lemnisci

/3. the medial bundle from the dorsal layer of the nucleus oliva-
ris superior

The latter fibres are strengthened by fibres from the tractus
Deiters ascendens.

Those fibres reach the corpus quadrigeminum posticum and pro-
bably still go farther.

This ascendent tract also is composed of rootfibres as well as of
sccundary fibres. But in this area of the lateral fillet there yet
remain an impoi-tant number of fibres, probably belonging to the
octavus system, chiefly issued from the distal parts of the olivary
nuclei, which are known insufficiently.

From the dorsal systema however a very important tract issues,
containing

G. The secundary fibres in the ascendent tract of Deiters.

They leave the nucleus of Deiters, in proximal direction, bend
medially and form the lateral part of the fasc. long. post. They
end in the nucl. N. IV and III, whereas:

7. The secundary fibres ascending in the fasc. longitudinalis pos-
terior , reach these nuclei united with the ascendent Deiters tract.
Nearly all the transverse fibres, issued from those two bundles to
provide the nuclei (not those , reaching the medial bundle in the
lateral fillet) are collateral fibres , and again their way is traced by
the root-fibres of the nervus octavus.

THE DESCENDING FIBRES OF THE SECUNDARY
SYSTEMS OF THE NERVUS OCTAVUS.

(Schema D).

The fibres of the dorsal system , composed of rootfibres as well
as of fibres of the secundary system , also form descendent tracts.

1. Fibres descending in the contralateral fasc. long, posterior.
They form a contralateral rather important tract, providing the

nucleus VI, and the distal end of the nucleus N. XII.

2. Fibres descending in the same-sided fasc, long, posterior.
Those fibres, slightly deviating ventrally in their distal course,

unite with longitunal fibres, sent distally in the praedorsal tract,
from the decussatio of Monakow and of Held. Together they go
towards the anterior column of the cord , where they are found
along the fissum anterior and the ventral margin of the medulla.

OF THE NERVUS OGTAVUS. 139

It may be followed till the sacral part of it. The same tract is

Fig. 21.

Scheme D.

Scheme uf the descending seciindary octavus-tibres.

found contra-lateral, but by far less important. It may be judged
to be a ventral descending octavo-spinal tract.

140 C. WINKLER. THE CEMTRAL CX)URSK ETC.

3. Fibres descending in the medial part of the formatio reticu-
laris oblongata.

These fibres are known as the deseendent tract of Deiters or
as the fasciculus vestibulo-spinalis. In the cord they take a position
at the peripherical margin of the lateral column , near the issuing
roots, which penetrate queer through it. The same tract is by far
less important at the contra-lateral side. It may also be followed
through the medulla till the sacral part of it. This tract may be
called a lateral descending octavo-spinal tract.

4. Fibres descending in the ,,aberrirendes SeitenstrangbiindeV',
They are only few descending fibres in the rubro-spinal tract.

In the oblongatii they are situated in the „aberrirendes Seitenstrang-
bunder*. In the cord they are found in the posterior part of the
lateral column in the triangle between formatio gelatinosa cornu
posterioris, pyramidal tract and Flechsig's dorsal cerebellar tract.

The same tract is found contra-lateral by far less important.

They may also be followed through the medulla till its sacral
part. This tract may be called a dorsal deseendent octavo-spinal tract.

The most important result of this anatomical study however is,
the following.

The nervus octavus , loith a small portion of primary fibres
with a larger postion of secundarg fibres , is in contact chiefly.

1. toith the collateral nuclei VI, IV and III,

2. tcith the contralateral nucleus VI.

3. with the collateral motor columns of the medulla through its
whole length.

Chapter III.

On the central distribution of the root-fibres
of the nervus octavus in pigeons.

The central distribution of the rootfibres of the Vlir*" nerve in
pigeons differs in many respects considerably from that, which in
the preceeding chapter has been described in rabbits.

Therefore a comparison between the central system of the nervus
octavus in these two species of animals is not very easy. It may
even be called impossible, whithout homologizing the different
fasciculi and nuclei, participating to the formation of this extensive
system. And every attempt to homologize the octavus-nuclei of a
bird with those of a mammalian will be proved a more or less
subjective proceeding. It only may be tried, when a very minute
knowledge of the central course of the rootfibres has been acquired.

My. views upon the central distribution of the rootfibres in
pigeons are based chiefly upon the examination of series of sections
through their cerebrum, treated with MARCHi-method within a
fortnight or three weeks after the removal of their labyrinth.

Those series were made in fi'ontal, horizontal and sagittal direction.

The removal of the labyrinth was executed by strictly following
the indications for this operation given by Ewald. As soon as the
operated pigeon begins to turn its head the in IIP** position —
generally after a fortnight — the animal is killed.

Now it must be observed, that in pigeons, the results of the
MARCHi-method are often less sharply defined, as they usually are
in rabbits. I believe that the rather high temperature of the blood
in birds, may serve to explain the fact, that black globules are
very often found every-where and in places, where they never might

1 42 C. WINKLER. THE CENTRAL COURSE

have been expected after lesions in the root-fibres of the nervus
octavus. Wherever a degeneration in the medulla oblongata is pro-
duced, nearly always black granules are found, for instance, in
the in termed uUary rootfibres of all the nerves and especially in
those of the III"*. The slightest degeneration in the oblongata
suffices to bring forward black globules nearly every-where. 1 believe
the reason of this fact, must be sought in the rapidity of the vital
functions in birds. I think, that in an early period after the opera-
tion the dislocation of the degenerated myelin-products begins and
that therefore the question whether there be a circumscript dege-
nerated area or not may be more difficult to resolve in birds.

This observation however only relates to doubtful cases. Impor-
tant and circumscript degeneration in the entering roots and in
their initial paths after the removal of the labyrinth is found with
equal certitude in pigeons as in rabbits.

1. The entrance of the rootfibres of the nervm octavus
in the medulla oblongata.

Within a fortnight after removal of the labyrinth , in both roots
of the Vlir*" nerve many degenerate fibres are found. For in pigeons
as in rabbits the VHP** nerve enters into the medulla oblongata
with two distinct roots. The one is the dorsal, distal or lateral
root, the other the ventral, proximal or medial root. In both roots
however, besides the degenerate fibres , many non degenerate fibres
remain after the removal of the labyrinth.

In frontal sections it is now easily demonstrated that the distal
root, lying laterally from the pedunculuscerebelli inferior, penetrates
into a nucleus, immediately after its entrance in the medulla
oblongata.

This nucleus covers the entering root like a dorsal cap, and
according to the nomenclature adopted by Edinger and Wallen-
berg, it may be called the nucleus angularis — the „Eckkern"
of these authors.

In this nucleus a large part of the degenerated dorsal rootfibres
enter, and as they spread through the nucleus, this nucleus itself
is intensely degenerated and found as a black spot after the removal
of the labyrinth (Plate XXIII fig. 26 A).

In more distal regions, as long as the angular nucleus is resting
upon the dorsal end of the dorsal root it is found laterally from
the inferior cerebellar peduncle (fig. 26 A). In sections, falling more
proximally (fig. 26 B and C) the nucleus retires at the dorsal end

OF THE NERVUS OCTAVUS. 143

of the inferior peduncle and the dorsal root, now still entering at
its ventral pole, embraces the nucleus with its degenerate fibres,
surrounding it ventrally and laterally, and giving it fibres, passing
queer through the nucleus. Most of these fibres gather at the dorsal
surface of the nucleus (fig. 26 A and B).

But at these levels, the ventral (proximal) root has also entered
into the medulla oblongata. Its fibres — thick degenerated fibres
after the removal of the labyrinth — perforate the inferior cerebellar
peduncle. Its most dorsally situated fibres here approach the dorsal
root-fibres and touch also the ventral border of the angular nucleus.
Ventral rootfibres therefore here enter in the ventral surroundings
of the nucleus angularis and continue to do so (Plate XXIII fig.
26 C and Plate XXIV fig. D) in more proximal levels, as the dorsal
rootfibres have disappeared. They provide the proximal ventral border
of it, until the nucleus joins the more lateral part of the nucleus
pedunculi inferioris cerebelli, from which the angular nucleus is not
distinctly separated.

Now the angular nucleus and its surroundings being provided
in the manner here described, there remains at its distal end a
bundle of degenerated fibres, chiefly dorsal rootfibres, that lying
immediately below the ependyma of the IV**" ventricle, takes a
medial direction.

On the other hand, the greater part of the ventral rootfibres,
which have passed queer through the pedunculus cerebellaris inferior
(fig. 26 C) and continue to do so in more proximal levels, also
take a straight medial direction.

These ventral root-fibres have lost some fibres in the ventral
border of the angular nucleus, but on the other hand their number
is increased by dorsal rootfibres, originating from the ventral sur-
roundings of this nucleus.

In this way there are found in distal regions two degenerated
bundles in the dorsal part of the oblongata.

The one, the dorsal bundle, leaves the dorsal surroundings of the
angular nucleus, and directly below its ependym , it runs parallel to
the bottom of the IV*^ ventricle. In proximal levels it soon disappears.

The other, a ventral bundle, chiefly composed of the continua-
ted ventral rootfibres, is much more impoi-tant, as it may be traced
in all proximal levels.

These two bundles (both composed of fibres of the two roots,
but the dorsal chiefly of dorsal root-fibres, the ventral chiefly of
ventral root-fibres) meet at the medullary surroundings of another
nucleus, situated in the lateral wall of the IV^** ventricle and the

144 C. WINKLER. THE CENTKAL COURSE

aquaeductus, immediately below their ependyma. This nucleus, con-
taining cells of middling and small size, may be called, conform
to the nomenclature adopted by Wallenberg, the nucleus parvo-
cellularis of the nervus octavus.

It has the shape of a half moon or of a bean.

Its convex face, looking dorsally and laterally in distal levels is
surrounded by a layer of meduUated fibres. From its hilus a new
fasciculus issues.

In distal regions this fasciculus, taking a ventro-medial direction
towards the raphe, is small (fig. 26 A,B,C).

In proximal levels it is an important bundle.

But there the hilus also changes its position. Opening to the
medio-ventral side in distal regions, it soon turns medially, and
in the proximal end of the nucleus, the hilus is even found ope-
ning dorsally (fig. 26 D and E).

This new fasciculus forms a part of the systema dorsale nervi
octavi, which soon will be discussed.

Now, as the drawings in fig. 26 demonstrate in a very evident
manner, the two degenerated bundles of rootfibres may both be
continued in the medullary surroundings of this nucleus. Those
surroundings now are completely degenerated at the lateral side of
the nucleus and among its cells every- where small black globules
are found. In the fasciculus, issued from te hilus and forming
a part of the systema dorsale n. octavi, there also are found several
degenerate fibres but their discussion will take place in the follo-
wing paragraph. At all events there may be spoken of a great contrast.
The lateral surroundings of the hilus are intensely degenerated, the
hilus itself is so in a far lesser degree.

Now, the ventral-root-fibres, in order to reach the parvocellular
nucleus, must necessarily cross the area, which is found between
this nucleus and the place , where they leave the fibres of the infe-
rior cerebellar peduncle, perforated by them.

This area may be called the portio interna of the inferior cere-
bellar peduncle and the ventral bundle, crossing it far dorsally
from the Y^^ spinal root, divides it into two unequal parts, a
ventral one much more extensive than the dorsal one. (fig. 26 C).

This area moreover is sharply defined. It is bordered ventrally,
by the spinal root of the V^*" nerve and by a great many trans-
verse dorsal fibres, to be discussed afterwards; laterally, by the
fibres of the inferior cerebellar peduncle (here perforated by the
entering root-fibres of the ventral root) and by the nucleus angu-
laris; medially, by the fibres issuing from the nucleus parvocellu-

OF THE NERVUS OCTIVUS. 145

laris — which I , anticipating , now call the dorsal sy sterna of the
nervus octavus — and by this nucleus itself (in distal regions); the
dorsal border of this area, in distal regions, is formed by the dor-
sal degenerated root-bundle and the angular nucleus. More proxi-
mally , this bundle having disappeared , there is found a new nucleus
in the dorso-lateral part of this area, between the nucleus parvo-
cellularis and the nucleus angularis. This nucleus is characterised
by the presence of very large cells and adopting Wallenberg's
nomenclature , I will call it the nucleus magnocellularis nervi octavi.
In this rather sharply defined area, in this portio interna of the
restiform body , difierent parts may be distinguished , which as they
comport differently to the root-fibres of the nervus octavus, may
have a different signification.

1^^. The spinal fifth root and the fibres of the inferior cerebellar
peduncle are diverging during their proximal course, leaving be-
tween them a triangular area, wherein fibres are found, showing
an oblique direction in frontal sections. In this way , there appears
in the latero- ventral edge of the portion a field of triangular shape ,
where after the removal of the labyrinth no degenerate fibres are
found.

2^^. Between the dorsal systema and the (fig. 26 A — C) triangular
area described here, there is found another field. It is of almost
spherical shape (fig. 26 A — E) and after removal of the labyrinth
several degenerated fibres — queer-sectioned in frontal sections —
are found in it.

In distal regions this area is situated laterally from the nucleus
of the N. X, and it is resting upon the dorsal face of the spinal
root of the N. V (fig. 26 A). It retains its position in the ventro-
medial edge of the portio interna in proximal regions. But it is
soon bordered dorsally by the parvo-cellular and the magno-cellular
nuclei, and latero-ventrally by the nucleus N. VI.

The degenerated longitudinal fibres , which in distal sections are
very numerous here, may gradually be traced issuing from the ventral
degenerated bundle of rootfibres (fig. 26 C and D). In this way
these fibres appear to be descending rootfibres, bending in a longi-
tudinal direction , and this area therefore may be compared with
the descending root. And as the ventral bundle contains chiefly,
though not exclusively ventral-root-fibres , it may be taken for gran-
ted that a few dorsal root-fibres, passmg ventrally from the angular
nucleus participate to these descendent fibres.

This area, that, conform to Wallenberg's nomenclature, may be-
called the „Acusticusfeld", thus contains a great many descending root-

Verband. Kon. Akad. v. Wetensch. (Tweede Sectie Di. XIV). 10

146 C. WINKLER, THE CENTRAL CX)URSE

fibres, most of them from the ventral, a few from the dorsal root.

In Nissi/s or in carmin-preparations of this region, or in other
preparations with succesful staining of the nerve-cells, it may be
demonstrated, that in this area nerve-cells are very numerous.
Cells of middling size are found along the fibres perforating the
inferior cerebellar peduncle. Cells of small, of middling and even
of large size are also found between the longitudinal fibres of
this area.

Now Marchi-preparations after removal of the labyrinth show,
that many of those descending fibres degenerate. In great number
they are found there, where the ventral root enters (fig. 26 D).
In more distal sections they seem to be gathered in two distinct
area's, the one is found more laterally, the other more medially
(fig. 26 C and B). The lateral field of degenerated descending
fibres, if traced distally, disappears at the beginning of the nucleus
N. X. A great many descending fibres apparently remain in the
area itself, and after a descendent course of relative short duration
end between the cells found there (fig. 26 C).

The more medial field of degenerated descending fibres may be
traced far more distally. From those fibres also several remain in
the area, but during their descendent course, they pass along the
nucleus of the YV^ nerve, sending fibres into it, and when the
nucleus of the X*^*' nerve appears, these fibres, situated dorso-laterally
from it (fig. 26 A) are giving fibres to this nucleus too. They have
disappeared, when the latter is no longer seen.

These all are descending root-fibres.

But in tracing the ventral bundle of degenerate root-fibres in
proximal regions, we find, that a part of them do not follow the
straight medial path, but slightly bend proximally to form ascending
degenerated fibres (fig. 26 D and E).

The ventral bundle, by which the portio interna was divided
in two area's, the dorsal one being by far the smallest, and chiefly
occupated by the magno-cellular nucleus, now divides. In its dorsal
part, ventro-late rally of the nucleus magno-cellularis, a great many
ascending degenerated fibres are found in proximal regions, but
fibres going medially to the nucleus parvo-cellularis also exist here.

In this way the ventral bundle divides itself in three distinct
portions of rootfibres.

There are V^ descending rootfibres. Most of these remain in the
here described area among the cells found there. Other fibres go
medial ward to aid in the formation of transvei'se dorsal fibres , and
provide the nucleus N. VI and that of the X (fig. 26 A — C).

OF THE NERVUS OCTAYUS. 147

2*y ascending fibres. Of these the greater part remain in the here
described area, among the cells found there. Other fibres provide
the proximal portion of the angular nucleus, and of the nuclei in
pedunculus cerebelli (fig. 26 D — E).

3^^ transverse fibres. Most of these participate to the formation
of the surroundings of the nucleus parvo-cellularis N. octavi. But
a great many of these fibres are going medialward.

To these latter other transverse fibres join, running in the same
direction, but issued from the descendent and ascendent roots. All
these fibres participate to the formation of the dorsal systema N.
octavi, wich will be treated afterwards, (fig. 26 A — E).

The large area here described indeed is an area, into which
most of the rootfibres enter. Together with the ventral bundle and
with the systema dorsale N. octavi, it offera by far the most
extensive, and perhaps also the most interesting part of the portio
interna of the pedunculus cerebelli inferior.

4^^. In the dorsal border of the portio interna, however, is found
the nucleus magno-cellularis already mentioned before.

This nucleus containing very large cells, and embraced by the
tmnsverse and ascending fibres of the ventral root — all degenerated
after the removal of the labyrinth — is found without any dege-
neration if the labyrinth is removed.

The embracing rootfibres do not end in it. Perchance a single
degenerate fibre may pass through it, but as a clear spot between
the black degenerated nucleus angularis and nucleus pai*vo-cellula-
ris, it is very distinctly marked in proximal sections. Distally the
nucleus may be traced, in the dorso-lateral edge of the portio
interna (fig. 26 B, C, D and E.), not so far as to the entrance
of the distal root. Going from this entrance in proximal direction,
at first the nucleus angularis, soon afterwards the nucleus parvo-
cellularis and at last the nucleus magno-cellularis, appears, and it
always retains its place between these two nuclei (fig. 26 B — E).

After all, a portio interna of the restiform body may be recog-
nised in pigeons as well as in rabbits , and in this area are found
different divisions differently behaving towards the octavus-rootfibres,
and composed by root-fibres as well as by fibres of other origin.

b. The rootfibres in the systema dorsale nervi octavi.

It has been demonstrated, that the ventral bundle was divided

in descending, ascending and transverse dorsal fibres. All those

fibres , but chiefly the latter ones have contributed to the formation

10*

148 C. WINKLER. THE CENTRAL COURSE

of the surroundings of the parvo-cellular nucleus. Now from the
ventral bundle an important number of fibres, takes a direct medial
course in order to reach the raphe. Degenerate fibres leaving the
(degenerate) surroundings of the parvo-cellular nucleus, and passing
through the bundle leaving the hilus of this nucleus, join the
degenerate transverse fibres , which also reach this bundle. All these
fibres reach the raphe at the place where the fasciculus longitudi-
nalis posterior is found, cross it, and continue their course in the
same contra-lateral bundle towards the hilus of the contra-lateral
nucleus parvo-cellularis. Together they form thy very important systema
dorsale nervi octavi wherein many rootfibres, degenerating after the
removal of the labyrinth, are found.

V^. An important number of degenerate fibres enter into the
conti-alateral dorsal system, and may be traced into the hilus of
the contra-lateral parvo-cellular nucleus. In distal regions there are
not yet found many degenerate fibres, but their number increases
rapidly in proximal sections (fig. 26 D, E). Here the contrast be-
tween the degenerated homo-lateral and contra-lateral nucleus is
marked. The lateral surroundings of the homo-lateral nucleus are
intensely degenerated , the hilus is so in a relative slight degree.
The hilus of the contralateral nucleus is intensely degenerated,
its surroundings are so only slightly (fig. 26 D E).

It is not only in this nucleus that degeneration is found. Here
however it is intense. From thence a few degenerate fibres spread
into the proximal part of the „Acusticusfeld'' and though their
number is small, they there take the same ascending and descen-
ding course as at the homolateral side.

In this way rootfibres not only reach the homo-lateral parvo-
cellular nuclei , but a very important number of them , passing
through the dorsal systema reach this contralateral nucleus (fig. 26
D, E and fig. 27).

2'^. The here described path however is not the only one follo-
wed by the rootfibres in the systema dorsale. During their course
towards the raphe many fibres leave the principal bundle. Fibres
enter into the formatio reticularis. There they first go ventrally,
gather dorsally from the facial nucleus and bend distally. But there
these fibres soon disappear. At the distal end of the oblongata they can-
not be distinguished with certainty among the small black granules,
which are found here spread over the whole section and such is
likewise the case in the spinal cord. It is impossible in pigeons
to draw a conclusion concerning the existence of dispersed degene-
rated fibres.

OF THE NEKYUS OCTAVUS. 149

3^^. Next to those fibres, other fibres leave the dorsal systema
to enter in both nuclei N. VI. In pigeons this nucleus, reaching
far ventrally, has a triangular shape and many fibres pass through
it in all directions. The homolateral nucleus receives degenerated
fibres from transverse dorsal fibres. In the contralateral nucleus
they chiefly enter through the fasciculus longitudinalis posterior.

On both sides however the degeneration found in the VI*** nuclei
is only slight.

4^^. The greater number of the degenerate fibres of the systema
dorsale enter in both fasciculi longitudinales posteriores and in the
fasciculi praedorsales. They bend there in longitudinal direction going
proximally and distally.

a. The ascending longitudinal fibres of the fasciculus longitudi-
nalis posterior offer many interesting peculiarities.

At the entrance of the octavus-roots evidently the contra-lateral
f. 1. p. is much more intensely degenerated than the homo-lateral
one. During its course next to the nucleus abducens fibres leave
it to provide this nucleus with a few fibres, but more fibres leave
it to gain the contra-lateral dorsal systema and the hilus of the
parvo-cellular nucleus.

Proximal to the nucleus N. VI the fasc. long. post, has lost its
degenerate longitudinal fibres, almost completely on both sides.

The proximo-dorsal shoots of the transverse doi-sal fibres however,
have not yet ended in these levels here. From those both fasciculi
longitudinales posteriores soon receive new degenerate fibres.

At the distal end of the IV*^ nucleus again both fasciculi have
degenerate fibres, obvious, though in small number. They leave
fibres in those nuclei and again the number of degenerated fibres
is reduced, increasing at the distal end of the IIP** nucleus.

In all these nuclei there exists a slight degeneration. On the other
hand the intermedullary root-fibres of these nuclei are covered with
large black granules. I am convinced that many of those globules
are situated in lymph-vessels and that they do not correspond with
degenerate nerve-fibres, but I also believe that others represent
degenerate fibres; as well as I am convinced, that in both fasc.
longitudinales posteriores, true degenerated fibres enter and leave
them again, because horizontal and sagittal sections demonstrate the
black globules, ranged in longitudinal rows, which may only be
interpreted as representants of degenerate fibres.

In the preceeding paragraph I have discussed the difficulties,
which MARCHi-method offers in pigeons.

It is impossible to interprete the true significance of all the

150 C. WINKLER. THE CENTEAL CX)URSE.

black globules, spread everywhere in the medulla oblongata, in
all sections made through it. I believe that many of those black
globules correspond with degenerate root-fibres situated in the dor-
sal part of the formatio reticularis and reaching in their course the
fasc. long. post.

But I also believe, that a large part of them do not cor-
respond to such fibres, but are transferred products of myelin-
degeneration.

Therefore I only accept the slight but evident degeneration in
both fasciculi longitudinales posteriores and I do not draw any con-
clusion as to the manner in which the fibres of the formatio reti-
cularis enter into both.

I am unable to decide whether any degenerate root-fibres may
reach the lateral part of the tegmentum, and as I have made no
injuries in the central systems of pigeons I cannot give an opinion
concerning this question.

h. The descending rootfibres. More interesting however are the
degenerate fibres, descending in the fasciculus longitudinalis posticus
and in the fasciculus praedorsjilis.

They are found on both sides and, as has been described be-
fore, at the entrance of the roots, they are more numerous in the
contralateral bundle. Followed in distal direction their number, howe-
ver, rapidly diminishes. Therefore the number of degenerate fibres in
the homolateral bundle soon prevails above that in the contra-lateral.
This is the case at the proximal end of the nucleus of the X'^.

At the distal end of the medulla oblongata, as a distinct difie-
rentiation between the fasciculus longitudinalis and fasciculus prae-
dorsalis no longer exists and as together they are forming the area
along the raphe, ventrally frbm the nucleus of the XIP** nerve,
this area contains a notable number of degenerate fibres at the
operated side. In the contralateral area there are only a few.

Through this area the descending rootfibres may be continued
in the funiculus anterior of the spinal cord. There they are situ-
ated along the fissura anterior and along the commissura anterior,
at the operated side. They gradually enter in the antero-lateral
part of the grey horn. Without doubt they provide in this manner
the homolateral cervical horn and the grey matter in the cervical
intumescentia. As to tracing them farther in the thoracical medulla,
I dare not confirm their reaching it.

Moreover I am not sure that in the other funiculi of the cervical
cord the presence of degenerate fibres, after removal of the labyrinth
may be denied.

OF THE NERVUS OCTTAVUS. 151

At the operated side, there are found at the peripherical margo
of the lateral funiculus and along the exit of the anterior rootlets,
without doubt more black globules than in other parts of the
medullated parts of the medulla, but here again Marchi-method
has reached its limits.

The only part, where degenerate fibres are found to a degree
important enough to be admitted as consequence of the operation,
is the anterior funiculus, though it is remarkable that in the lateral
part of the formatio reticularis of the medulla oblongata and along
the exit of the rootlets there always are found a few degenerate
nervefibres.

5'^. Returning now to the most proximal root-fibres of the dorsal
system, 1 have already demonstrated, that they were not distinctly
separated from the ascending rootfibres embracing the nucleus
magnocellularis.

From the medial fibres found there, transverse fibres, passing
through the surroundings of the proximal top of the nucleus par-
vocellularis or ventrally from it, contribute to the dorsal systema.

From the lateral fibres — the ending of which among the cells
in the walls of the IV^^ ventricle, or in the most proximal part
of the angular nucleus, or continuing their course in the nucleus
pedunculi cerrebelli or even in the cortex cerebelli has been
described — again transverse fibres go to the dorsal systema.

From these proximal dorsal fibres the greater number gain the
fasc. long, posterior and they have found their description as ascen-
ding fibres therein.

In this way rootfibres form an important dorsal system, providing
by means of the fasciculus longitudinalis posterior, both parvo-
cellular nuclei, in a slighter degree the nucleus of the VP** nerve
and the nuclei of the proximal eye-nuclei, whilst by means of the
fasciculus praedorsalis a rather considerable number of them enter
into the homolateral funiculus anterior of the cervical cord, going
through this to the antero-lateral part of the horn.

c. Comparuon between the central octavus-rootfibres in pigeons

and in rabbits.

If a comparison of the central octavus-system in mammalia and
in birds may be attempted, it is evident, that this attempt has no
other value, than as a more or less fortunate endeavour to homo-
logize the different fasciculi and nuclei, which together are forming
this part of the central system.

152 C. WINKLER. THE CBNTBAL COURSE

Now in the first place, we must observe, that in pigeons — as
likewise in other birds — there is not found any system, that may
be compared with the ventral octavus-system in rabbits.

I cannot ascertain the existence of fibres forming a corpus trape-
zoides, neither can I find a nucleus olivaris superior, nor a nucleus
para-olivaris, nor a nucleus trapezoides as differentiated nuclei.
Moreover, there exists no trace of a ventral-trunk of the root£bres
of the N. octavus.

Therefore: pigeons have no ay sterna ventrale of the Nervm octavus.

In accordance with this view" it might be supposed, that any-
thing like the ventral nucleus N. octavi, from which the greater
part of the corpus trapezoides originates, would not yet be diffe-
rentiated, or would be missing completely. This opinion is supported
by the situation of the angular nucleus, by its relation to the
dorsal root, by its place relative to the magnocellular nucleus and
to the cortex cerebelli, all these being identical to the relations
of the tuberculum acusticum in rabbits.

The dorsal root enters in it at its ventral border with the
greater number of its fibres, and continuates in a bundle found
dorso-laterally from it. The distal portion of the ventral root also
gives fibres to it. But the ventral root, perforating the fibres of
the pedunculus cerebelli far dorsalward from the spinal root of
the V^^® nerve, may not be compared with the complete ventral
root in rabbits. In rabbits the dorsal fibres of this root perforate
the area ovalis of the corp. restiforme far dorsalward from the
V*** nerve. At least in distal regions. And here again is an argu-
ment defending the view , that for the distal and ventral portions
of the octavus-roots are much reduced in pigeons.

This however is no impediment for the existing rootfibres to
take a course completely comparable, with that followed in rabbits.

In pigeons the rootfibres found in the ventral bundle, divide,
into three parts: a descending rootfibres, 3 ascending rootfibres and (?
transverse fibres going straight to the nucleus parvocellularis (the
ventral bundle sensu strictiori). The same is found in rabbits. Many
of the descending as well as of the ascending rootfibres remain among
the cells situated in the medio-ventral and central area of the portio
interna pedunculi cerebelli.

These fibres are completely comparable with the descending root-
fibres remaining among the cells of the nucleus griseus rami des-
cendentis, or with the ascending rootfibres remaining among the
cells of the aequivalent nucleus Bechterew found in rabbits.

Other descending fibres situated more medially in the portio

OF THE NEEVUS OCTTAVUS. 1 53

interna , send transverse fibres to the VI^^ nucleus , and going more
distally even into the X*** nucleus. More proximally those transverse
fibres either originate from the ventral bundle or from the ascen-
ding fibres and may be traced to the nucleus parvocellularis. To
this nucleus also a portion of the dorsal rootfibres (the dorsal bundle)
may be traced.

All these fibres follow the same course , which has been described
in rabbits, and it is evident, that the parvocellular nucleus in
pigeons has the same relation to these rootfibres, as in rabbits the
nucleus dorsalis N. VIII has.

In this nucleus the dorsal and ventral bundle meet in a similar
way as the systema latero-dorsale and the medial-roottrunk in rab-
bits are doing in the dorsal nucleus. Only in pigeons its distal end
is reduced, but its proximal end again is provided for by transverse
fibres of the ascending root, as in rabbits the proximal end of the
dorsal nucleus is.

And if in pigeons the nucleus parvo-cellularis really represent
the dorsal octavus nucleus, if the angular nucleus represent the
tuberculum acusticum with the not yet differentiated ventral octa-
vus-nucleus, if the cells in the medio-ventral and central area of
the portio interna may be homologised with those in the nucleus
griseus rami descendentis (in distal regions) or with those in the
nucleus Bechterew (in proximal regions), then only one nucleus,
the nucleus magnocellularis, remains to be homologized wuth the
nucleus of Deiters.

This magnocellular nucleus is situated in the dorsal edge of the
portio interna, between the angular and parvo-cellular nuclei, it
contains very large cells and after removal of the labyrinth, dege-
nerate rootfibres, though distributed e\ory where in the neighbour-
hood , may pass through it , but do not remain in it , as they do
in the nuclei parvocellulares or angularis. Therefore its position ,
its structure , its relation to the rootfibres are all pleading in favour
of the meaning, that this nucleus may represent, what in rabbits
is called the nucleus of Deiters.

Until now, there has been no great difficulty in comparing the
roots and nuclei of the pigeon and the rabbit.

Pigeons have no ventral system , consequently no intermedial
system is found , but a dorsal system they have.

In pigeons the ventral and distal portion are reduced, but the
dorsal systema is considerably developed and is built in a similar
manner as in rabbits.

Yet a very remarkable difference does exist.

15* C. WINKLER. THE CKNTEAL OOlfRSE

From the nucleus pftn^oceiiuiari^ a great number of fibres are
issuing. They leave its bilns and enter in the important systema
dorsale. After removal of the labyrinth these fibres degenerate
contra-latcrallv and in that case the contro-lateral nucleus, especially
its hilus, is degenerated nearly as intensely as the lateral surroun-
dings of the homolateral nucleus.

Pigeons therefore, having no ventml octavus-system , receive by
nieans of the systema dorsale nervi octavi rootfibres to both nuclei
parvocellulares.

Each nucleus parvocellularis , a very impoi^tant nucleus of the
yjlj}^ nerves receive a bilateral innervation of rootfibres from
the ;/. octavus.

The rabbit has not such a bilateral distribution of rootfibres
towards the dorsal nucleus or towards any other of the'octavus-nuclei.

After one-sided removal of the labyrinth in rabbits also fibres are
found passing through the dorsal part of the raphe , but they only
reach the nucleus of the VP*" nerve.

The important bundle of root-fibres to the contralateral nucleus
parvocellularis however is proper to pigeons. In rabbits it is mis-
sing. And this is a fact of physiological interest.

Now the dorsal system is not exclusively formed by this bundle.
A great many transverse dorsid fibres enter from the portio interna,
and increase the quantity of rootfibres in the dorsal systema.

These fibres offer again many points of comparison with those
in rabbits.

Rootfibres in both animals are going to the homolateral nucleus
of the VP**, in both fasc. longitudinales posteriores, and to the
contra-lateral VP^ nerve.

In pigeons however the direct innervation of the homolateral
VP** nucleus is a slight one , and the innervation of the contra-lateral
VP^ nucleus through the fasciculus long, posterior is also slight,
as the greater number of rootfibres, found here in the contra-
lateral ftisciculus longitudinalis posterior, retires towards the contra-
lateral nucleus parvo-cellularis.

In this way, only a few rootfibres enter in both VP** nuclei.

At different levels however rootfibres enter again in both fasciculi
longitudinales posteriores, going to both nuclei of the IV^^ and of
the IIP*" nerve. Only a few fibres are reaching those nuclei.
Therefore in pigeons all motor nuclei of the eye on both sides are
only to a slight degree provided with octavus-rootfibrcs.

In rabbits there is a notable quantitative difference as regards
the innervation of the motor nuclei of the eye. As described there,

OF THE NERYUS OCTAVUS. 155

both nuclei of the Vr^ nerve are provided with a great many
rootfibres. There also the intensity of the innervation is nearly the
same on both sides.

But besides the less important innervation of the IV^*^ homolateral
nucleus through the fasciculus longitudinal posterior, there exists
the important homolateral ascendant Deiters tract, carrying rootfibres
to the IV^^ and IIP'^ nuclei.

Therefore in rabbits is found an intense innervation of both
nuclei N. VT, and a preponderant homolateral innervation of the
IV*** nucleus and the distal end of the IIP^ nucleus.

This again is a difference of physiological interest. In pigeons
rootfibres of the Vlir** nerve, go to all motor eye-nuclei. They are
few in number, bilateral in their paths, and nearly equal in number
on both sides.

In rabbits rootfibres of the VIIP^ nerve also supply them. Many
of them provide both VI^*^ nuclei, but the homolateral IV^** and
III*^ nuclei are supplied by a much larger number of them than
the contralateral.

As to the descendent rootfibres, the difference is less considerable.
In rabbits as in pigeons there are found prepondering rootfibres
in the homolateral fasciculus anterior of the cord , and in both it
is doubtful whether there are found rootfibres in the descending
tract of Deiters in the lateral column.

Their path has been exactly described. The chief results there-
fore of the investigation of the rootfibres in pigeons are.

Pigeons have no ventral systema N. octavi. Their dorsal sysieina
is very important. The angular y the parvocellular and the magno-
cellular nuclei are intercalated in it as the tubercnlum acusticuniy the
dorsal nucleus N. Fill and the nucleus of Deitkrs are in mammalia.

The former two receive the endiiigs of rootfibres. Not the magno-
cellular nucleus.

Through the dorsal system the rootfibres of one N. octavus provide
both nuclei parvo-cellulares.

Through the dorsal system the motor eye-nuclei receive a bilateral,
symmetrical, but a very slight innervation of octavus-root fibres.

Through the dorsal system the homolateral motor horn of the
spinal cord — at least in its cervical part — receives a not un-
important innervation of root-fibres.

Chapter IV.

The influence exerted upon motility by the N. octavus

in rabbits and in pigeons with regard to the

central distribution of this nerve.

After the minute description of the anatomical details of the
octavus-systems , given in the preceeding chapters, an endeavour
may now be made to bring the central distribution of this nerve
in connexion with the physiological facts found after its section.
Especially the motor disturbances following its section on one side
may now be proved to have a relative simple genesis.

The intact eighth nerve provides, as is generally admitted, the
integrity of two functions.

The first of these, a true sensory function, is the function of
hearing.

The other one, more difficult to define, has been called by a
happy conception of Ewald, the tonic function of this nerve.

As regards hearing, there are strong arguments to postulate,
that fibres of the octavus-systems, conducting central ward the im-
pulses received by the irritation of ciliated cells in Corti's organ,
after having been interrupted many times f. i. in the ganglion of
the corpus quadrigeminum posticum and of the corpus geniculatum
mediale reach the temporal part of the cortex cereboi.

In that area of the cortex the perception of sound should be
localisated.

In regard of the tonic function of the N. octavus, it has been
the purpose of this monography to study the fibres of the octavus-
systems in their central course to the motor nuclei in the mesen-
cephalon, the medulla oblongata and the spinal cord.

THE CENTRAL COUESE OF THE NERVUS OCTAVUS. 157

In their psychological aspect however a striking diflference does
appear between these two functions.

Consciousness directly teaches us, that we hear. Everyone knows
what is meant, when hearing is spoken of. The „perception of sound"
is an expression with a definite meaning for everyone.

On the contrary consciousness teaches us nothing about a tonic
octavus-f unction.

Nobody knows what is meant, when a perception of equilibra-
tion is spoken of.

This idea is a result from the penetrating researches of the phy-
siologists.

Nobody knows the precise limits of the meaning of expressions,
such as „perception of equilibrium" and „dizziness'' are and as
consciousness does not give us an immediate perception of the tonic
function, it cannot be otherwise.

It is necessary to retain in mind, this simple though important
and even fundamental psychological difference, which is too often
forgotten.

For instance, often a question was laid before me, that demon-
strates better than anything else the confusion around this matter.

If it is beyond doubt — so was asked — that the alterations
produced in Corti's cells by sound-waves, find their way to the
temporal lobe of the cortex cerebri and consequently perception of
healing is localisated in this defined area of the cortex — in which
part of the brain may then be localised the perception of equilibration.

Such a question should not be asked.

Wether a sharp difference between the functions of the cochlear
and the vestibular nerve may be admitted or not, never a sensory
function as the perception of sound — our hearing — is, ought
to be compared, with the influence upon the motility exerted by
the eighth nerve, even if there existed a conscious sensation of this
sensu-motor or tonic octavus-function.

A similar opinion was held by one of the first investigators in
this matter, by Flourens. This author, after describing the two
nerves by which the nervus octavus is composed, and having postu-
lated that the cochlear-nerve acts as a sensory nerve, preparing the
function of hearing, speaks of the vestibular-nerve. He says: „rautre
nerf, le nerf des canaux-semicirculaires, nest pas un nerf de sens;
il est done de la faculte singuliere d'agir sur la direction des
mouvements."

GoLTz also refers, in his sagacious deductions and experiments
on the functions of the labyrinth, to the fundamental fact, that

158 C. WINKLER, THE CENTRAL COURSE

in frogs, the specific disturbances of the equilibrium found after
removal of the labyrinth , are not at all influenced by the removal
of the prosencephalon.

The later minute experiments of Ewald upon dogs, teaching that
the motor disturbances following the removal of the labyrinth , are
compensated and corrected to a certain degree by the motor area
of the cortex cerebri, are not in the least in cojitradiction with
the here expressed opinion ^).

All these authors are disposed to defend the view that the
influence exerted upon motility by the N. octavus is merely an
automatic function , playing beneath the cortex cerebri , without any
direct participation of the cortex to its genesis and my anatomical
researches also support this opinion.

Nevertheless it may be argued , that the octavo-motor innervations
like all other sensu-motor innervations, though localisated in subcor-
tical centres > may come to a vague perception.

I do not deny a priori the possibility of the perception of
innervations. There may be alleged many facts in favour of the
„Innervations-Gefuhle" as they were called in german litterature,
or of the „somato-psychic perceptions*' as Wernicke has called
these perceptions in his eminent treatise on psycho-physics.

But even in that case no direct comparison is allowed between
those complicated and little-known sensations, with the true sensory
perceptions (the „allopsychic*' perceptions of Wernicke) as hearing,
seeing, etc. are.

Yves Delage has demonstrated in a most proving way, that
our orientation into space , depends not upon the altering periferical
irritations in the labyrinth, but upon the altering tonicity in the
muscles of the eyes and of the trunk.

These muscles are under permanent regulating control of optic
and kinaesthetic impulses, as well as under the control of laby-
rinthic impulses.

But here we also meet with automatic control of equilibration.

In my country, at fairs or other popular amusements, there is often
found a room with moveable walls, which may be turned round.

Benches are placed upon the unmoveable floor, wherein people
take place. As soon as the turning of the walls begins, as the

*) These experiments may perhaps be a clue to the understanding of an inconstant
result found sometimes, long after the removal of one labyrinth in youpg bom rabbits.
I stated once a total atrophy within the crossed motor area of the cortex, with
a rather intense atrophy of the anterior pyramis-tract of that side, nearly a year after
the operation. Less intensive atrophy of it was also seen.

OP THE NERVUS OGTAVUS. 159

attic displaces, it is very curious to see how people are thrown
topsy turvy — though the floor does not move — and how their
equilibration is disturbed, now that unusual optico-motor impul-
ses are giving unusual irritation to the muscles of the eyes and trunk.

Optic impulses, when moving, greatly influence the movements
of the eyes and the trunk.

Not only labyrinthic, but also optic and kinaesthetic afferent
impulses are excercising a permanent control upon those movements
in order to fulfil the purpose of maintaining the equilibrium. But
this coordinate action is an automatic one.

There are no arguments to accept, that it is produced by an
organon perceiving equilibrium and , after perception , correcting con-
sciously the perceived faults in aequilibration.

The customary position of our body being regulated in the same
way, by the same sensu-motor automatic innervations, there remains
a large problem for anatomical investigations to elucidate the paths,
by which the impulses parting from the periferical endings are
directly and indirectly conducted towards defined motor nuclei.

As far as our knowledge goes till now, they do not pass through
the cortex. Their being subcortical paths can be proved.

But if — as may be probable — the cortex should perceive the
subcortical innervations, taking place in that extensive complex of
tracts and centres, such a perception should be sought in the
psycho-motor area of the cortex.

Not only Ewald's experiments point to this view.

There may exist a perception of the summary of all octavo-motor,
optico-motor and kinaesthetic innervations, balancing each other and
maintaining a resultant motor-in nervation as a very vague sensation,
not clear enough to speak to consciousness as the common sensory
perception does.

Every sudden and important change in the whole of these sub-
cortical innervations must necessarily cause disordei-s in the customary
resultant motion or position, but on the other hand they may be
the cause of a more or less intense perceived desorientation of these
somato-psychic functions. The expression, we are accustomed to use
in order to indicate every somato-psychical desorientation of this
kind, is „ dizziness" or „ vertigo".

Therefore the vertigo is not the origin of motor disturbances,
but every sensu-motor disorder of this kind may awake the somato-
psychical desorientation, called vertigo.

All these questions however; whether there exists a perception
of equilibrium? how that perception is altered? what vertigo may

160 C. WINKIJai. THE CENTRAL COURSE

be? are all merely psychological questions, and they are treated
here to a certain degree conform whith the hypothesis defended
by James, Lange a. o. in regard to the origin of psychical emotions
in general.

But their elucidation may win nothing by treating here quite
another question, which is often mixed up with them, but that in
reality only regards the modus of stimulation of the periferical
endings of the N. octavus.

Many sagacious reasonings have been used in trying to analyze
the modus of stimulation of the cells found in the maculae and
at the cristae ampuUarum, since Goltz has called attention to the
position of the semicircular channels and to the possibility that
changes in the pression of the endolymph may act as a stimulus.
Rotation-experiments initiated long ago by Purkinje, repeated
by Breuer, Crum-Brown, Mach a. o., extended by Yves Delage,
Kreidl a. o. have worked out the ingenious presumptions of Goltz
to a serious hypothesis. But rotation-experiments are experiments
suited to study an irritation of the here analysed function. Inte-
resting as they may be, they neither have a direct relation with
the loss of function of the endings of the N. octavus as it is produced
by the removal of the labyrinth , nor are they very well suited to
study the perception of equilibration or the origin of vertigo.

They may teach that irritation of the end-organs alters their motor
innervation in a distinct way, and what is of far more importance ,
they may prove the existence of mechanical stimuli adaequate to
the ciliated cells in the vestibulum of another origin than sound-waves.

For instance, nobody may doubt that the loss of otoliths in lower
animals (Verworn, Loeb a. o.) may produce distinct motor disorders,
comparable with those after removal of the labyrinth. Rotation now
may perhaps prove that a dislocation of otoliths in a definite
direction is the cause to irritation of distinct octavo-motor inner-
vations, and even rotation-experiments may defend the existence of
a definite direction of sliding of the otoliths in the maculae sacculi
et utriculi. In that case I willingly accept, that the motion of the
otoliths in the supposed definite direction is a stimulus adaequate
to the cells in the maculae. But I only see in this modus of
stimulation, the beginning of impulses given to octavus-fibres and
conducted by them to the centre. Motor innervations are following
these impulses. They are the cause of motor disorders, but there
is not a single argument compelling us to accept, the changes in
motion, seen in such cases, to be a consequence of altered perception.

in the same way the results of rotation-experiments may be

OP THE NERVUS OCTAVUS. 161

used to argue that variations either in the motion or in the pres-
sion of the endolyraph may be stimuli adaequate to the ciliated
cells upon the cristae ampuUarum. Here again motor innervations
may follow these stimuli after their being changed in nerve-impulses,
conducted by octavus-fibres. Here again no single argument is
delivered to prove that the changes in motility following them ,
should be produced consequent to an altered perception. For my
purpose , that does not regard the modus of stimulation within the
labyrinth adaequate to the there found nerve-endings, rotation-
experiments are lying beyond the limits of my researches.

The adaequate stimuli cause the afferent impulses. These are
given to octavus-fibres and bound to their central course.

Therefore the study of the central distribution of the N. octavus
touches the questions mentioned above, but it remains within its
own limits.

Now this study offers , as I have tried to demonstrate , no facts
arguing a distinct separation in the way followed by the two
octavus-roots.

On the contrary my researches in rabbits teach, that each of
them , the cochlear as well as the vestibular root , after having entered
the medulla, divides in three trunks of rootfibres (pag. 53 — 57).

The dorsal trunk (the stratum latero-dorsale C. R.) though com-
posed for far the larger part, of dorsal rootfibres, receives a
considerable number of ventral or vestibular-fibres. (The ramus
intermedins N. octavi). The medial trunk , though composed nearly
totally of ventral rootfibres, receives a few fibres from the dorsal
root or cochlear-fibres. Both roots participate nearly equally to
the ventral trunk (the corpus trapezoides).

From these trunks originate the rootfibres in the three important
octavus-systems , and rootfibres together with fibres of secundary
systems are consfituating the dorsal , intermediary and ventral systems
of the N. octavus.

After rootsection, the roots and the trunks of root-fibres, atrophy
totally. Not so the systemata. They only partly — as far as root-
fibres are contained therein — degenerate and their atrophy never
is a total one (page 59 and 67).

With the roots and trunks however a great many of small cells
atrophy or rather disappear.

They are found along the dorsal trunk (in the nucleus proprius
of the dorsal root, in the disto-ventral portion and round the
ventral octavus-nucleus , in the stratum latero-dorsale, in the
deep layers of the tuberculum and in the lateral part of the dorsal

Verhand. der Kon. Akad. v. Wetensch. (Tweede SecUe.) Dl. XiV. H

162 C. WINKLEE. THE CENTKAL COURSE

octavus-nucleus) along the medial trunk (in the nucleus proprius of
the medial trunk) along its continuations , the descending and ascen-
ding roots (in the nucleus griseus rami descendentis , in the nucleus
Bechterew, in the dorsal nucleus of the n. octavus) and along
the beginning of the ventral trunk (in the olivary bodies).

These cells may be regarded as intercalated cells, making con-
nection between primaiy rootfibres and greater cells from which
secundary systems originate, helped sometimes for this purpose by
direct collaterals of rootfibres.

For instance both nuclei of the N. abducentes are certainly inner-
vated by direct collaterals of rootfibres of the descending root, the
homolateral facial nucleus receives directly rootfibres of Held's
intermediary system. A few rootfibres innervate directly the proxi-
mal motor nuclei of the eye^ by means of ascending rootfibres in
the fasciculus longitudinalis posterior.

The larger cells in the tuberculum acusticum and in the dorso-
proximal portion of the ventral nucleus, not disappearing after root-
atrophy and in that case undergoing only slight atrophical changes
after rootatrophy, receive root-collaterals but mostly are connected
to the root-fibres by means of intercalate cells.

The gigantic cells in the nucleus of Deiters, not or nearly not
altering after root-atrophy, do not receive any direct collaterals of
the roots. Their connections with rootfibres are only made by means
of numerous cells found in the corpus juxtarestiforme (nucleus
griseus rami descendentis, nucleus Bechterew) and in the dorsal
octavus-nucleus, surrounding the nucleus of Deiters on all sides.

These cells are forming links between rootfibres and the very
important octavo-motor secundary systems, issued from the cells
of Deiters.

They are two important tracts. The one, the ascending Deiters tract,
connects those cells to the nucleus of the trochlear nerve and the
distal part of the oculomotor nerve. The other, the descending
Deiters tract, connects them, to the nuclei of the Vr**, VIP*",
X^^, Xr^, nerves, to the nuclei in the formatio reticularis late-
ralis of the oblongata and through the lateral column with the
motor horn of the cervical cord. It may even be pursued, though
much reduced, towards the sacral portion of the cord (page 119 — 125).

These secundary systems are chiefly homolateral tracts. A few of
their fibres only enter in the homonymous contralateral tracts. They
are accompanied by a few primary rootfibres.

In this way the first and most important octavo-motor system
is constituted.

OF THE NEEVUS OOTAVUS. 168

But it is not the sole octavo-motor system.

From Deiters cells, from the large cells of the tuberculum
acusticum and from the ventral nucleus new secundary systems issue.
They all cross the raphe, be it either as transverse dorsal fibres,
or as MoNAKow's fibres, or as Held's intermediary fibres.

Before doing so, however, they send ascending fibres in the
fasciculus longitudinalis posterior providing the nucleus of the N.
abducens and the proximal motor eye-nuclei. They send also des-
cending fibres to the nucleus of the XIl*** nerve , and through the
fasciculus praedorsalis, the anterior column and the anterior commissure
towards the cervical part of the motor horn of the spinal cord,
and though much reduced in number even to the thoracic and
lumbo-sacral part of it. Moreover transverse dorsal fibres inner-
vate the contra-lateral nucleus of the n. abducens to a considerable
degree.

In this way new homolateral tracts, though they have a slight
representation in the homonyme tracts of the opposite side, originate.
They chiefly are composed of secundary fibres accompanied by a
few rootfibres, in the beginning of their course. They may be
considered as another homolateral octavo-motor system , not quite
so important as the tract of Deiters but still considerable enough
to be mentioned. <

There are however still other octavo-motor systems, perhaps of
greater complexity.

We have seen a small quantity of rootfibres and of secundary
fibres reach the homolateral ventral spinal cerebellar ascending tract
(Gower's antero-lateral tract) and seeking on this way , in the path
followed by ascending spinal fibres , the homolateral as well as the
hetero-lateral medial nuclei tecti. Moreover some rootfibres pene-
trating through Bechterew's nucleus directly enter into those nuclei.

Now , as VAN Gehuchten , controUing researches of Russeu. ,
Thomas , Probst has proved ^) , from the medial nuclei tecti , a tract

*) I can completely affirm van Geiiuchten's statement, that after the medial trans-
verse section of the cerebellum on both sides a tract degenerates, at first ascending along
its internal border, then bending round the pedunculus superior, redescending lateraly
from it, between the spino-cerebellar ascending ventral tract and bracchiumconjunctivum
peduncnli superioris to seek its place between area ovalis C. E. and the spinal root of
the fifth nerve. It sends endings, methinks , among the nucleus Bechterew , Deiters and
nucleus griseus r. descendentis, and a few fibres (van Gehuchten*s bifurcation) may
find their way in the descending tract of Deiters; whereas other fibres still descend
towards the nucleus of Burdach.

I believe the here described tract to be a constituent of the congenial system of
kinaesthetic nature, rather than of octavo-motor nature, and I therefore mean the
experiments upon this bundle to be beyound the limits of these researches.

11^^

164 C. WINKLER. THE CENTKAL (JOURSE

descends in the lateral fillet, medial from the ventral spino-cere-
bellar ascending tract, to the lateral part of the corpus juxta-
restiforme, and having endings between the cells found there.

Here is another sensu-motor way, not so very important in regard
to octavus-impulses , but very important in regard to the congenial
kinaesthetic impulses, relying fibres from the two medial nuclei
tecti with the corpus juxta-restiforme and the nucleus of Deiters.

And at the same time we have seen a small quantity of fibre^s
mostly secundary, descend homolaterally into another known way
towards the horn of the spinal cord, in the so called rubro-spiual
tract. Here is another sensu-motor way, not very important, I
think, in regard to octavus-impulses, but touching to systems
issued from the red nucleus, whose relation to optic impulses is
probable, but as yet, insufficiently known.

Resulting from the details given in the second chapter, there
are demonstrated in rabbits important, mostly secundary, but to
a slight degree primary systems, forming connecting links between
the end-organs of the N. octavus and different homolateral motor
nuclei. The most important of them are the two first mentioned systems.

They connect the labyrinth-nerves to both nuclei of the N. abdu-
cens (ramus descendens N. octavi, fasciculus longitudinalis posterior
and transverse rootfibres) , to the homolateral trochlear-nucleus and
the distal oculomotor-nucleus (tractus Dkiters ascendens, fasciculus
longitudinalis posterior), to the homolateral motor nuclei in the
medulla oblongata, to the cervical motor horn of the medulla spinalis
and even to the thoraco-lumbal part of it (tractus Deiters descen-
dens, fasciculus praedorsalis and tractus rubro-spinalis).

In this way it may be understood, why after one-sided removal
of the labyrinth or after rootsection, in rabbits motor disorders of
the eyes appear, different on both eyes.

The homolateral eye misses the usual innervations of the N.
abducens, N. trochlearis and a part of the N. oculomotorius. If
this loss be complete, a forced position is seen towards the inner
canthus and downward, if incomplete, jerks of nystagmus tend to
produce this forced position. The influence of the remaining im-
pulses upon the proximal motor eye-nuclei is sufficient to explain
this position.

The contralateral eye only misses the usual innervation of its N.
abducens. Under the influence of the remaining impulses it is turned
laterally or dorsalward (pag. 19).

And in the same way it may be understood, why rabbits having
lost a preponderant innervation of the cervical motor spinal cord.

OF THE NERVUS OCTAVUS. 166

show the peculiar position of neck and head towards the operated
side under the influence of the remaining contra-lateral impulses
and are atonic at the homo-lateral, especially at the fore-leg.

The anatomy of the octavus-nerve may be fit to explain (p. 27)
the facts, that physiologists have taught us to be consequent to its
loss on one side, as regards the motor functions of the nerve.

Atony in all the homolateral muscles of head, neck and shoulder,
together with an incomplete relaxation of eye-muscles, differing on
both sides, may be sufficient to explain the forced position of head ,
neck and eyes towards the lost impulses. The correction of these
forced attitudes, following immediately on the removal of the second
labyrinth, their being replaced by a general atony in all muscles,
is in perfect accordance with the here adopted anatomical views (p. 37).

All disorders of motility however are produced without any inter-
ference of a conscious sensation of equilibrium.

Anatomically spoken, they are produced in subcortical systems.

Physiologically spoken, they are automatic motions.

Moreover the anatomy teaches us, that rootfibres of both roots
may contribute to the diflFerent octavo-motor subcortical systems.

Another important octavus-system however exists, the details of
which are described in the second chapter, equally composed of
diflFerent fibres and centra.

The greater part of all fibres composing it crosses the raphe before
taking an ascending course.

From those the most interesting are Monakow's fibres. Issued
from the dorsal system, and without any doubt being axons from
the large cells in the tuberculum acusticum, they reach, through
the dorsal layer of the crossed oliva superior, the medial bundle
of the internal and lateral fillet. Before crossing the raphe they
send descending fibres (collaterals) in the fasciculus praedorsalis of
the octavo-motor system.

In the lateral fillet they meet with fibres of different origin, but
taking all a part of their way in the ventral or in the intermedi-
ary octavus-system.

A few of them are rootfibres, more are originating in the crossed ven-
tral octavus-nucleus, still more in the crossed oliva superior and nucleus
para-olivaris. A great many of them issue from the homolateral nucleus
trapezoides and from the homolateral nucleus ventralis lemnisci.

All together they participate to the very complicated tract, which
is called the lateral fillet. The greatest number of them is medul-
lated at birth (root-fibres, Held's fibres, the layers a and h in the
corpus trapezoides, and a part of Monakow's fibres), others have

166 C. WINKLEE. THE GENTRAL OOUBSE

not yet myelin at that time (the stratum c of the corpus trape-
zoides, a large part of Monakow's fibres).

The ventral spino-cerebellar ascending tract only for a short time
is a constituent of the lateral fillet, as it soon takes its distal way
to the nuclei tecti, and the descending hook-like bundle, descending
from the nuclei tecti towards the corpus restiforme, also soon leaves it.

But the remainder of its fibres are going proximally, towards
the nucleus corporis quadragemini posterioris, to the corpus geni-
culatum mediale and to the sub-thalamic region.

Whatever now may be the function, probable a very complica-
ted sensu-motor function of the corpus quadrigeminum posterius
is unknown. So much is sure, that its ablation never causes the
forced attitude of eyes, head and neck, characterising the rootsec-
tion of the octavus, the ablation of the tuberculum acusticum, the
lesion of the DEiTERS-nucleus, shortly all operations in the region
of the corpus juxta-restiforme. Nevertheless its ablation produces
contmlateral motor symptoms, diflFerent from those after rootsection,
probable bound to proper afferent fibres

On the other hand it is stated, that in the corpus geniculatum
mediale is the origin of direct centripetal fibres to the temporal
cortex cerebri, where hearing is localisated, and therefore it is
evident, that among the fibres in the lateral fillet must be sought
those, whose function is to conduct true sensory or acustic impul-
ses to the cortex.

As we have seen, this fillet system is chiefly a contra-lateral system.

It however has a homo-lateral representation. After lesions in the
dorsal or ventral octavus-system its degenerations prevail contra-
laterally, but are not missing homolaterally. The contrary was the
case in the octavo- motor system. Degenerations in it were prevailing
homolaterally but were not missing contra-laterally.

Therefore, we may speak of a differentiation within the central
system between the chiefly homolateral octavo-motor system and the
chiefly contra-lateral sensory octavus-system.

But it must be kept in mind, that this differentiation is not at
all a sharp one. Both systems are originating from the dorsal, the
intermediary and the ventral octavus-systems, and as we have seen ,
in describing details, often those octavo-motor and sensory-octavus
systems are provided by the same fibres.

For instance, Monakow's fibres, true sensory-octavus fibres, send
fibres (collaterals) in the octavo-motor system through the fasciculus
praedorsalis, and on the contrary, from true octavo-motor tracts as
the ascending and descending Deiters tracts are, transverse fibres

OF THE NERYUS OCTAYUS 167

(collaterals) issue taking their way through the raphe in Monakow's
system. In relation with the anatomical views here defended it
may be easily understood, that the removal of one cochlea needs
give only very slight motor disorders, and that these disorders are
necessarily of the same kind as those following the removal of one
labyrinth, but less intense and of shorter duration.

For, the dorsal root is the smaller one of the two roots of the
nervus octavus. The number of its fibres may be estimated to be
one fourth of that of the ventral root. Moreover the greater part
of the dorsal root fibres enters into the stratum latero-dorsale and
the octavo-motor systems receive a much smaller quantity of fibres
from this layer than from the medial trunk of the rootfibres.

No wonder that the motor symptoms following the one-sided
loss of the dorsal rootfibres are less intense and more apt to cor-
rection by the remainings of the octavo-motor system, than those
after the loss of the whole labyrinth on one side.

On the other hand the dorsal root prevails in the innervation
of the ventral octavus nucleus and of the tuberculum acusticum
above the ventral root, and it henceforth is evident, that the loss
of fibres participating to the crossed octavus-system , may be intense
after cochlea-removal. Ventral rootfibres participating to this system
are however numerous enough to justify the presumption of their
influencing to a rather important degree upon this system, the
function of which was presumed to be the conduct of the perception
of sound. I do not see any contradiction between the here defended
views and the known facts.

From the contents of the vestibulum the macula sacculi has its
own nerve and this nerve issues from the cochlear nerve. Hence
this fact does not argue in favour of a sharp functional difference
between the macula sacculi and the cochlea, and the macula sacculi
has great morphological relations with the macula vestibuli.

The morphological differences between the roots founded upon the
presence of thick or of small fibres found in them , are also relative.

It is easily assumed, that a differentiation of the static organ
into a cochlea and a vestibular organ, did never lead to a total
but only to a partial separation of two functions, existing both in
the organ, from which the differentiation took place. Why should
animals having no cochlea or an incomplete developed one, not
perceive sounds?

Theoretically it offfers no difficulties to assume, that the original
static organ did not lose all its existing contacts with the sensory
system, and that the new differentiated one, the cochlea, did retain

loo

tacts ^itb the octavo-motor systems. The
A rest of the existing c ^^^^^^ ^^^ appropiate nerve-endings to be

static P'fl^l'^^^^^^ blows brings a part of them - the

stimumtei ^ r^rrevtion, and a farther developement of this

sound-waves — ^^ pei^ t" ^ r

Zrception was of great psychological importance.

\f t of these however — sound-waves as well as all changes
> do/vniph or in otoliths — produce sensu-motor impulses, to
wich only a vague perception is associated. From these no farther
psychical developement took place, but they gave rise to an auto-
matic motor function of high developement and of an enormous
importance for the animal.

In this way I am viewing the functions of the labyrinth related
to the central distribution of the N. octavus.

Now, as we have seen in the second chapter, in rabbits the
octavo-motor systems were chiefly homo-lateral, and their slight
contra-lateral representation was neglected. The sensory octavus-
systems , neglecting their less numerous homo-lateral representation,
were chiefly crossed systems.

The neglection of the homolateral or crossed systems however
is no longer permitted in regard to the octavus-systems in pigeons.
Their anatomical peculiarities, told in the third chapter were as
follows.

Firstly, the dorsal root was unimportant, perhaps in account
with the incomplete developed cochlea — the lagoena.

Secondly, and perhaps consequent to this, the tuberculum aciis-
ticum and the ventral octavus-nucleus were not yet differentiated.
They were represented in pigeons by a relative important nucleus,
the nucleus angularis, where as the ventral and the intermediary
octavus-systems were totally or nearly totally absent.

Thirdly, the ventral root having an important radiation in the
oblongata, together with the dorsal root, provides with direct root-
fibres the octavus-nuclei — the so-called nuclei parvocellulares —
of both sides. From these nuclei representing the dorsal octavus-
nuclei an important systenia dorsale nervi octavi issues, more con-
siderable than in rabbits. Through this dorsal system direct rootfibres
from one side reach as well the nucleus parvocellularis as the
corpus juxtarestiforme at the other side.

Fourthly , the nucleus magnocellularis, representing Deiters nucleus,
and the „ Acusticusfeld" representing the area of the radix descendens
and ascendens, with its grey masses (Bechterew's nucleus), are
without doubt similar organs , from which octavo-motor systems issue,
as they are in rabbits.

OF THE NERVUS OCTAVUS. 169

In this way, in pigeons, one N. octavus influences upon the
octavo-motor systems of both sides, though that influence is still
prevailing upon the homolateral system. Consequently there must
result a diflference in their physiological behaviour after the loss of
one labyrinth, if compared to rabbits.

From this anatomical view however a part of the motor distur-
bances, in pigeons difierent from rabbits may be undei'stood.

In rabbits the loss of one labyrinth immediately after the opera-
tions causes grave disturbances , forced attitudes of head , neck and
eyes to a maximal extensity and consequently rollings. Maximal
after the operation, those disorders undergo correction until a certain
amelioration is reached, nothing more. A part of the forced attitudes
remains permamently.

In pigeons, the loss of one labyrinth, has no immediate eflfect.
If it is sought for , atony may be found to prevail on the operated
side, but the non-operated side being damaged by the operative
shock to a rather important degree, is not yet capable of main-
taining a forced attitude. If correction occurs, it first is observed
at the less damaged side; and therefore at the third day, the
forced attitudes begin.

The influence of the intact N. octavus upon the octavo-motor
systems of both sides, though homolaterally prevailing, is important
enough to maintain automatically the usual position and to prevent
forced attitudes, sustained as it is by unaltered kinaesthetic and
opticomotor impulses, as long as the animal is quite at ease. It
does so , nonobstant the loss of one labyrinth.

But as soon as periferical stimuli (kinaesthetic, or optico-motor,
or octavo-motor of the sound side) or central stimuli (volition, emotion)
act, suddenly the diflFerent amount of innervation at the two sides
becomes evident and suddenly the forced position of the head, not
at all differing of that seen in rabbits, appears.

In this way during the first days after the removal of one cochlea
a pigebn bears itself as if it were incompletely atonic on both
sides, though atony at the operated side prevails. Afterwards it
behaves at intervals, as if one side were atonic, but only in cases
when the different amount of innervation of the two sides is brought
forward by augmentation of stimulation.

In pigeons, each N. octavus, sends a not veiy important number
of rootfibres towards all eye nuclei on both sides. They therefore
never show such a peculiar forced attitude of each eye as rabbits
do after the loss of one labyrinth.

That pigeons with their long neck, having lost one labyrinth, do

170 C. WINKLEE. THE CENTRAL OOUBSE ETC.

not roll like rabbits, but prefer, turning the head voluntary until
360° has been demonstrated long ago by Ewajj).

,As soon as both labyrinths are lost, the similarity of the motor
disorders in the two species of animals is striking again. All muscles
are atonic. To this in rabbits there is perhaps one exception difficult
to explain, as the motor V^** nucleus stands unaltered among the
degenerate fibres of the octavus-system.

In fact however, the difference of the motor disorders foUowing
the loss of one labyrinth, apparently so great between rabbits and
pigeons, is in accordance with the diflferent anatomical distribution
of their nervi octavi.

There may arise many controversions upon the subject to what
extent in different animals primary rootfibres are found in the
secundary systems. I do not believe these controversions to have
a fundamental value. The preponderance of the secundary systems
augments with the relative high development of the whole octavus-
system. They subentrate for the primary fibres.

For instance in dogs, there are found less numerous primary
fibres between the secundary of the corpus trapezoides than in rab-
bits and if Van Gehuchten be right, in guinea-pigs they should
be missed totally there.

I for myself believe, that even among animals of the same
species the relation between rootfibres and secundary is different
too. In rabbits for instance, in the corpus trapezoides, it may vary
from a few only to very many, but I never missed them there.

Of more value and still more determining the physiological be-
haviour of one-sided operated animals, the correction of the motor
disturbances seem to me. There may be a correction by means of
the ameliorated function of the remainings of the damaged system,
and there may be one, by means of substitution of quite other systems.

I do not believe that in rabbits the lost function is much restored
neither by the same-sided cerebellum, nor by the motor area of
the cortex cerebri, at least substitution of all lost function is
impossible there. Yet I found — though not constant — atrophy
of the same side of the cerebellum and of the motor area in the
cortex, if new-born animals were operated long ago.

Such atrophies necessarily are tertiary atrophies and therefore
they are inconstant. They may perhaps throw new light upon the
different manners in which substitution of the motor disorders may
occur after the loss of the labyrinth.

Explication ol the Plates and

description of the Figures and the

abbreviations.

Plate I.

Fig. la. A frontal section through the left half of the oblongata
of a rabbit, at the entrance of the distal (dorsal) root
15 days after removal of the left cochlea.

Fig. \h. A frontal section through the right half of the same
oblongata at the same level (both treated with Marchi). ^)

Py. = Pyramis anterior.
Lemn. med. = lemniscus medialis (principalis),
nucl. N. VII z=: nucleus of the facial nerve.

Ab. S. B. = MoNAKOW*s aberrirendes Seitenstrangbundel.
Tr. Deit. desc. — tractus Deitees descendens.
Corp. trap. =: corpus trapezoides.
r. d. N. VIII = radix dorsalis nervi octavi.

Ar. ov. =: area ovalis corporis restiformis (pedunculi cerebelli
inferioris).
fibr. dors, trans. = librae trans versae dorsal es.
Port. int. C. R. =: portio interna corporis restiformis.
Str. 1. d. =1 stratum latero-dorsale.
Tub. ac. = Tuberculum acusticum.
Str. prof, tub, ac. =: stratum profundum medullare tuberculi acustici.

I? z=i area with normal fibres between the degenerated fibres
in the stratum latero-dorsale.
str. 1. d. e tub. ac. = stratum latero-dorsale e tuberculo acustico.
str. 1. d. e. nucl. ventr. = // // // e nucleo ventrali nervi octavi.

a = inner layer of degenerated fibres of the stratum latero-
dorsale, giving fibres to the intermedial system of the
VIIIt»> nerve.

') The lithograph has turned the original drawing. Therefore the left side has

become the right one.

172 C WINKLER. THE CENTRAL COURSE

6 z:z outer layer of those fibres, from whiph a part of the
dorsal transverse fibres originate,
r. desc. N. VIII zz radix descendens nervi octavi.
nucl. dors. N. VIIT rz nucleus dorsalis nervi octavi.
Nuol. ventr. N. VIII =r nucleus ventralis nervi octavi.

f. 1. p. =1 fasciculus longitudinalis posterior,
f. pr. d. zz fasciculus praedorsalis.

The dorsal root is degenerated at the left side. Thedistri-
bution of its degenerated fibres is described in Chapter II.

Fig. 5. A frontal section through the medulla oblongata of a
foetal cat (just born) (treated with Weigert-Pal), at the
entrance of the nervus octavus. The myelinisated fibres
are blackened. The same indications are given as in fig. 1.
Moreover, there are found:

c. trap. syst. ventr. a = Systema (ventrale) a in the corpus trapezoides.

c. trap. syst. dors, b r:= Systema (dorsale) b in the corpus trapezoides.

c. trap. syst. dors, c ~ Systema . (dorsale) c in the corpus tradezoider.

syst. dors, d zz: syst. intm. — Systema (dorsale) d in the corpus trapezoides or the

intermedial system of the nervus octavus.
nucl. trap. =: nucleus trapezoides.
nucl. par. oliv. — nucleus para-olivaris superior,
nucl. ol. sup. := nucleus olivaris superior.
N. VI iz: abducens-nerve.
r. ventr. N. VII[ — radix ventralis nervi octavi.
fibr. rad. N. VII =: fibrae radiculares of the facial nerve,
nucl. Driters =: nucleus Deitees.
Tr. Drit. desc. =: tractus Deiters descendens.
Str. sup. tub. ac. — stratum superficiale medullare tuberculi acustici.
r. sp. N. V. = ramus spinalis of the nervus trigeminus,
h ::^ str. int. = fibres of Held or the intermedial system of the ner-
vus octavus.

Plate II.

Fig. 2. A frontal section through the medulla of a rabbit after
retnoval of the left cochlea , at the entrance of the ventral
octavus root (treated with Marchi-method). The extra-
medullar ventral root is free of degeneration.

fasc. 1. p. = fasciculus longitudinalis posterior,
genu N. VII = genu nervi facialis.
N. VII 1= radix nervi facialis,
nunc. dors. j =: nucleus dorsalis

r. desc. i ^:= radix descendens

a. z^ syst. interm.f = systema intermedium

b, T^ syst. dors. ' > N. VIII = systema dorsale ^ nervi octavi.
nucl. ventr. I = nucleus ventralis
r. dors. 1 := radix dorsalis
r. ventr. I =: radix ventralis

n. gris. r. desc. = nucleus griseus radicis descendentis.
str. med. :::: stria medullaris.

OP THE NERVUS OOTAVUS. 173

nucl. Deit. zz: nucleus Deitees.

Port. int. C. R. =z portio interna corporis restifonnis or corpus juxta-

restiforme.

Ar. oy. C. B. rz area o?alis corporis restifonnis.

Tub. ac. = Tuberculum acusticum.

r. spin. N. V. r=: radix spinalis ) . .

f. gel. N. V. zr formatio gelatinosaradicis spinalis 1 ^^^^^ tngemini.

n. ol. sup. = nucleus olivaris superior.

n. par. ol. sup. =: nucleus para-olivaris superior.

n. trap, iz: nucleus trapezoides.

N. VI :=: Nervus abducens.

nucl. N. VI 1= nucleus Nervi abducentis.

str. ventr. a. ) . =z stratum ventrale a. ^ . ^ .,

. , 5 c. trap. i. i. 1 1 ( corporis trapezoides.

str. dors. c. J ^ = stratum dorsale c. ( "^ ^

str. 1. d. i:r stratum latere dorsale.

str. 1. d. e. tub. ac. =z stratum }atero dorsale e tuberculo acustico.

str. 1. d. e. n. ventr. n: stratum latero-dorsale e nucleo ventrale.

Py. =r Pyramis.

fasc. praed. = fasciculus praedorsalis.

lemn. med. = lemniscus medialis.

Plate III.

Frontal sections through the medulla oblongata of a
rabbit, one year after the removal of the right labyrinth,
with octav US-section, in the young born animal.

In fig. 3 a. a frontal section through the right (atrophied) tuber-
culum acusticum is drawed at the entrance of the dorsal
root. (Preparation of Weigert-Paii).

In fig. 3 b. The corresponding frontal section through the left
(normal) tuberculum acusticum at the same level. (Pre-
paration as in fig. 3a).

In fig. 13 a. The frontal section through the right nucleus of
Deitbrs. (Preparation with picro-carminas ammoniac).

In fig. 13 b. The frontal section through the left nucleus of Deiters
(Preparation as in fig. 13a).

N. Dors. N. YIIl. ~ nucleus dorsalis N. octavi.

Port. int. C. R. = corpus juxtarestiforme or portio interna corporis
restifonnis.
str. med. sup. Tub. ac. =: stratum medullare superficiale tuberculi acustici.
str. med. prof. Tub. ac. = stratum medulare profundum tuberculi acustici.
str. 1. d. = stratum latero-dorsale corporis restifonnis.

-p ' 1 ' ^' y.yr J =: radix lateralis (dorsalis) N. octavi.

R. Spin N. V. rr radix spinalis N. quinti.

N. yentr. N. VIII = nucleus ventralis N. octavi.

Nucl. N. VII ~- nucleus N. septimi.

A. R. Ov. C. R. ^r Area ovalis corporis restifonnis.

H. 13 fesc. interm. N. VIII n^ Hbld's intermedial systema N. octavi.

174

C. WINKLER. THE CENTRAL COURSE

N. Deitebs. = Nucleus of Deitbiis.
N. Dors. (cell. lat. c) — nucleus dorsalis N. octavi (cellulae laterales).
N. Dors. (cell, ventr. d) zn nucleus dorsalis N. octavi (cellulae ventrales).
N. Dors. (cell, centr. 6) z^ nucleus dorsalis N. octavi (cellulae principales).
N. Dors. (cell. med. a) =z nucleus dorsalis N. octavi (cellulae mediales).
Nucl. N. VI (e) rr nucleus N. abducentis.
N. gris. r. desc. N. Vlir. =: nucleus griseus radicis descendentis N. actavi.
R. ventr. N. VIII zn radix ventralis N. octavi.

Plate IV.
Fig. 4. An oblique and frontal section through the left half of the
oblongata of a rabbit, 17 days after the removal of the
left labyrinth. The section touches the entrance of the
left (degenerate) dorsal root of the N. octavus.
Fig. 8. An oblique and frontal section at the entrance of the left
(degenerate) ventral root (the medial trunk of rootfibres)
of the same animal.

(Both preparations are treated with Marchi-method).

Pars, ventr.-med. n. ventr. N. VIII =:

r. dors. N. VIII =
Pars, dore.-lat. n. ventr. N. VIII zz

Str. pr. tub. ac. =

N. Deitebs =
N. tecti ~

D, V. fibr. rad. e. r. ventr. N. VIII =:

r. spin. N. V. zr

r. desc. N. VIII =z

st. =z f. interm =:

N. dors. N. VIII =

C. R. =

r. ventr. N. VIII =:

P. cer. sup. (Bracch. conj.) =

N. Becutkrew =

N. Dors. (cell, lat.) N. VIII zz

N. Dors. N. VIII (cell, princ.) =

N. gris. r. desc. z=

Aquaeductus zz

Genu N. Vlt __

F. L. p. =r

N. N. VI =

Plate V.

Portio ventro-medialis nuclei ventralis N.
octavi.

radix dorsalis N. octavi.
Portio dorso-lateralis nuclei ventralis N.
octavi.

stratum medullare profunduni tuberculi acus-
tici.

nucleus of Deiters.

nuclei tecti cerebelli (lateralis = nucleus
dentatus and mediales).
degenerate fibres penetrating through the oval
area from the radix ventralis N. octavi.
radix spinalis N. trigemini.
radix descendens N. octavi.
H eld's systema intermedium N. octavi.
nucleus dorsalis N. octavi.
corpus restiforme.
radix ventralis N. octavi.
pedunculus cerebelli superior,
nucleus of Bechterew.
nucleus dorsalis N. octavi (cellulare laterales).
nucleus dorsalis N. octavi (cellulae princi-
pales).

nucleus griseus radicis densendentis N. octavi.
Aquaeductus Sylvii.
genu N. facialis.

fasciculus longitudinalis posterior,
nucleus N. abducentis.

Horizontal sections through the right half of the me-
dulla oblongata three weeks after the removal of the
right labyrinth in a rabbit.

OP THE NERVUS OCTAVUS. 175

Fig. 9. This section touches the entrance of the ventral root and
its division in a descending and in an ascending root.

Fig. 10. This section touches more dorsally the bracchium con-
junctivum of the peduncuhis cerebelli superior and its
entrance in the mesencephalon.

(Both preparations are treated with Marchi-method).

R. dors. N. VIII iz: radix dorsalis nervi octavi.
P. ventr.-dist. n. ventr. N. VJI£ — portio ventro-distalis nuclei ventralis nervi octavi.
H = f. int. -j-r. dors, ad r. ventr. = Held's intermediary system + fascicalis inter-

medius dorsalis ad radicem ventralem.
P. dors. lat. n. ventr, N. VI I £ zz: portio dorso-proximalis nuclei ventralis nervi

octavi.
ar. ov. C. R. =: Area ovalis corporis restiformis.
N. sens. N. V. r= nucleus sensorius nervi trigemini.
Pes. cer, ad. pont. =: Pes cerebelli ad pontem.
Nucl, ventr. lemn. 1. zn nucleus ventralis lemnisci lateralis.
L. L. zz lemniscus lateralis,
nucl. gris. r. desc. N. VII [. =: nucleus griseus radicis descendentis nervi octavi.
N. Dors. N. VllI =z: nucleus dorsalis nervi octavi.
N. Deitees =z nucleus Betters.
S}'st. dors. N. VIU 1= systema dorsale nervi octavi.
nucl. Mot. N. V zz: nucleus motorius nervi trigemini.

form. ret. lat. =: Area lateralis of the formatio reticularis,
f. 1. p. zz: fasciculus longitudinalis posterior.
N. Daek. zi: nucleus Darkschevhtsch.
Corp. restif. =: corpus restiforme.
N. Bechterew zz: nucleus Bechterew.
Tr. Deitees asc. = Tractus Deitees ascendens.
r. desc. N. VII [ =: radix descendens nervi octavi.
L. L. ad c. q. p. =: Lemniscus lateralis ad corpus quadrigeminum
posticum.
N. dors. L. L. zz nucleus dorsalis lemnisci lateralis.
Ped. cer. sup. ==: pedunculus cerebelli superior.

Plate VI.

Fig. 19 a. B. Sagittal sections through the medulla of a not yet
born rabbit near the entrance of the octavus-roots.
(Weigert-Pal preparations).

r. N. V zz radix nervi trigemini.
r. N. VII zi: radix nervi facialis.
A. prox. (ventr.) N. VIII zz radix proximalis (ventralis or medialis) nervi octavi.
r. dist. (dors.) N. VI [I zz radix distalis (dorsalis or lateralis) nervi octavi.

f. interm. rad. iz: intermedial rootlet going from the proximal to the
distal octavus root,
c. trap, rz: corpus trapezoides receiving fibres from the distal and
from the proximal root als well as from the.
n. ventr. N. VUI zz: nucleus ventralis Nervi octavi.
tub. ac. zz tuberculum acusticum.

176 C. WINKLESR. THE CENTKAL COURSE

Fig. 19 c. A Horizontal section through the medulla of a not yet
born rabbit at the level of the genu N. facialis.
(Weigert-Pal preparation).

r. N. Ill :-- rootlets of the nervus oculomotorius.
tr. Deit. asc. iz: tractus Disitebs ascendens.

f. 1. p. iz: fasciculus longitudinalis posterior,
str. med. s. syst. dors. = stria medullaris sive systema dorsale nervi octavi.
1. lat. Z3 lemniscus lateralis,
u. ventr. 1. 1. ~ nucleus ventralis lemnisci lateralis.
P. Var. rz Pons Varoli.
f. sp. cer. ventr. = fasciculus spino-cerebellaris ascendens ventralis.
n. mot. N. V — motor nucleus nervi trigemini.
r. mot. N. V nz motor radix nervi trigemini.
gen. N. VII =: genu nervi facialis,
r. med. N. VIII -- radix medialis nervi octavi.
r. dors. N. VIII = radix dorsalis nervi octavi.
n. ventr. N. VIII = nucleus ventralis nervi octavi.
corp. R. = corpus restiforme.
r. desc. N. VIII ==: radix descendens nervi octavi.
nucl. N. VI =: nucleus Nervi abducentis.
f. sol. N. X =: fasciculus solitarius nervi vagi,
r. spin. N. V =: radix spinalis Nervi trigemini.
nucl. N. IX and N. X ^^ nucleus Nervi glossopharyngei and nervi vagi.

Fig. 6. A Cell-preparation of the normal tuberculum acusticum
(After a Nissl preparation).

n. pr. r. lat. N. VIII =: nucleus proprius radicis lateralis nervi octavi.
cell. parv. str. med. t. ac. =: cellulae parvae in the stratum griseum medium

tuberculi acustici.
cell. parv. str. sup. t. ac. ^r cellulae parvae in the stratum medullare superficiale

tuberculi acustici.
cell. magn. str. med. t. ac. = cellulae magnae in the stratum griseum medium

tuberculi acustici.
cell. parv. str. prof. t. ac. — cellulae parvae in the stratum profundura griseum

tuberculi acustici.
str. prof. med. t. ac. =: stratum prof, medullare tuberculi acustici.
cell. Deiters. — cellulae DtixERS.
ar. ov. C. R. = area ovalis corporis rectiformis.
cell. n. ventr. N. VIII == cellulae nuclei ventralis nervi octavi.

Plate VII.

Fig. 7. A series of cell-preparations through the normal nucleus
dorsalis nervi octavi, corpus juxtarestiforme and their
neighbourhood.

(After a NissL preparation).

Fig. 7 a. Represents the most distal, fig. 7 h, the most proximal

section of this series.

In all sections the figures mean.*

n. dors. N. VIII =:: nucleus dorsalis nervi octavi.
a. _: its medial group of cells.

OF THE NERVUS OCTAVUS. 177

h, =: its dorsal (principal or central) group of cells.

c. = its lateral group of cells.

d. = its ventral group of cells.

e. =: the nucleus nervi abducentis.
n. Deiters =3 nucleus of Deiters.

n. griseus r. desc. =^ nucleus griseus radicis descendentis nervi octavi.

tub. ac. =: tuberculum acusticum.

n. ventr. N. VII [ n: nucleus ventralis nervi octavi.

r. ventr. N. VIII z= radix ventralis nervi octavi.

r. N. VII =: radix nervi facialis,

genu N. VII =: genu nervi facialis.

N. V. = spinal root of the nervus trigeminus,

n. prop. n. ventr. N. VIII rz nucleus proprius radicis ventralis nervi octavi.

Plate VIII and Plate IX.

Fig. 15. N*". 1 — N"*. 16. A series of frontal sections from the
beginning of the medulla oblongata until the corpora
quadrigemina anteriora in a rabbit, three weeks after the
removal of the left labyrinth -f- the section of the left
nervus octavus. (Treated with MARCHi-method). The root
of the V^^ is touched by the section.

The drawings are representing.
N*^. 1 =1 the section through the medulla oblongata before the distal end of

the ventriculus IV.
N*^. 2 = idem through the medulla oblongata at the distal opening of the

ventriculus IV.
N^. 8 = idem, as the dorsal ascending spino-cerebellar tract (Flechsig's

Klein-Him-Seitenstrangbiindel) changes its place and the area ovalis

of the C. K. begins.
N°. 4 =z idem, through the nuclei N. XII, the transparent nucleus N. X,

the dorsal nucleus of the N. VIII and the distal end of the nucleus

of Deiters.
N°. 5 = idem, proximal from the nucleus N. XII, at the distal end of the

nucleus N. VII.

The descending octavus-rootlibres, degenerated inthese
sections, are described in Cliapter II of the paper.

N*^. 6 = idem, through the distal end of the tuberculum acusticum.

N°. 7 :^ idem, through the entrance of the distal (dorsal) root of the nervus

octavus, showing its direct rootfibres to the medial nuclei tecti.
N*^. 8 zz idem, through the nucleus ventralis nervi octavi, with the fibrae

perforating the oval area of the ventral root.
N°. 9 z= idem, through the proximal (ventral) root of the nervus octavus.
N*^. 10 = idem, through the nucleus of Becuterew, and the issue of tlie

VIU»' nerve.
N°. 11 zr idem, through the corpus trapezoides, showing its degeneration and

through the degenerate fasciculus spino-cerebellaris ascendens ventn»lis,

free at the surface of the lateral fillet.
N°. 12 = idem, through the issue of the nervus trigeminus.
N*^. 13 zz idem, through the distal end of the corp. quadigeminum i>osticum.
Verband. der Kon. Akad. v. Wetensch. (Tweede Beetle.) Dl. XIY. 12

178 C. WINKLER. THE CEmHAL COURSE

N°. 14 = idem, through the corp. quadrig. posteriora. The bracchia cerebelli

media are touching the med. oblongata.
N°. 15 iz: idem, through the distal end of the corpora quadrigemina anteriora

showing the degenerate fibres in the crossed lateral fillet.
N°. 16 rr idem, through the distal end of the nucleus N. IV.

The abbreviations here used are.
Py = Pyramis.
01 = oliva inferior.
N. fun. 1. TT nucleus funiculi lateralis.
Fr. Deiters de?c. r_- tract. Deiters descendens.
N. N. XII 1= nucleus nervi hypoglossi.
N. XII ~^ nervus hypoglossus.
N. G. r-z nucleus of Goll.
N. B. :zz nucleus of Burdacii.
N. C. R -- nucleus proprius cori)oris restiformis.
r. sp. N. V. rj ramus spinalis nervi trigemiui.
f. praed. —'~ fasciculus praedorsalis.
n. N. X. rr n. Nervi vagi,
f. sol. N. X. ~- fasciculus solitarius Nervi vagi,
f. Deff. desc. :- fasciculus Deiters descendens.

F. 1. p. -- fasciculus longitudinalis i)osterior.
r. desc. N. VIII. :~: radix descendens nervi octavi.
N. N. VII i^ nucleus nervi facialis,
port. int. C E. n. portio interna corporis restiformisnz corpus juxtarestifonne.
N. IX. - nervus glossophar\'ngeus.
Tub. ac. ~- Tuberculum acusticum.
ar. ov. G.. R. =: area ovalis corporis restiformis.

str. I. d ^^ stratum latero-dorsale corix)ris restiformis.
fibr. rad. perf. rz fibres of the ventral root perforating through the oval area,
r. dors. N. VIII. ~- radix dorsalis
n. ventr. N. VIII. -~- nucleus ventral is |
r. ventr. N. VI II. :r radix ventralis I

nervi octavi.

n. dors. N. VIII. ="- nucleus dorsalis

c. trap. :-: corpus trapezoid es.

syst. dors, n^ systema dorsale Nervi octavi.

genu N. *VII r_ genu nervi facialis.

f. sp. c. V. '-- fasciculus spino-cerebellaris ventralis.

N. Br.cHT. :^ nucleus Becuterew.

P. C. S. :^ pedunculus cerebelli superior.

n. mot. N. V. zs: nucleus motorius I

r. spin. N. V. 1^ radix spinalis ( . ^ .

XT TT 1- / nervi tricjemmi.

N. V. HZ radix I ^

n. sens. N. V. =z nucleus sensorius )

n. ol. sup. IT nucleus olivaris superior.

n. par. ol. = nucleus para-olivaris.

n. trap, rz nucleus trapezoides.

H = syst. interm. ~- H eld's systema intermedium nervi octavi.

c. q p. ~z corpus quadrigeminum posticum.

c. q. a. ~- corpus quadrigeminum anticum.

Br. pont. :- pedunculus cerebelli medius.

R. N. IV - radix j

N. IV -- deciissatio radicum [ nervi trochlearis.

n. N. IV =_- nucleus I

Ij. L. in lemniscus lateralis.

OP THE NERVUS OCTAVUS. 170

n. V. L. L. = nucleus ventralis lemnisci lateralis.
Mistakes are made in f\^. 15 N°. .3 where r. d. N. VII [ is found instead of
ol. inf., in fig. 16 N^. 4 where f. praed. N. dors. M. VIII is found instead of n.
dors. N. VIII, and in fig. 15 N°. 15 and N*'. 16 where N. VI is found instead
of N. IV.

Plate IX, X and XI.

Fig. 16 a — N. A horizontal series of sections through the central
system of a rabbit, seventeen days after the removal of
the left labyrinth -|~ section of the left nervus octavus.
The degenerate rootlibres are made visible with Marchi-
method. The sections fall in. a more or less oblique
direction. The left side is touched in a more ventral
level than the right half.

The drawings represent.

Plate IX.
Fig. 16 A =: a horizontal section at the level of the most superficial layer of thick

fibres (the systema a) of the corpus trapezoides.
Fig. 16 b = idem, through the ventral layer of small fibres (the stratum d) of

the corpus trapezoides.
Fig. 1 6 c = idem , through the not degenerate layer (the stratum c) of te systema

ventrale nervi octavi. The degenerate intermediary system is touched.
Fig. 16 D = idem, through the degenerate intermediary' system of Held.
Fig. 16 E = idem, at the level where the facial nerve and more proximally the

yth nerve leaves the medulla.

Plate X.
Fig. 16 P ^=: idem, touching the issuing root of the facial nerve (at the leftside)

just dorsally from its nucleus and from the olivary bodies.
Fig. 16 G =: idem, falling through the ventral part of the nucleus motorius Nervi

trigemini.
Fig. 16 H = idem, touching the genu N. VI [ and the nucleus of the nervus

abducens, at the entrance of the distal (lateral) octavus-root.
Fig. 16 I =: idem , at the level of the entrance of the proximal (medial) octavus-root.

Plate XI.
Fig. 16 K = idem, at the level of the dorsal nucleus, showing its innervation

by the descending rootfibres.
Fig. 16 L = idem, at the level of the tuberculum acusticum.
Fig. 16 M = idem, through the inferior pedunculus cerebelli, at its union with

the superior pedunculi cerebelli.
Fig. 16 N = at the level of the nuclei tecti.

The abbreviations are like those in the prececding drawings moreover there are.
f. rtfl. = fasciculus retroflexus or Meynert's bundle,
n. med. th. =: nucleus medialis thalami optici.
n. lat. th. =^ nucleus lateralis thalami optici.
c. g. I. =: corpus geniculatum laterale.
tr. opt. = tractus opticus,
fimbr. fom. :=z fimbria fomicis.

c. g. m. = corjnis geniculatum mediale.
f. ped. tr. = tractus interpeduncularis transversus.
N. N. Ill =: nucleus nervi oculomotorii.

12*

180 C. WINKLER. THE CENTEAL COURSE

pulv. th. opt. =: pulvinar thalami optici.
c. p. == commissura posterior,
g. hab. = ganglion habenalae.
g. interp. =: ganglion interpedunciilare.
N. R. =: nucleas ruber.
Dec. Br. conj. =: Decussatio braccli. conjunct, penduncul. cereb. superioris.

Plate XII.

Fig. 17 A, B, and c. Frontal sections through the medulla oblon-
gata of a not yet born elder foetus of a rabbit, (a
Weigert-Pal preparation) showing how far niyelinisation
of fibres has taken place. A is the most distal, C the
most proximal section.

The abbreviations found here are the same as in pre-
ceeding drawings.

In fig. 17 a. The non medullated layer /? is found between the two medullated
layers of the sy sterna dorsale (stria medullaris) nervi octavi.

In fig. 17 b. The non medullated layer (stratum c corp. tr.) is found between the
medullated layers of the systema ventrale nervi octavi.

In fig. 17 c. The medullated triangular field of the fasciculus spino-cerebellaris
ascendens, is making up to take its dorsal way in the lateral fillet.

Plate XIII.

Fig. 18 A — F. A series of sagittal sections through the central
system of a not yet bora elder foetus of a rabbit (a
Weigert-Pal preparation) showing the myelinisation of
the fibres at the time of birth.

The abbreviations found here are the same as in the preceeding drawings.
Fig. 18 a is a sagittal section just touching the lateral surface of the medulla. Most

proximally the nervus trigeminus enters, distally at first the proximal

octavus-root is seen, afterwards the distal octavus-root enters. Between

them is found the fasc. intermedins radicum.
Pig. 18 b is a dito, somewhat more medially. The corpus tnipezoides begins its

exfoliation from the nucleus ventralis. The fasciculus intermedins is seen.
Fig. 18 c is a sagittal section, at the level where the dorsal spino-cerebellar tract

(Flechsig's Klein Hirn-SeitenstrangBundel) enters into the cerebellum. It

is medullated , and crossed by medullated fibres of the ventral root going

to the stratum latero-dorsale.
Fig. 18 D is a sagittal section, at the most medial region of the area ovalis , or at

the most lateral region of the corpus juxta-restiforme. The medullated

IIelb's intermediary system is touched as a bundle of longitudinal fibres,

passing from the strat. latero-dorsale into the corp. trapezoides.
Fig. 18 E is a sagittal section, at the level of the facial nucleus. Held's system

now is a field of queer- sectioned small fibres. The section demonstrates

the beginning of the tractus Detteus descend ens.
Fig. 18 F is a sagittal section through the lateral end ofthegenuNervifacialis.lt

demonstrates the curvation in longitudinal direction of the tractus Deiters

descend ens.

Plate XIV and Plate XV.

OF THE NERVUS OCTAVUS. 181

Fig. 14 A — E, A series of horizontal sections, a fortnight after
rootsection of the nervus octavus, through the central
system of a rabbit. (MARCHi-preparation).

The abbreviations as in the preceeding drawings.
Plate XIV.

Fig. 14 A. The section falls through the radix descendens radicis vpntralis N. VIII
and the genu of the N. VII. It demonstrates the degeneration of root-
fibres in the ascending Dkiteus tract, in the fasciculis long, posterior,
in both fasciculi spino-cerebellares ventrales ascendentes , and round both
nuclei ventrales lemnisci laterales. Still better it is demonstrated in.

Fig. 14 B. A horizontal section falling somewhat more dorsal ly.

Fig. 14 c. A horizontal section at the level of the tuberculum acusticum shows at
the left side the union of the two bundles of the lateral fillet. The one,
the fasciculus spino- cerebellar is ventralis asoendens, and the other the
lemniscus ad corp. quadrigeminum posticum. At the right this union has
not yet taken place.
Plate XV.

Fig. 14 D and E = Horizontal sections through the nuclei tecti cerebelli, demon-
stfate, the distal end of the fasciculus spino-cerebellaris ventralis ascen-
dens on both sides , their deviation into the nuclei tecti and their decussatio
in the corpus medullare cerebelli.

Plate XVI and Plate XVII.

Fig. 20 A — F, Fig. 21. A series of horizontal sections through
the brain and a series of frontal sections through the
medulla of a rabbit ten days after a proximal section
through the corpus juxtarestiforme.

The injury is found in fig. 20 a — d in x. Its most
dorsal white surroundings are found in fig. 20 a. The
incision enters medio- ventrally from the tuberculum acus-
ticum in the nucleus of Deitehs, and from the IV^*" ven-
tricle it goes proximally and laterally from the IV^'' nucleus
in fig. 20 b.

The largest extension of the injury is found in fig. 20 v,
where it nearly reaches the lateral fillet, and in fig. 20 n
where it divides the Bracchium conjunctivum pedunculi
cerebelli superioris, causing its centripetal degeneration.
It touches the ventral part of the lateral fillet with its
most ventral end in fig. 20 e.

From this injury many secundary degenerations exit.

Fig. 20 a. The root of the IV^*^ nerve is sectioned. The decussatio and the opposite
root of the nervus trochlearis is degenerated. The fasciculus spino-veutralis
ascendens is degenerated on both sides.

Fig. 20 B. A horizontal section through the tuberc. acusticum. This is degenerated in
ail its layers. (The superficial as intensive as in the deep layers.) Both
trochlearis nuclei are degenerated.

Fig. 20 c. A horizontal section somewhat more venfniUy, demonstrating the dege-
neration in the tractus Deiters ascendens.

182 C. WINKI^R. THE CENTRAL COURSE

Fig. 20 u. A horizontal section througli the entrance of the octavusroots and the
knee of the facial nerve. The section demonstrates the degenerated tractus
D BIT BBS ascendens , the degenerated fasciculus longitudinalis posterior and
the transverse fibres, passing through the contralateral nucleus Deiters
and the beginning of the contralateral tract of Deiters. with slight
degeneration.

Fig. 20 E. A horizontal section touching the exit of the V^^ nerve. It demonstrates
the degenerate homolateral tract of Dettbrs round the facial root, and
more distally the degeneration in the praedorsal tract and in the rubro-
spinal tract.

Fig. 20 E. A horizontal section touching the facial nucleus and olivary bodies, with
degeneration in the three descendent longitudinal tracts, the praedorsal
tract, the dssceuding Deiters tract, and the rubro-spinal tract.

Fig. 21. Sections at different levels of the medulla, to demonstrate the farther
course of the descending tracts in the cord.

In these preparations, the lesion tonches the fillet,
and an injury of the rubro-spinal tract at the level of the
issuing trigeminus-root cannot be excluded.

Plate XVIII.

Fig. 22 A — H. A series of frontal sections, through the central

system of a rabbit, eleven days, after a transverse section

through the left lateral trunk of the corpus trapezoides.

In fig. 22 B — D the injury of the system is indicated

by the letter x.

In fig. 22 a. The section falls through the corpora ([uadrigemina anteriora. In the
right lateral fillet fibres to the ventral layer of the nucleus corp.
([uadr. posterioris are degenerated. A slight transverse degenerated
layer of fibres ventrally from the nucleus or the IV^h nerve is seen
(PaoBST bundle).

Fig. 22b. This section, through the proximal parts of the olivary bodies, is
touching the proximal end (by x) of the incision.

The Corp. trapezoides and the sy sterna ventrale nervi octavi is nearly
totally degenerated.

Fig. 22 c. The section touches the injury^ by x. Between the lesion and the
//uberrirendes Seitenstranji;bUnder' the intact medio- ventral end of the
Vth spinal root is found. The dorso-lateral fibres of this root are sectioned
and degenerated distally, as is sei-n in all distal sections. Here, in
the aberrirendes Seitenstrangbiindel , a tract degenerating distally is
found (rubro-spinal bundle), and the slight degeneration in the des-
cending tract of Deiters and in the praedorsal tract is evident.

Fig. 22 D. The section touches the entrance of the ventral octavus-root.

Fig. 22 b. The entrance of the distal octavus root.

Fig. 22 F. A section through the proximal i ^ ^ ^i vtt^k i
T^. „„ . .. .1 1 ^1 1- i 1 ' part of fhe Xlpn nucleus.

Fig. 22 G. A section through the distal \ *

Fig. 22 H. A section through the distal end ot the oblongata.

In fig. 22 D— II. The area's of the rubro-spinal tract, of the descending tract of

Deiters and of the praedorsal tract, are marked by degeneration in

the different levels, where the section touches them.

In this case it is not probable that the rubro-spinal

OF THE NERVUS OCTAVUS. 183

tract should have been directly damaged by the incision.
Notwithstanding the rubro-spinal tract is degenerated in
a rather important manner.

Plate XXL

Fig. 23. A frontal section through the oblongata of a rabbit 16
days, after the transverse division of the lateral trunk
of the corpus trapezoides (by x), at the entrance of the
octavus-roots, in order to demonstrate the degeneration
in the corpus trapezoides.

Plates XIX, XX at XXL

Fig. 25 A — o. A series of frontal sections through the central
system of a rabbit, eight days, after a double-sided
ablation of the tuberculum acusticum. In fig. 25 e — i
(by x) the double-sided injury is surrounded by a sharp
line to make it demonstrable.

Plate XIX.
Fig. 25 A. The most proximal section through tlie corpora quadrigemina anteriora.

There is an intense degeneration on both sides in the ventral layer
of fibres of the nucleus corp. (juadr. jwstici.

Moreover an intensive degeneration (more on the left than on the
right side) in the fasc. long. post. , here united with the ascending Deitbrs
tract, and in both nuclei of the IVth nerve.
Fig. 25 B. The section through the corpora quadrigemina posteriora and the lateral
fillet.

There is an intense degeneration in the lateral fillet, especially in its
medial bundle (f. m. 1. 1.), and in its lateral layer the fibres round the
ventral nucleus have degenerated.

The fasc. long. post, begins its separation from the tract. Deitkrs
ascend. (The separation between the two tracts is distinct In fig. 25 c
D and e) and fibres detach from the ascending Deiters tract during its
course to reach the medial bundle of the fillet. In the decussatio ven-
tralis tegmenti another degeneration is found, reaching the place where
the //aberrirendes Seitenstrangbiindel" enters into the lateral fillet. The
most lateral fibres of the fillet remain without degeneration.
Fig. 25 c. The section touches the place, where the pedunculi cerebelli medialis
leave the medulla.

Degenerate fibres are found in I'y The fasciculus longitudinalis posterior,
2'y the ascending Deiters tract (which at this moment leaves the f. 1. p.
to deviate laterally), noth tracts send transverse fibres crossing the raphe ,
that may be followed in 3'y the medial bundle of the lateral fillet.

4'y. The lateral bundle of the fillet with the nucleus ventral is lemnisci.
5'y transverse fibres in the ventral decussatio tegmenti towards the place
of the //aberrirendes Seitenstrangbiinder* 6'y the fasciculus spino-cerebel-
laris ascendens ventralis.
Fig. 25 D. The section touches the middle of the nucleus ventralis lemnisci. There
are found the same degenerations as in the former. The ventral decussatio
tegmenti has ended , its degenerated area finds a place laterally from the
nucleus ventralis lemnisci.

184 C. WINKLER. THE CENTRAL CX)URSE

Fig. 25 B. The section touches at the right side the lesion. The pedunculos oerebelli
inferior (its oval area) being cleft , this oval area is d^enerating towards
the cerebellum. Transverse fibres unite the two ascending Deiters tracts.
The medial bundle of the fillet touches the lateral bundle at the dorsal
top of the distal end of the nucleus ventral is lemnisci. The sy sterna ven-
trale nervi octavi is degenerated.
Plate XX.

Fig. 25 F. The section touches the lesion in i ou both sides. Degenerated are l^y the
fasciculus longitudinalis posterior 2'y the tractus Deiters ascendens. 3^y
MoXAKOw's decussjition of transverse fibres going to the dorsal layer of
the oliva superior (medial bundle of the fillet). 4'y The systema ventrale
nervi octavi.

Fig. 25 G. The section touching still in x the double-sided lesion falls through
the exit of the VIP^ nerve.

MoNAKOw's transverse fibres towards the dorsal top of the nucleus
olivaris superior are totally degenerate.

Fig. 25 H. The section touches the tuberculum acusticum and the nucleus ventralis.
Degeneration is found in. I'y. The systema dorsale (Monakow's stria medul-
laris). 2'y. Held's intermedial system. 8^y. The tractus Deiters descen-
dens. 4^y. The systema ventrale.

Fig. 25 I. The section touches the nucleus facialis and the distal end of the tuber-
culum acusticum. On both sides is found degeneration in l^y the tractus
Deiters descendens. 2iy. The fasc. long. post, and the fasciculus praedor-
salis , S^y in the fasc. rubro-spinalis 4'y in the nucl. facialis , 5b' in the fibr.
trans versae dorsalis and 6'y in the radix descendens N. VIIF.

Fig. 25 K. The section falls through the Xll^h nucleus, demonstrating the degene-
ration in the tracts descending towards the cord.

Fig. 25 L. The section througli the distal end of the med. oblongata. The position
of the tractus DBrrERS descendens, the fasciculus praedorsalis and the
rubrospinal tract.
Plate XXI.

Fig. 25 M N and o. Sections through different levels of the cervical cord (G^ , Cg , O3) to
demonstrate the position of the f. praedorsalis, the descending Deiters
tnict, and the rubro-spinal tract.

Plate XXI and Plate XXII.

Fig. 28 A — F and fig. 12. Series of sections through the medulla
oblongata of the rabbit, six months after the ablation
of the left tuberculum acusticum made in the young born
animal. The lesion is found in tig. 28 in a — D. The
nucleus ventralis is ablated, but the octavus-roots have
but a slight atrophy. The series is drawn to demonstrate
the atrophy of the systems in the fillet. (VVeigert-Pal
preparation).

Plate XXI.

Fig 12. A part of the section in fij?. 28 b, limited by a circle, is drawn by an
enlargement of ^^^/i- The nucleus ventmlis and the larger part of the
corpus trapezoides being lost, it is seen, that fibres of the octavus-root
(the dorsal root) pass immediately into the corpus trapezoides.

Fiff. 28 a. The section through the distal end of the tub. acusticum.

OF THE NERVUS OCTAVUS. 185

Fig. 28 B. The section through the middle of this nucleus. Those sections are drawn

to demonstrate the extensity of the lesion.
PL.VTB XXII.
Fig. 28 c. The section through the distal end of the nuclei olivares superiores. It

demonstrates :

The loss of fibres in the corpus trapezoides and the atrophy of the
^ nucleus olivaris superior , at the operated side. The loss of the stria

meduUaris at that side and the loss of fibres of the //aberrirende Seiten-

strangbiindel" at that side:
Fig. 28 D. The section falls through the proximal end of the lesion The same fibres

are atrophied as in fig. 28 c.
Fig. 28 E. The section falls through the genu N. VII. The crossed //aberrirendes

Seitenstrangbiinder' now has lost a great many fibres and so have the

surroundings of the crossed nucleus ventralis lemnisci (atrophied itself).
Fig. 28 F. The section falls through the fillet. There is atrophy.

1 in the superficial layer of the fillet at the operated side.

2 in the nucleus ventralis lemnisci 1

3 in the medial bundle ( i? ii l i i i en i.
. . ,; , . , , ,, } of the contra-lateral fillet.

4 in the lateral bundle j

5 in the aberrirendes Seitenstrangbiindel )
The decussatio ventralis tegmenti contains less fibres at the operated side
than contralaterally.

Plate XXIII and Plate XXIV. Fig. 26 a— e and fig. 27.

Fig. 26 A — E. A series of frontal sections through the medulla
oblongata of a pigeon three weeks after the removal of
the labyrinth, demonstrating the degeneration of root-
fibres.

Fig. 27, A longitudinal section through the primary octavus-nuclei
of a pigeon three weeks after the removal of the labyrinth.
(These are Marchi-preparations).

The abbreviations used here are:

N. ang. N. VIII =: nucleus angularis J

r. lat. N. VIII =: radix lateralis | nervi octavi.

r. desc. N. VIII =: radix descendens I
r. N. X =: radix nervi vagi,
r. spin. N. V =: radix spinalis nervi quinti.
C. R. = corpus restifome.
N. N. XII = nucleus nervi hypoglossi.
n. parvocell N. VIII = nucleus parvocellularis nervi octavi.
A. =: z'acusticusfeld".
r. med. N. VII t =: radix niedialis nervi octavi.

fibr. dors. =:: fibrae dorsales radicis nervi octavi.
y^ rz trunc. med. = medial trunck of octavus-root fibres,
f. dors. N. VIII rz systema dorsale nervi octavi.

f. 1. p. ~z fasciculus longitudinalis posterior,
n. magnocellul. N. VIII =: nucleus magnocellularis nervi octavi.
n. cer. rz nucleus pedunculi cerebelli.
N. VII rz nervus facialis.
N. VI =: nervus abducens.

186 C WINKLER. THE CENTRAL COURSE, ETC.

Fig. 26 A. The section through the entrance of the dorsal (lateral)
root and angular nucleus.

Fig. 36 b. The section through the entrance of the ventral (medial)

root and the distal end of the nucleus parvo-cellularis.
Fig. 26 c. The section through the distal end of the nucleus niagno-

cellularis.
Fig. 26 D. The section through the middle of the nucleus magno-

cellularis and the nucleus pedunculi cerebelli.
Fig. 26 E. The section through the proximal end of the medial

trunk of rootfibres (the radix ascendens N. octavi)).

Fig. 27. A horizontal section through the nucleu angularis, parvo-
cellularis, magnocellularis and pedunculi cerebelli.

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List of books, consuli(3d in studying the nervus Oclavus.

G. Tkicomi Allbgra.

Hkrm. Aubert.
Yves Deiagk.

JOHANN PURKINJE.
JOHANN PURKINJE.

B. Baginsky.

Studio sperimentale sulla via acustica foiula-
nientale. Le Nevraxe. Vol. VII. 190G
p. 229-280.

Physiologiscbe studien liber die Orientierung
(1888). Unter Zugrundelegung von

Etudes experimentales sur les illusions sta-
tiques et dynamiques de direction pour
scrvir a determiner les fonctions des canaux
semicirculaires de I'oreille interne. (1886)
init einem Anhang.

Ueber den Schwindel (1825).

Beitrage zur naheren Kenntnisz des Schwin-
dels aus heautognostischen Daten.

Med. Jahrbucber Bd. 6. 2. p. 79—125.
Wien 1820.

Ueber den Ursprung und den centralen Ver-
lauf des N. acusticus des Kaninchens.

ViRciiows Archiv. Bd. 105. 1886. S. 28.

Zur Kenntnisz des Verlaufs der hinteren
Wurzel des Acusticus und des Verhaltens
der Striae medullares. Sitz. der Berl.
Ges. f. Psych, und Neur. 11 Nov. 1889.

Arch, fur Psych. Bd. XXIII. p. 291—292.

Ueber den Ursprung und den centmlen
Verlauf des Nervus acusticus des Kanin-
chens und der Katze.

ViRcnows Arch. Bd. 119. 1890. S. 91.

Ueber die Folgen der Driicksteigerung in
der Paukenhohle und die Function der
Bogengange. Arch. f. An. und Phys. 1881.
p. 201 — 235.

188

B. Baginsky.
B. Baginsky.
W. Brchterew.

W. VON Bechterew.

W. VON Bechterew.
W. VON Bechterew.
W. VON Bechterew.
W. VON Bechterew.

W. VON Bechterew.

Arthur Biedl.
Robert Boyce.

C. WINKLEE. THE CENTRAL COURSE

Zur Physiologic tier Bogengange.Arch. f. An.

und Phys. 1S85. p. 252—266.
Ueber den Meniereschen Symptonien-complex.
Berl.Klin. Wochenscbrift. N^ 45 & 46. 1888.
Ergebnisse der Durchschneidung des N.

acusticus, nebst Erorterung der Bedeutnng

der semicircularen Kantile fiir das Korper-

Gleichgewicht.
PpLfGER's Arch. f. d. ges. Phys. Bd. XXX.

1883. p. 312—347.
Ueber die Bestandtheile der Hintei-stninge

des Riickenmarks auf Grund der Unter-

suchung ihrer Entwicklung.
Neurol. Centrlbltt. Bd. IV. N^ 2. p.

31—33. 1885.
Zur Anatomie der Schenkel des Kleinhirns,

iusbesondere der Briickenarme. Ibidem

Bd. IV. N^ 6. p. 121—125. 1885.
Ueber die innere Abtheilung des Striekkor-

]>ers und den achten Ilirnnerven. Ibidem.

Bd. IV. N^ 7. p. 145—147. 1885.
Ueber die Liingsfaserzuge der formatio reti-
cularis medullae oblongatae et pontis.

Ibidem. Bd.IV. NM5.p. 337— 336. 18s5.
Zur Frage fiber den Ui-sprung des lliir-

Nerven und iiber die physiologische Be-
deutnng des N. Vestibularis.
Ibidem Bd. VI. N^ 9. p. 193—198.
Ueber den Schleifenschicht. (Sitz Ber. der

Ktinigl. sachs. Gesellschaft der Wissen-

schaften 4 Mai 1885).
Ibidem Bd. IV. N^ 15. S. 356.
Die Leitungsbahnen im Gehirn und Rucken-

mark. Leipzig 1894. (libei-setzt von I.

Weinberg). S. 65 u 7.
Zur Frage iiber die Striae meduUares des

verlangerten Markcs.
Neur. Centrbltt. 1892. Bd. 11. S. 297.
Absteigende Kleinhirnbahnen.
Neur. Centrlbltt 1S95. Bd. XIV. S. 434, 493.
Contribution to the study of descending

degeneration in the brain etc.

OF THE NERVUS OCTAVUS.

189

Robert Boyce.

Joseph Breuer.

J. Breuer.

A. BUMM.

Cr.ARKE.

James Collier and
E. Farqihar Buzzard.

James Collier and
E. FarquhAr Bi zzard.

Cramer.

A. Crum Brown.

Proceedings of the Royal Society Vol 5 5. 1 894.
Phil, trans. Vol. 186. Part I. 1895.
Neur. Cent. Bltt N^ 13. 1894. S. 466.
A contribution to the study of:

I. some of the decusating tracts of the
mid-and interbrain and

II. of the pyramidal system in the mesen-
cephalon and bulb.

Phil. Trans. Vol 188. 1897.

Ueber die Function der Bogengange des Ohr-
labyrinthes. Mediciuische Jahrbiicher. Wien
1874. p. 72—124.

Beitmge zur Lehre vom statischen Sinne
(Gleichgewichts-organ , Vestibularapparat
des Ohrlabyrinthes). Mediciuische Jahrbii-
cher. Wien 1875 p. 87—156.

Studien fiber den Vestibular-Apparat. Wien
Sitz. Ber. (Abth. Ill) Bd. CXII. p. 353.
1903.

Experimenteller Beitrag zur Kenntnisz des
Hornerven-Ursprungs beim Kaninchen.

Allgem. Zeitschrieft fur Psych. Bd. XIV.
1889. S. 568 und Jahressitzung des Ver.
deutsch. Irrenartze im Bonn. 16 und 17
Sept. 1888. Neur. Ctbltt. 1888. S. 59.

Proceedings of the Royal Society 1861, p. 359
Philosophical transactions 1858 p. 231.

The Degenerations resulting from lesions of
posterior Nerve Roots and from trans-
verse lesions of the spinal cord in man.
A study of twenty cases.

Brain 1903 Vol. XXVI p. 559.

Descending mesencephalic tracts in Cat , Mon-
key and Man ; Monakow's Bundle etc.
Brain 1901. Bd. XXIV p. 177.

Beitriige zur feineren Anatomic der medulla
oblongata und der Briicke etc. Jena 1894.

On the sense of rotation and the anatomy
and the physiology of the semicircular
canals of the internal ear

Proceedings of the Royal Society. Edinburgh
T. VIII 19 Jan. 1874.

190

C. WINKLER. THE CENTRAL COURSE

J. VAN DeEN.

O. Deiters.

J. Dejerine.
L. Edinger.

L. Edingeh.

L. Edinger.

Tk. W. Engelmann.
J. Rich. Ewald.
J. Rich. Ewald.

J. Rich. Ewald.
J. Rich. Ewald.

David Ferrier and
\V. Aldren Turner.

P. Elechsig.

Journal of Anatomy and Physiology. Vol. VIII.

Nieuw Archief v. binnen. en buitenlandsche
geneeskunde etc. 1848 p. 304.

Untersiichungen uber Geliirn und Rucken-
inark der Saugethiere. Braunschweig
1865.

Anatomic des centres nerveux. Paris 1895,
1901.

Vorlesungen fiber den Ran der nervosen
Centralorgane des ' Menschen und der
Thiere. G^^" Auflage, 1900.

Ucber Ursprungsverhaltnisse des Acusticus
und die directe Kleinhirn Bahu. Neur.
Centrbltt. 1886 Bd. VI p. 286.

UntersuchuHgcn fiber die verglcichcnde Ana-
tomic des Gehirns. N°. 5 Untcrsuchungen
fiber das Vorderhirn der Vogel. Abh. der
Senckenberg naturf. Gesellschaft Bd. XX.
1903.

Ueber die Function der Otolithen. Zoologi-
scher Anzeiger N^ 258. 15 Aug. 1S87
p. 439—444.

Zur Physiologic der Bogengange.

Pfluger*s Arch. f. d. ges. Phys. Bd. XLI.
p. 463—483.

Zur Physiologic der Bogengange. Fortsetzung.
Ucber Bewegung der Pcrilymphe. Pfli-
ger's Arch. f. d. ges. Phys. Bd. XLIV.
1889 p. 319—326.

Phvsiologische Untcrsuchungen fiber das En-
dorgan des N. Octavus. Wiesbaden 1892.

Ueber die Beziehungen zvvischen der exci-
tabeln Zone des Groshirns und dem Ohrla-
byrinth. Berl. Kl. Wochenschiift 189.5.
N°. 42. S. 929.

A record of experiments illustrative of the
symptomatology and degenerations follo-
wing lesions of the cerebellum and its
peduncles and related structures in mon-
keys. Phil. Trans. Bol. 185. p. 753. 1894.

Die Leitungsbahnen im Gchirn und Rucken-
mark des Menschen u. s. w. Leipzig. 1876.

OF THE NERVUS OCTAVUS.

191

P. Flechsig.

p. Flechsig.

P. Flechbig.

A. POREL.

A. FoREL und

B. Onuprowicz.

A. FoREL.

FOVILLE.

Fraseu.

p. Flourens.

A. VAN Gehuchten.

A. VAN Gehuchten.
A. VAN Gehuchten.

Zur Lehre vom centralem Verlauf des Sin-

nesnerven.
Near. Centrbltt. 1S86. Bd. V- N^ 23. S. 545.
Weitere Mittheilungen (iber die Beziehun-

gen des unteren Vierhugels zum Honier-

ven. Ibidem 1890. Bd- IX N°. 4. S. 98.
Zur Anatomic des vorderen Sehhiigelstieles ,

des Cingulums und der Acusticusbahn.
Ibidem 1897. Bd. XVI. N°. 7 S. 290—295.
Einige Hiraanatomische Betrachtungen und

Ergebnisse. Archiv. fur Psychiatrie. Bd.

XVIII. 1887. p. 162—198.
Weitere Mittheilungen fiber den Ursprung

des N. acusticus. Neur. Centrbltt. Bd. IV.

1885 p. 193.
Vorlaufige Mittheilung iiber den Ursprung

des Nervus Acusticus. Neur. Centrbltt.

Bd. IV 1885. p. 191.
Traite complet de TAnatomie et physiologic

du systeme nerveux cerebro-spinal. Paris

1844 p. 503.
An experimental research into the relations

of the posterior longitudinal bundle and

Deiters nucleus.
Journal of Physiology. Vol. 27. p. 327. 1901.
Memoire presentee a TAcademie des scien-
ces Seance du 27 Dec. 1824.
Experiences sur les canaux semicircularis de

Toreille chez les oiseaux. Seance du 11

Aout 1828.
Annales des Sciences naturelles T. XV. p. 118.
Recherches expej'imentales sur les proprietes

et les fonctions du systeme nerveux dans les

animaux vertebres 2"*® edition. Paris. 1842.
Nouveau precede de section intracranienne

du trijumeau du facial et de Tacoustique.

Le Nevraxe. Vol. 11 1900. p. 45—55.
Recherches sur la voie acoustique centrale

Le Nevraxe. Vol. IV. 1903 p. 231—301.
Les connections centrales du noyau Deiters

et des masses grises voisines. Le Nevraxe.

Vol. VL 1904. p. 19—75.

192

C. WINKLER. THE CENTRAL COURSE

A. VAN Gehuchten. Recherches sur la terminaison centrale des

nerfs peripheriques.

I. Le nerf intermediaire de Wrisberg. Le
Nevraxe. Vol. I. 1900. p. 3—13.

II. Le faisceau solitaire. Le Nevraxe. Vol.
L 1900. p. 171—199.

III. La raciiie bulbo-spinale du trijumeau.
Le Nevraxe. Vol. IL 1901. p. 173—191.

IV. La racine posterieure des deux premiers
nerfs cervicaux. Le Nevraxe. Vol. II. 1901.
p. 227—257.

V. La racine posterieure du huitieme nerf
cervical et du premier nerf dorsal. Le
Nevraxe. Vol. IV. 1903. p. 55—77.

VI. Le nerf cochleaire. Le Nevraxe. Vol.
VIII. 1907. p. 125—147.

A. VAN Gkhichtkn. Le corps restiforme et les connexions bulbo-

cerebelleuses. Le Nevraxe. Vol. VI. 1904.
A. VAN GEHrcHTEN. Les pedoncules cerebelleux superieurs. Le

Nevraxe. Vol. VII 1904 p. 29—87.
A. VAN Gehuchten. Le faisceau en crochet de Russell ou fais-
ceau cerebello-bulbaire. Le Nevraxe. Vol.

VII. 1905 p. 117—101.
A. van Gehuchten. Anatomie du systeme nerveux de Thomme.

4® edition. Louvain. 1906.
Ueber die pliysiologische Bedeutung der

Bogengange des Ohrlabvrinths.
PflCger's Archiv. f. d. gcs. Phys. Bd. Ill

1870. p. 172—192.
Ueber die Verriclitungen des Groszhirns

Bonn. 1881.
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F. GOLT/.

H. Held.

11. Held.

OF THE NERVUS OCTAVUS.

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W. B. Hadden and
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S. KiRILZEW.

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Alois Krkidl.
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C. WINKLER. THE CENTRAL CX)URSE

M. Lewandowsky.

LoNGKT.

N. LoWKNTHAL.

L. LniAM.

ViTTORio March I e
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V. Marchl

VlTTORTO MaRCHJ.

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'Ih. Mevnkrt.

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Anatoniie et Physiologic du systeme Nerveux
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La region pymmidale de la capsule interne
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SuUe degenerazioni discendenti consecutive a
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Sulle degenerazioni consecutive all' estirpazione
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Zur Eudigung des Nervus Acusticus im Ge-
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OF THE ^ERVUS OCTAVUS.

195

E. Mach.
Midden DORP.

M. Magendie.

C. VON MONAKOW.
C. VON MoNAKOW.

C. VON MoNAKOW.
C. VON MoNAKOW.

1\ W. MOTT.

E. MiNZKR und

H. VVlENEU.

E.. MfNZEii.

MlNGAZZINl.

F. W. Morr.

II. MUNK.

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Grundlinieu der Lehre von den Bewegungs-

Empfindungen. Leipzig 1875.
Ilet vliezig slakkenhuis in zijn wording en in

den ontwikkelden toestand. Groningen

1867.
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und des corpus restiforme. Neur. Ctbl.

Bd. I. 1882. p. 480— p. 482.
Ex])erimenteller Beitrage zur Kenntnisz des

corpus restiforme, des iiusseren Acusticus-

Kernes und deren Beziehungen zum

Riickenmarke. Archiv. fiir Psych. Bd.

XIV. 1883. p. 1—15.
Striae acusticae und untere Schleife. Archiv

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Expcrimentelle und puthologisch-anatomische

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etc. Archiv fur Psychiatric. Bd. XVII. 1895

p. 1 — 129, p. 386—479.
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Beitrage zur Anatomic des Central Nerven-

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N°. 14.
Beitrag zum Aufbau des Central Nerven-

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Neur. Ccntrlbltt. 1895 Bd. XIV. S. 956.
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1894.
Experimental incpiiry upon the afferent tracts

of the central nervous system of the

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Berlin. 1890.

13*

196

C. WINKLER. THE CENTRAL COURSE

J. J. MUSKENS.

J. J. Musk ENS.

J. J. MUSKENS.

II. Obeusteinek.
B. Onufrowioz.

W. PAvr.()\v.
A. Pick.

MoiuTZ Pkobst.

MoiuTz Probst.

MoiuTZ Pkobst.

Over degeiieraties in het centrale zenuw-
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cerebelli.

Versl. dcr K. Ak. v. Wet. Wis en Natuurk.
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I. p. 267.

Anatomisch onderzoek onitrent klein-hersen
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Deel XIV. II. p. 575.

Waarnemingen omtrent de physiologic en
de pathologic dcr dwangbewegingen en
dwangstanden en daarmede verwante af-
wijkingen in de innervatie dcr oogballen.

Ilandelingcn dcr K. Ak. v. Wet. 2**® Scctie
Deel VIII. 1902 N^ 5.

Anleitung beim Stadium des Baues der
nervosen Central Organe. Leipzig und
Wien. 188S und 1896.

Experimcnteller Beitrag zur Kenntnisz des
Ursprungs des N. acusticus des Kanin-
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Lc faisceau de Monakow ou faisceau rubro-
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Bcitriigc zur Pathologic und pathologischen
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Kxperimcutcllc Untcrsuchungen liber die
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das dorsalc Langsbiindel und die hintcre
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XXXIII. lift. 1.

Zur Kenntnisz des Bindcarmes der Ilaubcn-
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Monatschrift f. Psychiatric und Neurolo-
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Ucber die vom Vierhiigel, von dcr Briicke
und vom Klcinhirn abstcigende Bahncn.
(MoNAKOw's Biindcl etc.) 1899. Deutsche
ZeitsL-hrift fiir Xcrvenhcilkunde. Bd. XV.
p. 192.

OF THE NERVUS OCTAVUS.

197

MoRiTz Pkobst.

Santiago Ramon y
Cajal

G. Retzius.
G. Rktzius.

Roller.

A VAN RossEM.
Max Rothmann.

Zur Anatoinie und Physiologic des Klein-
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Textura del sistema nervioso del honibrc y
de los vertebrados. 1899 — 1904. Ueber-
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Oblongata.

Das Gehor-Organ der Wirbelthiere. Stock-
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Die Endigungsweise der Gehorncrven. (Bio-
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fur Psychiatric Bd. XXXVllI. p. 230.

Gewaarwordingen en reflexen , opgewekt van
uit de halfcirkelvormigc kanalen. Diss.
In. Utrecht. 1907.

Ueber das Monakow'sche Biindel. Neur.
Centrbltt. 1900. Bd. XIX. p. 41. Vor-
trag in Berl. ges. fur Psych, und Nerven-
krankheiten 12 Dec. 1899.
I. S. RisiEN Russell, P. E. Batten and James Collier.

Subacute combined degeneration of the spi-
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p. 39.
I. S. RisiEN Russell. The origin and destination of certain afferent

and efferent tracts in the medulla oblon-
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to the study of some of the afferent and
efferent tracts of the sjiinal cord. Brain
1S97, Bd. XX.

Degenerations consequent on experimental
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Suir origine del nervo acustico. Archives Ital.
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Lehrbnch der Physiologic. 1858.

Anatomisch physiologisch onderzoek over het
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I. S. RisiEN Russell.

L. Sala.

M. SCHIFF.

J. S. C. Scuroeder

VAN der KoTJC.

198

C. WINKLER. THE CENTRAL COURSE

J. S. C. SCHROEDER
VAN DER KOLK.
SCHRADER.

G. SCHWALBE.

g. schwalbe.
Stanislaus von Stein.

Stanislaus von Stein.

J. Steiner.
Stilling.

Andre Thomas.

Andre Thomas.
Armin Tschermak.

Max Verworn.

A. Wallenberg.
A. Wallenberg.

C. Wernicke.

Over het fijuere samenstel en de werking van

het verlengde merg. A'dam. 1858.
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Al-chiv. Bd. XLI. p. 75. 1887.
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gen. 1880.
Lehrbuch der Anatomic der Sinncsorganc. Das

Gehororgan. Erlangen. 1887. p. 288 —

p. 392.
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schen libersetzt von Dr. C. von Krzywicki.

Jena. 1894.
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Icidcn. Samraelreferat. Internat. Centralbltt.

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p. 407.
Die Functionen des Ccntralnervcnsystems und

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Bau des Ilirnknotens oder der Varolischen

Briickc. Jena. 1846.
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rinthique. (C. R. de la Soc. de biologic.

1898. 12 fcvr.
Le cervelet. 1897.
Ueber die Folgen der Durcbschncidung des

Trapeskorpers bei der Katze. Neur. Centr.-

bltt. Bd. XVIII. 1899. S. 674—685,

731—741.
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Archiv f. d. Ges. Phys. Bd. L. 1891. p.

423—472.
Die Sccundare Acusticusbahn der Taube. Anat.

Anzeiger 1898. Bd. XIV. N^ 14.
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Bd. XX. S. 50.
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OF THE NERVUS OCTAVUS.

199

C. Wernicke.
N. Wyrubow.

Th. Ziehen.

Tfl. Ziehen.

H. ZWAARDEMAKER.

Gruiidrisz der Psychiatric. Leipzig 1900.
Psycho-physiologische Einleitung.

Ueber die centralen Eiidigungen und Verbin-
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Centralbltt. 1901. Bd. XX. S. 434.

Handbuch der Anatomic dcs Mcnschcn, hcr-
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Ncrvcnsystcm. Tbcil I. Jena 1899.

Die Entwickelung der Leitungsbahnen in
OsKAR Hertwig's Handbuch der verglei-
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Inlciding tot ecn bespreking van dc ziekte van
Meniere. XP® Nederl. Natuur- en Genees-
kundig Congres. Leiden 6 April 1907.

I N D E X.

pag-

iNTRODUenON 3

Chapter 1. The removal op the rabbit-labyrinth. The section
OF the N. octavus and op its prolongations in the central

NERVE-SYSTEM.
The DISTURBANCES OF MOTION FOLLOWING ON THESE OPERATIONS.

1 . A few technical remarks on the removal of the labyrinth

in rabbits 6

2. The operations through the bulla ossea 9

a. the removal of the cochlea 13

h. the removal of the entire labyrinth 15

c. the sectioninp^ of the corp. trapezoides 17

(I. the section of tlie dorsal octavus-tract 17

2. IVie acute motor troubles arising aftei' one-sided removal «
of the labyrinth 19

3. Permanent disturbafices of motion after the one-sided
removal of the labyrinth 29

4. The disturbances in motion in rabbits after the extirpation

of the labyrinth on both sides 34

5. The results of destruction of the cochlea 36

5. The effects of the sectiori of the dorsal secundary tracts

of the N, octavus 37

6. A comparison between pigeofis after one-sided removal of

the labyrinth and rabbits after the same (rperation * 39

7. Conclusions concerning the disturbances of motion 'fotind
after extirpation of the labyrinth 42

THE CENTRAL COUBSE OF THE NERVUS OCTAVUS. 201

pag-
Chapter II. On the distribution op the nervijs octavus in

THE central nervous SYSTEM IN RABBITS 45

L Methods of investigation. Introduction 45

2. The roots of the nervus octavus

a. The actual view upon llie signification of the N. cochlearis and the

N. vestibularis and their continuation in the lateral and ventral root 48

3. The primary si/stems or the root-fibres of the nervus octavus
a. The fresh degeneration in the root-fibres taking place after the isolated

removal of the cochlea and the initial course of the dorsal (lateral) root in

the central system 53

h. The fresh degeneration in the root-fibres taking place after the section
of the Vnit*> nerve and the initial traject of the ventral (medial) root in the
central system 55

c. The supposition that both roots send their fibres, though in different
quantities , in the same paths , is confirmed by the study of the myelinisation

of the roots in the rabbit 67

d. The supposition that both roots send their fibres in the corpus trapezoides

is also confirmed by Gudden's method 59

e. The systema ventrale nervi octavi 61

/. The myelinisation-method offers the same results as the Marchi-method ,

in regard to the position of the root fibres and secundary fibres in the systema

ventrale nervi octavi 64

(J. The secundary atrophy confirms the existence of lootfibres in the systema

ventmle 67

//. The most dorsally situated root-fibres and Held's intermediary system. 69
X\ The longitudinal rootfibres ascending towards cerebellum and metence-

phalon 73

/. The rootfibres in the systema dorsale nervi octavi 77

/;/. The results of the secundary atrophy and of the myelinisation-method

in regard to the systema dorsale nervi octavi 83

n. The nucleus dorsalis nervi octavi 88

o. The portio interna corporis restiformis 92

/;. The portio interna in the embryo of the rabbit. Its atrophy after root-
section 97

q. The descending octavusroot. The transverse dorsal fibres 101

4. The secundary systems of the nervus octavus 105

a. The secundary systems in the systema ventrale and in the
systema intermedium nervi octavi. 107

b. The longitudinal secundary systems from the systema
dorside nervi octavi 119

5. Summary of results 129

The tibres of the dorsal root 130

The fibres of the ventral root 133

The ascending secundary systems 135

The descending secundary systems 139

202 C. WINKLER. THE CENTRAL COURSE, ETC.

CUAFFER III. On the (CENTRAL DISTRIBUTION OF THE ROOT-FIBRES

OF THE NERVUS OCTAVUS IN PIGEONS 141

a. The entrance of the root-fibres 142

b. The rootftbres in the systenia dorsale nervi octavi 147

c. Comparison between the central octavus rootfibres in

pigeons and in rabbits 151

Chapter IV. The influence exerted upon motility by the

N. OCTAVUS IN rabbits AND IN PIGEONS WITH REGARDS TO

the central distribution of this nerve 15g

^Explication of the platf^ and description of the figurf^

and the abbreviations 171

List of books consulted in studying the N. octavus 187

COUNTWAY

HC 2VX1A

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