SECT. XXIII. 3. SYSTEM. 209 



III. Another feries of glandular veflels is called the abforbent 

 fyitem ; thefe open their mouths into all the cavities, and upon 

 all thofe furfaces of the body, where the excretory apertures of 

 the other glands pour out their fluids. The mouths of the ab- 

 forbent fyftem drink up a part or the whole of thefe fluids, and 

 carry them forwards by their living power to their refpeclive 

 glands, which are called conglobate glands. There thefe fluids 

 undergo fome change, before they pafs on into the circulation ; 

 but if they are very acrid, the conglobate glands fwell, and fome 

 times fuppurate, as in inoculation of the fmall pox, in the plague 

 and in venereal abforptions ; at other times the fluid may per- 

 haps continue there, till it undergoes fome chemical change that 

 renders it lefs noxious ; or, what is more likely, till it is regurgi- 

 tated by the retrograde motion of the gland in fpontaneous fweats 

 or diarrhoeas, as difagreeing food is vomited from the ftomach. 

 The powers?of abforption are (hewn in No. I. of this Se&ion, 

 both thofe of the blood and of the chyle of animals, and of the 

 fap-juice of vegetables, to be much greater than has comonly 

 been conceived. To which may be added, that the moving 

 force of the chyle in the receptaculum chyli and thoracic duel: 

 mud be equal to the moving force of the blood in the fubclavian 

 vein, as otherwife the chyle could not enter into that vein, un- 

 lefs it be fuppofed to poflefs a fyftole and diaftole near the heart ; 

 which alfo affords an argument to (hew, that the progrefs of the 

 blood in the veins, and that of the chyle in the abforbent fyftem, 

 originates from a fimilar caufe, that of their abforptive powers. 

 ^ IV. As all the fluids, that pafs through thefe glands, and ca- 

 pillary veflels, undergo a chemical change, acquiring new com- 

 binations, the matter of heat is at the fame time given out ; this 

 is apparent, fmce whatever increafes infenfible perfpiration, in- 

 creafes the heat of the ikin ; and when the a&ion of thefe veflels 

 is much increafed but for a moment, as in bluftiing, a vivid heat 

 on the fkin is the immediate confequence. So when great bil- 

 ious fecretions, or thofe of any other gland, are produced, heat 

 is generated in the part in proportion to the quantity of the fe- 

 cretion. 



The heat produced on the fkin by blufhing may be thought 

 by fome too fudden to be pronounced a chemical effect, as the 

 fermentations or new combinations taking place in a fluid is in 

 general a flower procefs. Yet are there many chemical mixtures 

 in which heat is given out as inftantaneoufly ; as in foJutions of 

 metals in acids, or in mixtures of eflential oils and acids, as of 

 oil of cloves and acid of nitre. So the bruifed parts of an un- 

 ripe apple become almoft inftantaneoufly fweet ; and if the chem- 

 ico-animal procefs of digeftion be flopped for but a moment, as 



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