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Symposium on the development and structure of the lymphatic system. VII. The hamolymph glands of the sheep

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62
The Snatomical Record.
The method of development of the extensive subcutaneous lymph
sacs of the trunk of the frog from the ramification of at first simple
tubular vessels (the lateral lymph trunks), is like that imagined by
Ranvier, and recently described by G. Goldkger for the similar sac
of the posterior extremity of the frog.
VII.
The Haemolymph Glands of the Sheep.
BY
ARTHUR W. MEYER,
Assistant Professor of Anatomy, University of Minnesota.
From a study of sheep fetuses, of the new-born, of lambs of
varying ages and of several thousand carcasses of sheep, the following
conclusions regarding the development, occurrence, structure, and, secondarily, of the function of the hsmolymph nodes, seem justified.
The earliest differentiation between the adage of lymphatic and
hamolymph nodes is seen in foetuses about 9.8 em. long. In such
fetuses the typical hsmolymph nodes can be seen, and all stages of
development from these early nodes to mature nodes can be obtained
by making serial sections of the tissue, in the lumbar region for example.
A study of such series shows that the hzemolymph nodes arise from
mesenchyme, and later become vascularized.
The hmolymph nodes have an irregular distribution, are not;
constant in oqcurrence, and disappear with age. They may be found
anywhere near the viscera from the base of the skull to the rectum, but
are never found on the abdominal wall, on the diaphragm or in the
inguinal or subscapular regions, in both of which places lymph glands
are found. Subcutaneous nodes, so constant in bovines, were never
found in sheep. No definite grouping of the haemolymph nodes was
found but a para-rectal, a lumbar or pre~ertebral,a thoracic or paravertebral, a mediastinal and a deep cervical group might be spoken of.
In young sheep 30-40 glands is a fair estimate, though the widest
differences in size and occurrence exist.
Hundreds of injections from adjacent glands, made directly upon
the carcass immediately after death, supplemented by similar injections
in excised tissue, and further injections of carmine gelatine and Prussian blue from the aoha and vena cava in fetuses, lambs and voung
sheep, together with repeated injections of lymph glands and of the
The Anatomical Record.
63
large lmphatic trunks, prove conclusively that the haemolymph nodes
of the sheep are entirely independent of the lymphatic system, and
that they are not intercalated in the course of veins.
The structure of the hoemolymph nodes varies from that of a dense
mass of lymphatic tissue with many or no follicles and erythrocytes to
a sac of blood containing but a few remnants of lymphatic tissue. Between these extremes every transition is found. The nodes of young
lambs usually contain more follicles, and quite frequently these are so
closely packed that their contiguous sides are flattened. They often
contain blood spaces and occasionally an arteq-, but, as a rule, injection
masses do not penetrate them.
Other conclusions were these :
1. That the reticulum is not lined by endothelium.
2. That the circulation is an open one.
3. That the peripheral sinus and blood sinuses are not in direct connection with either the renous lacunae of Weidenreich or with the
arteries, sare deyelopmentally.
4. That the peripheral sinus and blood sinus are inconstant structures, while the venous lacunre are always present, even if not evident,
on cross section of a node.
5 . That the peripheral sinus and blood sinuses often contain more
reticulum and leucoc?-tes than the venous lacunz, and that they are not
injected from the arterial or venous side unless high pressures are used.
6. That the arterioles open directly into the venous lucunae and that
the latter communicate with. each other and with the veins.
7 . That the relation of the vein or veins to the node is an exceedingly
variable one, and is frequently merely a contact relationship.
8, That small yeins occasionally join the h ~ m o l y m p hnodes by penetrating the capsule near the periphery. and that these veins are afferent
winq.
9. That the rclation of the arterv to the node is a constant one.
10. That it is easy to distinguish a haemolymph node from a lymph
nodc hy mcans of injection, and that it is equally easy to distinguish a
w n o w injection from an arterial one.
11. That the giant cells, hyaline cells (Drummond) and large phapocytic cells arise from the connectire tissue and reticulum cells in both
the embryonic and adult node.
I?. That iron was never found and that the change in color on
exposure to hydrogen sulphide. rariously used, does not indicate that
hnmol~niphnodes contain an excess of iron.
64
The Anatomical Record.
13. That pigment is rarely found in haemolymph nodes, but frequently in lymph nodes.
14. That the blood cells in the peripheral sinus and blood sinuses are
generally well preserved, while those in the venous lacunae are frequently
degenerated.
15. That a definite hilum can seldom be recognized macroscopically.
16. That fat was never found in haemolymph nodes, that a degeneration into fat was not observed, and that the haemolymph nodcs appear
before fat appears in the fetus.
17. That no classification into spleno- and marrow-lymph nodes is
possible.
18. That “mixed” glands, ie., true haemolymph glands, were not
found.
19. That the occurrence of haemolymph nodes has no recognizable
relation to fatness, sex, pregnancy, castration, hygienic conditions, to
tuberculosis or some acute bacterial infection or scvere infections with
Chophagastoma columbanum, but that age has an important bearing
upon the size and number, and, to some extent, upon the structure of
the nodes.
20. That the hzemolymph nodes of the sheep, goat and bovines are
very similar in structure.
21. That in view of these facts, the word haemolymph as applied to
these nodes in the sheep is a misnomer, and that the term h m a l node,
suggested by Lewis, is to be preferred.
VIII.
Subcutaneous and Subpanicular Hsemolymph Glands.
BY
w.
ARTHUR
MEYER
Asmintant Proteami of Anatomy. U n i v d t y of Minnenota.
On examination of carcasses of beeves in abattoirs a number of
haemolymph nodes can usually be found lying in the subcutaneous fat
over the neck and shoulder and, more particularly, in the region directly
anterior to the hip. These nodes vary in number from one to a dozen
on each half of the carcass and have the same appearance as those in
the lumbar prevertebral region. They vary in size from a half to one
and a half centimeters, are oval or circular in outline and usually
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development, structure, vii, gland, sheet, system, symposium, lymphatic, hamolymph
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