lilra-Oni Eutiilnu 
OF 
TWENTY-TWO YEARS’ GROWTH, 
Removed at the Baltimore and. Ear 
By J. J. CrtlSOLM, M.D., 
Clinical Professor of Eye and Ear Surgery in the University of Maryland.) 
WITH A DESCRIPTIONS THE [MICROSCOPIC CONDITION OF THE tTUM0R, 
By H. KNAPP. M.D.,' JJ > 
[Eepkinted fbom Archives op Ophthalmology and Otology, Vol. III., 1, 1873.] 
Ufltk: 
WILLIAM WOOD & COMPANY, 
27 Great Jonfs Street. INTRA-OCULAR ENCHONDROMA, OF 
TWENTY-TWO YEARS’ GROWTH, 
REMOVED AT THE BALTIMORE EYE AND EAR INFIRMARY. 
By J. J. CHISOLM, M.D., 
Clinical Professor of Eye and Ear Surgery in the University of Maryland. 
WITH A DESCRIPTION OF THE MICROSCOPIC CONDITION OF THE TUMOR. 
By H. KNAPP, M.D., 
OF NEW YORK. 
S. H. V , of Virginia, aged twenty-five, was born a healthy 
infant. At the age of three years his parents noticed a difference in 
the size of his eyes, the left one being slightly enlarged. Upon further 
examination and by the use of tests, the sight in it was found defective. 
Prior to this discovery both eyes were supposed to be perfect. From 
that period until the present, covering an interval of twenty-two years, 
the left eyeball has continued 
steadily to increase in size, at 
times accompanied by pain. 
He has been pursuing the 
avocation of a farmer, and 
continued work until he left 
home to seek surgical advice. 
In his desire to get rid of this 
projecting and horrible defor- 
mity he entered the Baltimore 
Eye and Ear Infirmary for 
surgical treatment. 
His general health is good, 
height 5 ft. io in., weight 
about 130 lbs. The right eye 
is perfect. In the place of 
the left eye, a rounded mass 
protrudes (see figure, from 
a photograph), which seems to be as large as the fist. After appar- 
1 2 
Chisolm and Knapp : 
ently filling the orbital cavity, the growing tumor has gradually pro- 
jected forwards until it has attained a prominence of 2J inches 
from a level of the face, having about the same dimensions of 2\ inches 
in its vertical and transverse diameter. An immensely expanded, 
hypertrophied, and movable upper lid, as a broad curved belt, .covered 
the upper three-fourths of the free surface of the projection. In this 
overgrown lid the orbicular muscle was well developed, as indicated by 
the numerous crescentic ridges which encircled the facial base of the 
tumor, and which were made prominent through the subcutaneous bun- 
dles of muscular fibres. On the upper and outer surface of the tumor, 
apparently under the thickness of the lid substance, was an elastic, soft 
swelling, supposed to be the lachrymal gland, pushed out of its natural 
site, and drawn forward by the growing mass. The mucous or con- 
junctival tissue covering the exposed face of the tumor was thickened, 
but was otherwise apparently healthy, possessing the usual mobility of 
this membrane over the sclerotic coat of the eye. The lower con- 
junctival cul-de-sac had been effaced in the continued requirements of 
the enlarging growth, so that the Meibomian edge of the lower lid was 
directly continuous with the conjunctival covering of the tumor. The 
upper conjunctival cul-de-sac had not been altogether obliterated, but 
remained as a very superficial groove separating the edge and inner sur- 
face of the upper lid from the anterior surface of the protrusion. Under 
the ocular conjunctiva, which, although thickened, was still translucent, 
an appearance of healthy, white sclerotic was visible. All traces of 
corneal tissue had disappeared, and in its stead was a thick, red con- 
junctiva, covering which were crusts of desiccated mucus. From this 
fleshy surface he reports that several serious hemorrhages have from 
time to time taken place. Of this serious complication I could detect 
no evidences, as there was no appearance of ulceration when the an- 
terior surface of the tumor was exposed by the removal of the mucous 
crusts; There were no large vessels visible on the surface of the 
tumor. 
The entire anterior and exposed face of the growth was kept con- 
stantly bathed by an abundant lachrymal secretion, which, in a certain 
oblique light, could be seen oozing from beneath the upper lid, from 
the direction of the soft, elastic swelling already noticed as lying upon Intra-Ocular Enchondroma. 
3 
the upper and outer surface of the tumor, and supposed to be the lach- 
rymal gland. 
The long-continued pressure of this ever-slowly increasing growth 
had caused, by absorption, an increase in size and a change in direction 
of the outer border of the orbit. It had also in a measure displaced 
the nose from its median position. After leaving the orbit the 
growth had not spread out suddenly, becoming bulbous, but had 
retained a uniform diameter in every direction of about two inches 
and a half, which measured the degree of expansion of the orbital 
opening. 
The whole tumor, which was uniformly ovoidal in shape, possessed 
limited movements, synchronous with those of the sound eye. When 
firmly held and a to-and-fro movement imparted to the hand, similar 
movements were extended to the growth. Careful palpation elicited 
no fluctuation, although a decided feeling of elasticity pervaded the 
entire tumor. 
The history, symptoms, and appearance of the projecting mass indi- 
cated an intra-ocular tumor of very slow growth, which, after twenty- 
two years of steady increase, was still incarcerated within the chambers 
of the eye, and isolated by the much expanded and thickened, but, to 
all appearances, otherwise normal sclerotic coat. Believing that the 
eye was the seat of a malignant growth, which, from some unexplain- 
able cause, had taken on a very irregular and unusual development, its 
extirpation was advised and assented to. The operation, which was 
performed under chloroform, in the presence of Prof. Gross, of Phila- 
delphia, and others, was similar to the ordinary enucleation so familiar 
to ophthalmic surgeons. After extending the outer canthus, on account 
of the great size of the tumor, the conjunctiva was incised around the 
former site of the cornea, the tenotomy of the various muscles was 
easily effected, and after passing a long, heavy scissors, curved on the 
flat near the point, to the very apex of the conical cavity of the orbit, 
the optic nerve was divided, and the whole mass at once glided out of 
the socket, leaving a huge but apparently healthy cavity, devoid of all 
fat and lined from rim to apex with a thickened periosteum. Hemor- 
rhage, not excessive, was readily controlled by sponge pressure. 
The case made good progress for the first few days. On the fourth 4 
Chisolm and Knapp: 
night from the operation there was a hemorrhage of a few ounces. On 
the fifth night this was again repeated without the source of hemor- 
rhage being discovered. On the evening of the ninth day a very severe 
hemorrhage took place, which was deemed sufficiently serious to war- 
rant me in ligating the common carotid. On the morning of the tenth 
irregular tetanic symptoms supervened, and he died on the fourth day 
after the ligature had been applied. There had been no recurrence of 
the hemorrhage. 
The mass removed was a smooth, regularly ovoidal 
tumor, about three and a half inches in its longest dia- 
meter, corresponding with the axis of the orbit, and two 
inches and a half in its vertical and transverse diame- 
ters. Its outer surface was the expanded and thick- 
ened sclerotic coat of the eye, which apparently had not 
been broken through at any point by the growth from 
within. To this outer surface were attached the mus- 
cles of the eyeball. When the tumor was laid open 
the whole sclerotic sac was found filled with a solid con- 
tents, mottled in appearance, and of varied consistence, 
among which were conspicuous white nodules of differ- 
ent sizes. These proved upon section to be cartilage, 
which character was confirmed by microscopic exam- 
ination. 
It is so very unusual to find cartilage in the growths 
within the eyeball, that this rare specimen of tumor was 
deemed worthy of a more careful examination. Prof. 
H. Knapp, a recognized authority on intra-ocular 
growths, has very kindly consented to make the exam- 
ination for me, and to him are we indebted for the fol- 
lowing carefully prepared and most valuable report of 
this rare pathological specimen :— Intra- Ocular Enchondroma. 
5 
ANATOMICAL EXAMINATION OF THE PSEUDOPLASM. 
The tumor (Fig. i, Tab. A), hardened in Mueller’s 
fluid, was roundish, having a diameter of two inches 
and a half. It was surrounded by connective tissue in 
the form of an irregularly dense capsule (Fig. i, a). On 
the transverse section its bulk consisted of hard nodes 
(Fig. i, b), separated from one another by fibrous tissue 
connecting with the capsule. A considerable portion of 
the tumor, about one-fifth of its size, was softer and had 
a fibro-granular appearance (c). 
The enveloping capsule consisted in its outer part of 
dense undulating and parallelly striated connective tis- 
sue, containing a very scanty amount of cells and blood- 
vessels. Its similarity with the structure of the sclerotic 
was marked. The inner layers of the capsule had more 
blood-vessels and cells, and the layer near the nodes 
was filled with small round formative cells, scattered 
sparsely through the fibres; besides them smaller and 
larger cells lay together in spindle-shaped spaces be- 
tween the bundles of fibres. These layers, therefore, 
presented the connective tissue in the state of growth 
or proliferation. 
The fibro-granular part (c) of the tumor showed a 
net of connective-tissue fibres (Fig. 2) which was freely 
traversed by blood-vessels (v), and abundantly inter- 
spersed with formative cells (f). In addition to these 
elementary parts this portion of the tumor contained a 
good deal of fat, in the form of globules ([m), and 
granulated bodies (g). Teased preparations of this 
substance showed long fibres with double outlines 
(o), spindle-shaped (s), stellate (h), and small round 6 
Chisolm and Knapp : 
cells (r), the latter here and there in dense clus- 
ters (u). 
The structure of the hard nodes discovered the two 
varieties of cartilage, the hyaline and the fibrous, in 
very characteristical pictures. The hyaline variety (Figs. 
3, 4) prevailed over the fibrous (Fig. 5). It consisted of 
a yellowish, homogeneous, or very finely granular, 
glassy-lookingmatrix—intercellular substance—in which 
cartilage-cells of different forms were embedded. Oval 
cells with one or two nuclei (Fig. 3, a) ; small, round, oval 
and irregular spaces containing three and more nuclei 
(b); large, irregular cavities densely filled with nuclei 
(<c), and free nuclei (d), were promiscuously placed in 
the homogeneous hyaline basis-substance. In many 
places the matrix appeared interspersed with free nuclei 
alone (Fig. 4). Part of the nuclei were small, round 
and pellucid (d) ; another part were small and shrivelled 
up (b) ; others {cd) large, oval, round, club-like, dumb- 
bell shaped or irregular. Their interior was either 
homogeneous and transparent (c), or finely or coarsely 
dotted (d). 
The fibrous portion of the cartilage (Fig. 5) showed 
an irregularly striated matrix in which the same cellular 
elements were embedded as in the hyaline portion. 
Where the nuclei predominated (a), the matrix had com- 
monly a granular appearance, with fine, short lines; 
where the larger cells were prevalent (b), the matrix 
was markedly fibrous. 
Blood-vessels ran in different directions through the 
fibrous part, but were absent in the hyaline portion. 
From the foregoing description it is evident that the Intra-Ocular Enchondroma. 
7 
tumor was, as Dr. Chisolm declared it to be, an en- 
chondroma. There is, further, no doubt that it was, 
from beginning- to end, an intra-ocular growth. The 
history showed the gradual enlargement of the eye- 
ball, together with failure of sight. Had the enlarge- 
ment been only apparent, due to exophthalmus, in con- 
sequence of an orbital tumor, no impairment of sight 
would have been noticed at the outset of the difficulty, 
for we see the protrusions of the eye reach very high 
degrees before the vision becomes impaired. The fact 
that the sclerotic coat/before and after the operation, 
was seen to envelop the growth; furthermore, the 
movements of the tumor concomitant with those of the 
other eye; the insertions of the ocular muscles into the 
surrounding coat—sclerotic; their division in the enu- 
cleation of the eye ; the gliding of the whole mass out 
of the orbit after the muscles and the optic nerve had 
been severed:—all these circumstances show that the 
growth was within the eye. As far as I can ascertain, 
this case is the only one of its kind on record. I have 
consulted many older and modern works on morbid 
growths, as . well as the text-books of ophthalmology, 
without finding a mention of intra-ocular enchondroma. 
As this case introduces a new species of tumor into the 
field of ophthalmology, I have endeavored not only to 
define its character, but to trace its origin and develop- 
ment. If we look for analogy, and remember that car- 
tilaginous tumors, though originating mostly in the bone 
and periosteum, not infrequently arise from the con- 
nective tissue of other organs, especially the fasciae, 
(for instance in the parotid gland), we may assume that 8 
Chisolm and Knapp : 
the tissue in which, most likely, the above-described 
enchondroma took its first root, was the sclerotic. The 
exceedingly slow increase of the tumor also favors the 
theory that it started from the sclerotic, a tissue which, 
containing but a few blood-vessels, could only furnish a 
scanty supply of nutritive material to the pseudoplasm. 
We know, however, that chondromata in general are of 
very slow growth. The majority of them, like the pres- 
ent case, are first noticed in early youth; some are con- 
genital. The sclerotic could be recognized in this 
specimen with the microscope. Its outer layers appear- 
ed as usual, but the inner were infiltrated with nuclei 
and cells of an indifferent character, such as are found 
at the border of every growing neoplasm. Near by lay 
hyaline cartilage. There was, therefore, an immediate 
transition between the sclerotic and the tumor, indica- 
ting either that the cartilaginous tissue grew from, or 
grew into the sclerotic. The correctness of the latter 
view was borne out by the fact that I saw here and there 
stellate and angular pigment cells crowded into the scle- 
rotic tissue. All who are familiar with intra-ocular neo- 
plasms know how the pigment cells of the choroid 
move when this membrane itself is destroyed. They 
follow the course taken by the proliferating new ele- 
ments. In spite of this, I think that the enchondroma 
originated in some part of the inner layers of the scle- 
rotic, spread toward the vitreous, destroyed every 
tissue within the eyeball, and, after filling the globe 
completely, began to press and encroach upon other 
parts of the sclerotic, gradually expanding it by its 
steady increase. Thus the choroidal pigment may have Intra-Ocular Enchondroma. 
9 
been carried with the newly-formed cells into the scle- 
rotic when they reached and invaded the opposite side 
of the eyeball. 
There was no indication of a special caiise for the 
development of this growth. C. O. Weber, in his 
statistics of 237 cases of enchondroma (Die Knocheit- 
geschwulste, Bonn, 1856, p. 138), showed that in about 
half the cases where a history was given, an injury 
was the cause of the chondromatous growth. 
R. Virchow assumes (.Morbid Tumors, 1, p. 505) 
that the enchondromata of the soft parts commonly ori- 
ginate in the interstitial connective tissue, in which 
“ chronic inflammatory, or at least irritative ” conditions 
lead to the new formation of connective tissue, which is 
the matrix of the enchondroma. The cellular elements 
of the connective tissue multiply by division, the inter- 
cellular substance becomes denser and more abundant, 
the cells are surrounded with capsules, and the car- 
tilage is formed (Virch., 1. c., p. 506). 
In the case above described there was no history of 
a trauma. Without any inconvenience to the patient, 
or irritation of the eye, the globe was noticed to enlarge, 
sight failing, and a white reflex shining through the 
pupil. This evidently was caused by newly-formed 
tissue in the posterior part of the eye. No other than 
connective and cartilaginous tissues being present in 
our specimen, we have no reason to disagree with the 
great pathologist, but may assume that the first step of 
the pseudoplasm was new formation of connective tissue. 
This we find well marked in the outer layers of the 
specimen, from which it runs through the tumor in 10 
Chisolm and Knapp : 
various directions, forming septa between the nodes (d, 
Fig. i), and accumulating in larger quantity in the soft 
portion (c, Fig. i). There is still, as we have seen, an 
active proliferation going on in this connective tissue 
(Fig. 2), resulting not only in its increase, but in its con- 
version into cartilage. In the outer layers of the cap- 
sule nothing is found but undulating and parallel fibres, 
interspersed with some nuclei; in the inner layers and 
the septa arising from them, the nuclei become more 
and more numerous, and their gradual conversion into 
cartilage cells can be easily observed. In the softer 
places of the granular portion there is a network of 
delicate fibres, containing nuclei and small cells (Fig. 2), 
but in the denser places of the granular portion the cells 
become larger, obtain a double outline, and one or seve- 
ral distinct nucleoli (Fig. 7). At some points the cells lie 
isolated between the nuclei and fibres of the connective 
tissue ; at others crowded together and forming clusters 
walled in by a fibrous capsule (Fig. 7, d). Two and 
more cells very frequently are found in the same cap- 
sule (Fig. 7, a, c, d). The fibres in the basis-substance 
have become coarse. Thus we see fibrous cartilage at 
the side of proliferating connective tissue in the same 
microscopic field of vision (Fig. 6). In some places 
there are smaller and larger accumulations of cartilage 
cells, surrounded by connective tissue which is but little 
changed (Fig. 7). Such accumulations are the starting 
points of new nodes of the growth, which, itself, is but 
an agglomeration of many separated or coalescent nodes 
(Fig. 1). 
Whereas the development of the fibrous cartilage Intra- Ocular Enchondroma. 
11 
could be clearly demonstrated to consist in a gradual 
conversion of the connective tissue elements (Fig-. 7), 
the hyaline cartilage showed different modes of devel- 
opment. 
(1.) The isolated clusters of cartilage cells above men- 
tioned (Fig. 7), formed the nuclei of hyaline nodes, 
being distinguished from the cells of the fibrous carti- 
lage by their yellow color and lustrous appearance. 
The deposition of hyaline intercellular substance com- 
pleted the formation of true cartilage (Fig. 7, b, c). 
These yellow clusters may be likened to seeds strewn 
into the young connective tissue, which they gradually 
absorb by their own growth. Some of them contain 
only a few cells, but have, nevertheless, thick capsules, 
and represent simple breed-cells (Fig. 7, a); others are 
compound clusters, consisting of a varying number of 
smaller clusters and isolated cells enclosed in a common 
large capsule (Fig. 7, c, d). The microscopic picture 
of these compound clusters nearly resembles the macro- 
scopic appearance of the whole tumor (Fig. 1). The 
growth of the neoplasm by proliferation of cells is dis- 
tinctly visible in these clusters. The matrix in which 
they are embedded is provided with blood-vessels, 
which I did not see enter into one of the clusters. In 
some places there were embedded into the fibrous basis- 
substance larger gra?iular bodies (Fig/ 7, e), which do 
not exactly resemble the accumulations of granular fat, 
the dots varying too much in size, being dark through- 
out, viz., without a transparent centre, and irregular in 
outline, unlike the little circles with white centres which 
compose the globules of granular fat. Here and there a 12 
Chisolm and Knapp: 
nucleus was surrounded by similar dark granules (Fig. 
6, a), resembling a coarsely granular cell body, around 
which no membrane was visible. 
2. The fibrous cartilage was converted into hyaline 
cartilage by gradual extension ofi the hyaline basis sub- 
stance into the fibrous matrix ofi the fibro-cartilage. 
There were numerous yellow patches of true cartilage 
scattered through the fibrous cartilage. The line 
of transition between the two was ill-defined and 
often imperceptible. The hyaline cartilage, in its 
growth, absorbs the fibro-cartilage as well as the con- 
nective tissue. 
3. Agglomerated formative cells were directly con- 
verted into cartilage cells by diffuse deposition of hya- 
line substance. To a large extent, especially in pre- 
parations taken from the larger nodes of the specimen, 
the structure of this pseudoplasm presented a dense 
accumulation of nuclei, or small round cells, resembling 
medullary tissue, for instance, glioma (Fig. 8). These 
small, round, formative cells (a, Fig. 8) were mostly of 
the same size, finely granular, pellucid, and colorless. 
Some had distinct nucleoli, others had none. Their 
contour was always well defined. They were pervaded, 
in most places, by an irregular network of, mostly, coarse 
fibres (Fig. 8, b). In the immediate vicinity of this 
white medullary tissue, yellow, pellucid, faintly-lustrous, 
small and large patches (d, Fig. 8) appeared, which con- 
tained the same kind of cells, embedded in hyaline 
intercellular substance ; some of these cells, however, 
were shrunken. These hyaline patches extended in 
irregular lines (c, Fig. 8) into the medullary structure, Intra- Ocular Enchondroma. 
13 
communicated with one another, broadened, and encom- 
passed smaller and larger irregular spaces, which were 
densely filled with formative cells. Where the deposi- 
tion of hyaline substance had only begun, its border line 
was commonly ill-defined, as in Fig. 8 ; but where it had 
advanced further, its boundary was sharp, and the en- 
closed spaces resembled breed-cells, as b and c in Fig. 3, 
and e in Fig. 4. Following these patches up a greater 
distance from their boundary lines, I found that the 
small round cells-—or nuclei—enlarged, became oval, 
had one or several distinct nucleoli; obtained body—cell 
contents—and capsules around them, multiplied their 
nuclei, and aggregated in clusters, thus exhibiting all 
the features of true cartilage. 
The more I studied the histology of this specimen— 
and I employed a good deal of time at it—the more I 
was convinced that the increase of the tumor was less 
effected by multiplication of cartilage cells in the way of 
cell division, but by the conversion of formative cells 
into cartilage cells. This process was very active, both 
in the fibrous and the hyaline portions of the pseudo- 
plasm. The formative cells were either sparsely strewn 
into the connective tissue, or so densely crowded to- 
gether that they recalled the structure of marrow, or 
encephaloid tumors ; but here and there they were sur- 
rounded by hyaline substance, which could be easily 
recognized by their yellow color and lustrous appear- 
ance. Thus, as in the growth of other tumors, so in 
that of enchondroma, the formative cell plays the most 
important part. 
In regard to its clinical importance, the specimen 14 
Chisolm and Knapp : 
above described must be pronounced an innocent or 
benign growth. Though in very rare instances metas- 
tatic cartilaginous tumors have been observed (Paget, 
Virchow), there was no indication of malignance in this 
case. The tumor was, moreover, completely encap- 
suled, even after having destroyed the eyeball long 
before. Its first appearance in early youth, and its slow 
growth, are features which it had in common with 
chondromatous neoplasms in general. 
As an intra-ocular tumor, it is novel and unique. 
The few cartilaginous tumors to be found in ophthalmo- 
logical literature were located either on the outside of 
the sclerotic and cornea (Von Graefe and Schweigger, 
Arch. vii. 2, p. 5), or in the orbit (Fano, L Union Medi- 
cals, 1859, t. iii., p. 557, reprinted ix\ Demarquays Tu- 
meurs de I'Orbite, p. 365, and Mackenzie, Treatise, 4th 
Edition, p. 330). 
The removal of the tumor was indicated, and, if done 
at an earlier time, would probably not have been 
followed by after-hemorrhage and its fatal conse- 
quences. 
I would not omit to thank Prof. Chisolm very cor- 
dially for having kindly given me the opportunity of 
examining so interesting a specimen, which, on account 
of its rarity, forms a very valuable contribution to the 
knowledge of ocular tumors. This being the first and 
only case of its kind ever observed in that locality, I 
took particular pains to investigate, describe, and illus- 
trate it in such a way as to leave no uncertainty with 
regard to its nature. 
As there are, in reality, no unique cases, I doubt not Intra- Ocular Enchondroma. 
15 
that this observation of an intra-ocular enchondroma 
will soon be followed by others. H. Knapp. 
New York, Nov. 7, 1872. 
Explanation of the Drawings on Plates A and B. 
Fig. i. Section through the Enchondroma. 
a. Fibrous capsule. 
h. Hyaline nodes. 
c. Fibro-granular substance. 
d. Fibrous septa between nodes. 
Fig. 2. Proliferating connective tissue and its elementary parts, 
g. Fat in granulated bodies. 
f Formative cells. 
m. Fat in isolated globules. 
t. Net of connective-tissue fibres. 
v. Blood-vessels. 
o. Long fibres with double outlines, 
j. Spindle-shaped, h, stellate, and r, small round cells. 
u. Small round cells in clusters. 
Fig. 3. Hyaline cartilage. 
a. Oval cell with two nuclei. 
b. Smaller irregular spaces containing several nuclei. 
c. Large irregular cavity densely filled with nuclei. 
d. Free nuclei. 
Fig. 4. Hyaline Matrix interspersed with free nuclei, 
d. Nuclei, small, round, and pellucid. 
b. Nuclei, small and shrivelled. 
c. Nuclei, large, oval, round, club-like, dumb-bell-shaped, or 
irregular. 
Fig. 5. Fibrous cartilage. 
a. Nuclei in a granular or finely striated matrix. 
b. Larger cells in a coarsely fibrous matrix. 
Fig. 6. Fibrous cartilage developing from proliferating connective 
tissue. 
a. Nucleus surrounded by dark granules. 16 
Chisolm and Knapp. 
Fig. 7. Smaller and larger accumulations of cartilage cells in con- 
nective tissue. 
a. Simple breed-cells. 
b, c. Deposition of hyaline substance around the cells. 
d. Large capsule. 
e. Coarsely granular bodies. 
Fig. 8. Agglomerated formative cells, converting into hyaline car- 
tilage. 
a. Small round pellucid cells, densely accumulated, as in me- 
dullary tissue. 
b. Network of coarse fibres pervading the cells. 
d. Yellow, pellucid, and faintly-lustrous patches, extending 
c. in irregular outlines into the medullary tissue. 
Erratum : The small letter a on the left border of Fig. 8 should 
be d. 7h&..4. 
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