G L A N D. 



mentioned; and as this action is nearly conftant, t)icy arc 

 aJmoft incefRintly exerted. 



It is evident that all glandular affettions mufl imply a 

 diforder in the powers above-nu-ntioned ; fince difeafcs of an 

 organ are particularly determined by alterations of the lead- 

 ing properties ; of thofe which conftitute the peculiar life of 

 the part. Obfervation proves this: we fee tliefe properties, 

 when augmented or diminifhed, producing on one fide increafed 

 fecretion, as in diabetes, mercurial falivation, cholera mor- 

 bus, &c. ; on the other, a decreafe or even fufpenfion of the 

 funclion, as in acute diftafcs, where all the fecretory tubes 

 feem, as it were, clofed for a time; for inllance, in fuppref- 

 fion of urine, dry ftate of the mouth, &c. On other occa- 

 iions the nature of the glandular fenfibilitv is changed, and 

 it harmonizes with fufeflances which are not admitted in the 

 healthy ftate : hence the innumerable varieties of the lecretcd 

 fluids under circumftaiices of difeafe. The cyftic bile in the 

 dead body prefents numerous varieties of tafte, fmell, colour, 

 and confiilence. The numerous alterations of the urine are 

 V'-ell known. The faliva is lefs liable to change ; but how 

 dirFerent is it in many difcafes from its ordinary condition. 

 Nothing can lefs refemble urine or bile than the fluids often 

 difcharged from the bladder and liver: whence then arife 

 theie dilferences? from the variations in the organic fenfibilitv 

 bringing the part into a relation with thofe fubftances, wliich 

 were foreign to it in the natural ftate. Thus the fame gland, 

 without any change in its llrudure, but merely by altered 

 modifications of its vital powers, may be. the fource of in- 

 finitely varying fluids. jNIiglit not this be carrii-d fo far as 

 to allow that the kidnev, by alTuniing a fenfibility analogous 

 to that of the liver, may aflually form bile ? why fliould it 

 not fecrete bile, fince it does feparate other fluids fo widely 

 different from the urine? 



In the healthy rtate, the mode of fenfibility in each gland 

 is nearly uniform; and the fccreted fluid is confequently 

 nearly the fame in its compofition and properties. But the 

 mode is changed by numerous caufes in diieale. An hylle- 

 rical attack, cc meson; fuddenly the kidney refufes to tranf- 

 Diit the principles whic-li colour t!ie urine, and that fluid is 

 coalequently diichargcd limpid ; as the pai-oxyfm fubiides, 

 the natural type of the fenfibility is reftored, and the urine 

 has its accuftomed chaiadlcrs. In an epileptic fit, a thick 

 frothy faliva is difchai\eji?d from the mouth in abundance ; 

 as the attack goes ou', the falivary fecretion returns to its 

 natural fl;ate. 



/ Tiie various changes in the organic fenfibility, and the 

 ^fenfible contractility of the glands, do not afFe<£t the 

 fiuKftion of fecretion only; but when they laft for fome 

 time, tiicy influence nutrition alfo. From the difturbances 

 of this procefs arife thofe various organic affe^ions, of 

 which the glandular fyilera offers the moll abundant harveil 

 to the pathological auatomift. We cannot avoid noticing, 

 ID difiedting rooms, the num.erous difeafes obferved in lliis 

 part of the body compared to otliers. The glands, the 

 Ikan^ the mueous, ferous, aud cellular fyfl.em, hold the firft 

 Ank in this refpeft; and in all thefe the tvio properties 

 above-mentioned exiil ia the higlicll degree, and are called 

 into adlion, not merely by nutrition, but alfo by various 

 other funitions, whicli refide in the capillary 1) ilera, as e.^- 

 Lalation, abforpticn, and fecretion. 



The preceding account of the phyfiology of fecretion, 



chiefly deriviid from the " Anatomie Generale' of Bichat, 



fee ms to amount to little more, than :his, that each fecretory 



I ' - ;n produces its peculiar product, in confequence oi its 



.Ting pecvdiar vitid properties, which, when vanoufly 



'.:fied under particular circumtlanccs, enable the orgiui to 



_ rate very di&rect fluids from the blood. And tiiit we 



believe to be a pretty correct ftatement of the extrnt of oar 

 knowledge of this fubjeft. But anatomifts and pliyfiologifts, 

 not fatisficd with this fimple fact, have endeavoured to de- 

 velope the exaft mechanifm of the ]-rcc.fs, and it will be 

 ncccffary for us to recount fome of their opinions. In all 

 obfervations on this fubject, it v.ill be well tor us to lemcm-. 

 ber that fecretion is not confined to the animal kirgdom, 

 but prevails alfo in the vcgctcble world. We frcquentiv 

 obfcrve the lap giving origin to peculiar and different juices 

 in the various parts of the fame plant, and reafoners from, 

 analogy have gone fo frr as to admit the exilleiice of a glan-- 

 dular fyftem in vegetables. We fli-!l be induced, bv this 

 circumftance, not to lay too much (Irefs on the peculiar 

 i'rufture of the L-oretory organs in the more complicated 

 animals, as effential to the bilfinefs of fecreJon. Many of 

 the facts already noticed, concerning tiic feparr.t on of per- 

 fectly fimilar, or at lead very clofely refembliiig fluids, by 

 means of totally diiTimilar organs, w;H tend to the f.ime de-- 

 duttion And this mode of argument may be dill further 

 fupported by v;u-iuu3 examples in comparative anatomy; 

 where we find fluids of the fame clafs fecreted in animals of 

 different orders, in organs of very different cxteriiil appears 

 ance. The kidnies of birds are really conglomerate in their 

 llrufture; and a fluid, cxaftly refembling tiie pancreatic of 

 warm-blooded animals is formed by the tubulir pvloric ap- 

 pendages, varioufly conftituted in different genera of hlhes. 

 Of the different explanations, by which phyfiologiils have 

 fucceffively attempted to elucidate the funclion of fecretion, 

 molt are completely hypothetical and improbable. In moll in- 

 ftances it has been affimied that the various animal fluids are 

 all contained in the blood ; and fecretion, according to this 

 opinion, confiils fimply in their feparation by means of the 

 glands. Differences in the diameter, length, and folds o£ 

 the veffels, and fi-.ppofed varieties in the holes wiih which 

 the glandulai- fyllem is fuppofed to be perforated, have been 

 employed as the means of rendering the mechanifm of fecre- 

 tion intelligible ; he:ice the exprefiions of fiivcs, filter?, and 

 ftrainers, fo frequently employed in phyfiology. We are 

 difpenfed from the neceifity of cwmmentiiig on the glaring 

 abfurdity of comparing a gland to a fiete or filter, and of 

 deciding which of thele mechanical explanations is the mod 

 exquifitely foolifli, bv the completely gratuitous nature of the 

 fundamental propofition. The modern analyles of tlie blood 

 have no longer even the fi.adow of an excufe for regarding 

 this fluid as a mixture of all the animal hquors, and for fup- 

 pofing that it is formed of faliva, bile, gallric jiiitr, 

 urine, &c. fince we can difcover no trace of luch fluids in 

 it. Although all the elements neceffary to form thefe pro- 

 ducts, as well indeed as thofe of the folids, are in fact found 

 in the blood, they exift in it in a different ftate cf combina- 

 tion. The blood is nianifeflly an homogeneous liquor, 

 capable of forming all aninial matters from the moit tranf— 

 parent and pure water, as the cutaneous exhalation, to the firm 

 fabric of the bony fyllem ; from it are formed faliva, bile, 

 and urine ; and it ferve;. alfo for the nutrition of mufclis, 

 membranes, and nerves ; but none of thefe modilicntions of 

 animal iubllance are contained ia it perfectly formed. 



Their jirccipitation, fays Vourcroy, in tlie tiffues t<r- 

 which they belong, cannot be rega:ded as a fimple fepars- 

 tioii ; fidce it is accompanied by a modificalit-n in the proper- 

 ties, nature, and compoliticn of each. Thus t.he cerebral 

 pulp is not exaCtlv the fan.e albu.ninous matter as tliat in 

 the ferum of the bleed ; the gelatine is not ifijlattd in tliis 

 fluid, as in the membranous tiffue ; the mulcular fibrinc is 

 not completely id'.a;!cai in its character with that wi.ich cxifts 

 in the blood ; and the pholpl.ate «f lime is not aCoiiated in 

 the latter to the srelatiuous fubilance, which unites iu part:- 



cl«* 



