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QM455 .H85 An Eskimo brain. By

RECAP

An Eskimo Brain

BY

ALES HRDLICKA, M.D.

NEW YORK

THE KNICKERBOCKER PRESS

NEW YORK

1901

Q/W455

MM

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An Eskimo Brain

BY

ALES HRDLICKA, M.D.

NEW YORK

THE KNICKERBOCKER PRESS

NEW YORK

I9OI

An Eskimo Brain

BY

ALES HRDLICKA, M.D.

NEW YORK

THE KNICKERBOCKER PRESS

NEW YORK

I9OI

40 13778

KISHU AND MENEE (PHOTOGRAPHED ON THEIR ADMISSION TO BELLEVUE HOSPITAL)

AN ESKIMO BRAIN
By ALES HRDLICKA

The brain in question ' is that of Kishu (or Kissuk), an adult
male Eskimo of about forty-five years of age, who died of acute
general tuberculosis.2 Kishu was a chief of his tribe ; he meas-
ured 1.64 m. in height, weighed about 170 lbs., was muscular,
and in every respect normally developed. He died at Bellevue
Hospital within less than five months after the inception of his
disease. Plate XIII shows him (together with his son) as he ap-
peared on admission to the hospital.

The autopsy was performed in my presence by Dr Harlow
Brooks. I am indebted to Dr Brooks for notes concerning the
general condition of the brain and its membranes, and to the
authorities of Bellevue hospital and the American Museum of
Natural History for the privilege of examining the specimen*
Before the skull was opened, I obtained the following measure-
ments of the head :

Diam. antero-post. max 19.8 cm.

Diam. lateral max 1 5. 1 cm.

1 The specimen was examined in 1896 and reexamined in igoi. A preliminary
report on it was published by the author in the Proceedings of the Amer. Medico-
Psychological Assoc, 1899, and a full report in the American Anthropologist,
n. s., 3, 1901.

8 Kishu was one of the six Eskimo who were brought to New York in 1896 by
Lieutenant Peary, from the neighborhood of Smith sound. Of these six Eskimo,
four, including Kishu, have since succumbed to acute tuberculosis ; one was sent back
to Smith sound, and a boy of about twelve years survives, after having recovered from
incipient pulmonary tuberculosis, in the care of Mr Wallace, the former Superintend-
ent of the American Museum of Natural History. The brains of the three other
Eskimo who died, as well as an additional specimen, — the brain of an Eskimo girl
from Alaska, — will be reported upon in detail by Mr Edward A. Spitzka, of Columbia
College. Some measurements and observations which I have made of these brains
will be included, for comparison, in this paper.

3

4 AN ESKIMO BRAIN

(Cephalic index 76.26.)
Height (from line joining the aud. meati to

bregma) about I4-2 cm.

Circumference maximum of the head 56.8 cm.

Diam. biauricular (between the depressions
over the roots of zygomae, in front of

the ear) 13-2 cm.

Diam. frontal minimum 10.4 cm.

Diam. bigonial 1 1 . 1 cm.

Diam. bizygomatic max 14.5 cm.

Height of face : chin to nasion 12.3 cm.

chin to interciliary line 14.3 cm.

chin to insertion of hair 20.0 cm.

These measurements agree in the main with those which I
made of the other Eskimo from the same locality, thus showing
that Kishu was not racially exceptional.

The scalp was found to be less than the average in thickness ;
this was undoubtedly due to advanced general emaciation. The
skull was entirely symmetrical ; the sutures mostly still pervious ;
skull-cap thin. No adhesion of the dura ; the soft membranes
normal. Several masses of Pacchionian granulations over the
longitudinal sinus. No signs of tuberculosis,1 nor any other
pathological lesion, within the cranial cavity. Very small quan-
tity of fluid. There was a pronounced pigmentation of the pia
and arachnoid from the pons to over and below the calamus
scriptorius.

Weight of brain, denuded of dura mater, after a few minutes'
exposure for drain, 1503 grammes.2 The specimen was laid in
20 parts 5 % formaline and 80 parts 95 % alcohol.

1 The brain and the heart were about the only organs in which no tubercular lesions
were found.

2 Mean weight of white male brain in 154 men of mean height of 1.680 m. equals
1361.5 grams (Broca) ; mean weight of white male brain in 168 men of mean height
of 1.679 m- equals 1357.5 grams (Manouvrier).

AN ESKIMO BRAIN 5

Examination of the Brain

(Three weeks after death)

Weight

The brain and its principal parts, denuded of the membranes,
weigh, after 15 minutes' drainage, as follows:

Whole encephalon 1 325.0 gr.

(Loss in three weeks through solution and

through loss of membranes 178.0 gr.)

Cerebrum 1 155.0 gr. or 87.17% of the total.

Right hemisphere 577.0 gr.

Left hemisphere 578.o gr.

Cerebellum 142.0 gr. or 10.72 % of the total.

Pons and bulb 2S.0 gr. or 2.1% of the total.

The proportions of the cerebrum and cerebellum to the whole
brain are very nearly like those of whites,1 but the relative weight
of the pons and bulb is slightly greater.

GENERAL OBSERVATIONS

Cerebrum

The hemispheres in general are very well developed. The
gyration is pronounced and rather more complex than that
found on the brains of average whites. The principal sulci are
deep. The thickness <>f the gray matter shows no appreciable
difference from that observed in the brains of whites. The gyra-
tion of the left hemisphere is perceptibly more complex, particu-
larly in the frontal lobes, than that of the right. A striking
feature is the predominance on both hemispheres, but more espe-
cially on the right, of vertical gyration.

1 In the white brain, the proportionate weight of the cerebellum, medulla, and
pons together is to that of the whole brain in the adult as 13 to 87 (Huschke). The
cerebellum is 10.7 of the lotal encephalon (Meynert). According to Broca, the rela-
tive weights to that of the whole encephalon are: cerebrum, 87.3$ ; cerebellum, ro.6 %;
pons and bulb, 1.91 %. As to the hemisphere, in 264 men Broca found the right to
be the heavier in 138 cases, the left in 105 cases ; the weight was even in 21 cases.

6 AN ESKIMO BRAIN

The hemispheres show certain gross and many small asym-
metries. The principal of the gross asymmetries are the differ-
ences in the limbic, temporo-sphenoidal, and occipital lobes. All
these, as well as the minor peculiarities of the brain, will be
described later.

Norma Superior. — Viewed from above, the cerebrum is dis-
tinctly hexagonal in its outline. The longest sides of the hexagon
are the antero-lateral lines, upon which follow, in the order
named, the anterior, the postero-lateral, and the posterior lines.
The outline of the frontal lobes is quite angular.

The Norma Lateralis, or the outline of the cerebrum when
looked at from the side, is obliquely quadrilateral. The antero-
inferior line (base of the frontal with the antero-inferior boundary
of the temporal lobes), and the postero-inferior boundary (base
of temporal and occipital lobes), are nearly straight. The two
superior lines, moderately convex, meet over the precuneus.

The right temporal lobe is perceptibly higher than the left.

There are a few specially prominent points on the external
surface of each hemisphere : on the left such points are the
supramarginal and the second temporal gyri ; on the right, the
supramarginal (somewhat less than on left), second temporal, and
ascending parietal convolutions.

Norma Ventralis, or the outline of the base of the hemi-
spheres, is oval, almost square anteriorly and tapering posteriorly.
The basal surface of the frontal lobes slopes toward the middle
and there is a marked elevation on each frontal lobe along the
median fissure. These elevations are somewhat larger than those
found ordinarily in the brains of whites. The olfactory nerves
run along their middle. Each of the elevations comprises ap-
proximately two-sevenths of the base of each frontal lobe, and
they, together with the sloping of the rest of the basal surfaces,
impart to the inferior portion of the approximated frontal lobes a
boat-keel-like appearance.

Norma Anterior.— The outline of the anterior lobes forms

AN ESKIMO BRAIN J

superiorly and laterally a regular arch, while inferiorly it consists
of two shallow arches (concavities of the inferior surface of the
frontal lobes), which meet over the median eminence. The
outer terminal points of the arches are, as usual, situated higher
than the inner ones.

The anterior surface of the frontal lobes is almost vertical.

Principal Measurements of the Cerebrum '

Length maximum of left hemisphere 18.0 cm.

Length maximum of right hemisphere 17.9 cm.

Width maximum of cerebrum 13.6 cm.3

As to the parts situated at the base of the cerebrum, nothing
unusual was found. The anterior perforated spaces are not
appreciably larger than in whites. The optic commissure is well
formed ; the optic nerves are strong. Hypophysis of ordinary
size and appearance. Crura cerebri, cut at the niveau of the
mesial border of the hippocampal gyri, are exactly equal in size.
Their cross-section measures on each side 2.8 cm. in greatest
length and 1.7 cm. in greatest width.

There were no marked anomalies in the cerebral circulation.
The ventricles were not opened.

External Conformation of the Hemispheres
principal sinuosities. fissure of sylvius
The horizontal and ascending, or, more properly in this case,
the anterior and posterior, branches of the pre 'sylvian begin sepa-
rately, from the superior limiting sulcus of the insula on the
right, and from a common fovea, connecting with that sulcus, on
the left side.3 The anterior branch is in line with, and appears
like a continuation of, the anterior limiting sulcus of the insula.

1 For additional and comparative measurements, see the end of the paper.

* By an oversight this measure was given in the preliminary report as 14.2 cm.,
which was incorrect.

3 This, according to Cunningham, is also frequently the case in whites. In
80 hemispheres examined by that author, two separate limbs of the presylvian were
found 15 times (32.6 %) on the right and 15 times (44.1 %) on the left side.

8 AN ESKIMO BRAIN

Length of the anterior branch, 1., 2.8 cm., r., 2.6 cm.
Length of the posterior branch, 1., 1.2 cm., r., 2.0 cm.

On the left the posterior branch is very short, and on both
sides the anterior branch is the longer (the reverse of that gen-
erally found in white people).

The anterior branch connects on the right, over a submerged
but not deep gyrus, with a descending branch from the inferior
frontal sulcus.

The several important opercula situated along the lower
border of the hemispheres in the neighborhood of these two an-
terior branches of the Sylvian, differ somewhat in size and form.
(See the description of the inferior frontal gyrus.)

The stem or main limb of the Sylvian runs in a nearly
straight line ; it measures, from the anterior branch of the pre-
sylvian to the bifurcation, 6.5 cm. on the left and 5.2 cm. on the
right hemisphere.1

The depth of the Sylvian fissure is considerable throughout.
It measures :

Left Right

At the origin (x) of the anterior branches 3.0 cm. 3.1 cm.

In middle between x and the precentral sulcus.. . . 2.9 cm. 2.6 cm.
Opposite the precentral sulcus 2.8 cm. 2.7 cm.

The anterior branch of the presylvian measures at middle,
left, 2.4 cm. ; right, 2.2 cm. Of the terminal branches of the
Sylvian, the superior measures, left, 2.6 cm. ; right, 2.2 cm. The
inferior measures, left, 1.8 cm. ; right, about 0.8 cm. in depth.

The above figures show that, except at its beginning, the left
Sylvian is the deeper at all points of measurement.

The main limb of the Sylvian presents the following points of
interest on the two sides of the brain :

On the left, 0.5 cm. behind the posterior presylvian, there be-
gins within the Sylvian, over a deep annectent loop, by means

1 The left fissure is longer than the right one in the whites* and the disproportion
"is evident at all points of growth" (Cunningham, Contr. to the Surf. Anat. of the
Cerebr. Hemispheres, 1892, p. 127 ; also Eberstaller).

AN ESKIMO BRAIN 9

of the diagonal sulcus, a pronounced, long, composite, vertical
furrow, which runs nearly parallel with the central fissure and the
precentral sulci, and terminates above not far from the superior
border of the hemisphere. The sulcus shows a number of medium
deep and deep annectent fascicles.

On the right a similar furrow begins from the Sylvian, over a
submerged loop, 0.6 cm. posteriorly to the hinder branch of the
presylvian, and ascends in a quite straight line to within a few
millimeters of the superior frontal sulcus. This furrow, in aver-
age as well as at maximum, is deeper than that on the left
(maximum depth on the right, 1.7 cm.).

A little over 1.0 cm. posteriorly to the last mentioned furrow
there begin from the Sylvian, on both sides, over a loop situated
very deeply on the right and at medium depth on the left, the
central fissures.

The base of the ascending frontal gyrus shows on each side a
small trans-precentral, the base of the ascending parietal convolu-
tion a similar trans-postcentral sulcus. These sulci on the right side
are entirely hidden in the Sylvian, but on the left side both reach
to and slightly beyond the inferior border of the convolutions.

Finally, 0.5 cm. anterior to the bifurcation on the right and
almost at it on the left, the Sylvian connects on each side, over a
submerged but quite superficial gyrus, with the united postcentral
sulcus.

The inferior lip of the Sylvian shows on the left the extremi-
ties of four, on the right of three, transtemporal depressions. One
of these furrows on the left and one on the right effect a shal-
low communication with the superior temporal sulcus.

Of the terminal branches of the Sylvian the superior is 2.4 cm.
in length on the left, and 2.6 cm. on the right side ; they both
end, as usual, in the supramarginal gyrus. The inferior ramus on
the left runs 3.0 cm. horizontally and bifurcates ; one of its
branches, 2.5 cm. long, passes upward into the angular gyrus,
while the other, 1.0 cm. long, descends backward. On the right

10 AN ESKIMO BRAIN

the inferior terminal branch runs 1.5 cm. backward and down-
ward and joins, over a deep gyrus, the first temporal sulcus.

The superior terminal branch on the left makes two connec-
tions : one, shallow, posteriorly, with a sulcus running downward
and forward from the interparietal, and one, deeper, anteriorly,
with a horizontal furrow running backward from the lower part
of the postcentral sulcus. The inferior branch on the left con-
nects, not far from the bifurcation, over a submerged annectent
gyrus, with the posterior portion of the first temporal sulcus.

On the right side the superior terminal branch of the Sylvian
fissure is better developed than the inferior, and is deeper than
the latter. It ascends for 2.0 cm. into the supramarginal gyrus,
running parallel to the central fissure, and ends in a short T.
The lower terminal branch descends for 1.3 cm., over two medium
deep anastomotic fascicles, and joins the ascending ramus of the
first temporal sulcus.

Annectent Gyri. — On the left a strong column, at medium
depth, between parietal and temporal lobes, at the beginning of
the lower terminal branch of the Sylvian. On the right a similar
but more superficial column, at the beginning of the inferior
branch, and another more posteriorly in the same.

CENTRAL FISSURE

Left Right

Length (in a straight line, with

sliding compass) 9.0 cm. (50 $ of the total 8.6 cm. (48 <f0).1

length of the
hemisphere)
Depth, maximum 2.3 cm. 2.5 cm.

The fissure begins on both sides within the Sylvian, probably
by means of the subcentral sulci of Eberstaller.2 The origin

1 According to Schafer (Quain's Anat., 10th ed., ill, 1, p. 143), "the length of
the fissure in whites is about 2/5 (or 40 %) of the whole length of the hemisphere.
It is relatively longer and more curved in the anthropoid apes than in man." (See
additional measurements.)

'2 Cunningham (op. cit., 63) found a connection of the central and Sylvian in 19 %
of hemispheres (of whites) ; Benedict {Anat. Studien an Verbrecher-Gehirnen,

KISHU'S CEREBRUM (DORSAL ASPECT)

AN ESKIMO BRAIN II

of the central fissure is situated 0.6 cm. below the borders of the
Sylvian on the left, and 1.5 cm. on the right It nearly connects
on the right with the superior limiting sulcus of the insula. A
short distance above the Sylvian border, the left central fissure
shows a submerged, but not very deep, annectent gyrus; on the
right there are two such fascicles in a similar location.

The form of the central fissure is quite tortuous, especially on
the right. The left fissure, neglecting minor bends, is, from
above downward and with reference to the frontal lobe, convex,
concave, convex, concave, much convex, and nearly straight ;
that on the right, convex, concave, convex, concave, convex.

Each of the fissures sends a number of incisures into the
adjacent convolutions. On the right, 3.3 cm. above the Sylvian,
the central fissure connects, over a quite superficial annectent
gyrus, with the postcentral sulcus.1

The two fissures show no submerged interruption.

The superior ends of the central fissures are situated almost
opposite; distance from the same to the superior border, left, 0.5
cm. ; right, 0.5 cm.2

Additional measures :

Left Right

(i) Origin of central fissure (on the lip of the Syl-
vian) to frontal pole 3 7.3 cm. 6.5 cm.

(2) Superior extremity of central fissure to frontal

pole 10.9 cm. 10.8 cm.

Wien, 1872, p. 96) found a complete connection in 18 and an incomplete one in 6 of
38 hemispheres examined. Giacomini (Varieta d. circonvoluzioni cerebrali dell' uomo,
Torino, 1882, cited by Cunningham) found such a connection only in 21 among 336
hemispheres. Retzius {Das Menschengehirn, 1896, I, p. 100) found the connection in
23 % of the hemispheres of Swedes.

1 Retzius observed, on the brains of whites, anastomosis of the Rolandic fissure
with the inferior postcentral sulcus in 9 %, with the superior in 3 % of the cases.

2 Cunningham (op. cit. , p. 162), in 52 hemispheres of white children and adults,
found the following conditions in this respect : "(a) In 60 % the upper end of the
fissure cut the upper border of the hemisphere and appeared on the inner surface ; (b)
in 21 £ it just reached the upper border ; and (c) in 19 % it fell short of the upper
border."

6 This and the following measures are the horizontal distances between vertical
planes at the points mentioned.

12 AN ESKIMO BRAIN

Left Right

(3) Origin of central fissure to occipital pole 10.7 cm. 11.4 cm.

(4) Superior extremity of central fissure to oc-

cipital pole 7.1cm. 7.1cm.

Reduced to per cent, of the total antero-posterior diameters
of the hemispheres, these distances are :

Left Rigkt

(1) 4°-6 ^ 36-3$

(2) 60.6 <fo 60.4 <fo

(3) 59-4 io 63.7 i

(4) 39-4 i 39-6 i

PARIETO-OCCIPITAL FISSURE

The fissure appears on both sides like a direct and equally deep
continuation of the calcarine stem. It runs on each side, in nearly
a straight line, upward and slightly backward to, and on the left
2.1 cm., on the right 1.5 cm., over, the superior border of the
hemisphere. The extremity forms on each side a small T, which
is surrounded by a pronounced paroccipital gyrus.

The average depth of the fissure is 2.3 cm. on the left and 2.3
cm. on the right side ; its length, from its junction with the cal-
carine stem to the superior border is on the left 4.0 cm., on the
right 4.2 cm.

The fissure on the left connects over a submerged but quite
superficial gyrus with the sub-precuneal sulcus, while that on the
right shows a slightly deeper connection with a sulcus from the
cuneus.

There are only a few very deep annectent bundles within
each fissure.

CALCARINE STEM AND SULCUS

The stem is simple, its course on each side slightly wavy. Its
length is 2.6 cm. on the left, 3.3 cm. on the right ; its average
depth on both sides about 1.5 cm. ; at its junction with the pari-
eto-occipital it equals the latter in depth.

Both calcarine sulci communicate with the stem over a sub-
merged but not very deep gyrus. The left sulcus is nearly

AN ESKIMO BRAIN I 3

straight ; the right one describes anteriorly a moderate curve.
The sulcus on the left is free from connections and gives off but
two small incisures ; that on the right connects superficially with
a cuneal sulcus and sends from its curve a deep branch, i.o cm.
long, downward to the basi-mesial border.

The calcarine sulcus extends on both sides to the dorsal sur-
face of the occipital lobe, and terminates in a small bifurca-
tion. The most distal point is on the left 1.55 cm., on the right
1.3 cm., in a straight line beyond the border of the hemisphere.

The length of the calcarine sulcus from its junction with the
stem to the border of the occipital lobe is 4.6 cm. on the left, 4.8
cm. on the right side. It is on both sides much shallower than
the stem.

There are a number of connecting fasciculi within the two
calcarine stems and sulci. On the left there is a deep bundle
in about the middle of the stem and reaching from the base
of the stem to the point of the cuneus ; there are also two bundles
at medium depth behind the junction of the stem and the sulcus
and passing from the gyrus lingualis to the cuneus ; and there is
another fascicle of medium depth in the sulcus, about 2 cm. from
the occipital border. On the right side we find similar annectent
gyri in similar locations, but the bundle in the stem passes down-
ward to the bottom and does not visibly reach the cuneus.

COLLATERAL FISSURE

This furrow is of considerable extent, particularly on the
right. Its total length, in a straight line, is 8.15 cm. on the left,
and 1 1.3 cm. on the right.

The anterior termination of the fissure is on both sides free
and simple ; it is distant from the pole of the temporal lobe on
the left 5.7 cm., on the right 2.9 cm.

On both sides, nearly in the line of continuation of the collat-
eral fissure and incising the antero-mesial border of the temporal
lobe, is found a well-developed fissura rhinica. This furrow is

14 AN ESKIMO BRAIN

particularly marked on the left side where the collateral is
shorter.

Posteriorly, the left collateral fissure terminates in a line about
3 mm. from the border of the hemisphere, while on the right
it reaches the border. Both of the fissures connect, each by a
shallow sulcus, with the third temporal.

Each collateral gives off several incisures. In the posterior
half of both fissures are found, at medium depth, annectent
bundles which pass between the fusiform and lingual lobules.

CALLOSO-MARGINAL FISSURE

The gyration on the mesial surface of this brain presents
several very interesting modifications. The calloso-marginal is
duplicated on the left and almost triplicated on the right side.
The main fissure is on both sides throughout continuous and
connects freely and deeply with the paracentral. It is on both
sides doubled by a pronounced mesial frontal sulcus. This is
deep and continuous on the left, more shallow and interrupted by
an isthmus on the right. In addition the right callosal gyrus is
traversed along its entire superior extent by a shallow, inter-
rupted sulcus, which runs parallel with the calloso-marginal fissure
and separates the surface of the callosal into two nearly equal
superior and inferior portions.

The left calloso marginal begins in a simple way below the
genu of the callosum ; the right proceeds from a subrostral sulcus
which curves about a lobule on the posterior extremity of the
mesial portion of the frontal lobe.

During its course, each of the calloso-marginal fissures gives off
a few small branches or incisures. On the left, as well as on the
right, four such small branches indent the superimposed part of
the superior frontal gyrus.

There is on both sides a well-developed rostral, and on the
right also a transverse subrostral sulcus ; there is also a fair repre-
sentation on each side of the postlimbic sulcus.

PLATE III

KlSHU'S CEREBRUM (BASA^. ASPECT)

AN ESKIMO BRAIN I 5

The paracentral sulci are well curved and both end on the
dorsal surface of the hemisphere : the left in a line, 1.5 cm. from
the median border and 0.7 cm. behind the superior extremity of
the central fissure ; the right in a T, with the posterior branch
much shorter than the anterior, 1.6 cm. from the median border
of the hemisphere and 0.5 cm. behind the terminus of the central
fissure.

The average depth of the calloso-marginal is 1.0 cm. on the
left, 1.3 cm. on the right ; that of the paracentral 1.5 cm. on the
left and 1.8 cm. on the right side.

Annectent Gyri. — There are in the calloso-marginal five or six
deep bundles on the left and seven or eight such bundles on the
right, passing between the callosal gyrus, the superior frontal
convolution, and the paracentral lobule.

MINOR FISSURES OR SULCI

Frontal Lobe. — The superior frontal sulcus on the left is a con-
tinuous furrow, which runs, in a tortuous way, from the anterior
portion of the orbital surface to within a few millimeters of the
superior precentral sulcus. On the right a similar but somewhat
less tortuous furrow extends from the orbital border of the
frontal lobe to the superior precentral sulcus, connecting with
the same.

Each of the sulci sends off a number of transverse branches
and incisures. That on the left communicates with the medial
frontal sulcus of Eberstaller and with the vertical furrow anterior
to the precentral sulci ; that on the right connects with the
medial frontal and the superior precentral sulcus.

The depth of each of the superior frontal sulci averages about
1.5 cm., the maximum depth measured being 2.8 cm. (on the
left).

Mesially from the superior frontal sulci we find on each side
of the brain, but particularly on the left, small segments of Cun-
ningham's mesial sulcus.

1 6 AN ESKIMO BRAIN

The medial frontal sulci of Eberstaller are only fairly well
represented.

The inferior frontal sulcus can be isolated with more facility
on the left than on the right hemisphere ; it does not connect on
either side with the inferior precentral sulcus.

The left inferior frontal sulcus is in two portions; it begins
posteriorly 3 mm. in front of the middle of the inferior precentral,
intersects the anomalous vertical furrow, and terminates about
2 cm. in front of this furrow in a shallow Y. A few millimeters
inferiorly and posteriorly to the lower terminal branch of this Y
begins the second portion of the sulcus. This portion consists
mainly of the sulcus radiatus, and sends six branches into the
adjacent convolutions.

On the right side, that part of the vertical furrow which cor-
responds to the diagonal sulcus connects, 1.9 cm. above the
Sylvian, with a short but deep T branch, 1.0 cm. long, which runs
directly forward and probably represents the posterior extremity
of the inferior frontal sulcus. The anterior portion of the same
consists of the sulcus radiatus, possibly joined with the fronto-
marginal sulcus. This portion, as on the left, shows six
branches. One of these connects inferiorly with the anterior
branch of the presylvian ; another ascends to within a short dis-
tance of the median frontal sulcus.

A small independent depression indents on each side the sur-
face of the pars triangularis of the inferior frontal gyrus.

All the frontal sulci show numerous submerged annectent
gyri.

The anomalous vertical furrow which runs on each side an-
terior to and nearly parallel with the precentral sulci, has been
referred to in the description of the Sylvian.

The precentral sulcus consists on each side of two independent,
radiating segments of considerable depth. On the left these
segments are isolated ; on the right the superior connects, over a
deep annectent bundle, with the first frontal sulcus, while the

AN ESKIMO BRAIN I 7

inferior joins and probably forms the superior part of the
anomalous vertical furrow.

Above the superior precentral there is on each side an inde-
pendent, triradiate sulcus extending to the upper border of the
hemisphere and bounding laterally the ascending frontal con-
volution ; it looks like a third part of the precentral.

Orbital Surface. — The Sulcus Olfactorius presents a typical
conformation. It is a long depression, running from i.o cm.
at base to 0.5 cm. at terminus laterally to the median fissure,
quite deep, terminating on the left side in a free line and
on the right side in a small Y. Slightly anteriorly to the end a
small transverse sulcus crosses the border of the hemisphere on
the left, and a small semicircular sulcus indents the border on the
right side. The parts of the first frontal gyrus traversed by the
olfactory sulcus are, as previously stated, quite prominent.

Besides the olfactory, each of the orbital parts shows two
other antero-posterior sulci. One of these, the outer, is apparently
the orbital sulcus. Its form on the left is that of a Y, or of a K
with the lower branch interrupted, while on the right side it
forms a somewhat crooked X.

Both of these figures are situated somewhat more externally
than is usual, and between them and the olfactory furrows we
find on each side a distinct separate sulcus. On the left this
sulcus consists of two branches and indents the first frontal con-
volution. The anterior branch communicates with the main
ramus of the orbital sulcus. On the right side the sulcus begins
near the root of the olfactory nerve and then passes forward,
bounding the first frontal gyrus.

The transverse orbital sulci present nothing extraordinary.

Parietal Lobe. — The postcentral sulcus shows neither on the
left nor on the right any superficial interruption.1 It connects on

1 According to Cunningham, in the brains of adult Irishmen the postcentral
sulcus was found complete and separated from the interparietal sulcus (as on the right
in the Eskimo brain) in 11?; it was found complete and communicating with the
interparietal (as on the left in the Eskimo brain) in 60 % of the hemispheres.

1 8 AN ESKIMO BRAIN

both sides with the Sylvian and on the left side also with the
interparietal sulcus.

The left postcentral is very long, reaching to within 0.5 cm.
of the superior border of the hemisphere, where it connects, over
an imperfectly submerged gyrus, with a vertical sulcus from the
precuneus.

The connection of the postcentrals with the Sylvian is not
effected by the trans- postcentral sulci.

The course of both postcentral sulci, and particularly of that
on the left, is tortuous.

Each sulcus gives off during its course several incisures and
small branches. On the left side, 1.4 cm. above the Sylvian bor-
der, a quite deep branch passes backward through the supra-
marginal convolution and communicates with the superior
terminal branch of the Sylvian. Three cm. above the Sylvian
the left postcentral connects, over a submerged gyrus, with the
interparietal sulcus. Opposite this junction a branch, 1.4 cm. long
and looking like the anterior terminus of the interparietal, passes
forward and slightly upward into the ascending parietal gyrus.

In its upper third the left retrocentral sulcus gives off three
smaller branches. The lowest one of these passes backward ; the
middle one indents the ascending parietal gyrus and ends near
the central sulcus ; the third branch passes upward, ending in
front of the dorsal termination of the paracentral fissure. The
main limb of the sulcus then bends backward and runs toward
the aforementioned connection with the precuneal.

The right postcentral sends off four branches or incisures,
one of which, 2.0 cm. long, passes backward from near the mid-
dle of the sulcus. Two and a half cm. above the Sylvian the
right postcentral connects, over a submerged but not deep
fascicle, with the central fissure.

Superiorly the sulcus divides into two branches, the anterior
1.4 cm., the posterior 2.4 cm. in length, which surround, in the
form of a broad Y, the extremity of the paracentral sulcus.

PLATE IV

ri / ■■:

Lateral aspect

Mesial aspect
THC HEMISPHERES OF KISHU'S CEREBRUM

AN ESKIMO BRAIN

19

Each postcentral shows in its course a number of more or less
deep annectent fascicles.

The trans-postcentrals are in their usual position, but only
that on the left (as was the case with the trans-precentrals) reaches
the dorsal surface of the hemisphere.

The interparietal sulcus on the left commences, with a small T,
somewhat inferiorly and anteriorly to the end of the superior
terminal Sylvian, 1.8 cm. from the Sylvian bifurcation. Seven
millimeters above its beginning the sulcus connects, over a sub-
merged but not deep gyrus, with the postcentral. From this
point the interparietal runs in a slight curve 4.2 cm. upward and
backward and joins freely the paroccipital sulcus. The inter-
parietal gives off three larger branches, one of which runs down-
ward, into the supramarginal, and the other two upward, into the
superior parietal gyrus. There are within the sulcus several deep
but no interrupting connecting bundles.

On the right side we find an anomalous deep furrow, uninter-
rupted except by very deep bundles, running from a point well
down between the supramarginal and angular gyri, in a wavy
course, parallel in the main with that of the postcentral sulcus
and central fissure, to and 1.0 cm. over the superior border of the
hemisphere, ending on the precuneus.

From this furrow, above its middle, begins, over a depressed
but still partly visible gyrus, the horizontal part of the inter-
parietal. This is angular, but 0.8 cm. long (in a straight line), and
connects with the paroccipital.

The vertical furrow separates a stout and prominent con-
volution which runs parallel with the ascending frontal and
ascending parietal gyri. The superior portion of the vertical
furrow lies, independent of both, between the postcentral and the
anterior curve of the paroccipital sulcus.

The minor parietal sulci will be mentioned with the descrip-
tion of the convolutions.

Occipital Lobe. — The anterior as well as the lateral occipital

20 AN ESKIMO BRAIN

sulcus is fairly well represented on both sides. The anterior
sulcus on the left connects with the ascending branch of the
superior temporal, the anterior and lateral furrows on the right
with the anomalous medio-temporal sulcus (q. v.). The lateral
sulcus on the left is in the form of an H and is without
connections.

Temporal Lobe. — The sulci on the superior or intrasylvian sur-
face of the lobe have been mentioned.

The lateral surface is higher on the right than on the left side.
Its sulci are on both sides deep and the gyrations distinct.

The superior or first temporal sulcus begins on both sides
in a line near the pole of the temporal lobe. It is preceded on
the left by a small transverse furrow, on the right by a shallow
depression.

The horizontal portion of the superior temporal is continuous on
both sides. Its form is wavy on the left, more straight on the right
side. It terminates on the left in a line 1.8 cm. posteriorly to the
Sylvian bifurcation and within 0.3 cm. of the inferior terminal
Sylvian. The ascending portion is separate. On the right the
horizontal portion runs to a point about 1.2 cm. posterior to the
Sylvian bifurcation, connects with the inferior terminal Sylvian,
and proceeds without interruption backward and upward as the
ascending ramus.

The horizontal portion on the left connects, 1.6 cm. before its
posterior end, over a submerged but not deep gyrus, with a
parallel, medio-temporal1 sulcus, 4.4 cm. long, which separates the
posterior half of the middle temporal gyrus into an inferior and
a superior portion. The horizontal branch on the right connects,
by means of a shallow transverse sulcus, with the second tem-
poral, and more posteriorly as well as quite superficially with the
medio-temporal.

The ascending branch on the left begins with a short vertical

1 This term suggests itself from some similarity of this to the medio-frontal sulcus
of Eberstaller.

AN ESKIMO BRAIN 21

part that connects with the inferior terminal Sylvian. It runs
backward and slightly upward, almost in line with the horizontal
portion. It connects with the ascending part of the second tem-
poral, and finally joins the anterior occipital sulcus.

On the right the ascending branch runs in an angular manner
upward and backward, terminating a short distance below the
paroccipital. This branch also has a shallow connection with the
mcdio-temporal.

The mcdio-temporal sulcus is even better marked on the right
than on the left. Beginning somewhat posteriorly to a vertical
from the Sylvian bifurcation, it runs backward and upward,
parallel with the ascending portion of the first temporal, to the
occipital lobe. It connects with both the horizontal and ascend-
ing portions of the first temporal and also with the anterior as
well as with the lateral occipital sulci.

Both the first and the medio-temporal sulci send off shorter
branches and all show deep connections passing between the
adjacent gyri.

The mean depth of the horizontal ramus of the left superior
temporal sulcus is 1.8 cm., that of the right, 2.1 cm. The ascend-
ing rami are not so deep. The depth of the me dio-temp orals is
less than that of the horizontal, but slightly greater than that of
the ascending portion of the first temporal sulci.

The second or middle temporal sulcus is composed on each side
of two separate segments ; each of these shows some secondary
ramifications.

The anterior portion on the left commences with a curve,
passes in a wider curve backward and slightly upward, and ter-
minates, nearly vertically below the central fissure, with several
marked radiations. The posterior left segment begins in a Y
slightly above and posteriorly to the termination of the first part,
and runs slightly downward and backward, to and along the in-
ferior border of the hemisphere, terminating in a simple manner
about 1.6 cm., in a straight line, from the occipital pole, under the

22 AN E SKIMO BRAIN

lateral occipital sulcus. Two and seven-tenths of a cm. anteriorly
to its end this segment gives off, over a deep annectent fascicle,
an ascending portion, which runs with several bends directly up-
ward to connect with the ascending part of the first temporal
sulcus.

On the right side, the first portion of the second temporal has
its simple beginning i.o cm. in a straight line from the pole of
the temporal lobe ; it passes 4.6 cm. backward and ends in a
small bifurcation. A short distance anteriorly to this bifurcation
the sulcus communicates with the first temporal.

The posterior segment on the right begins a little posteriorly
to the bifurcation of the first part, in the form of a doubly curved,
nearly transverse line. This line bends, runs backward and down-
ward, reaches the inferior border, sends a 1.3 cm. long branch
backward and inward into the third temporal gyrus, passes again
to the dorsal surface of the hemisphere, and ends in a long Y
figure, the lower extremity of which reaches to below the lateral
occipital sulcus.

The third or basitemporal sulcus is unusually well developed,
particularly on the left side.

The sulcus on the left is continuous, somewhat wavy in form,
and measures 9.3 cm. in length (in a straight line). It effects
a shallow connection with the collateral.

The right sulcus consists of three large separate segments,
which extend from near the pole of the temporal lobe to within
1.7 cm. of the occipital pole. The segments send off a number
of radiating branches, and the posterior one connects with the
collateral.

On both sides the third temporal sulcus contains a number of
submerged, more or less deep, annectent fascicles.

THE INSULA

The conformation of the surface of the island is quite similar
on the two sides of the brain (figs. 57, 58).

AN ESKIMO BRAIN

23

Fig. 17 — Left insula. S.L.S., S.L.A., S.L.P., Sulci limitantes
insula;, superior, anterior, posterior; S.C.I.. Sulcus centralis
insulae ; S.P-c. I., Sulcus post-centralis insulae.

The marginal or limiting sulci of the insula are very deep,
especially anteriorly, and they are continuous, except over the
antero- inferior ex-
tremity or pole of
the insula.

The superior
limiting sulcus com-
municates on both
sides with the two
branches of the pre-
sylvian; it also gives
off on each side two
short branches up-
ward, and a deep
short incisure down-
ward, into the insula
itself. The average
depth of the su-
perior limiting sulci
is 2.8 cm., and in the
course of each there
are several strong
annectent fascicles
passing between the lobes of the island and the overlying
opercula.

At the posterior inferior angle of the insula there are two strong,
almost superficial annectent bundles, connecting the superior tem-
poral gyrus with the insula ; there is on each side also a strong
connecting bundle between the anterior extremity of the posterior
lobe of the insula and the superior temporal convolution.

The central sulcus of the insula is independent on the left,
but it communicates with the superior limiting sulcus on the
right side. The central sulci average only 0.5 cm. in depth, and
each shows anteriorly a submerged anastomotic fascicle.

Fig. 28— Right insula. P-s.A., Presylvian anterior; P-s.P., Pre-
sylvian posterior ; S.D., Sulcus diagonalis ; a, Trans-precen-
tral sulcus ; F.C., Central fissure ; b,Trans-postcentral sulcus ;
c. Postcentral sulcus.

24 AN ESKIMO BRAIN

Besides the above sulci, each insula shows a small furrow
which divides its posterior lobe into superior and inferior por-
tions (sulci retrocentrales insulae). There is also on each side
a curving but not very deep sulcus which passes from below over
the pole of the insula. This sulcus ends freely on the anterior
lobule of the insula on the right, but joins the anterior limiting
sulcus on the left side.

The anterior and posterior lobes of the insula are well defined
and show the ordinary planes. Gyri breves fairly well marked.

CONVOLUTIONS

Frontal Lobe. Dorsal Surface. — The frontal gyri are rather
more complex and tortuous than in average whites. The dorsal
portion of the left superior frontal gyrus is slightly narrower in
front than that of the right (left 2.85 cm., right 3.05 cm.), but
somewhat broader posteriorly (left 2.8 cm., right 2.5 cm.). In
about the middle, the left gyrus sends downward a prominent,
shoe-like convolution, which indents the middle frontal gyrus.
The dorsal parts of both superior frontal convolutions show, be-
sides the segments of the sulcus mesialis of Cunningham, a con-
siderable number of transverse depressions.

The middle or second frontal gyrus is on both sides of an
irregular form and partly subdivided by the medial frontal sul-
cus. The posterior portion of the convolution on the left is es-
pecially well developed, and is separated from the more anterior
portion by the vertical furrow. Both middle frontal gyri have
numerous superficial and deep connections with the neighboring
convolutions.

The inferior or third frontal gyrus is in this brain, contrary
to the general rule, more extended antero-posteriorly and more
redundant on the right than on the left side. This excess is
especially marked in the right middle or triangular part (cap of
Broca).

The convolution shows numerous connections ; the orbital and

AN ESKIMO BRAIN 2$

triangular parts connect on both sides superficially with the middle
frontal gyrus.

The ascending frontal convolution is somewhat stronger on the
right than on the left. It is on both sides most slender in its
middle fourth. It is on both sides continuous from the Sylvian
fissure to the superior border of the hemisphere. Superficial con-
nections.— On the left : a broad isthmus to the inferior frontal ;
a superficial annectent gyrus to the middle frontal ; similar gyrus
to superior frontal ; and, at the median border of the hemisphere,
three superficial annectent gyri, one to the superior frontal, one
to the paracentral, and one to the ascending parietal convolu-
tions. On the right there is a broad superficial connection with
the pars basilaris of the inferior frontal; and similar connections
anteriorly with the middle and superior frontal, and superiorly
with the paracentral and ascending parietal gyri.

Mesial Surface. — The left marginal gyrus is considerably
higher than the right one. Its height is, from the orbital surface
to the calloso-marginal fissure, on the left 2.2 cm., on the right
1.8 cm. ; opposite the anterior pole, on the left 3.2 cm., on the
right 2.5 cm. ; and the average height of the upper part is, on the
left 2.6 cm., on the right 2.3 cm. On both sides the marginal and
the calloso-marginal gyri stand to each other, as to size, in an in-
verse relation.

The inferior extremity of each marginal gyrus is marked by
the sulcus rostralis transversus and connects almost superficially
with the inferior extremity of the limbic lobe (carrefour olfactif
of Broca). The posterior extremity of the marginal gyrus com-
municates on the left by two superficial, on the right by one
superficial and one deep, annectent gyri with the paracentral
lobule.

As to the convolutions on the orbital surface of the frontal
lobes, on the left the first and third frontal gyri, both markedly
developed, join a little posterior to the middle of the surface, and

26 AN ESKIMO BRAIN

the second frontal gyrus forms a wedge anteriorly between them.
On the right, the second passes between the first and third gyri
as a narrow band to the root of the olfactory nerve, where it joins
the extremities of the other frontal convolutions.

The olfactory tracts and bulbs show nothing unusual.

The Parietal Lobe. — The ascending parietal gyrus is somewhat
more voluminous on the left hemisphere (average width on the
left about 1.2 cm., on the right about 1.0 cm.). The base of the
convolution on the left measures, antero-posteriorly, 3.2 cm., of
that on the right 1.9 cm. Both gyri show a constriction between
their lower and middle thirds, and a marked development of the
latter portion. The upper third is on each side slender, tapering,
and not raised fully to the niveau of the neighboring parts.

The upper extremity of the gyrus connects superficially with
the ascending frontal, paracentral, and superior parietal convolu-
tions ; the lower part connects, by means of submerged but not
deep fascicles, with the ascending frontal and supramarginal gyri.

The superior parietal gyrus is throughout somewhat larger on
the left side. Anteriorly it communicates on both sides super-
ficially with the ascending parietal, and in a similar way posteriorly
with the superior occipital convolution. Inferiorly there are nu-
merous submerged fascicles of connection between the superior
and inferior parietal gyri.

The left superior parietal convolution is separated by trans-
verse sulci into two parts, the middle of which is very redundant.
The right gyrus is somewhat similarly divided into two portions,
of which the anterior is the more redundant.

The convolution shows on each side a number of lateral and
surface indentures.

The paroccipital gyrus forms on each side a well-marked loop,
which surrounds the extremity of the parieto-occipital fissure.
The left gyrus is larger than the right one.

The inferior parietal convolution as a whole is larger on the

AN ESKIMO BRAIN 27

right, compensating for the smaller size, on that side, of the supe-
rior parietal.

The supramarginal gyrus is fairly well defined on the left and is
divided from the angular gyrus by a vertical branch proceeding
from the interparietal sulcus (the sulcus intermedius primus, Jen-
sen, Eberstaller). On the right side the marginal convolution is
larger and more redundant ; its operculum, or the triangular
part between the two terminal branches of the Sylvian fissure, is
especially well developed. The gyrus is bounded posteriorly by
the inferior extremity of the vertical parietal sulcus.

The angular and postparietal gyri are nicely differentiated
loops, separated by a vertical depression (sulcus intermedius
secundus, Eberstaller) on the left, but are of irregular form and
separated only from below by the extremity of the ascending
branch of the superior temporal sulcus on the right side.

All the parts of the inferior parietal convolutions show minor
lateral or surface indentations, and numerous deep as well as
superficial connections.

The paracentral lobule is much better isolated anteriorly on
the left than on the right. The left lobule is also slightly more
redundant, though slightly less high and not any longer than that
on the right side.

The surface of the left lobule is indented by two Y-shaped and
one lineal, that of the right by one Y-shaped and two lineal, sulci.

Precuneus. — This lobule is separated completely on the left,
incompletely on the right, from the limbic gyrus, by the posterior
limbic or subprecuneal sulcus. The surface of the left precuneus
is indented by four vertical sulci, two of which connect with the
posterior limbic, while the other two pass over the border of the
hemisphere, where the anterior communicates with the posterior
terminal branch of the postcentral sulcus, and the posterior one
forms the anterior boundary of the paroccipital gyrus. On the
right, the precuneus presents a Y-shaped sulcus in connection

28 AN E SKI MO BRA IN

with the intralimbic and postlimbic sulci, while its superior
portion is indented by the terminus of the anomalous vertical
parietal sulcus.

Both the paracentral lobule and the precuneus show numerous
deep, besides the superficial, connections with the adjacent gyri.

Occipital Lobe. — The lobe measures, from the anteroinferior
extremity of the cuneus to the occipital pole, on the left 4.7 cm.,
on the right 4.9 cm., which is respectively 26.1 % and 27.4$ of
the whole length of the hemisphere (see also additional measures).

The gyration of the lobe in the Eskimo brain under con-
sideration is not inferior to that met ordinarily in whites. It
presents, as is often the case, some difficulty to analysis, but no
very extraordinary features.

The cuneus -is bounded by almost straight lines. It is lower,
but longer, on the right hemisphere. Its superior border is in-
dented on the left by two, on the right by one incisure. Its sur-
face shows on the left an independent triradiate sulcus with
branching extremities ; on the right a large, somewhat Y-shaped
sagittal sulcus, which connects with the parieto-occipital, and a
quadriradiate sulcus, one of whose branches connects with the
collateral.

Temporal Lobe. — The superior temporal gyrus is considerably
stronger on the right than on the left side (mean height of the
left, 0.8 cm. ; of the right, 1. 1 cm.). The left gyrus is particularly
slender and is slightly depressed in its middle.

The left convolution is interrupted by one of the transtem-
poral furrows which connects with the superior temporal sulcus.

The right superior temporal gyrus appears to be composed
of three imperfectly separated portions, namely, a long anterior
part, reaching to within 1.0 cm. of the bifurcation of the Sylvian,
separated from the rest of the gyrus by two incisures (one
superior and one inferior), which almost meet, and a shallow de-
pression. The more anterior of the following two parts is in the

AN ESKIMO BRAIN

29

form of a larger oblong lobule, situated between the depression
just mentioned and the connection of the inferior terminal Sylvian
with the superior temporal sulcus. The third part is a small,
partly depressed isle projecting from the second part into the
Sylvian and separated from that part by a shallow sulcus.

The middle or second temporal gyrus is also more voluminous
on the right side ; both are quite redundant.

The anterior half of the convolution on the left is curved, on
the right straight and wedge-shaped. The posterior half on each
side, somewhat less redundant, is divided into two parallel,
nearly equally strong portions by the secondary medio-temporal
sulcus.

The anterior portion of the right gyrus is indented by two
vertical sulci proceeding from the second temporal ; the anterior
of these connects with, while the posterior reaches very near to,
the first temporal sulcus.

The superior posterior portion of the right gyrus is separated
by a connecting branch between the first and medio-temporal
sulci.

Both gyri show a number of more or less marked lateral in-
cisures and a few minor surface furrows.

The inferior or third temporal gyrus lies, on both sides of this
Eskimo brain, almost wholly on the inferior surface of the tem-
poral lobe. It is easily isolated.

The gyrus is on both sides strongest in about its middle third,
its anterior and posterior extremities tapering a little. It is on
each side incised by a number of incisures which pass into it
from both the second and third temporal sulci, but it is nowhere
totally interrupted. In its middle enlargement the gyrus is on
each side indented by an independent ramifying sulcus, which
on the left has the form of a double joined Y, and on ^he right
approaches the form of H. Excepting the anterior and pos-
terior, the gyrus has one superficial connection on the left
(with the anterior portion of the second temporal) and two on

30 AN ESKIMO BRAIN

the right side (with the anterior part of the second temporal and
with the fusiform lobule).

The fusiform gyrus, well defined on both sides, is throughout
more voluminous on the right. The left gyrus shows, near its
posterior third, a shallow interruption. The borders of both
convolutions are indented by a number of more or less pro-
nounced incisures. The gyri show numerous submerged con-
nections with the third temporal and the lingual convolutions.

The lingual gyrus, well defined, connects on both sides,
anteriorly, superficially, and freely, with the gyrus hippocampi ;
posteriorly, near the occipital pole, with the fusiform lobules.

The gyrus is partly divided on both sides into halves by a
branch from the collateral fissure. The anterior portions are some-
what tongue- or pear-shaped, the tapering ends connecting with
the hippocampal gyri, and each is indented by a quite prominent
sagittal sulcus. The posterior extremity of this sulcus, on the
right, connects with a branch from the collateral. The posterior
half on the left is nearly straight and more slender than the an-
terior one ; that on the right forms a marked loop. The surface
of the posterior portions, also, is indented on each side by a small,
mainly sagittal depression.

THE LIMBIC LOBE

This lobe differs remarkably on the two sides. It is much
larger over almost its entire extent on the right side, as will be
indicated by the following measures (taken between the sulcus of
the callosum and the external boundary of the gyrus) :

Left Right

Antero-inferiorly, below the rostrum (above Broca's

carrefour olfactif) 0.3 cm. 0.5 cm.

Anteriorly (horizontally) 0.5 cm. 1.0 cm.

Superiorly, beneath the first frontal or marginal

gyrus 0.85 cm. 1.5 cm.

Superiorly, below the paracentral lobule 1.5 cm. 2.1 cm.

Superiorly, below the precuneus 2.0 cm. 2.6 cm.

Posteriorly, opposite the cuneus 1.6 cm. 1.4 cm.

AN ESKIMO BRAIN

31

The lobe begins on both sides at the well-developed olfactory
lobule or space of Broca, below the rostrum of the callosum. Its
ascending portion and a part of its horizontal portion are entirely-
smooth on the left ; on the right side the external boundary of these
parts shows many depressions, and the horizontal part is traversed
by the previously described sagittally running, shallow sulcus.

All the parts of the limbic lobe behind the line which bounds
anteriorly the paracentral lobule are much more developed than
the parts anterior to this line. On the left this posterior portion
of the lobe is traversed by a number of transverse sulci and has
the appearance of being composed of four or five loops lying in
close apposition. On the right, there is a somewhat similar for-
mation of loops, but their outline is more angular. Directly
beneath the splenium both lobes become very narrow and soon
after blend with the hippocampal convolutions.

Deep bundles connect the limbic lobe on each side with the
mesial part of the first frontal gyrus and the parietal lobule.
The connections of the lobe with the precuneus are on the left
all submerged, though not deep, while on the right side besides
these deep bundles there is also, posteriorly, a superficial annectent
gyrus between the two structures. A few deep fascicles pass
between the lobe and the cuneus and lingual gyrus.

HIPPOCAMPAL GYRUS

This gyrus is somewhat larger on the right side. It is almost
isolated externally on the right, only a small annectent gyrus
passing from it, between the fissura rhinica and the inferior
temporal sulcus, to join the fusiform convolution. On the left
side this connection is broader. The surface of the gyri is
smooth. Both gyri connect superficially with the lingual con-
volutions. The uncus is well marked on both sides.

The parts within the limbic lobe show nothing extraordinary.
The callosum is exceptionally strong and very nearly equal on
the two sides. Its measurements are as follows :

32 AN ESKIMO BRAIN

Diameter antero-posterior maximum 7-9 cm-
Maximum height of anterior enlargement i-45 cm-
Maximum height of posterior enlargement 1.5 cm.

Maximum height between the enlargements 1.0 cm.

Minimum height between the enlargements 0.75 cm.

The dentate gyrus is well differentiated and the fimbria well
developed.

Cerebellum, Pons, Medulla

All these parts appear to be very well developed ; they are
symmetrical and present no gross deviation from the shape
and conformation of the same parts as generally observed in
whites.

Measurements of Cerebellum

Height maximum 5-7 cm.

(in fresh brain 5.8 cm.)

Diameter antero-posterior maximum 1 6.8 cm.

(in fresh brain 7.0 cm.)

Width maximum 2 10.4 cm.

(in fresh brain 10.6 cm.)

Antero-posterior length of worm 4.3 cm.

Maximum height of worm 4.0 cm.

Maximum depth of anterior fossa 2.2 cm.

Maximum depth of posterior incisure 1.3 cm.

Depth to the top of the worm (from a plane corresponding to

the highest points on each cerebellar hemisphere). 1.3 cm.

Measurements of the Pons

Width maximum 3.5 cm.

Height (vertical) from fourth ventricle 2.9 cm.

Length (antero-posterior) 2.5 cm.

Measurements of the Medulla

Thickness maximum infero-superiorly 1.8 cm.

Thickness maximum laterally 2.0 cm.

1 About 1.0 cm. from the median line on each side.

9 At about the junction of anterior third with posterior two thirds.

AN ESKIMO BRAIN

THE CEREBELLUM

33

The great horizontal fissure encircles the organ completely.
It averages 1.6 cm. in depth. On its bottom many slender rods
are seen to pass from one part of the cerebellum (superior) to
the other (inferior), all directed obliquely outward. (There are
similar rods within all the other sulci.)

All the usual lobes of the upper surface (as well as all the
divisions of the worm) are present and well developed. There
are two lobules situated laterally to the lingula (which faces for-
ward) ; these two lobules are joined 2 cm. outward to the alae
lobuli centralis. These last are very small and hidden. The
lingula, with the wings and the central lobule, gives a very good
appearance of a moth, with wings converging upward.

Central lobe small. Folium cacuminis double ; uvula con-
sists of eight segments of which the last two (in pyramid) are
small.

The pyramid is breast-shaped, with the apex posteriorly and
a deep notch anteriorly ; into this notch are received the last two
little segments of the uvula. The lateral masses are anteriorly
separated and form two distinct parts, applied over the ex-
tremity of the uvula. The parts connect anteriorly by deep
annectent fascicles with the cerebellum. Tuber portions small.
None of the lobes and parts of the lower surface and lower worm
present anything extraordinary.

Summary of the Main Peculiarities of Kishu's Brain

As a whole, this Eskimo brain is heavier and larger than the
average brain of white men of similar stature. The excess of
weight over the averages of both Broca's and Manouvrier's speci-
mens (averages which agree well with those obtained by Bischoff,
Boyd, Sims, Huschke, and other observers) amounts to almost
150 grammes.

As to size, the average antero-posterior diameter of the white
male brain ranges, according to Huschke, between 16.0 and 17.0

34 AN ESKIMO BRAIN

cm. (mean 16.5 cm.), and the average maximumlateral diameter
14.0 cm. The mean of these measures, which largely removes
the disturbing element of the shape of the brain, is 15.25. The
crude measurements of Kishu's brain amount, for the length, to
18.0 cm. for the left and 17.9 cm. for the right hemisphere, and
13.6 cm. for the maximum breadth of the cerebrum. These
figures give us the mean of 16.5, which is to that in whites as
108.2 to 100.

The different parts of the brain do not show the same relative
weight proportions as they do in the average white brain, and
the same is true of the relative size of the principal parts of the
cerebrum. The cerebellum, and particularly the pons with the
bulb, is relatively somewhat heavier in Kishu than in whites ;
while as to the main cerebral parts the most remarkable feature
is the relative smallness of the parietal portion (see additional
measurements).

In its external conformation this Eskimo cerebrum rather ex-
ceeds that of an average white male in the number, extent, and
depth of the sulci, and in the complexity of the gyrations.

Both hemispheres, and especially the right one, show a gen-
erally marked tendency to vertical gyration. The left side shows
one, the right two, large, anomalous, composite, vertical furrows.
The gyration of the left hemisphere is in general somewhat more
complex than that of the right one.

The pars triangularis of the inferior frontal convolution, the
temporal lobe, inferior parietal gyrus, and limbic lobe are all
larger on the right than on the left ; on the other hand, the
mesial part of the superior frontal gyrus, the middle frontal gyrus,
the paracentral lobule, the precuneus, and the mass of the occipi-
tal lobe, are larger on the left than on the right side.

There is a great length of the postcentral sulci, particularly of
that on the left. The left Sylvian (main limb) is longer, the left
central fissure is situated (in a horizontal direction) slightly more
posteriorly and is slightly more vertical than the right. There is

AN ESKIMO BRAIN

35

a bilateral, longitudinal division of the mesial part of the supe-
rior frontal gyrus and a tendency on the right to a similar division
of the limbic lobe ; and on each side there is a pronounced medio-
temporal sulcus, dividing sagittally the posterior part of the mid-
dle temporal convolution.

Besides those enumerated, there are many other interesting
minor features of the brain which need not be repeated.

Comparative Notes

The collection in the Medical Department of Columbia Uni-
versity includes, besides that of Kishu, the brains of three other
Eskimo of the same party and originally from the same locality
(Smith sound). One of these specimens is from Nooktah, a man
older than Kishu ; another from Atana, a woman of about the
same or a little more advanced age than Kishu ; and the third
from Avia, a girl of ten to twelve years of age. A detailed report
on these three brains is being prepared, as hitherto mentioned,
by Mr E. A. Spitzka ; my independent work on the same extends
over those points only which are of particular interest in connec-
tion with the specimen here described, including the more im-
portant measurements.

The general gyration in these additional Eskimo brains, com-
pared with that in average adult whites, is very good, particu-
larly over the frontal lobes, in Nooktah, good in Atana, rather
simple in Avia. In all the external conformation is more com-
plex on the left hemisphere. The frontal gyration in Nooktah is
not less complex than that in Kishu, but the whole brain of the
latter is more developed and richer.

The insulae are both quite exposed anteriorly in Atana,
less so in Avia, and covered, or very nearly so, in Nooktah as
well as in Kishu.

The ascending frontal gyri are both very strong in Atana, the
ascending parietal gyri on both sides and the ascending frontal on
the right in Avia.

36 AN ESKIMO BRAIN

The anterior and posterior portions of the presylvian are sepa-
rate in all three brains, as in that of Kishu.

The central fissure, which in Kishu commenced in the Syl-
vian, has a similar origin on the right side in Avia ; in all other
instances it reaches near to the Sylvian. The superior termina-
tion of the fissure reaches the superior border in Nooktah and on
the right in Atana, and passes slightly to moderately over it on
the left in Atana and on both sides in Avia. In the girl the
course of the fissure is remarkably vertical.

A longitudinal division of the mesial part of the superior
frontal gyrus, found in Kishu, is also present complete on left,
interrupted on right, in Nooktah ; slightly incomplete on left,
small traces on right, in Atana ; and on the right in Avia.

The limbic lobe shows traces of longitudinal division, as on
the right in Kishu, on the right in Nooktah, and on the left in
Avia. The lobe that shows the traces of division is in both
cases, so far as these traces extend, higher than that of the op-
posite side, as was also the case in Kishu.

A furrow somewhat similar to the pre-precentral vertical
furrow in Kishu is seen on the right in Nooktah, while sinu-
osities, somewhat similar to the right vertical post-postcentral
one in Kishu, occur on the left in Atana and on the right in
Avia.

The postcentral sulcus is single in all cases, except on the
left in Avia, where it exists in two portions.

The temporal lobe is slightly higher on the left side in Nook-
tah and Avia (see the measurements). The first temporal gyrus
is in all cases moderately to well developed. The medio-tem-
poral sulcus, though present in segments in Nooktah and Atana,
is by no means as clearly distinguishable as in Kishu.

Broca's cap, or that part of the inferior frontal convolution sit-
uated between the two portions of the presylvian, is, contrary to
what was the case in Kishu, in all these brains better developed
on the left side.

AN ESKIMO BRAIN

37

The extremities of the occipital lobes are in all three brains
of about equal size and not disproportionate as in Kishu.

Additional and Comparative Measurements

The subject of brain measurements is still in its infancy.
Although many brains have been measured, particularly since
Huschke and Broca, there is yet no standard system of encepha-
lometry comparable with that of the measuring of the head
or cranium. Every author of importance has thus far chosen his
own points from which to measure, and there is no regulation of
either the methods or instruments. There is no more important
part of the body and at the same time no part with which more
care and accuracy are required in measuring, than the brain, and
these two conditions ought to prompt an early and thorough
systematization of procedure. As it is, the brain measurements
of one author can scarcely be compared or joined with those of
any other.

The most disturbing factors in measuring the brain are, first,
its softness and the consequent yielding and deformation of the
organ when removed from the cranial cavity ; this difficulty can
now be effectually counteracted by a formaline-alcohol or forma-
line hardening of the organ before the opening of the skull.

The second important factor, which thus far has not received
sufficient attention, is the different shape of the brain in different
individuals and especially in different races. No one would think
of comparing, or uniting in a series, the dimensions of a dolicho-
cephalic with those of a brachycephalic skull, and similar distinc-
tions should be established in brain measurements.

The choice of instruments is very important. Even if the
tape only be used, considerable differences in the measurements
are obtained according to the width of the same.

Some, and perhaps many, of the measurements of the brain
carry valuable indications which we today do not appreciate.
The knowledge of the organ will certainly progress, and meas-

38 AN ESKIMO BRAIN

urements taken with care, even if not essential now, may in the
future be found of value.

A more detailed discussion here of these important matters
would be somewhat irrelevant to the subject of this paper. The
above remarks are thought to be a proper introduction to the
following figures and comparisons.

The measurements of Kishu's brain, which was carefully pre-
served, between cotton, in a mixture of formaline and alcohol,
are, as I have certified on the skull, almost absolutely correct.
The brains of Nooktah, Atana, and Avia were preserved in a
weak solution of formaline. Nooktah's brain is fairly well pre-
served and its measurements are apparently quite correct ; the
brains of Atana and Avia, however, have suffered a rather con-
siderable change in form, and the absolute measurements of these
specimens have but little meaning. The relative proportions of
the various parts of the cerebrum were undoubtedly much less
affected than the absolute measurements and are probably still fit
for consideration.

The surface measurements were taken by a tape 0.8 cm.
broad, while the diameters were obtained on a graduated plane
(Mathieu's) and by the accurate sliding compass used in osteom-
etry. Three repeated measurings gave fairly even, though in but
very few instances exactly the same, results.

The points from which the various dimensions were taken and
the methods will be explained with each measurement.

Measurements
approximate length of the lines of norma anterior, kishu :

Left Right

Antero-lateral lines 11.5 cm. 10.3 cm.

Anterior lines 1 8.3 cm.

Postero-lateral lines 8.2 cm. 7.8 cm.

Posterior lines 2 5.9 cm.

1 Taken between two cardboards applied to the antero-lateral planes of the brain,
the line measured touching the anterior surface of the frontal lobes.

2 Obtained in a way similar to that of the anterior lines.

AN ESKIMO BRAIN 39

MAXIMUM LENGTH OF THE HEMISPHERES

Left Right

Kishu 18.0 cm. 17.9 cm.

Nooktah 16.8 cm. 17.0 cm.

Atana (17.1cm.) (17.1cm.)

Avia (15.3 cm.) (15.3 cm.)

In one of the males the length of the left exceeds slightly
that of the right hemisphere, while in the other male the condition
is reverse; in the two females the length of both hemispheres is
equal.

In whites the left hemisphere is almost generally slightly
longer (Eberstaller,1 Cunningham 2).

MAXIMUM WIDTH OF THE CEREBRUM ; CEREBRAL INDEX, COMPARED

to cephalic (on the living).

(Breadth X ioo\ / Breadth of Head X ioo\
Length ' V Length of Head I

Kishu 13.6 cm. 75.8 76.26

Nooktah.... 13.1cm. 77.5 81.4

Atana (12.3 cm.) (7 1.9) 80.6

Avia (n. 6 cm.) (75-8) 72.9

It can be seen that while the brains of Kishu and Nooktah

have kept nearly the same relative proportions as they must have

had in life, that of Atana became relatively longer and narrower

and that of Avia shorter.

ARC MEASURES ALONG THE SUPERIOR BORDER S
a. Anterior Point (Cunningham) to Central Fissure.
Left Right

Kishu.. 17.0 cm. or 63.0$, 17.7 cm. or 65.1$ of the total mesial length.
Nooktah 16.7 cm. or 66.5 <f0, 16.7 cm. or 64.5 <f0.
Atana. . (15.3 cm. or 59.8 #), (15.0 cm. or 60.5 <£).
Avia. . (15.5 cm. or 64.6$), (15.0 cm. or 62.5 f0).

'Eberstaller, Das Stirnhirn, Wien and Leipzig, 1890.

'Cunningham, D. J., " Contrib. to the Surface Anatomy of the Cerebral Hem-
ispheres." Roy. Irish Acad., Cunningham Mem., VII, 1892. All the following
references to Cunningham relate to this work.

8 Eberstaller measured from the anterior perforated space to the occipital pole.
Cunningham, whom I follow, takes the same measures "from a point on the upper
or mesial border which corresponds to the level of the outer part of the superciliary

40 AN ESKIMO BRAIN

This relative length of the precentral part to the total mesial
arc, this latter being taken as ioo, is termed by Cunningham the
frontal or fronto-Rolandic index, and is in whites, according to
the same author (pp. 55, 175), as follows :

In 12 5^ to d\ mos. embryos 52.7

In 24 full-term foetuses 53.5

In 82 adults 53-3

In apes and monkeys from 55.9

in chimpanzee to 45.4

in mangaby.

b. Central to Parieto- Occipital Fissure
Left Right

Kishu 4.3 cm. or 15.9 <f0, 4.3 cm. or 15.8 <f0 of the mesial arc.

Nooktah. ... 3.9 cm. or 15.5 $, 5.0 cm. or 19.3 % of the mesial arc.

Atana (5.8 cm. or 22.7 f0), (5.2 cm. or 21.0 <f0) of the mesial arc.

Avia (5.1 cm. or 21.2 <f0), (5.3 cm. or 22.1 f0) of the mesial arc.

Cunningham, who terms the proportion of the central parieto-
occipital fissure segment to the whole mesial arc (this being taken
as 100, the parietal index), obtained the following in whites (p. 55):

Parietal Index

In 12 5 1 to d\ mos. embryos 28.5

In 24 full-term foetuses 25.7

In 82 adults 25.5

In 4 orangs 21.3

Further, in 4 chimpanzees 19.9

In 5 cynocephali 22.6

In 5 macaques 19.0

In 7 cebi 20.6.

margin of the frontal lobe. This border is very far from being horizontal. Its outer
part is on a much higher level than the inner part. As it is traced inwards it is seen to
take a sudden curve downwards towards the cribriform plate of the ethmoid bone,
where it merges with the mesial border. A line drawn horizontally inwards from the
high outer part of the superciliary border of the frontal lobe cuts the mesial border of
the cerebrum at the point which I arbitrarily selected as the anterior end of the cere-
brum. It lies, as a rule, just below the most projecting part. Behind I took the most
prominent part of the occipital pole." " The first of these points maybe distinguished
as the frontal point, and the latter as the occipital point. Further, the distance between
these two points measured along the upper border of the hemisphere may be termed
the mesial length." (Loc. cit., pp. xi, xii.)

Cunningham's anterior point has no advantage over that of Eberstaller, and I em-
ploy it only to enable comparison of my own with Cunningham's indices.

AN ESKIMO BRAIN 4 1

c. Parietooccipital Fissure to most Prominent Point on the Occipital Pole
Left Right

Kishu 5.7 cm. or 21.1 <fc, 5.2 cm. or 19. 1 $ of the mesial arc.

Nooktah . . . .4.5 cm. or 17.9 <fc, 4.2 cm. or 16.2 f0 of the mesial arc.

Atana (4.5 cm. or 17.6 f0), (4.6 cm. or 18.5 <f) of the mesial arc.

Avia (3.4 cm. or 14.2 <fi), (3.7 cm. or 15.4 <?0) of the mesial arc.

Cunningham terms the relative distance of the parieto-occipital
fissure from the most prominent point in the occipital pole the
occipital index, and obtained for whites (pp. 55, 56):

In 12 5^-6^- mos. embryos 18.8

In 24 full-term foetuses 20.8

In 82 adults 21.2 ; also, in

4 orangs 23.2

4 chimpanzees 24.2

5 cynocephali 29.7

5 macaques 31.0

7 cebi 33.0.

Among adult whites, in 45 men the occipital index was 20.8 ;
in 35 women the occipital index was 21.7.
The total mesial arc (from the anterior point, Cunningham,
to the most prominent point on occipital pole) was :

Left Right

Kishu 27.0 27.2

Nooktah 25.1 25.9

Atana (25.6) (24.8)

Avia (24.0) (24.0).

The above indices show in the Eskimo some remarkable features
which are undoubtedly more than individual variations. There are
in all the Eskimo, but especially in the men, relatively high frontal
and low parietal indices. The parietal indices in the two females
and the occipital indices in the two males and the adult female,
though also lower, approach more those in whites. There is in
the four Eskimo, according to these surface measurements, rela-
tively a more extended superior frontal and a more restricted
superior parietal area than in the average whites.1

1 Compare in this connection, and with the horizontal dimensions that follow, the
seemingly conflicting measures of Fere, Passet, and Giacomini, referred to by Dejerine,

42 AN ESKIMO BRAIN

There is another and somewhat more accurate way in which
the dimensions of the main parts of the cerebrum may be deter-
mined. If the hardened hemisphere is placed on the graduated
board in such a way that the most prominent frontal and occipital
points are on a line which runs lengthwise along the middle of
the board, we can then secure, by means of two vertical planes
and a rod-measure or an ordinary compass, any desirable horizon-
tal distance from the cerebral extremities. Such distances, com-
pared with the total horizontal length of the hemisphere, give
indices which are somewhat more accurate and perhaps not inferior
in value to those obtainable by surface measuring. Following
this procedure on the Eskimo brains, I have obtained the following
figures and proportions:

a. Horizontal Length, Frontal Pole to Superior Extremity of Central Fissure
Left Right

Kishu.... 10.9 cm. or 60.6 $, 10.8 cm. or 60.4 $

of the length of the hemisphere.
Nooktah.. 10.9 cm. or 64.9 f0, 10.7 cm. or 62.9$

of the length of the hemisphere.
Atana (9.6 cm. or 56.1 </0), (10.0 cm. or 58.5 f0)

of the length of the hemisphere.
Avia (9.8 cm. or 64.1 f0), (9.3 cm. or 60.8 %)

of the length of the hemisphere.

b. Horizontal Distance, Superior End of Central to Parieto-occipital Fissure 1
Left Right

Kishu.... 4.1 cm. or 22.8 <f0, 4.0 cm. or 22.3 <f0

of the length of the hemisphere.
Nooktah.. 2.3 cm. or 13.7 </0, 3.5 cm. or 20 6 f0
of the length of the hemisphere.

Anat. d. Centres Nerveux, Paris, 1895, p. 249. The coincidence of the relatively
somewhat small occipital with relatively small parietal lobes is quite curious. Gratiolet
(quoted by Cunningham, p. 59) states that in man the occipital lobe is extremely re-
duced ; and formulates the law that "the more highly organized a member of the
group is, the smaller is the relative size of the occipital lobe." Quite as striking, how-
ever, is the small relative size of the parietal lobe in the ape.

1 The measurements are taken between the points of intersection by the fissures of
the superior border of the hemisphere. Where the parieto-occipital fissure bifurcated
before reaching the superior border (left in Atana, right in Avia), the measurement
was taken to a prolongation of the main limb of the fissure. Same with surface
measurements.

AN ESKIMO BRAIN

43

Left Right

Atana. . (5.1 cm. or 29.8 f0), (4.6 cm. or 26.9 <f)

of the length of the hemisphere.
Avia. . . . (4.0 cm. or 26.1 fo), (4.4 cm. or 28.8 </0)

of the length of the hemisphere.

c. Horizontal Distance, Parielo-occipital Fissure to Occipital Pole
Left Right

Kishu. ... 3.0 cm. or 16.7 <f0, 3. 1 cm. or 1 7.3 <f0

of the length of the hemisphere.
Nooktah. 3.6 cm. or 21.4$, 2.8cm. or 16.5 $

of the length of the hemisphere.
Atana. . . (2.4 cm. or 14.0 $), (2.5 cm. or 14.6 <f)

of the length of the hemisphere.
Avia.... (1.5 cm. or 9.8$), (1. 6cm. or 10.5 $)

of the length of the hemisphere.

These measurements show almost generally a higher relative
proportion of the region between the central and parieto-occipital
fissures than was the case with the surface measurements, which
indicates that the region is relatively more flat than the others.

Two more notable facts shown by both the arc and the hori-
zontal measurements are a very small parietal and a large occipi-
tal portion on the left in Nooktah and the small occipital portions
in Avia.

A more detailed study of the figures shows that, so far as
their size is concerned, the main portions of the cerebrum tend to
compensate each other.

DISTANCE OF THE LOWER EXTREMITY OF THE CENTRAL FISSURE FROM

THE FRONTAL POLE

Cunningham measured this distance over the surface of the
frontal lobe, comparing the dimension thus obtained with the entire
arc running in the same line from the mesial border of the ante-
rior to that of the posterior extremity of the hemisphere. I have
followed the same method, but have supplemented it with the
horizontal distance, as with the preceding measurements. The
results are as follows :

44 AN ESKIMO BRAIN

Surface Distance of the Base of the Central Fissure fro?n the Mesial Border of

the Anterior Extremity

a. Arc to the base

of central fissure. b. Complete

: lateral arc.

Centesimal relation

of a

to b.

Left

Right Left

Right

Left

Right

Kishu. . .

10.8 cm.

11. i cm. 25.2 cm.

24.5 cm.

42.9

45-3

Nooktah.

10.7 cm.

10.5 cm. 23.3 cm.

23.1 cm.

45-9

45-5

Atana. . .

. (n. 2 cm.

10.6 cm.) (22.9 cm.

23.1 cm.)

(48.9

45-9)

. ( 8.0 cm.

8.6 cm.) (21.3 cm.

21. 1 cm.)

(37-6

40.8)

The centesimal relation of a to b is termed by Cunningham
(p. 179) the lower Rolandic index and was:

In 17 adult whites, males 43.7

In 20 adult whites, females 43.0

The index differed but little in children and human embryos ;
in apes and monkeys it ranged (p. 175) from 39.2 in the orang and
chimpanzee to 43.8 in cebus.

The horizontal distance of the base of the central fissure from
the frontal extremity, and its centesimal relations to the length
of the hemisphere, are as follows :

a. Distance to base of central fissure. Centesimal relation of a to

length of hemisphere
Left Right Left Right

Kishu 7.3 cm. 6.5 cm. 40.6 36.3

Nooktah 7.6 cm. 7.5 cm. 45.2 44.1

Atana (8.3 cm. 7.8 cm.) (48.5 45-3)

Avia (5-4cm. 5.9 cm.) (35.3 38.6).

LENGTH OF THE CENTRAL FISSURE

a. Diameter, from lower to upper extremity, b. Length measured by a thread fol-
taken by the sliding compass. lowing all the windings of the fissure.

Centesimal relation of a to Centesimal relation of b

length of hemisphere. to mesial length.

I. r. I. r. I. r. I. r.

Kishu 9.0 8.6 50.0 48.0 11. 7 11. 5 43.0 42.3

Nooktah.... 8.0 8.4 47.6 49.4 10.7 11.0 42.6 42.5

Atana (7.3 7.7) (42.7 44.9) (10.8 10.6) (42.2 42.7)

Avia (7.9 7.7) (51.6 50.3) (11.0 10.3) (45.8 42.9)

AN ESKIMO BRAIN 45

Cunningham (p. 191), taking the length of the fissure accord-
ing to b and comparing it with the mesial arc, obtained in whites :

In 5! to b\ mos. embryos 16.7

In full-term foetuses 32.8

In 4- to 5-year-old children 33.9

In 16 adult females 40. 1

In 14 adult males 38.6

and in the chimpanzee 5 1. 1

orang 47.2

hamadryas 41.1

The length of the fissure, as seen from the above, is relatively
greater in the Eskimo than in the whites ; there is no decided
sexual difference.

The straight length, or diameter, of the fissure can serve, in
connection with the horizontal measures (from the vertical plane
rising from the anterior extremity of the hemisphere to the two
extremities of the fissure), in determining a Rolandic angle (by
projection).

LENGTH OF THE SYLVIAN

Taking this length with a compass, from the exterior point of
intersection of the Sylvian by the anterior or horizontal portion
of the presylvian, to the angle which the ascending terminal
branch forms with the main limb of the Sylvian, Eberstaller
(quoting Cunningham) found it in whites as follows :

Up to 5.0 cm., left in 22 <f0, right in 45 tf0 of hemispheres.

5.1-6.0 cm., left in 42 f0, right in 44 <f0 of hemispheres.

6.1-7.0 cm., left in 27 f0, right in 11 $ of hemispheres.

Over 7.0 cm., left in 9 $, right in 0.6 <f0 of hemispheres.

These figures show that the left Sylvian is more often the
longer. Cunningham (p. 122) obtained similar results, but he
measured the fissure from " the point at which its trunk appears
on the outer surface of the hemisphere." As this point is almost
generally less clearly defined than that employed by Eberstaller,

46 AN ESKIMO BRAIN

I follow the latter authority. The Sylvians in the Eskimo
measured as follows :

Centesimal relation to the length of the
hemisphere

Left Right Left Right

Kishu 6.5 5.2 36.1 22.9

Nooktah 6.2 4.8 36.9 28.2

Atana (6.4 5.1) (37.4 29.8)

Avia (5.4 5-9) (35-3 38.6)

The left fissure is, in three of the Eskimo, both absolutely and
relatively, decidedly longer than the right one.

Two additional useful and quite easy measures are, I think,
the maximum breadth of the frontal lobes, measured by the
sliding compass, with the branches applied over the most promi-
nent points on the dorsum of the orbital parts of the inferior
frontal gyri ; and a diameter between the extremities of the tem-
poral and occipital lobes. These dimensions in the Eskimo are
as follows :

BREADTH OF THE FRONTAL LOBES

Centesimal proportion to maximum.
Breadth width of the cerebrum

Kishu n. 5 cm. 84.6

Nooktah 10. o cm. 76.3

Atana (7.9 cm.) 64.2

Avia (7.5 cm.) 64.7

These figures demonstrate well the superiority of the frontal
lobes in Kishu's cerebrum, and the inferiority in this respect to
both the males of both of the females.

TEMPORO-OCCIPITAL LOBES

Left

Kishu 14.2 cm.

Nooktah 13.2 cm.

Atana (13.1cm.)

Avia (12.0 cm.)

Centesimal relation to the length
of the hemispheres

Right

Left

Right

14.3 cm.

78.9

79-9

13.5 cm.
(13.4 cm.)
(11. 7 cm.)

78.6

(76.6)
(78.4)

79-4
(78.4)
(76.5)

AN ESKIMO BRAIN 47

In this particular measurement the four brains show remarkable
similarity.

PREVIOUS RECORDS ON ESKIMO BRAINS

The only previous records concerning Eskimo brains of which
I could learn are those made by Chudzinski, published in the
Bulletin de la Soci/te d 'Anthropologic de Paris, 1886.

The brains described by this author were those of Tobias
Ignatius, male, 23 years; Paulus Abraham, male, 35 years; and
Ulrika Henocq, female, 24 years. The locality from which these
subjects came is not stated, but there are reasons to believe that
they belonged to the eastern Greenland Eskimo.

The three brains present some interesting similarities, but also
many characteristics different from those of any of the specimens
noted in this paper. In order to facilitate a comparison I shall
introduce the principal part of Chudzinski's report.

The brains show " a considerable volume of the cerebral hemi-
spheres " ; " then one can see that the convolutions which con-
stitute the external surface of the hemispheres.are large, simple,
and very poor in secondary divisions, and that the sinuosities are
but little flexuous." " That simplicity is especially marked over
the frontal lobes " ; " the same lobes are at the same time
flattened infero-superiorly."

" The Sylvian fissure appears to be shorter than ordinarily,
nearly horizontal, and of very simple contours," except in the
woman, where it is little more complex, especially on the right.
" Its anterior branch is generally very short and in the brain of
P. A. altogether hidden by the temporal lobe."

" The Rolandic fissure is very long." " It is flexuous, espe-
cially in P. A. Ends on mesial surface " (in all ?).

" Occipital fissure very short externally. Calcarine fissure long
and flexuous, especially in U. H."

" The frontal lobe is relatively short ; the other lobes are, on
the contrary, well developed, especially the parietal."

48 AN ESKIMO BRAIN

" The first frontal gyrus is very large, especially in Tobias, but
shows only a few incisures."

" The development of the second convolution is enormous,
especially in P. A." " The gyrus is very simple in Tobias."
" Among other features, there is a double anastomosis with the
ascending frontal."

" The third frontal gyrus is very little developed ; it is short
and as ramassie sur elle mime" " In Tobias it is reduced to a
small, nearly smooth isle." Better developed in U. H.

" Ascending frontal gyrus very large." " Ascending parietal
gyrus very flexuous in Paulus, very large in Tobias." The two
gyri (asc. frontal and asc. parietal) are slender in U. H.

" The parietal convolutions generally simple and very ex-
tended," especially the second inferior.

" Occipital lobe generally simple, especially in Tobias."

Temporal lobe: " Extreme slenderness of first convolution " ;
" uncommon size of second convolution."

Internal (mesial) surface : " Enormous development in breadth
of the mesial part of the first frontal convolution, especially in
Tobias; a division of that convolution into two secondary gyri
by an uninterrupted sulcus on the left hemisphere in Paulus."
The secondary sulcus seems to be continuous with the subfrontal
fissure. Similar sulcus on right in Paulus, but in several places
interrupted by annectent gyri.

The convolution of the corpus callosum is generally very ex-
tended ; but its breadth is very remarkable in Tobias, in its pos-
terior part, and anteriorly in Ulrika, in whom it seems to divide
itself along its middle into two secondary gyri."

The ovalaire lobule is enormous in Ulrika ; on the other hand,
the cuneiform is small, and in Ulrika it is reduced to a " pli de
passage" hidden, in large part, in the calcarine and occipital
fissures.

The similarities in the brains reported upon by Chudzinski
and the one described here consist of the large volume of the

AN ESKIMO BRAIN

49

cerebral hemispheres; long central fissures; sagittal division of
the mesial parts of the superior frontal gyri ; the large size of the
limbic lobe in Tobias, and the large size of the lobe with a ten-
dency toward a longitudinal division in Ulrika.

The dissimilarities are : the poor differentiation in Chudzinski's
specimens of the convolutions and the simple character of the sulci,
especially over the frontal lobes; a defective development of the
inferior frontal convolution (particularly in Tobias); very large
ascending frontal and ascending parietal convolutions ; simplicity
of parietal convolutions ; great slenderness of the superior temporal
gyri ; and very small cuneus.

The causes of the many dissimilarities are not clear. The
morphological inferiority of the two male brains described by
Chudzinski, and, on the other hand, the marked superiority of
Kishu's and even of Nooktah's brain, may be to some extent
individual conditions and represent more the extremes than the
average of Eskimo brains. At the same time it is possible that
Paulus Abraham and Tobias Ignatius belonged to some family
of the great Eskimo tribe intellectually less developed than the
Smith Sound group to which Kishu and Nooktah belonged. The
Smith Sound party which Lieutenant Peary brought to New
York were by no means dull or incapable people. This is espe-
cially well demonstrated in Menee, the son of Kishu, who has not
only shown a remarkable facility for adjusting himself in every
way to civilized life, but has made very good progress in the
public school.

The marked differences of the specimens described by Chud-
zinski and in this paper from those of the whites, as well as
among themselves, makes a future acquisition of Eskimo brains
very desirable.

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