GLAND. 



foiwd : hence the devclopement of fteatomatous tumours in 

 tiie liver, of ferous cyfts in the kidiiies, and of hydatids in 

 both, without the fecrction being at all diiiurbed The 

 li.er is fometimes eucreafcd three or four-fold by internal 

 tuiiioiirii, uitliout its proper tiffae bsing augmented : the 

 latter forms a kind of Lpta between the fwellings in whicli 

 the bihary fccretion gojs on. 



Bhnd-vjfeh — Glands, which are not furrounded by a 

 membrsnj, receive their arteries from ill quarters. An 

 abundance of fmall branjhL-s from the neigiiboi'.rinf; trunks 

 penetrates the furfac^? of tl^e falivary and lacrymil glands, 

 the pancreas, &c. They firll run between the loocs, pene- 

 trate into the fmaller dirlfions, and are finally difperfed on 

 the acini. The branches coming from different quarters 

 anailomofe freely in the gland. 



Where the organ is fiirrounded by a meinbrane, as in tlie 

 liver, kidney, te'.Hs, Sec, the arteries penetrate on one fide 

 only, generally at a more or lefs deep notch, and in a lingle 

 confid'rable trunk, which, however, is fometimes previoiifly 

 divided into a fev.- fmaller branches. Tiie part, at which 

 the aitery enters, is always the fartheft removed from the 

 acfion of external bodies ; a remark, which is common to 

 all important organs, as the lungs, inteftines, fpleen, S;c. 

 The convex furface of thefe, where the vetTels are the 

 fmallcfl, and where hemorrhage would confequently be at- 

 tended witli the leaft danger, is alv.ays turned outwards. 

 When it has entered the gland, the main artery quicklv di- 

 vides into various branches, wiiich diverge and are fubdivided 

 as they approach the convexity. They have various 

 branches in the body of the organ, as they proceed, and 

 end by producing a large number of capillaries, covering 

 the furface of the organ. Sometimes they come througii, 

 are vifible on the furface, ..nd ramify between it and the in- 

 Tcding membrane. Tlie raoR favourable m.ethod of obferv- 

 ing the di.lribution of the arterial fy.'em in thefe organs is 

 to injeft them with hard inje;:Vion, and to deftroy the animal 

 fubftance by means of inimerfion in muriatic or nitric acids : 

 a call of :he vafeular fyilem, even to its very minute divi- 

 fions, may be obtained in this way, and fuch preparations, 

 on account of their elegance, are contained in all cabinets. 

 Ruyfch, who was remarkable for his dexterity in thefe 

 procefTes, found that the fr.all arteries were differently ar- 

 ranged in the different organs. In the kidney they are con- 

 voluted, fo as to form, through the v.'hole fubllance of the 

 organ, fm;:l] granular bodies lefs than a pin's head, which 

 are the ::cini already alluded to. The furface of the liver is 

 covered, aiter a fuccefsfid injeftion, with innumerable ca- 

 pillaries arranged in a ftellated form, and giving the appear- 

 ance of little tufts of minute arteries, when the part is cor- 

 roded, Vihich have been compared to camel's hair pencils ; 

 and this arrangement has been termed the penicillous. A 

 fimilar difpofition is obfervable in tiie fpleen. 



Some have conceived that the large arterial trunks of 

 glands communicate to the organs an interior motion very 

 nivourabli to the esecution of their functions. Thefe bo- 

 dies are placed, for the moA part, in the trunk, and there- 

 fo.-« near to the heart ; and their veffels generally enter after 

 a ihort courfe, fa that the iaipulfe has been confidered, fi-om 

 this caule, to be more powerful. The fpermatic arter)- is 

 a remarkable exception to this obfervation, and the llownefs 

 of the fcminal fcciction has been explained from this caufe. 

 We own that v.x- cannot diicover any very convincing argu- 

 ments in proof of tlu-'fe pofitions. 



The veins accompany the arteries throvighout, in their 

 diflribution to the glands ; v/e have no diftinction here of a 

 iupcrficial a:id deep-lcated fet. Tiie liver is the only exam- 



4 



pic in which red blood enters on one fido, and black e-oc 

 out m the oppofite direclion. * 



Bko^oflL.hnds—T\x: quantity of blood contained 

 habitually in thele organs diff. rs rem..rkal>Iy in ihc- dififcr- 

 ent parts ot the iy-ilem. ,. The conglomerate glands con- 

 tain >vry httle. It imparts no colour to thefe or|an5, wl-icl, 

 a.-e wnitLTi in the.r appearance, and only require the water 

 to be changed two or tin-ec times in mrxeration. 2 The 

 mucous gland ;, proflate, and teilicle contain a larger cuan- 

 tity. 3. Th_- hver and kidney have fuch a'con!id.r.:bl por- 

 tion, that they differ widely in this refpcct from the rell of 

 the gla:=dubr fyflera. They co«tain a lar^e quantity ex-en 

 atter oeath from haemorrliage, or when the gku.ds are fud- 

 denly removed from a living animal. Hence, \;he» we ma- 

 cerate thtfe organs, it is ncceffary to renew tl.e water at 

 leaa twelve times before it ceaf^s to be blwdy : when we 

 preierve them in alcohol, long prc%ioas mjiccration is ncccf- 

 fary, to prevent the fpirit from becoming turbid by the 

 blood. Tins large quantity of blood oc.-afions the glandj 

 now under conliceration to be lieavier tiian the otiicr part,* 

 of the fyilem ; iicnce, too, arifes their diilinguifiiing red co- 

 loin-, which is not more e(fenti-JIy inherent in thdr tiffue, 

 than in mucous furfaccs or mufcles : in fact repeated v.alh- 

 ings will difcharge it as cfreftually. TJic liver then exhibits 

 a grevilh appearance, which appears to be the proper colour 

 of Its tiffue, as wliite is that of the mufcr.lar fibre. The 

 hue of the kidney fee:ns to lie lefs im-nediately influenced 

 b)- the blood. It retiiins a degiee of rednefs after frequent 

 rLne»\als of the macerating water ; and the pulp produced 

 by leaving it in v.ater for fome months, with frequent 

 changes, flill has a red tint, alth.ough lefs deep tiian in the 

 recent Hate. Does tlje ilate of the fecretion influence the 

 quantity of blood contained in gir.ndular organs ? Is there 

 more blood fent to the kidney, when the urinary fluid is fc- 

 parated abundantly, than w hen it pafles off flouly ? or is 

 there lefs returned by the veins in the former cafe ? 



Nerves. — Glands receive two kinds of nerves, i. The 

 kcr)-mal and falivary glands, the tonfils, &c. are fupphed 

 almoil exclufively from the cerebral nerves. 2. Ti;c teCi- 

 cles, proftate, and liver, derive nearly an equal portion from 

 the brain and the ganglia. 3. The kidney and moil of ll:i; 

 mucous glinds, S:c. are almofl entirely fupphed fr^m liie 

 ganglia. Thefo remarks apply to thofe nerves only, which 

 are unconnecled with the arteries ; for each .irtcrial trunk 

 penetrating a gland, is furrounded by a nervous network be- 

 longing to the fyilem of tlie ganglm, and verj- manifell in 

 the hu-ger organs, as the liver and kidney, where' the plexufcs 

 come from the femilunar ganglion, in the falivary glands, 

 where it is derived from the lupcrior cervical, in the teilie 

 from the lumbar, &c. 



The nerves are fmall compared to the fi/.e of the glands.. 

 We mull not decide on this fubjeft from thofe which enter 

 t'ce parotid and fubmaxillary ; for the nerves merely travcrfe 

 thofe organs, leaving a few branches behind them. But 

 the liver obvioufly polfeffes as fmall a fupply as any organ in 

 the economy, which receives nerves at all. Nerves enter 

 the glands, like the vx-ffels ; that is, tliey come in on all 

 fides where there is no furroundin^ membrane ; and enter at 

 the notch in other cafe.';. They divide and fubdivide, as 

 foon as they ivacli the gland, and are quickly loll. There 

 are never an;- ganglia in the interior of thefe orcjins. 



We knov. but little of the cshaiing and abfurbintr vefK-Ia 

 in the lubflante of gland.*, where they are merely iubfer\i- 

 ent to the purpofes of nutrition. 



Propcrlles of the GLmdular Ttjfne. 



I. Properi'it!. defied, from, tki'ur Or^anizu/icM—'Thi.-k in. 



yety 



