which he calls communicating tubules ( Vcrbindungscanalcheri). Eingeweidel. , p. 324.

9 This has been done by Frey with fishes and amphibia ; by Hiifner with birds,
fishes, etc. ; by Gross with fishes and tritons, and by Hyrtl with some sorts of fishes.
According to Seraphina Schachowa (Unters. ueber die Niere. Diss. Bern, 1 870) the
convoluted tubule of the first order is connected to Henle' s loop by a spiral tubule,
while the ascending portion of the loop exhibits an expanded part immediately above
the loop, and a spiral part, which latter becomes continuous with the ascending limb
of the loop. Between the ascending part of the loop and the intercalated portion
Schachowa describes a new tubule, which she calls the " irregular tubule."

The spiral tubule is lined with an epithelium which has a striated appearance in



THE KIDNEY.



213



The Hood-vessels of tlie kidney. The renal artery and vein,
before entering the hilum, divide and subdivide within the
sinus of the kidney. Small branches, which are given off at
the hilum, also supply the fibrous capsule of the gland. Veins
accompany the arteries as far as the arches already referred to.
But here a difference is to be noted. The arteries never anas-
tomose, but form the straight vessels of the cortical substance
proper, which again send off twigs to form the glomeruli.




FIG. 99. Kidney of pig. Injection of artery and vein. Vertical section at boundary layer : A,
artery ; B, vein : C, glornerulus ; D, capillaries of the cortical portion ; E, vasa recta formed from
capillaries D. x 96.

At the arches, however, the veins anastomose, and a branch
accompanies the straight artery of the cortical substance proper
(Fig. 99, B). The glomerulus is formed from the arterial twig
above referred to (Fig. 89, D). This enters the capsule directly
opposite to the point where the latter becomes continuous
with a convoluted tubule, and divides into two or more



its first portion. The expanded part of the ascending loop is lined with cells having
very thick prominent rods, and whose lumen is exceedingly small. '

The irregular tubule has an angular, irregular outline, is of very varying diameter,
in some portions two, three, or four times as broad as in other portions, a condition
due to its peculiar lining epithelia, which are angular and present numerous pro-
the rods are exceedingly thick and prominent.

As yet I have been unable to confirm Schachowa's researches.




214 MANUAL OF HISTOLOGY.

branches which subdivide again and again (Fig. 100) to form
loops or coils ; these latter unite again and form a vessel equal
in size to the one which entered the capsule. The first is

called, as already described, the affer-
ent ; the second, the efferent vessel,
and the glomerulus is formed by the
division and reunion of the branches
of these two vessels ; the whole form-
ing a rounded tuft within the capsule.
The vessels of which a glomerulus is
composed have the same diameter as
FIG. loo. Giomeruius from kidney small capillaries i their coats are struc-

of pig. Ludwig. ' . . .

tureless and provided with elliptical

nuclei. The efferent vessels are not veins ; on leaving the cap-
sules they break up into capillaries, which anastomose freely
with each other and surround the tubules of the cortex, form-
ing, in this way, a network with circular meshes (Fig. 99, D).

At the boundary layer the capillaries unite to form vessels
which are two to three times larger than the original capillaries.
These vessels take a straight course through the medulla to-
ward the apices forming the so-called vasa recta ' (Figs. 99, E,
and 89, G). The vessels immediately below the boundary layer
are arranged in bundles at the side of the pyramidal prolonga-
tions, and run parallel with them in that part of the medulla
(Fig. 89). They give off branches in the medulla, and near the
apices of the pyramids again form a capillary network which
surrounds the collecting tubules. The returning vessels (veins)
have about the same course, anastomose freely with each other,
and empty into the venous arches at the boundary layer.
Other veins are formed by the union of capillaries immediately
underneath the capsule ; these have a stellate form, 3 the centre
of each star indicating the commencement of a vein. Such
veins, passing downward through the cortex and receiving
branches on the way, empty finally into the venous arches
above referred to. The venous arches also give rise to vessels
of larger calibre, which run parallel to and accompany the ar-
teries of the medulla, and at last unite to form the renal vein.

Injections of the kidney. The kidney may be injected with
gelatine either through the artery or vein. It is best accom-

1 Bonders: Physiol., L 2 Venae Stettatce, Verheyen.



THE KIDNEY. 215

plished by the artery, under constant pressure (mercury).
Beale's blue injecting fluid l answers very well ; the writer's car-
mine-glycerine fluid 3 also acts exceedingly well, but it is very
difficult to obtain a good double injection of artery and vein.
I have found the most successful method to be the following :
Take a fresh bloodless kidney (dog, pig) and inject the vein
under constant pressure with the blue gelatine mass. 3 Next
place the kidney in iced water for a few minutes to harden the
gelatine, and then attach to the artery a very small constant-
pressure injecting apparatus, the receptacle for the injecting
fluid containing the writer' s carmine fluid. After regulating the
amount of pressure, the whole apparatus, with the kidney, is
placed within the receiver of an air-pump and the air slowly
exhausted. In this way the arteries become filled with fluid.
Allow the gland to harden in alcohol and mount the sections
in balsam or dammar. Kidneys in which the vein and artery
have been injected may have the collecting tubules filled from
the ureter with yellow injecting fluid, thus making a triple
injection. Sections of kidney hardened in alcohol may be
stained with borax- carmine, and afterward bleached in a di-
lute hydrochloric acid (1 to 10) solution, or a concentrated one
of oxalic acid. When the vessels of a kidney have been injected
with blue gelatine, staining with carmine gives good results.

Thiersch's yellow injecting fluid is made as follows : Prepare a solution of
bichromate of potassa, one part of the salt to eleven parts of water, and a solu-
tion of nitrate of lead of the same strength. One part of the potassa solution
is placed in a small basin and mixed with four parts of a concentrated solution
of gelatine. Two parts of the lead solution are placed in another basin and
mixed with four parts of jelly. These are to be slowly and thoroughly mixed
together at a temperature of 75 to 90, and then heated in a water-bath at a
temperature of 212 for half an hour or more. Filter carefully through flannel
(Beale : Microscope, p. 90).

The kidney stroma. In the cortical substance the stroma
is reduced to a colloid material which binds the tubules to-
gether. In the lower part of the medulla, in the fresh state,

1 See page 205.

* Carmine, 5 grammes; glycerine (anhydrous), 50 grammes; add caustic potassa
until the carmine is dissolved, and neutralize with pure, concentrated muriatic acid.

3 Gelatine should be first immersed in water until it becomes softened and then
gently heated until dissolved. Add soluble Berlin blue, or Beale's blue fluid, until a
good color is obtained. Inject while hot.



216 MANUAL OF HISTOLOGY.

the stroma is a colorless, transparent substance, which, after
immersion for a variable time in a solution of euro mate of po-
tassa or ammonia, resolves itself into a thin fibrous reticulum,
containing at regular intervals round or elliptical nuclei ; *
these, according to Schweigger-Seidel, belong to stellate or
spindle-shaped corpuscles, which may be isolated by macera-
tion in hydrochloric acid. The nuclei are only seen in the
lower portion of the medulla ; the fibrous appearance of the
stroma is retained some distance beyond this point.

The nerves follow the course of the arteries of the kidney
and seem to supply only those vessels.

The lymphatics at the hilum are derived from the interior
of the organ, and from a network of small lymph-branches
situated between the bundles of fibres of the capsule. The
latter communicate with lymph-canals in the interior of the
organ. 2

The capsule of the kidney is a fibrous tissue, containing
some few elastic filaments. It is divisible into two layers, an
outer and an inner one. The former, about 0.1 to 0.2 mm. in
thickness is continuous with the connective tissue which sur-
rounds the blood-vessels at the hilum ; the latter, about 0.025
mm. in thickness, terminates at the points where the papillae
enter the calices. Immediately underneath the inner layer, is
a large meshed reticulum of smooth muscle-fibres, 3 some of
which traverse the substance of the gland for a short distance.

The calyx, at its junction with the papilla, is covered with
epithelium, which is continued on to the apex of the papilla ;
it contains, in addition, muscle-fibres disposed at right angles
to one another, and connective tissue.

Natural injection of the tubules of the ~kidney by the
sulphindigate of soda.* The first to inject the kidney in this
way was Ghronsczewski ; 6 but his experiments were not very
successful, at least so far as the kidney was concerned. Those
of Heidenhain 6 which have been confirmed by the writer, 7 give



1 Henle : loc. cit. 2 Ludwig, in Strieker's Manual.

3 Eberth : Med. Centralbl., No. 15, 1872.

4 Commonly known in the laboratory and in commerce as indigo-carmine.

5 Chronsczewski, in Virchow's Archiv, Bd. XXXI., p. 187; also Bd. XXXV., p.
158.

6 Max Schultze's Archiv, Bd. X., p. 1, and Pfliiger's Archiv, Bd. IX., p. 1.

7 Mayer ; Histol. of Kidney. Prize dissert. , 1876.



THE KIDNEY. 217

the most satisfactory results. To insure this desirable end, it
is necessary that the sulphindigate of soda be pure.

O. Maschke, of Breslau, the apothecary who manufactures the pure sulphin-
digate of soda for Prof. Heidenhain, writes to that author as follows : " The
indigo- sulphate of soda was prepared from the phoanicin-sulphate of soda. If
the latter compound be heated for half to one hour, at a temperature of 60 to
70 C., with five or six times its volume of sulphuric acid of a specific gravity
of 1,840, it resolves itself completely into indigo- disulphate of soda and
indigo-monosulphate of soda (indigunterschwefelsaures Natron). I have
chosen this mode of preparing the salt because the indigo-gelatine and indigo-
brown can easily be separated from the phoenicin-sulphate of soda, without
marked loss, and in this way I obtain a sufficiently pure substance for future
use. An easier method of preparing the salt is the formula given by Crum
and Berzelius. One part of best indigo in powder is gradually added to seven
or eight parts of pure sulphuric acid, specific gravity 1,84=0, in a large vessel,
and the two thoroughly mixed. After the liquid has ceased to froth, the
Vessel is covered with an animal membrane and put aside for three days, during
which interval it is to be frequently shaken. To this solution thirty to forty
volumes of water are added, and the whole carefully filtered. To the resulting
clear solution as many parts by weight of crystallized carbonate of soda as
there were of sulphuric acid, are added. Owing to the effervescence which
now takes place, the vessel in which the mixture is prepared must be of large
size. For this reason it is better to substitute the acetate of soda, or chloride
of sodium, or simply sulphate of soda, for the formation and precipitation of
the indigo-disulphate of soda takes place with any soda salt which does not
decompose the "indigo -disulphuric acid. The mixture is now filtered, and the
precipitate dried over a water-bath. It is then pulverized and treated re-
peatedly with absolute alcohol, which dissolves any indigo-monosulphate of
soda, acetate of soda, or indigo-red, which may have remained." In this way
the indigo-carmine is obtained in a pure state. The crystals are copper-colored,
but the salt is blue in the pulverized state. The indigo-carmine of commerce
is an impure article and cannot be used for natural injection.

For injection, a cold saturated solution of the sulphindigate
of soda is used ; the salt may be dissolved in boiling distilled
water, and the solution allowed to cool. A dog or rabbit
answers for the purpose of injecting. The animal is properly
fastened to a board, and the external or internal jugular vein
dissected up and exposed. In either of these vessels a canula
with stop-cock, previously filled with the indigo-carmine
solution, is inserted. The injection into the jugular may be
made downward or upward the latter is preferable. A syr-
inge, graduated in cubic centimetres and containing the sol-
ution of indigo-carmine, is now attached to the canula, the
stop-cock opened and a small quantity of the solution injected



218 MANUAL OF HISTOLOGY.

into the vein. Not more than 5 c.c. should be injected at one
time. If the animal be a white rabbit, the result oi ! the first
injection shows itself in a few seconds, for the animal soon
becomes quite blue. After five or ten minutes another 5 c.c.
of the solution may be injected, and so on until 20 to 50 c.c. of
indigo-carmine solution have been employed, the amount
varying according to the size of the animal.

The excretion of blue urine takes place soon after the first
injection of indigo-carmine. As soon as a sufficient quantity
has been excreted the animal is killed in the following manner :
The abdomen is opened and the descending aorta looked for ;
when found, the canula of a syringe, filled with absolute alcohol,
is attached. The jugular vein is now cut across, and while
the animal bleeds to death absolute alcohol is injected up the
aorta or into the renal arteries. A safer and better way is to
inject the renal artery at once with absolute alcohol ; in either
case the renal veins should be cut across. The kidney is at
once removed, placed in absolute alcohol, and then divided
into several pieces, to insure a rapid action of the spirit.
While the indigo -car mine is being injected into the jugular
vein, the animal should be wrapped up in flannel or cotton-
batting so as to be kept warm. No air should be allowed to
enter the vein, or the animal may die before the experiment is
concluded. Injection of absolute alcohol through the renal
artery should be accomplished before the animal has bled to
death, or, at least, immediately afterward. When the kidney
has been thoroughly hardened, vertical and transverse sections
are to be made through the cortical and medullary substances,
and examined in glycerine saturated in chloride of potassium ;
or, better still, in resinous turpentine.

If the injection of absolute alcohol be delayed, either through lack of skill in
the experimenter, or any mishap, the indigo salt within the kidney becomes
diffused over the entire organ by absorption of water from the contained ves-
sels, and the whole kidney becomes of a uniform blue color. Such glands
must be laid aside, for sections made therefrom, even after immersion in abso-
lute alcohol, are worthless, and will only confuse the microscopist. The abso-
lute alcohol of the shops is not always absolute, as is well known. It has a
great affinity for water, and, in handling, rapidly absorbs moisture from the air.
To make it absolute, I heat sulphate of copper (pure) at a low red-heat. This
drives out the water of crystallization, and changes the color from blue to
white. Of this I mix a large spoonful or more, while still hot, with a pint of
the so-called absolute alcohol, and tightly cork the vessel, which is then to be



THE KIDNEY. 219

shaken occasionally, but not used for a week or more. The affinity that water
has for anhydrous sulphate of copper is greater than that of the alcohol, and
the latter readily gives it up. As soon as the anhydrous sulphate regains its
water of crystallization it assumes a blue color again.

Everywhere in the sections it will be seen that the glomeruli
or their capsules are entirely free from color, while all the
tubules possessing the rod-epithelium have a more or less blue
color, according to the quantity of indigo-carmine excreted.
The lumina of the convoluted and other tubules are generally
filled with the crystallized indigo-salt. In examining sections,
it soon becomes evident that the convoluted tubules and that
part of Henle's loop which possesses the rod-epithelium, alone
excrete the indigo-salt, while the other tubules merely contain
it in their lumen, the salt having been washed down, as it were,
from above by the water filtered through the capillaries of the
glomeruli.

Instead of using the sulphindigate of soda, Heidenhain, in his second series
of experiments, substituted a solution of uric acid in caustic soda. The renal
artery was injected with alcohol containing acetic acid. The result showed
that urate of soda, like the indigo-salt, was excreted only by the tubules pos-
sessing the rod- epithelium. The capsules were entirely free. The addition of
acetic acid to the alcohol caused the uric acid to be precipitated in the shape
of rhomboid crystals within the tubules. In this condition Heidenhain found
them. The hypothesis set down by Bowman, years ago, that the tubules of
the kidney excrete the solid constituents of the urine merely, while the glome-
ruli serve as a filter for the fluid portion, is therefore correct.

If the quantity of indigo solution injected into the jugular
be small, and the animal killed soon after, the kidney being
treated as above detailed, the microscopic sections exhibit
the following appearance : glomerulus and capsule are not
acted upon ; the narrower branch of the loop and the collect-
ing tubules are free from any crystallized salt, and their epi-
thelium clear. In the convoluted tubules and the broad part
of the loop, the following phenomena may also be observed :
their lumina are entirely free from any deposit of indigo-car-
mine, though here and there the rod-epithelium is not stained.
In the greater number it is colored of a light blue color. In some
the rods and nuclei are uniformly stained ; in others the rods
alone show the blue color, while the nuclei are not stained.
This constitutes the first stage of the excretion of indigo-car-



220



MANUAL OF HISTOLOGY.



mine through the kidneys. If a larger quantity of indigo
solution be injected, and the animal dealt with as above, the
second stage of the excretion is seen. Here, again, the glome-
ruli, the capsules, and the collecting-tubules are free from
color, the rod-epithelium stained blue, and their nuclei dark
blue (Fig. 101, F). In a few of the convoluted tubules and the
ascending broad branches of the loop, crystals of indigo-salt




PiG.101. Kidney of dog. Natural injection of secreting portion, artificial injection of artery, vein,
and capillaries. Transverse section through cortical substance : A, afferent vessel, filled with injected
material; B, efferent vessel, also filled with injection; E, glomerulus, injected and Ijing within its cap-
sule : epithelium of latter distinctly seen : D, capillaries surrounding the convoluted tubules, and dis-
tended with the injection ; at this point four capillaries are seen to unite and form a vein ; C, convo-
luted tubule, filled with crystals of indigo-carmine ; F, convoluted tubule, in which the nuclei have a
dark color. The striations of Heidenhain are beautifully shown in the convoluted tubules, x 200.



fill the lumina. So, also, in some of the descending narrow
branches of the loop. In the third stage the rods are color-
less, while their nuclei are still blue. Masses of the indigo -
salt fill the lumina of the convoluted, looped, and collecting
tubules ; the glomeruli and their capsules are colorless. In
the last stage, the salt is contained in the lumina of the col-
lecting tubules only, all the rest of the gland being free from
it, and consequently colorless. From the above it will be



THE KIDNEY. 221

seen that the rod -epithelium alone excretes the indigo-salt, and
it may be presumed, therefore, that the function of the glome-
ruli is to act as a filter for the fluid portion of the urine. Thus
the salt is washed from the convoluted into the collecting
tubules, and thence into the pelvis of the kidney. The action
of absolute alcohol on a solution of sulphindigate of soda is to
precipitate that salt. It is this action within the kidney which
fixes' the dye, as above set forth.

Beautiful specimens may also be obtained by various modi-
fications of the above process.

The following formulae and results are given by Heidenhain :

1. Babbit or dog ; section of spinal cord, injection of only 5 c.c. of the in-
digo solution, the animal being killed after ten minutes. Result : pyramidal
portion and boundary layer free from indigo-blue. In the cortical substance,
some of the convoluted tubules are filled with the crystalline salt ; in the
greater number the epithelium is colored of a uniform blue, the nuclei possess-
ing the same tint ; the lumen is usually free.

2. Same conditions as above, excepting that 20 or 25 c.c. of the solution
is injected. Medulla free from indigo blue. In the cortex a great many of the
tubules are filled with the pigment, while the epithelium is stained blue, the
nuclei of a deep blue color.

3. Same conditions as in 2, excepting that the animal is killed one hour
after injection. Nuclei of the rod-epithelium stained deep blue, rods clear ;
convoluted and collecting tubules filled with crystals of pigment.

Instead of using absolute alcohol for injecting the renal
artery, the writer's carmine-glycerine fluid may be employed.
After having injected the artery in this way, the kidney is
placed in a vessel of absolute alcohol, and divided into small
pieces while immersed in that fluid. The glycerine being anhy-
drous, prevents the diffusion of the indigo-salt within the kid-
ney, while the alcohol fixes the pigment. Sections should be
made from the cortex and medulla, and mounted permanently
in resinous turpentine. If the glycerine injection has been suc-
cessful, all the glomeruli and capillaries will be filled with a
transparent red mass (Fig. 101). If the indigo excretion has
reached the third stage, the collecting tubules in the medulla
will be filled with blue crystals of indigo-carmine, and the vasa
recta with a red mass, the two arranged in alternate rows.
Such specimens leave nothing to be desired in the way of
demonstrating the structural relations just described.



222 MANUAL OF HISTOLOGY.



BIBLIOGRAPHY.

FERREIN. Mem. del'acad., p. 502. Paris, 1753.

MULLER. De glandularum, etc. Leipz., 1830. And Unters. lib. d. Eingew. d.

Fische. Berlin, 1845.

HUSCHKE. Lehre d. Eingeweide. Leipz., 1844.
GERLACH. Miiller's Archlv, p. 378, 1845, and p. 102, 1848.
VIRCHOW. Virchow's Archiv. Bd. XII., p. 310. 1857.
BEER. Die Bindesubstanz d. Niere, etc. Berlin, 1859.

LUDWIG. Handb. d. Phys. Bd. II., p. 628. And Wiener med. Wochen. 1864.
ROTH. Diss. Bern, 1864.

CHRONSCZEWSKI. Virchow's Archiv. Bd. XXXI. , p. 153. 1864.
SCHWEIGGER-SEIDEL. Die Niere, etc. Halle, 1865.
STILLING. Bin Beitrag, etc. , Diss. Marburg, 1865.
HUFNER. Vergl. Anat. u. Phys. d. Harn. Leipz., 1866.
LINDGREN. Z. f. rat. Med. 1868.

GROSS. Essai sur la structure microscopique des reins. Strassbourg, 1868.
ISAACS. Jour, de la phys. Tome. I., p. 577. 1858.
LUDWIG. Strieker's Manual. 1871.
EBERTH. Centralb. f. d. med. Wiss., p. 227. 1872.
HENLE. Eingeweidel., 2 Aufl. 1874.

FREY. Mikroskop. 6 Aufl. 1877. And Handb. 4 Aufl. 1874.
HEIDENHAIN. Schultze's Archiv. Bd. X. 1874. And Pfluger's Arch. Bd. IX.

1874.

SCHACHOWA. Unters. lib. d. Niere. Diss. Bern, 1876.
NUSSBAUM. Beitr. z. Anat. und Phys. d. Niere Sitzungsber. d. Niederrh. u. Sw.

Bonn, 1877.

RUNEBERG. Nord. Med. Ark. XI., 2. No. 13. 1879.
HENSCHEN. Akad. Afhandling in Upsula. Stockholm, 1879.
KLEIN and SMITH. Atlas of Histology. Part XI. 1880.



CHAPTER XV.

THE MALE EXTERNAL AND INTERNAL OEGANS OF GENERATION,
WITH THEIR GLANDULAR APPENDAGES.

BY DR. J. HENRY C. SIMES,
Lecturer on Histology, University of Pennsylvania.

Penis. The copulative organ of the male consists of erec-
tile tissue, and is made up of three bodies, each enclosed in a
fibrous membrane, the tunica albuginea. Two of these bodies
are termed corpora cavernosa; the third corpus spongiosum ;
through the latter the urethra passes.

The tunica albuginea consists of connective tissue and elas-