Sect. XXIX i. 2. ABSORBENTS. < 239 



branes, which line the larger cavities of the body, as the thorax, 

 abdomen, fcrotum, pericardium, take up the mucus poured in- 

 to thofe cavities ; and are diftinguiihed by the names of their re- 

 fpective cavities. 



Whilft thofe, which arife from the internal fmfaces of the 

 urinary bladder, gall-bladder, falivary duels, or other receptacles 

 of fecreted fluids, v may take their names from thofe .fluids ; the 

 thinner parts of which it is their office to abforh : as urinary, 

 bilious, or falivary abforbents. 



2. Many of thefe abforbent veiTeis, both lacteals and lymphat- 

 ics, like fome of the veins, are replete with valves : which feem 

 defigned to aflift the progrefs of their fluids, or at lead to pre- 

 vent their regurgitation ; where they are fubjeeted to the inter- 

 mitted preflure of the mufcular, or arterial actions in their 

 neighbourhood. 



Thefe valves do not however appear to be necefTary to all the 

 abforbents, any more than to all the veins ; fmce they are not 

 found to exift in the abforbent fyftem of fifh ; according to the 

 difcoveries of the ingenious, and much lamented Mr. Hewfon, 

 Philof. Tranf. v. 50., Enquiries into the Lymph. Syft. p. 94. 



3. Thefe abforbent vefiels are alfo fur mined with glands, 

 which are called conglobate glands ; whefe ufe is not at prefent 

 fufficiently inveftigated ; but it is probable that they referable 

 the conglomerate glands both in ftructnre and in ufe, except that 

 their abforbent mouths are for the conveniency of fituation placed 

 at a greater diflance from the body of the gland. The con- 

 glomerate glands open their mouths immediately into the fan- 

 guiferous veffels, which bring the blood, from whence they ab- 

 forb their refpectiye fluids, quite up to -the gland - 7 but thefe 

 conglobate glands collect their adapted fluids from very diftant 

 membranes, or cyfts, by means of mouths furnifhed with long 

 necks for this purpofe j and which are called lacteals, or lym- 

 phatics. \ 



4. The fluids, thus collected from various parts of the body, 

 pafs by means of the thoracic du<St into the left fubclavian near 

 the jugular vein ; except indeed that thofe collected from the 

 right fide of the head an dneck, and from the right arm, are car- 

 ried into the right fubclavian vein : and fometimes even the 

 lymphatics from the right fide of the lungs are inferred into 

 the right fubclavian vein : whilft thofe of the left fide of the 

 head open but jufl: into the fummit of the thoracic duct. 



5. In the abforbent fyltem there are many anaftomofes of the 

 vefiels, which feem of great confequence to the prefervation of 

 health. Thefe anaftomofes are difcovered by direction to be 



very 



