GLAND. 



Althor.j^h the two firll ckfTcs of glands have do refervoirs, 

 wemay infome degree regard the diiiercut ramifications of their 

 excretory tubes as fupplyiiigthcir place. Thcfe, indeed, as well 

 as in the glands, which have refervoirK, are l\abitiially full of 

 the fecreted fluid. Under whatever circiimllaiices the indi- 

 vidual may have died, we may always produce a confiderable 

 fiow of proilatic'fluidby prciFure on the gland. The papilla 

 of tho.kidney affords urine on the prefTure, feclions of the liver 

 flunv bile in the hepatic duclj, and the lactiferous vefiels are 

 full of milk, for which there is no otlicr rcfcrvoir. From 

 variations in the quantity of fluid, in the latter iuitance, the 

 greater or lefs fize of the brcail, during fuckliug, entirely de- 

 pend^. 



It appears in general that the paffiige of the fecreted fluids 

 ill the exct^tory duds is much flower than that of blood 

 in the veins, or of h mph in the abforbi;ig velfels. Urine 

 isconllautly fiov/ing through the ureters ; but a much great- 

 er proportion of blood would pafs through a vein of equal 

 diameter, while thi? bladder was fllling. I'he rate of motion 

 however varies under different circumllancrs, tiie faliva isex- 

 creted much more quickly during a meal, and urine paffes oft 

 much fafter after watery drinks. 



The fize of the excretory tubes varies very coniiderably. 

 I. Where fcveral are produced from one gland, they are 

 <«ery fmall, and fomctimes fearcely perceptible. TJiey ruu 

 in a llraight line, have no communications, and open immedi- 

 ately on quitting the gland. 2. Thole which are Angle are 

 larger ; bearing a proportion however to the fi/.e ot tlie gland, 

 excepting the hepatic duCt, which is inanife'.tly very fmall in 

 comparifon to the bulk of the liver. They pafs for lome 

 diflance after quitting the gland, and are produced by the 

 union of fuch tubes as belong to the Lift mentioned clals ; fo 

 that if their ifolated excretory tubes were to be united toge- 

 ther, a connnon Angle duel would be formed rcfembling 

 thofe of this fecond kind. Tlie pancreas is the only iuilanee 

 in which the common duel is ccnicjiJed in tlie iubftance of the 

 gland : and there is no other inilaiice, but the tcftls, where 

 it forms convolutions, lo as to be much longer tiian the courfe 

 tlirough which it palles. 



Whatever the arrangement of the excretory tube; maybe, 

 tiiey all pour their fluids either on the furface of the body, 

 as in the cerumiuous and febacoous ghuids, a d the breaft ; 

 oron the furface of mucous membrane;!, as the mucous, falivary, 

 pancreatic and hepatic excrotories. Tiie Ikiu and mucous 

 membranes, therefore, are the only parts mniiteiicd by glan- 

 dular fluids ; no duels terminate on ferouj or fynovial 

 furfaces. The excretorics of the pretended articr.b.r glands 

 would form an exception to this obfervation, if the glands 

 exifted. They never terminate in the cellular membrane ; 

 and if a conimunieatiou fliould take place, by accident, ab- 

 Ceefles are formed by the fupervening irritation, as in urinary 

 fiilulae ; or inflammation occurs iu the tr.ick of the extrava- 

 fated fluid, producing adhefions, whicii preferve the cellular 

 fyllem from more extenflve infiltration. Thus the alimentary 

 canal may be regarded as a kind of general excretory, fupcr- 

 added to thofe of the liver and pancreas, Sec, and expelli.ag 

 in one mafs all the fluids feparately poured through their 

 lefpeftive duils into its cavity. Inde;:d, all fecreted fluids 

 fse.Ti defig'ied to be thrown out of tiie body. Separated from 

 the mafs of blood, they are heterogeneous to it, and do not 

 enter the general circulation again in a ftate of health. 



All the excretory ducl^ have an internal mucous mem- 

 brane, which is a continuation of the cutaneous or mucous 

 furface, on which they terminate. In addition to this they 

 all polfefs an exterior fubftance, including the mucous canal, 

 and- differing confiderably in the parlieidar glandr. It is a 

 very thick and" peculiar fubllance in tlic vas deferens : an 



extremely denfe and clofe texture, refemUing that of tTi« 

 arteries and veins in the hepatic and falivnry tubes, S;c. 

 The latter is very dift'erent from ordinary cellular fubftance. 

 It does not appear that thefe tubes pofl'efs any membranu 

 befldcs the tifl^iie juil defcribed, and the mucous lining. 

 Every excretory tube has its bhjod-veffels. The ureters re- 

 ceive very manifell arterial branches from the renal and fper- 

 matic arteries : the hepatic ai'lcry fupplies the biliary tubes,, 

 and the Stenouiiui duel has its l-vanches from tlie tratifverfalis 

 faciei. Various nerves fro.n the ganglia accom.pany the 

 llood-vcffcls ; but they never form inch intricate plexufes as 

 round the arteries. 



The excretory duels poffefs chiefly the vital properties of 

 tiie mucous fyilein, whicli has the greaiell fliare in their for 

 mation. Their fyrapathies are, therefore, nearly of the fame 

 kind. 



2 . Of th: other Syjlems belong'w^^ lo tlie fonmiUon of the Glands. 



CeUular fuhjlance. — Glands differ much in the proportion of 

 this tiffue, wliich they contain, and may be divided accord- 

 ingly into two claffes. It is very abundant in the fahvary 

 organs, ii; tlie pancrea.s, and lacrymal gland, and in alt fuch 

 as have a conglomerate or granulated llruCture and white 

 appearance. Every gland of this clafs is divided into lobes 

 very diftincily iiolatcd by grooves filled with this texture, 

 and determining the tuberculated furface which charafterizes 

 the exterior ot the organ. Each lobule, and every glandu- 

 lar acinus, down to the imallcfl diviflon, i^ covered by cellular 

 fubftance : hence tlie whole conflfts of an affemblage of 

 fmall diftincT; bodies, connected together only by the circum- 

 ilance of their excretory tubes being united to form a com- 

 mon dufi, and which we could conceive to be perfetlly ca- 

 pable of exercifing their functions if adtually feparate. We 

 lee this in the parotid ; where fmall acccflory portions are 

 often fcen in the courfe of tiie duift, completely unconneftcd 

 with the principal gland. The fubmaxillary and fublingual 

 are foinetimes continuous, foinetimes ifolated. The cellular 

 tiflue in thefe glands often contains an abundance of fat. 

 This is particularly obfervabie in the breaft, the volume of" 

 whicii fomctimes depends on the fi7e of the gland, foine- 

 times on an accumulation of the adipous fubilance ; a dif- 

 ference, which is very eafily recognized by the touch. 

 Hence the quantity of milk is not always in proportion to 

 the apparent f:7.c of the mammre. In the proper conglome- 

 rate glands, however, the adipous fubftance feldom amounts 

 to a very confiderable quantity. The connecting threads. 

 are very ftiort and flender in t!;e teilis. In thofe glands, which 

 have a denfe parenchyma, as the hver, kidney, proilate, and 

 mucous organs, there is wry little cellular tiffue, and hence 

 the facility with which fome of them may be torn. Their. 

 fubftance never contains fat. The nniituous ftate of the. 

 liver in various difcafes does not invalidate this obfervation ; 

 for the fat then enters into its compofition as an cffential 

 element of the organ, and is fubftituted in place of the co-. 

 louring matter, which difappears ; it is not contained in 

 cells. Fat may be feea alfo in the interior of the kidney, 

 b'.it it is round the pelvis, and not in the proper parenchyma 

 oi tiie gland. The tonflls, proilate, and n-^ucous glands 

 never contain any. Serous fluids are never thrown out in 

 the fubftance of glands, which have a clofe parenchyma ;■ 

 they are not affefted in cafes of the mofl general and extca- 

 five anafarca. We cannot, however, doubt the exillence 

 of cellular tiffue in fuch glands : maceration demon ftrates it. 

 The fungous tumours, growing from thefe organs, contain 

 much of it ; and it is principally feen round the veffels, as- 

 in the capfula Gliffoni. This texture, indeeJ, is often dif^ 

 ea'-ed, while the proper fjibftanxe of the g!an,d remains. 



found : 



