GLAND. 



Tlie fecretion or mucus is often performed in a fpecics of 

 firi;cture, which docs not feem to polTeisany thing of a fjlan- 

 dular nature : in fmall membranous canals, which will admit 

 brillles for about half an incli in length, ending by blind ex- 

 tremities in the cellular fubllance, and terminating by oblique 

 apertures on the furfaccs of the mucous membranes to which 

 they belong. Neither acini nor round follicles can be dif- 

 covered opening into fuch canals, which are technically named 

 finufes or lacunje, and which, in the urethra, Have a p'fT- 

 feCl'y fmooth iurface. Some of thefe are fimple, as in tlic 

 fcpt'jra narium, tlie ur,;thra of both fexes, the entrance of 

 the varina, &c. ; others are ramified, as in fome inllances in 

 the male urethra ; in the recfc of the uterus, &c. 



The glands, which produce various matters of an unftuous 

 defcription, appear to be very fimple in tlieir ftrufture, but 

 they are moftly fo fma!l as to prevent us from entering into 

 much detail concerning their organl/ation. The ceruminous 

 glands of the ear are imall round bodies, difpcrfed in the inter- 

 Itices of the cellular fub'.linc:-, and each of which poffeffes a 

 duel, penetrating the integuments of the meatus auditorlus, 

 and ending on its furface by an open mouth. They 

 feem to coiifift of fimple membranous cavities. The organs, 

 which fecrete febaceous matter, in various parts of the inte- 

 guments, do not feem to diff 'r efrentially from thefc. They 

 are round membranous cavities, with their fides covered by 

 numerous vafcular rsir.ifications, opening on the furface of the 

 part to v.'hich they belong, with or without the intervention 

 of a fimpL* djCi. Where they produce a fluid which con- 

 cretes, it may be exprefitd from them in the form of a fiender 

 white thread. The areola of the nipple, the nymphas, and 

 the other external female organs, the corona glandis of the 

 ma'.?, the nofe, and particularly the cavity between its ala 

 and the cheek, Jie upper lij), and the hollows of the exter- 

 nal ear, poilefs numerous glands of this defcription. The 

 Meibomian apparatus of the eye-lids is only a rather compli- 

 caied fpecimen ot^the fame ilrufture ; feveral fimple glands 

 open into a common duct. 



Tlie proftate pofiefles a peculiar ftrufture, which can 

 hardly be referred with propriety to any of the fpecies iirll 

 enumerated. 



■ The glandular tiffue, cut in flices and dried in the air, 

 liifes its original colour, acquires a dark hue, and even a 

 blackiih tint in the liver and kidney, on account of the 

 large quantity of blood which they contain : if the latter 

 vifcera are repeatedly waflied, before they arc dried, they 

 continue to appear greyifii. The glandular tiffue, in its dried 

 llate, is remarkably hard and brittle. If kept moift and cx- 

 pofed to the air, it becomes putrid very rapidly, and cxhaU-s 

 ill that flate a highly difagrecablc odour. A greater quantity 

 of amraoniacal matter is formed. The liver is particularly 

 diilinguiflied for the infupportable ilench caufed by its pu- 

 ti-cfaction. The kidney goes lefs rapidly into that ftate. 

 When boiled, tlie glandular fubllance produces at firll a grey- 

 i{h fubllance, which troubles the water uniformly at firll, 

 and is then collecled in an abundant froth at the top. 'i'his 

 prodacl is mofl abundant in the prefent, the luufcidar, mu- 

 cou.s and cellular fyftems ; and leall in tlie cartilaginous, 

 tendinous, fibrous, &c. The froth produced by its boiling 

 is of a deeper colour, and feems to contain more numerous 

 principles, than that derived from the wliite organs. 



Like all other fyllems, the glands grow hard at the firll 

 periods of ebullition, but inilcad of becoming Ibfter after- 

 wards, as the others do, the continued boilirig makes them 

 more and more hard ; fo that after fi\e or fix hours of ebulli- 

 tion, their firmnefs is triple or quadruple that which be- 

 longs to them naturally. Tiiis phenomenon is ir.oil remarkable 

 in the liver. Wlien removed immediately after the firll .corru- 



gating effeA^ of the hot v.-ater, they do not difplay theel-!*- 

 ticity whicii the other fyllems pofTefs at this time. A tendon 

 or mulcle in fuch a (late, if drawn, rellorcs itfelf immedi- 

 ately, while a (lice of liver break?. The abfence of 

 fibrous matter perhaps is the real caufe of this difference. 

 The ludden aftlon of naked fire crifp. and corrugates tRe 

 furface, as in all the other folids, and produces a hard exte- 

 rior crull. 



Maceration in water produces different efTecls on the diffir- 

 ent g'andi. The liver refills longer than the kidney, which, 

 after two months, is reduced to a reddifli pulp fwimminy in 

 the water, while the former Hill preferved its form and dcn- 

 fity, and had undergone no other change than <rom a red to 

 a blucilh brown colour. The falivary glands exhibit much of 

 the whitifli, unftuous and firm matter, »vhich is feen in all 

 cellular organs after long maceration. This does not arife 

 from an alteration of the glandular tilTue, but f:o;n the fat 

 contained in the abundant cellular texture of thefe parts. 



Acids adl on ihe glandular tiflue nearly as upon the others. 

 They reduce it ir.to a pulp, varying in its colour, and in 'he 

 promptitude of its foneation accord!:. g to the nature of the 

 acid employed. The fidphuric acls moll quickly, and gives 

 a black pulp, while the nitric renders it yellow. They acl 

 much more (lowly on the glands after boiling than before. 



Generally fpeaking, the glands are much lefs digcllihle than 

 mod other animal iubllances; particularly in their boiled (late : 

 for coClion produces in them quite oppolite effefts to thofe 

 which it exerts on the cartilages, tendons, and all the fibroui 

 organs, which are rendered lefs denfe, more gelatinous and 

 vifcous, and more fpeedily diffolvable by the gadric juice. 

 Tlie gl.mds would probably be digefted more cafily, if eaten 

 raw. Liver is lels digeftible in proportion as it is longer 

 boiled. Bichat made a comparative trial of it in a raw and 

 dreded (late : the former was reduced into a pulp in the do. 

 mach of a dog, when the latter had undergone a very flight 

 alteration. 



Excretory lubes. — All glands have tubes for the purpofe of 

 conveying away the fiuids, which they feparate from the 

 blood ; and as thefe canals are only found in glands, their 

 confid-ration belongs to that of the peculiar tilfue of the 

 gland The excretory duels have an uniform origin in all 

 glands. They arife like veins, by an infinite number of ca- 

 pillary tvibes, which appear to begin at the acini, where 

 thefe cxill. Each acinus is laid to have an arterial and venous, 

 as well as an excretory tube. Arifing in this way from all 

 the interior of the gland, they foon unite together, iHto more 

 confiderable tubes, v.-liich generally rus in llraight lines 

 tlirough the glandular tiffue, unite to each other, and form 

 at lall one or more large tubes. 



Glands are to be dittinguilhed into three kinds, with re- 

 fpecl to their excretory tubes. I. Some tranfmit their fecrr- 

 tion through feveral dufts, each formed by fmaller ones, anJ 

 opening near togcUier, but diilindlly.and without any < ommu- 

 nication. In fome cafes thete leparate apertures arc found 

 on a more or lefs dillincl prominence, as in the brv^all, prol- 

 tafe, and fublingual glands. Sometimes the orifices are found 

 in a depreffion, in a kind of cul-de-fac, as in the tonfils, the 

 foramen cxcum of the tongue. &c. 2. Other and more nu- 

 merous (rlands pour out tlieir fluids by a fingle tube, and there 

 is nothing remarkable in general in the orifice. 3. Some 

 o-lands depofit the prodt:ce of their fecretion in a rcfervoir, 

 where it is retained, in order to be expelled at particular 

 times. Such are the kidnies, liver, and tetlicles. Inthi-cafe 

 there aiiiil be two excretory tubes ; one to convey the fecre- 

 tion from the gland to the refcrvoir, and the other to tranf- 

 mit it to its final deftination.. Tlicfe refervoirs are tJicrrfore 

 evidentlv coniiccled vrith the excretory ti-bej. 



P p J Althougfc 



