SECT. XXVI. i. 4. OF GLANDS. 227 



troublefome or noxious according to the importance of the func- 

 tions of the part affected : on the fkin and bronchise, where.^this 

 fecretion ought naturally to evaporate, it becomes fo vifcid as to 

 adhere to the membrane ; on the tongue it forms a pellicle, 

 which can with difficulty be fcraped off j produces the fcurf on 

 the heads of many people ; and the mucus, which is fpit up by 

 others in coughing. On the noftrils and fauces, when the fe- 

 rretion of thefe capillary glands is increafed,it is termed fimple 

 catarrh , when in the intedines, a mucous diarrhoea ; and in the 

 urethra, or vagina, it has the name of gonorrhoea, or fluor albus. 



4. When thefe capillary glands become inflamed, a dill more 

 vifcid or even cretaceous humour is produced upon the furfaccs 

 of die membranes, which is the caufe or the effect of rheumat- 

 ifm, gout, leprofy, and of hard tumours of the legs, which are 

 generally termed fcorbutic ; all which will be treated of here- 

 after. 



II. i. The whole furface of the body, with all its cavities and 

 contents, are covered with membrane. It lines every veflel, 

 forms every cell, and binds together all the mufcular and per- 

 haps the offcous fibres of the body ; and is itfelf therefore prob- 

 ably a fimpler fubftance than thofe fibres. And as the contain- 

 ing veflels of the body from the largeft to the lead are thus lined 

 and connected with membranes, it follows that thefe membranes 

 themfelves confid of. unorganized materials. 



For however fmall we may conceive the diameters of the 

 minuted veflels of the body, which efcape our eyes and glafles, 

 yet thefe veflels mud confid of coats or fides, which are made 

 up of an unorganized material, and which are probably produ- 

 ced from a gluten, which hardens after its production, like the 

 filk or web of caterpillars and fpiders. Of this material confid 

 the membranes, which line the (hells of eggs, and the (hell itfelf, 

 both which are unorganized, and are formed from mucus, which 

 hardens after it is formed, either by the abforption of its more 

 fluid part, or by its uniting with fome part of the atmofphere. 

 Such is alfo the production of the (hells of fnails, and of (hell- 

 fifh, and I fuppofe of the enamel of the teeth. 



2. But though the membranes, that compofe the fides of the 

 mod minute veflels, are in truth unorganized materials, yet the 

 larger membranes, which are perceptible to the eye, feem to be 

 compofed of an intertexture of the mouths of the abforbent fyf- 

 tem, and of the excretory ducts of the capillaries, with their con- 

 comitant arteries, veins and nerves : and from this condruction 

 it is evident, that thefe membranes mud poflcfs great irritability 

 to peculiar dimuli, though they are incapable of any motions, 

 that are vifible to the naked eye : and daily experience (hews us, 



that 



