GLAND. 



WooJ-vtffTels into tlio cxcretoiy dufts ; e. x.r- in tlic kidney 

 and liwr. As Ru> fch continued liis invelligations, lie found 

 that the bodies coniidered as jrUindular and hollow acini by 

 Malpighi, are mere blood-veflels. After accurately injcftiiig 

 t!ie liver and kidney, and macerating them in water, lie found 

 them refolvcd into i'mall cluflcrs of blood-vefTels, and proved 

 tiiis fo clearly by his preparations, that Bocrhaave, who had 

 been a warm' defender of Mblpiglii's doftrine, in defence of 

 which he wrote the Epillola dc Fabrica Glandularuni, ad F. 

 Ruyfch., was induced to renounce his opinion. The elegant 

 preparations of Ruyfch, and his appeal to the evidence of 

 didetlion, and other anatomical invelligations, brought nioft 

 anatoniifls over to his opinions, which, indeed, are generidly 

 received in t!ie prefcnt day. Haller gives the following fum- 

 mary of his opinions on this fubjcft. " Vifcera nempe fe- 

 crclioni deftinala, corumque imprimis acinos, glandulafquc 

 i-onglomcratas,meriscomponi vafculis,ce!lulolx tels ope con- 

 iunftis, CO cum vinculi robore ut confiftat acinus, aque fui 

 fiinilibus, laxioribus fills fibi annexis, totus et integer deduci 

 pofilt. In quoUbet prseterea acino, vaforumve glomerc, ex 

 cadem fententia, dudlus excretorius eft, plurefs'e duftuli, qui 

 de artcriola minima, tanquam rainulus minor et fanguiiii ini- 

 pervius, deccderc videtur, qu^ fabrica in rene certo repcritur, 

 m aliis quidem colis magna cum veri fpecic ex conjeftura ad- 

 mlttitur. Secretio adeo a vulgari fanguinis circuitu hafte- 

 Bus differt, quod in ifta quidem arteriola minima cylindrica, 

 in vcnam fibi aequalem, aut aiiipliorem continuetur, quo: fan- 

 guinem recipere apta fit, in humorum vero feparatione ductus 

 excretorius, rubro vafculo arteriofo minor, tanquam ramus 

 ex eo vafculo prodcat." Element. Phyfiolog. lib. 7. feft. 2. 

 J 14. The opinions and arguments of Ruylch may be 

 collcfted ill his anfwer to the letter of Boerhaave mentioned 

 above, in fome of his otiier epillles, and ia various of his 

 Thefauri. He has given fevcral iigures reprefenting the dlf- 

 tribiition of the minute vofTels in various organs, and proves 

 latisfaftorily that the bodies called acini by Malpighi are 

 merely minute velTels : he Ihews this concerning the fpleen 

 and brain, as well as in the glandular vifcera. On the fub- 

 jedl of this controverfy, we may obferve, that its importance 

 does by no means warrant the pains bellowed on it, and 

 the noife made by the combatants in condui^ting it. The 

 nature of the invcftigation, which is carried on entirely in 

 the minute elements of the body, and profecuted by means 

 cf magnifying glades, injeiTtioii, ir.accratioR, and corrofioii, 

 rendfers the conclufions, which we arrive at, in great meahire, 

 uncertain ; and tlie parts, of which the llructure is fought, 

 are fo exceedingly fmall, that neither opinions can be conii- 

 dered as clearly demonftrated, or fatisfaftorily refuted. The 

 mode, in uliich fecretlon is effefted, is enually obfcure, which- 

 ever of the two fuppolilioiis we may ;.d jpt : neither of them 

 folves the myftery. Ltt us admit w'.ih Ruyfch that the c::- 

 crctory tube is continuous with the fecreting artery ; fhall 

 v,e then underftand how fucli infinitely diverlified products, 

 all differing from each oth.er, and from the blood, are form- 

 ed from the common mafs of that fluid : Shall \ve be able 

 to point out the precife fpot in the continuous canal where 

 the blood ends, and tiie bile, urine, or milk begins ? and to 

 explain hozu the change is elTeAed ? If, on the contrary, we 

 fuppofe, with Malpiglii, that arteries, ramifying on fmall 

 membranous cavities, depolit the new prodatts in tliofc re- 

 ceptacles, our ignorance of the points in queftion is neither 

 more aqr lefs complete than in the other cafe. Too much 

 iabv'ur has been alr.^dy fpent on thefe idle difquifitions ; 

 modern anatomills have judged wifely in abandoning them, 

 and in preferring the ta!k of collefting facls concerning the 

 fcatural and difeafed ftrutture and fundlions of our frame. 

 With fiich inipreilioas, concerning the value of ihcfe pur- 



fults, wc were much diverted, at obferving thj cojijplacency 

 with which Ruyfch, the great authority 'ol the two lail cen- 

 turies on the ftrufture of glands, contemplates Ms own doc- 

 trines, and the fang-froid with which he reprefents his own 

 difcoveries, as the immediate produce of a direct divine re- 

 velation. " Placuit bonitati dlvini hitc rcvclare iveis la-. 

 boribus jam fenilibus. Invidi, et inimici mei hxc ridebant 

 in initio, fed Deus cui foli oy.nis gloria et honor, hscc ita' 

 benedixit poftea,'' &:c. Epillola Anatcm. adv. c. H. Boer- 

 haave. 



The organization of all the glands is by no means fo uni- 

 form as to admit of our referring the mode cf glandular fe- 

 cretlon to any one mechanifm. The mammary gland and 

 tellis do not refemble the texture of the organs already de- 

 fcribed. In both of thefe, which again are widely diflerent 

 in all their fenfible properties frtim e;\ch other j there ij a 

 vail congeries of fecretory tubes, inlinitclv convoluted, wiMf 

 vafcular ramifications copior.fly diilributed among them. In 

 the ultimate elementary parts of ttiefe glands, as far as our 

 fenfes can purfue them, we difcover nothing but minute, fer- 

 pentiiie, and very {lender tubes ; whicl-: are particularly ob\i- 

 ous in the tellis, without any trace of Malpighian or Ruy fch- 

 ian acini. In the breaft, indeed, the exlitence of thefe bo- 

 dies has been a matter of difpute, and arguments, not de- 

 ficient in plaufibillty, have been addused on both isdes of ' 

 this important quelHon, which, like many religious mylle- 

 I'ies, is involved in juil fo much cbfcurity, as Co make it a 

 very fuitable fubjcdt for polemical sx'-reife. 



The organs of the mucous fccretion, in gc;:eral, do not 

 fall within the defcriptiop already given of the glaiiduFar 

 ilrufture. Thefe fcem to exhibit, in many inilauces, a very 

 fimple form of gland, of which, however, the atllou is no 

 more underllood, than that of the more complicated kinds. 

 They confill of fmall receptacles, lined by the membrane 

 covering the part, receiving the fecretion, and pouring it out 

 by a fingle orifice in the centre. Very fimple glands of this 

 kind are feen at the root of the tongue : their figure is circular 

 or elliptical ; the cavity is lined by a thin membrane, fur- 

 rounded by a pulpy vafcular fubftance, which caufes a fuper- 

 fii'lal prominence, in the centre of which is a fimple aperture, 

 affording mucus on preffure after death. 



In other inllances, the membranous part is more confpi- 

 cuous, and the glandular fubftance lefs ccnfiderable, or in- 

 deed hardly perceptible, fo that the whole feems to be form- 

 ed merely of membrane. Thefe have been called cryptsE, 

 folliculi. Sec. Their figure is generally circular or oval, and 

 they are lined by continuations of the membrane, to wliich 

 they belong. They are placed in the cellular fubflarcc, and 

 may poffeis more or lefs of the pulpy vafcular matter. They 

 have fimple excretory tubes, coinmencliig from the hollow of 

 the membranous cavity, and terminating by open orifices en 

 the furface of the part to which they belong, as the mouth, 

 fauces, trachea, or inteftines. Preffure forces tlie fecreted 

 mucus from the open orifice. To this clafs may be referred 

 the glands of the lips, cheeks, epiglottis, pharynx, and ccfo- 

 phagus, tliofe of the foft palate, trachea, iloniach, and intef- 

 tines. 



Thefe more fimple kinds of crypts or follicles are united in 

 diflerent inllances, fo as to compofe larger mnfles. Some- 

 tim.es tliey are fimply contiguous, conncfled by loofe cellular 

 fubilance, and poffeis each its proper duft : e. g. at the back 

 of the tongue, and about the arytenoid cartilages. SucJi have 

 been called glandulje congregatoe. In other inllances, nu- 

 merous follicles, included in a common covering, depofit 

 their mucus in one or more large cavities, into w hich feveral 

 follicles open. The tonfils afford an e.sample, and liave bcca 

 called glandule conglutinats, 



Th« 



