Histology. Par. XIII. 1880.
FRET. Histology. 1880.
THE PANCREAS.
PPLUGER, E. F. W. Strieker's Manual of Histology. 1872.
EENAUT, J. Sur les organes lympho-glandulaires et le pancreas des vertebres.
Compt. rend. Acad. des Sciences. Vol. LXXXIX., p. 247. Paris, 1879.
FOSTER, M. Physiology. 1880.
BIBLIOGRAPHY. 419
THE THYMUS GLAND.
WATNEY, H. Note on the Minute Anatomy of the Thymus. Proc. Roy. Soc., Vol.
XXVII., p. 369. London, 1878.
AFANASSIEN. Structure of Thymus. Archiv fiir mikroskopische Anatomic, Band
XIV., Heft 134.
THE THYROID BODY.
BOECHAT, P. A. Thesis on the Structure of the Thyroid Gland. 1873.
BAUER, E. CRESWELL. Researches on the Minute Structure of the Thyroid Gland.
Philosophical Transactions Lond.Roy Soc., Vol. CLXVL, Pt. 2, p. 557. 1876.
Proc. Royal Soc., Vol. XXVII., p. 56. London, 1878.
ZEISS, OTTO. Mikroskopische Untersuchungen iiber den Bau der Schilddriise. Strass-
burg, 1877.
POINCARE, M. Contribution a 1'histoire da corps thyroi'de. Jour, de Panatomie,
p. 122. 1877.
KLEIN, E. Atlas of Histology. Par. XIIL 1880.
THE PITUITARY BODY.
Journal de medecine, de chirurgie et de pharmacologie do Bruxelles, Vol. LXIX. ,
p. 305. 1880.
KLEIN, E. Atlas of Histology. Par. XIIL 1880.
CHAPTER XXVI.
THE THICK CUTIS VERA.
BY J. COLLINS WARREN, M.D.
THE portions of the skin usually selected for liistological
purposes are those in which the papillae or hairs are best shown.
The glands are also carefully described ; but little attention,
however, has been given to the anatomy of the cutis vera as an
organ by itself, consequently those parts have not been ex-
amined where it is found in its most highly developed form.
The skin varies greatly in thickness ; on the inside of the
arms and thighs, and on the anterior aspect of the body gen-
erally, it is much thinner than behind. In the former case,
particularly in delicate women, it is exceedingly soft and plia-
ble, a thin fold being easily raised and rolled between the
thumb and finger. In the latter it is exceedingly thick in the
back and shoulders of hardy adults, appearing as a veritable
hide, being much thicker than the skin of many pachyderma-
tous animals. Here it measures 5.5 mm. and even more in
thickness ; when tanned it resembles sole leather. This struc-
ture is composed of bundles of fibres interwoven in various di-
rections. On the surface of these bundles lie the flat connective-
tissue cells, disposed in rows and occupying the intervals, the
tissue being somewhat analagous to tendon. The cutis is, in
fact, a sort of tendon or aponeurosis ; from its under surface
it sends out fibrous prolongations of considerable size, and in
some animals these are actually attached to muscles. 1 In man
we find them dipping down into the subcutaneous fat, in the
back forming a very dense and firm mesh-work. Fatty tumors
1 M. Renaut : Anatomie generate de la peau ; Annales de Dermatologie efc de
Syphilographie ; Tome neuvieme, No. 5 ; Satterthwaite : New York MedicalJournal,
July, 1875.
THE THICK CUTIS VERA.
421
growing in this part of the panniculus adiposus are, for this
reason, extremely difficult to enucleate.
The papillae are but imperfectly formed, and are represented
by an undulating line. At short intervals are the follicles of
the lanugo hairs, which penetrate only the superficial layers of
the cutis, the sweep of whose fibres would be otherwise un-
broken were it not for the
existence of a structure,
hitherto undescribed, 1 which
connects the bases of the
hair-follicle with those parts
in which we find the root of
the longer hairs imbedded
the panniculus adiposus.
This consists of a nearly
vertical cleft, or slender col-
umnar-shaped space, ex-
tending from the last-named
structure in a somewhat ob-
lique direction through the
deeper and middle layers of
the cutis, and terminating
at the base of the follicle
which rests upon it. This
space is occupied by adipose
tissue in its entire length ; hence, the term " fat-columns,
" fat-canals," 2 would seem to be an appropriate name.
The length of this space (in very lean individuals the fat is
absent, and we then see a delicate mesh-work of connective tissue,
and the trunk of a blood-vessel) is about 4 mm. ; its width
rather exceeds that of the hair-follicle above. Its long axis is
placed at a slight angle to that of the follicle, which in most
cases is nearly perpendicular to the surface, and is nearly
parallel to that of the erector pili muscle (b). At about the
middle of this axis are given off two horizontal prolongations,
usually partially filled with fat-tissue, appearing like a pair of
1 In the latest treatises of the skin, no such structure is described. See Die Haut-
krankheiten fur Aerzte und Studirende von Dr. Gustav Behrend. Berlin, 1879; Patho-
logic und Therapie der Hautkrankheiten von Dr. Moriz Kaposi. Wien, 1879.
2 Note on the Anatomy and Pathology of the Skin, by J. C. Warren. Boston Medi-
cal and Surgical Journal, April 19, 1877.
" FIG. 179. Section of skin from back of an adult,
showing colurnna adiposa and lanugo hair. Magnified
about eight diameters : #, epidermis : ft, erector pili mus-
cle ; rf, fat column ; e, sudoriparous gland ; /, cutis vera ; g,
adipose tissue ; fi, hair ; A, cone fibreux ; p, lateral cleft.
or
422
MANUAL OF HISTOLOGY.
extended arms, or the remaining branches of a leafless trunk (p).
Near this point is suspended the coil of a sweat-gland (e\ held
in place by a few delicate fibres which find their insertion at
the top of the canal or cleft. The duct of the gland runs to the
top of this space, whence it may be traced to the side of the
hair-follicle, whence it finds its way to the surface. (In dogs
the sweat-duct opens directly into the follicle, a short distance
from its mouth.) The fibres of the cutis appear, in vertical sec-
tions, to terminate abruptly at its edges. There does not ap-
pear to be any structure resembling a " limiting membrane."
At its base there is sometimes a slight widening of the cleft,
and on the side toward which its axis leans, the fibres of the
cutis collect to form a bundle which penetrates the subcutane-
ous fat (Cone fibreux de la
peau #, Fig. 179). The upper
extremity is rounded off in
somewhat dome-shape.
The erector pili muscle, tak-
ing its origin from the papillary
layer of the cutis, is inserted
partly into the base of the fol-
licle, which its fibres embrace,
and partly into the apex of the
fat-canal ; in some sections the
fibres seem to penetrate this
space, but probably surround
it, although some of them may
be attached to those delicate
bands of fibrous tissue which traverse the column of fat-cells.
The muscle lies on the side corresponding with the inclination
of the hair externally, and appears almost continuous in its
direction with the fat-column beneath it.
The sebaceous gland lies between the muscle and the follicle
at the apex of the angle made by them ; a lobe is found also
on the opposite side.
The number of these columns corresponds to the number of
hairs, as they are not found elsewhere. In some sections of
skin, half an inch in length, as many as five may be counted ;
they are seen to best advantage in the thickest portions of the
skin, but may be found on the shoulders and arms, breast, ab-
domen, and lower extremities. At some points they appear
FiO. 180. Section of skin from the shoulder of
an infant, magnified seventeen diameters : a, epi-
dermis ; &, erector pili muscle ; c, sebaceous gland ;
d, fat-column ; e, sudoriparous gland ; g, adipose
tissue ; h, hair.
THE THICK CUTIS VERA. 423
as slight indentations in the section ; at others as long canals.
They are well shown in the skin of an infant (Figure 180), and
in a fo3tus of nine months. In the pig, the lower border of the
cutis appears to the naked eye, when seen in section, like the
teeth of a saw. Under the microscope, the apex of each inden-
tation contains the bulb of a hair. In thick hides these inden-
tations become clefts or canals, and we find frequently a
sweat-gland situated at about the middle of each. The canals
are oblique, as are also the hair-follicles, and the axes of the
two are more nearly parallel than those in the human subject.
In thin skins the canals are either so short as hardly to pass
for such, or, if the hair is not of sufficient length to extend to
the bottom of the cutis, absent. A thick skin and the ex-
istence of downy hairs are, then, the conditions necessary for
the presence of this structure in its most marked forms. I have
not found them in the face, although in some individuals they
probably exist there, nor in the thinner skin already alluded to.
In the lip of the rat the long hairs are imbedded in a transpa-
rent, mucous-like connective tissue, and their roots are sur-
rounded by numerous bands of muscle. It is interesting to
note the fact, that under each root are to be found vertical rows
of fat-cells, arranged end on end like the beads of a rosary, but
there appears to be no cleft in the surrounding tissue to en-
close them. In order to obtain a preparation of skin which
shows these structures in their entire length, the section must
be made vertical to the surface, and in a direction which corre-
sponds with the inclination of the cleft of the hair above the
surface. This coincides with the fine folds or " grain" of the
skin. Sections made in any other direction give but a frag-
ment of the canal, which appears then nearly as an isolated
lobule of adipose tissue. Even with these precautions it is
difficult to obtain a good specimen, unless the razor is guided
by the eye and, as in embryonic skin, the canals are not large
enough to be seen, it is greatly a question of luck whether a
good section can be obtained.
TJie blood-vessels are well shown by an injection of Berlin
blue in the foatus near full term. In each canal, as well as in
the intervals between them, the arterioles which nourish the
cutis ascend from the subcutaneous system of vessels, which
forms a fine net-work in the panniculus adiposus. Those in
the canals, on reaching the lateral clefts, bifurcate, giving a
424 MANUAL OF HISTOLOGY.
branch on either side, which anastomoses sparingly through
subdivisions with the adjacent arterioles in the middle layer of
the cutis, and give origin to the papillary and sub-papillary
network of capillaries, which here can be considered as one
and the same. At the point of bifurcation of the main vessel,
branches are given off which ascend farther in the canal and
form a delicate net-work surrounding the sudoriparous gland
(" Wundernetz"). The anastomosis of the vessel about the
hair- follicle is particularly rich and fine, and unites intimately
with the superficial layer of capillaries. The hair-follicle, with
its subjacent fat-column, thus forms the centre of a rich system
of arterioles and capillaries, which extend from the panniculus
adiposus to the papillae.
The lymphatics. The following experiments were made to
determine the question of the presence of lymphatics in these
canals, and also to observe to what extent fluids and particles,
pressed up from below, could be forced to the surface.
Skin was taken from the body of a lean adult, twenty-four hours after death.
A small amount of the loose areolar tissue was left adherent to its lower sur-
face. The skin being prepared by warming for a few minutes in water of
about 90 P., Berlin blue was injected, by means of a subcutaneous syringe,
into the loose areolar tissue, which was rapidly distended by the fluid. The
specimen was then thrown into strong alcohol. A similar fragment of skin
was stretched like a drum, over the end of a brass cylinder, to which it was
firmly attached by an open brass cap and screws. The cylinder being held
vertically, Berlin blue was poured upon the skin, the upper surface of which
looked downward. A rubber cork, perforated by a glass tube, was securely
fastened to the top of the cylinder, and the tube was connected with an appa-
ratus designed to exert any atmospheric pressure required. Pressure sufficient
to raise a column of mercury twenty-eight millimetres was continued for an
hour and a half, the skin being pressed out with great force in dome-shape
at the bottom of the cylinder, which was kept during this time in blood-warm
water. The specimen was then placed in alcohol. It was observed that the
injection mass had gone, at one or two points, to the surface, and on making
vertical sections of the skin the next day, the cutis was found to be penetrated
by the mass in vertical blue lines, which united at various intervals by hori-
zontal branches, occasionally so numerous as to present an almost continuous
blue surface. The subcutaneous areolar tissue was almost uniformly colored
blue.
Opinions on the character and distribution of the lymphat-
ics of the skin seem to differ. For instance, Neumann de-
scribes them as vessels distributed through the skin in two
THE THICK CUTIS VERA.
425
horizontal layers a superficial and a deep one the vertical
connection between the two being found only at comparatively
rare intervals. 1 Renaut regards the skin as a lymphatic sponge,
the minutest ramification being but the space between the bun-
dles of fibres ; the coarser differing from these in having an
endothelial lining (connective-tissue cells ?), there being in
neither case a true wall, which is found only in the lymphatic
vessels of the subcutaneous tissue. 2 Vertical sections taken
from the specimens of skin injected by puncture, showed a
similar, but not so complete an injection, as was effected by
FIG. 181. Injected lymph-system magnified about eight diameters : a, epidermis; /, cutis vera; ff,
adipose tissue ; h, hair.
the present method. The latter seems to possess special ad-
vantage, as a larger lymph surface is exposed at one time.
Fig. 181 shows the route taken by the Berlin blue, which, as
will be seen, ascends in nearly vertical columns through the
fat-canals to the base of the hair-follicles, going round the
sides of the sweat-gland. When a slight amount only had
passed into the canal, a medium power of the microscope
showed the blue lying in and staining the tissue accom-
panying the ascending blood-vessel in the so-called "perivas-
cular space." The lateral clefts were filled with the mass,
1 Zur Kenntniss der Lymphgefasse der Haut, von Isidor Neumann.
2 Renaut. Op. cit.
426 MANUAL OF HISTOLOGY.
which extended far enough to communicate with that com-
ing from an adjacent column. From this point there is a
delicate and freely anastomosing network, marking out the
spaces between the bundles of fibres of the cutis. The lateral
anastomosis, lower down, is not so free, and in the uppermost
layers, owing probably to the compression of the bundles of
fibres, there is little blue to be seen. From the top of the canal
the injection surrounds the base of the hair-follicle, on one side
ascending vertically and giving off horizontal branches, and
on the other following the interval between the lower border of
the erector pili muscles and the fibres of the cutis. The main
route is through the canals, there being no penetration from
below elsewhere. A similar method of injection of these spaces
is seen in certain forms of disease. A subcutaneous, round-
celled sarcoma infiltrating the skin, gave a similar configura-
tion. Also that form of congenital nsevus which develops in
the panniculus adiposus, and in a few days after birth begins
to appear on the surface. Another instance is that variety
of purulent infiltration of the subcutaneous tissue, which is
most frequently seen under thick skin and known as carbun-
cle. The wandering cells find their way to the surface through
these canals, and thus give the characteristic, punched-out
appearance to the skin.
It is evident from these examples that a free communication
exists between the interspaces of the fibrous bundles of the
cutis, and the subcutaneous tissue, and that this is effected by
no closed system of vessels.
The special function of these canals is not so evident. In
addition to furnishing a, route for the blood-vessels and lym-
phatics, there would seem to be some connection with the hair
and its apparatus. The constant relation which they bear to
this structure, and the erector pili muscle, would suggest an
arrangement designed to facilitate the action of the muscle,
according to Biesiadecki. 1 This muscle, by its contraction,
raises the hair from the position which it occupies, nearly hori-
zontal to the surface, to a vertical one. Any movement of the
root of a lanugo hair would be well nigh impossible, imbedded
in the dense tissue of the cutis, were it not for a yielding
structure like that of the columns, an elongation of which
1 Strieker's Handbuch der Lehre von den Geweben des Menschen und der Thiere.
THE THICK CUTIS VERA. 427
would aid the contraction of the muscle. In specimens where
the muscle is found in a state of contraction, the hair-follicle
is bent like a bow, the root being drawn through the arc of a
circle. The presence of fat near the hair-bulb is made possible
by this structure, a condition which is constant with all hairs.
That the fat is not an incidental feature of their structure,
which might be considered merely a cleft for the transmission
of vessels, is rendered probable by the observation of rows of
fat-cells beneath each hair in the lip of the rat, where no special
channels exist, and, also, by the fact that such columns of fat
do not accompany the nutrient vessels of the skin, in those
parts where the hairs are not found. It seems, therefore,
probable, that this structure has some bearing upon the nu-
trition of the hair.
Sweat-glands are found not only in these canals, but else-
where in the thick cutis ; the coil of the gland is then usually
situated at a level a little below the middle of the cutis vera,
and not in the subcutaneous adipose tissue, as in thin skin.
CHAPTEK XXVII.
UEINAEY EXCEETOEY PASSAGES ; SUPEAEENAL CAPSULES.
BY EDMUND C. WENDT, M.D., NEW YORK CITY,
Curator of the St. Francis Hospital, etc.
THE renal pelvis, the calices, ureters, and bladder, all consist
essentially of three layers, which are an inner mucous mem-
brane, a middle muscular coat, and an external fibrous layer.
In the
KENAL PELVIS
we find the mucous membrane lined with stratified epithelium,
the cells of which are large and variously shaped. Three dif-
ferent forms are readily distinguished. The most superficial
layer consists of fiat or polyhedral cells of various sizes, each
one containing a round or oval nucleus, or, as frequently hap-
pens, two nuclei. Peculiar dark granules, often of large size,
surround the nucleus, and are quite distinct from the finely
granular protoplasm of these cells. Then comes a layer of
conical or club-shaped bodies, each one again furnished with
a round or oval nucleus. Every cell also possesses a long
basal process, which appears to attach it to the subjacent
tissue. The bulbous portion of these corpuscles is turned
outward in the direction of the surface. Wedged in between
the processes just mentioned we find the third variety of
cellular elements. These are oval or rounded bodies contain-
ing ellipsoid nuclei. At the renal calices we find a sharp line
of demarcation between the cylindrical columnar epithelium
of the papillary ducts and the stratified pavement epithelium
of the pelvis. The epithelial layer has a thickness here of
0.045-0.09 mm.
The connective-tissue portion of the mucous membrane is
devoid of papillae, contains sparse elastic fibres, and is rich in
THE URETERS. 429
fixed corpuscles, the inoblasts of Krause. There is no true
basement-membrane. Below this stratum we find a submu-
cous layer, which is abundantly furnished with elastic tissue,
and contains a few simple acinous glands with ducts having a
lining of cylindrical epithelium.
The muscular coat is composed of bundles of smooth mus-
cle-cells forming an inner layer, with a peripheral direction of
its constituent anatomical elements, and an outer layer concen-
trically arranged. The " papillary sphincter" is but a thick-
ening of this latter layer.
The external fibrous layer forms a thin connective-tissue
membrane, not always clearly marked here, whereas in the ure-
ters and bladder it is found to be well developed.
The blood-vessels of the pelvis are derived from the renal
artery and vein, and form capillary networks characterized by
polygonal meshes. The lymphatics and nerves are found to
have the same distribution as in the ureters.
THE URETERS
have a structure which closely resembles that of the renal pel-
vis. The mucous membrane shows the same varieties of epithe-
Hum ; its connective-tissue components are similarly arranged ;
and the external investing membrane is composed of the same
kind of tissue already described. But in addition to the two
muscular layers^ which here attain a greater development, we
find a third muscle coat, so that we can now distinguish an in-
ternal and external longitudinal from a middle circular layer
of muscular elements.
Engelmann has described a close reticulum of blood capil-
laries lying immediately under the epithelial stratum, but its
existence is made doubtful by the negative statements of other
authors.
Glandular bodies are not found in the ureters. The peri-
pheral layer of fibrous connective- tissue possesses conspicuous
elastic bundles in the lower portion of the ureters.
The distribution of the blood-vessels is like that of the pel-
vis already described. The lymphatics are well developed here,
forming several networks in the different layers of the ducts.
Nerves are likewise readily distinguished, some of the nerve-
430
MANUAL OF HISTOLOGY.
fibres being also furnished with ganglion cells. Their mode of
termination in the muscular layer is not definitely known, but
may be assumed to resemble that of ordinary smooth muscu-
lar-tissue.
THE BLADDER
has the same type of structure as the ureters, but contains, in
addition, a serous covering in its upper portion. The different
coats of the bladder are, however, much thicker than the cor-
responding layers in the other urinary excretory passages.
Th^ epithelial lining of the mucous membrane shows the
three varieties of its cellular elements in a clearly defined man-
ner.
The connective-tissue stratum presents 110 noteworthy pe-
culiarities, if we ex-
cept the comparative
abundance of simple
acinous glands.
The bundles of
muscle -cells in the
muscular-coat inter-
lace, forming irregu-
lar, long-stretched
meshes. This irregu-
lar arrangement pre-
vents the distinct rec-
ognition of successive
, a ceii of the layers, each with a
largely prevailing di-
rection. Nevertheless,
we find in the external portion of the muscle-coat some pre-
dominance of longitudinal bundles, together with an abundant
supply of elastic fibres. The anterior wall and vertex of the
bladder show this arrangement very conspicuously, in fact the
muscle-fibres have here received a separate name, that of detru-
sorurince. The vesical neck shows a tolerably distinct thicken-
ing of its circular muscle-fibres, which is known as the sphincter
vesicce. It should always be borne in mind that the arrange-
ment of the muscular coat is apt to vary in different individuals,
the description here given will, however, be found to apply to
the majority of cases.
FIG. 182. Epithelium of the urinary bladder,
second layer ; ft, a cell of the first layer ; c, shows the first, second,
and third layers of the epithelium in connection. Obersteiner.
SUPRARENAL CAPSULES.
431
The blood-vessels form a capillary network in the mucous
membrane, which is situated about midway between the epi-
thelial stratum and the muscular coat. In other respects they
present no peculiarity worthy of note.
The lymphatics are less abundant in the bladder than in
the ureters. They, also, lack noteworthy peculiarities or
special features of interest.
Plexuses of nerve-fibres are found in the subserous connec-
tive-tissue, and also in the muscular coat. Microscopic ganglia
and groups of ganglion cells are also met with.
SUPRARENAL CAPSULES.
The suprarenal capsules (glandulce suprarenales) are small
flattened bodies, two in number, situated somewhat above and
Fio. 1&3. Cellular groups and trabeculae of the cortical substance, from the suprarenal capsule of the
Frog. Eberth.
in front of the upper end of either kidney. They are usually
triangular or semilunar in shape, although round and oval