GLAND. 



«r animal fifbflanees, as well as othtr parts of the fcicncc, 

 has been enriched ; mijijht havx led us to expeft that the 

 dlaflification of the fluids would have been reformed accord- 

 ing to their conllitucnt principles, and brought into a con- 

 dition correfpondlng to the reft of the fcicnce. Fourcroy 

 has indeed given fuch a diftribution of the fubjcft in his 

 Elements of Chemillry ; but he docs not feeni to value the 

 arrangement very highly, as he has not continued it in his lafl 



treat work, the " Syfteme des Connoiffances Chin-.iques." 

 n proportion as the various animal products are analyfed 

 with more accuracy, they are found to poflefs fpecific clia- 

 rafters which diftlnguilh them from each other ; and tlivr.'- 

 fbre render it impoflible to refer them without impropriety 

 to anv general heads : accordingly in the moft recent and 

 able chemical works, they are enumerated and confidered 

 feparately. In this point of view, therefore, the exaftnefs 

 and perfection of modern analytis renders our attempts at a 

 general arrangement of tlie animal fluids unavailing ; and 

 it has only ferved hitherto to Ihew the defects of lucli me- 

 tliods 



Dumas, in his " Principes de Phyfiologie," adopts a dif- 

 ferent plan, which he calls a natural phyfiological one, and 

 to which he afcribes the advantage of connecting clolely the 

 knowledge of the fluids with that of their ufes. " This 

 method,'" he obferves, " which is the moil natural and ufeful 

 of all, is to refer the fluids to the various organic fyilems in 

 which their fecretion takes place, to make a clafs of humours 

 for each fyftem, to confider each of them as infeparable 

 from the fyllem to which it belongs, aad to conduC\ the 

 ftudy of both together. We (liall therefore have as many 

 different clafles or fpecies of fluids as there are organic 

 fyftems in the body. This iimple and natural method of 

 confidering the fubjeft appears to me to be preferable to 

 the more laboured arrangements founded on the efTential na- 

 ture and chemical compofition of the fluids, becaufc it is 

 BOt expofed to that uncertainty, which the imperfection, 

 the variations, and even the progrefs of our knowledge con- 

 cerning the nature and properties of animal matters, mufl 

 unavoidably occafion-. It is, moreover, the moft eafy and 

 inftruftive way to confider the fccreted fluids in their rela- 

 tions to the folid organs, with wTiofe funftions they are 

 concerned. The diftribution of the animal fluids with re- 

 gard to the fevcn organic fyftems of which the human body 

 is compofcd, will be better underllood by prefenting it in 

 a tabular view, where their relations, influences, and ufes, 

 «ill be immediately perceptible. 



Fluids of the nervous 

 or fenlitive fyftem. 



' Fluid of the ventricles of the brain, 

 Aqueous, vitreous, and cryftalline 



humours of the eye. 

 Tears, 



Meibomian fecretion, 

 Mucus of the nofc, 

 Cerumen, 



Fluid of the labyrinth of the ear, 

 SaLva. 



Of the mufcular 

 moving fyftem. 



f Fibrine, 

 < Serofity, 

 (.Fat. 



Of the vafcular or ca- 

 lorific fyftem. 



■ Mucus of the trachea and air-vef- 

 fels, 



Fluid of the pericardium, 



pleura;. 



Pulmonary exhalationj 

 ^ Blood. 



Of the vifceral fyftem 

 or organs of fupply. 



*^ Mucus of the mouth, pLaryns, and 

 ocfophagus, 



• ftomach, 



inteftines, 



kidney and bladder.) 



Of the lymphatic or 

 colIcCling fyftem. 



Of the fexual or repro- 

 duclive fyftem. 



Of the bony or fun- 

 porting fyftem. 



Oaftric fluid, 

 ^ Pancreatic fluid, 

 Intcftinal fluid, 

 Exhalation of the abdominal ca- 



vitv, 

 Bile,' 



I-iquor of the renal capfiiles, 

 Urine. 



f Rcfidue of all the fluids, and of 



nutrition, 

 <j I>ymph, 



I Fat of the cellular tifTue, 

 [Mucous fluid. 



Proftatic liquor. 



Mucus of the uretlim, 



; ■ vagiua, 



J Seminal fluid, 



j Exhalation of the tunica vaginalis. 



Contents of the ovarian vcficles, 

 { Liquor aninii, 

 1_ Meconium. 

 r Gelatine, 

 -j Medulla, 

 (.Svnovia. 



Of the fluids juft mentioned, fome are fecrcted in certain 

 org.ins belonging to their refpeCtive fyftems ; e. gr. tliofe 

 of the condomerate glands, of the glandular vifcera, &c. ; 

 others are formed over whole organic fyftems, without any 

 particular apparatus, as the exhalation 'in the cellular mcni- 

 brane, that of the circumfcribed cavities, &c. ; while others 

 are not the produce of fecretion, but move freclv throus^li 

 all parts of the fyftem in which they are concerned, as the 

 blood and contents of the abfoi-bing fyftem. AVith the 

 latter we have nothing to do at prcfent ; neither does the 

 organization, from which the fluids of the middle clafs are 

 produced, come under our confideration in this article, 

 but it \y\\\ be dcfcribed in Integuments, ME.MuitANE, and 

 Ckli.ular SuBSrANCE. 



The phyllologiLid theory of the fecretions muft be foimded 

 on a perfect knowledge of the nature of the animal fluids, 

 and of the ftructiu-e of tlie fccretory organs. The folution 

 of the interefting probleni.s ai-iUng out of this fubjtft, can 

 be expected only from tlie union of anatomy, cnli^httned 

 by juft views of phy Ileal fcienee, with chemilin,-, fupported 

 and direded by pliyliological obfcrvation. The fccretory 

 organs are of various kind:', and prcferve a couftant rela- 

 tion to the kind of fecretion, and the manner in which it 

 is efleCted. Thofe fluids, which feem to be derived from 

 the blood, with the leaft change, are not produced by a 

 complicated (nganic apparatus The exhalation, which 

 moiftens the furfaccs of the circumfcribed cavities, the 

 aqueous vapour of the lungs, and the cutaneous pcrfpira- 

 tion are formed by organic fyftems, compofcd chiefly of 

 vafcular raniiflcations, witliout poflefling any thing that is 

 at all an:jl .gous to glandul.ir ftrufture. The arrangement 

 of the fibrous tin"ue of n.nfcles, and of the bony fabric, ad- 

 mit of the fame remark ; if we fuppofe that thcfc organs 

 habitually lecrete fibri:ie or bony matter. But thefe arc 

 cafes, which come under the defcription of nutrition, and 

 ill tliis fcufe all parts of tlic body may be called fccretory or- 

 gans. 



