GLAND. 



•vtry nightly marked in this fyflcm, probaWy from its tex- 

 ture not partaking at all of the fibrous nature. In ordtr 

 that an organ fhould be fufceptible of elongation and fubfo- 

 qucnt contraftion, \vitho\it injury, its component particL-s 

 mull pofTefs a certain degree of cohefion ; and this attribute 

 particularly belongs to fibre. The glandular fylleui, too, is 

 fubject much lefs frequently to caufes of diltention and con- 

 traction, than thole which are made up of fibres. Where 

 the liver contains a large quantity of blood after death, in 

 confcquence of the venous fylleni being overloaded, its 

 bulk remains the fame : its fnbilance is comprefied by the 

 reflifls. The enlargement of the teflicle in gonorrhxa, 

 and of the parotid glands under certain circumftances, and 

 their fpecdy fubfequent reduction, prove that thefe organs 

 poffefs a certain degree of exteufibility and contrac'tility. 

 Are the hver, kidney, and other internal glands fubjeft to 

 fimilar acute enlargements ? The phenomena now alluded 

 to may take jilace in the cellular tilTue of the glands, and 

 therefore fnppofe a lefs degree of extenlibility in the 

 proper fubllance of the gland than might at firll have been 

 fiippofed. 



2. Vital propcii'i'S of the glanih, and phyfiology of fecreUon. — 

 The remainder of the invelligation is much more difficult 

 than what we have already gone through. The nature and 

 properties of the fluids, and the ftrudfure of the fecreting 

 organs, may be determined in a great meafure by the evi- 

 dence of our fenfcs : but when we endeavour to explain why 

 each particular fluid is feparated by its refpeclive organ, the 

 determination of the quellion implies a knovvledgc of the hid- 

 den firufture of the minute elements of our body, about 

 ■which we mull eiiher be' filent, or attempt conjectural ex- 

 planation, at fome rifle of expofmg ourfelves. The objeft 

 then is, to fliev.-, why, in the healthy fliate of the body, 

 faliva, and no other fluid, is conftantly feparated from the 

 blood in the parotid gland, bile in the liver, and urine in 

 the kidney ; and how it happens that the nature of the fecre- 

 tion never changjes, fo that urine (hould be formed in a 

 Salivary gland, fdiva in the kidney, bile in the mammary 

 ■glands, &c. The difficulty of the undertaking is increafed, 

 and the profpcft of arriving at a fatisfaclory- conclufion di- 

 trJnifiied, by this circumftance; that in the different claflcs 

 of fluids, each is not conllantly feparated in an organ of a 

 particular ftrutlure. If that were the cafe, it would only 

 be neceflary to determine the relation which the fliructure 

 of the gland bears to the nature of the fecreted fluid: 

 but the very contrary is the cafe. Fluids of each kind are 

 produced by eveiy variety of glandular apparatus: thus 

 ■water is formed by the arteries of the fliin, without any 

 •glandular arrangement, by conglomerate glands, in the in- 

 ftance of the falivary apparatus, and by a glandular vilcus 

 in the cafe of the kidney: mucus is fecreted by membranous 

 furfacss, and by different kinds of glands ; and laftly, oily 

 matters are poured from the arteries of -tlie cellular mem- 

 brane, from yarious febaccous glands, from the veflfels of 

 the flcin, from the liver, &c. Again, there are inllances in 

 the body, of organs, which we flioulJ, a prion, have pro- 

 nounced, without hefitation, to be glandular, and which yet 

 perform no fecretion. Such are the fpleen and thyroid 

 gland, to wiiich we may perhaps add the thymus and renal 

 capfules.' The fpleen is a remarkable inllance of the arrange- 

 ment of the minute arteries, called the penicillouf, which is 

 feen alfo in the liver, and confidered to have much connec- 

 tion with the peculiar funftions of the fecretory organs. In 

 this place,, too, we fliould mention tlie curious iat?ls, concern- 

 ing the formation of certain fluids, under particular circum- 

 ftances, by qjher glands than thofe \\'hich ordinai-ily produce 

 ri.iera. 



Haller has collcfled, in his groTX work, a vaft number of 

 fads of this d.Mcription; of which, if we fliould rejeft all 

 that may fcem infufficiently authenticated, th^re will remain 

 quite enough to prove the poiiit decifively. To the chaptir 

 in which thefe details are contained, he prefixes this fenteuci : 

 " fere quilibet humor per quodcunque colum feparari jx- 

 tell;' and the cafes wliich he cites, fulh" jullify his con- 

 cluding paragraph: " Quando ha;c exempla repetemus, con- 

 fl.abit, non eiufdcm unice clallis diverfos liumores fua inter 

 fe cola commutare, fed etiani per muci organa aquam, j),- 

 muci, aqiix et adipis cola lympham et fanguinem, per aqu, 

 muci et lympha; vias adipem, bilem far.guinenique fcceri. 

 atque adco omnino, nullum in animuto eorpore feparatoriu:: 

 organum efi'e, quod non omnium clailium humore> fuis cum 

 dotibus fecernere queat." Element. Pliyfiolog lib. 7. cap. i. 

 ^.9. When thefe circumllances are conlidered, it w." 

 very probably be lufpected that the caufes of the differcuL 

 in the fecreted fluids cannot be traced in the obvious flruL- 

 ture of the glands; but that the reafon why a peculiar fluid 

 and no other is feparated from each gland, in the healtin 

 ilate of the body, lies much deeper, and flows from foii. ■ 

 conditions of the organs, whicli are inacceffible toourfenfes. 

 We fliall endeavour to illuftrate the fubjecl as far as well 

 authenticated facls will afliil us, and Ihall mention the o] ■ 

 nions v.-hich have been moil prevalent on the fubjeft. It v. .., 

 be an ealler tafl< to fliew how unfatisfaftory nioft of thefe 

 are, than to fubfl;itute any thing more rational in their place. 

 We proceed to point out the vital properties of the 

 glands. 



No part of the fyflem pofleiTtS animal contractility, or 

 the power of voluntary motion. Different glands fcem to be 

 difierentl)- circumftauced with refpecl to the correfpondiug 

 fpecies of fenf.bility. The peculiar and opprcfilve fenfatiou 

 occafioned by coniprcfuon of the tefl:icle, is well known. 

 Conliderable and continued prefiure on the pai-ndd gland 

 has produced great fuffering ; but large nerves pafs through 

 this organ. The liver may be injured in a living animal, 

 without caufmg any of the ufual figns of pain; and Haller 

 makes the fame obfcrvation concerning the glandular fyllem 

 in general, but his flatemcnt is not perfectly explicit: " Uni- 

 verfse glandulas expericnti miiiime irritabiles videntur, neque 

 vehementer aut morbos fentiunt, aut illatas a profeftore in- 

 iurias." Elem. Phyfiol. t. 2. p. 377. Stones in the kidnitS 

 often caufe very fevere pain. From thefe apparently contra- 

 diftory circumilances, we can only conclude that animal fen- 

 iibility, which is varioufly modified, may exift. in organs, , 

 w here certain agents do not excite it at all, while others de- ^ 

 velope it very readily. In faft, various morbid alterations 

 render this property very manifefl; iu the glai-ds. The pain 

 of inflammation bears, indeed, a pecuhar charadlei' in the 

 glandular fyilem. ; it is generally obtufe and heavy. 



Properlies rf the organic life. — Senfible organic contrafli- 

 lity does not exift in the glandular fyflem : but the two 

 other organic powers are exhibited in their higheft flate of • 

 developement, and are almoft conftantly in operation, being ■ 

 concerned in fecretion, excretion, and nutrition. Organic 

 fenfibility enables the gland to diftinguifh iu the mafs of ' 

 blood thofe materials which are fcitable to its iecretion ; 

 and by its infeniible contrafiility, it has the po\yer of re- ' 

 jccfing whatever is heterogeneous. The blood contains the 

 materials of all the fecretions, of the nutrition of all organs, 

 and of all the exhalations. From this common refervoir each ' 

 gland draws what is requifite for its fecretion, each organ for 

 its nutrition, and every ferous furface for its exhHlation. 

 The pecuhar mode of organic fenfibility enables each living 

 part to diftinguilh what its functions require. Tlie whole 

 bufinefs of glandular ailion rcfts on the two powers juft 



mentioned ; 



