Section IV,
OP THE LYMPHATIC GLANDS.
] In majiy parts of the body the course of the abr sorbeiits is iiitcri'upted by certain oval or round bodies^) which have been named, from tlieir supiiused rewm-l blance to acorns, (/landa. TTiey are jJso called, in order i to distinguish them from other parts which bare, receive^ the same appellation, absorbent and conglobaie glu|id«: and by Chnussier they were denominated lympJialic yon- ' yliom, because it is thought by many anutumisLs, Uifi|tJ they bear tlie same relation to tlieir vessels, as the ner- j vous ganglions do to the nerves.
They are principally situuted in the trunk of tluj body, where tlieir number, which is liable to variituou,| is very considerable. A few are found on Uie fbccj, several arc placed before and behind the car; in the neighbourhood of the lower jaw tliey ore clustered toge- ther ; and on the sides of ibv internitl jugular vein they form a kind of chain, and are therefore called the glao-
SITUATION, SIZB, COLOUR. 319
dulso concAtenatae colli. The absotbQiit gknds nbouod io the cheHl ; they are placed under the sternum, luxtuiid the primitive hlnod -vessels, on the sides of thu vertubrai, ftnd some in the intercot^tal spaces ; the greatest nutn* ber Jie on the lower part of the windpipe, and on the broncliial tubes. The dbdomen incloses a great mul- titude of ihcsf bodlL's ; the mesenteric are extremely numurous ; the number of the rae»ocolic, luinbar, and iliac, is also ^ery considerable. In the limbs the con* globate glands are not numerous. In the fore-arm, Mascagni has represented three or four; a few are placed in the upper arm, and several are contained in the axilla and on the side of the thorax. The leg has usually one gland ; three or four Fu-e observed in the ham ; a few are situated near the femora! arterj- ; in the groin there are from eight to eleven glands ; and, lastly, some are placed on the hip, underneath the gluteal musdes.
' Their size and shape are ^'arious. Some are an inch ia length, and uIIilts not more than two or three lines; ID gcucrul the large glands are placed near ttic lym- phatic tninks, and the smaller ones towards the branches. The majority nf these bodies are oval or almond-shaped ; but many art.* globular, and others are round and flat^ or even triangular.
The absorbent glands are generally of pale red or flesh colour, which is of a deeper tinge in young than in old animals. The colour is not the same in all parts of the body. Thus the mesenteric glands are lighter than those of the limbs, and during the passage of the chyle through tlicm, they are us white as milk ; tliose of the liver are said to be yellowish, and it is well
320
CONNEXION OP VESSELS WITH GI.AND8.
known that tliosu of Uiv luogs arc blucish, or even quil)a .black.
Each lymphatic gland is inveftt«<l by a capsule, whit^J is composed, as Dr. Hunter properly remarked, of con-j jdeused cellidAr membrane It adheres very tutimalelf to the subiitnnci: of tlte gbind, from which it caaaut be separated without division by the scalpel. Tlui cXf temal surface, on the contrar)-, is lio loo^Jy attache^l to the surrounding cellular tis-we, that the glands ii their healthy state arc \X'ry moveable ; but they become fixed and consolidated from tiic vifecta of diaease. , ,
The ab^orbvut vi^els pass into one or more of liif j glands which bik situated in their cuurso. It in stat«<( | by MsAcagni, and his authority on this point hiu> ibeeo generally admitted, that there is no lymphatic in -Um I body which does not puss tlirough at least one gUof 1 before it terminates in the hu-ge tnmks. A different opinion wiLt supported by Hcwson, who thought thLni were lymphatics which entered tlie thoracic duct Vfitbf out having passed through any ^and.* I believe ih».\ the statement of Ma.»cagni, when it is conKned to tb« larger vessels, is in most instances correct; but th« recent discovery of the free communications between the lymphatic and venous bntuchcs, shews that it caat not be extended to the small ves.tels. ,, ,
"Die absorbents which enter the glands arc C«lle4' voM in/erentia, and those which paw out of them. Kit! termed va$a efferetUia. Each of tlie former having ap^
P
- That Ibii Mmclimcs <N3ciin, it proved by an exp«riiligal pwfwitwd by Cniiltihaiik, In wbicli Ihe Ihoncic duct wm ioJMleil fram lymptMlK v«*mU on iht back, without injcctiRg any gland.— y(W. »/" M« Ahort. fnttb,'
'^''fl'RtjfcTUTi*' OP LYMPHATIC GLANDS.
p»«achcd within a quarter of an inch' of the gland, divides into three or four smaller branches, which sulweqtipntly continued into its substance, where they ramify in a very intricate manner. After being thus imhutdy dinded, thcy re-imite and gradually become I(irg«r, till nt length, at the distance of about a quarte^ of* an inch from the opposite side of the gfand, they all join to ftrrm the vas efFerens.* The number and «Jzc'of "the lymphatics whicli enter any gland, are liable to ■ great Tnriation ; sometimes there arc only two or three, and at othtTs there are twenty or thirtj-; the vasa effercntk are usuaUy fewer in number, but larger in WM. ''^t '■' "' ' '>!
" Vihen the blood-vessels have been Bucccssfiilly ia- jectfd, it is observed that the absorbent glands receive a large supply of arteries. It also appears that these bo- dies are generally covered on the exterior by a minutd fletwork of Innphatic vessels. Nervous branches can' betraccd, although with difficulty, to the glands ; and it is probable that they distribute filaments to tlie interna} (rubstanoe. The opinions of anatomists concerning the minute structtu-e of the lymphatic glands arc of a very unsatisfactory character. According to Hewson, Mon- ro, Meckel, and others, the glands are principally made* up of the convolutions of the vasa inferentia ; wliilst it Ws contended by Malpighi, W. Hunter, and particu- layly by Cruikshank, that they contain numerous cell.*)' in which the vasa jnfi;rcntia terminate, and from which the vasa effercntia arise. Each party has appealed to anatomical observations in support of these theories, and each has also given plates in illustration of their,
I
- Falconet, Exprr. Inquirio, p. S3. V
m
FUNCTlONft OP AB60RBBKTS.
*
Mew. The source of all this contnHiction appears to have bcco puiiitt-d out by Miiscagiii, who ascertained that the lynipluitic vessels, baviDg frcdy dtvidud and ramttied within the glands, are dilated in Home pUces and suddenly contracted in others, so that when they ere injected they present the appearance of small emi- Dcnccs on the outer surface, and of cells in the interior. This obsen'aUoD has been confirmed by Uic dissec- tions that were made a few years since by Beclard, which prove that the abnorbenLs have an erectile dispo- sition as they nuniiy within their glands. The use of these bodies is not known ; but, as they are only p08< Bcsscd in the more perfect animab, it is probable that they render the absorbent Sjstem more complete. t. Id the earlier periods of life the lymplmtic glands arc rather larger and softer than they are in the adult ; they also contain more fluids. In old persons they become liarder and smaller ; but they never disappear, notwithstanding what has been stated on the cuntnuy by some distinguished writers.