82 Compofition of the Blood. [Book IX." 



or lefs in quantity, according to the date of the blood; 

 the red mafs, in the mean time, contracts greatly, in its 

 dimenfions, expelling the watery liquor from its pores, 

 and confequently increafing in firmnefs and denfity. 

 This reparation happens in the body after death, and 

 produces thofe concretions in the heart, and large vef- 

 iels, thofe adheiive mafTes called polypufes, which 

 were formerly fuppofecV to have exifted during life, 

 and fome times to have been the immediate cccafion of 

 death. By agitation, blood continues fluid ; but a con- 

 fident fibrous matter adheres to the flick or inftrument 

 made ufe of to ftir it, which by repeated ablution in 

 water becomes white, and appears to be very fimilar 

 to the fibres of animals obtained by wafhing away the 

 other adhering matters. Received from- the vein in 

 warm water, blood depofits a quantity of tranfparent 

 filamentous matter, the red portion continuing diffolved 

 in the water. On evaporating the fluid, a red fub- 

 ftance in the form of powder, or eafily reducible to it, 

 is left. Blood infpiflated- to drynefs leaves a dark co- 

 loured mafs, amounting at a medium to about one 

 fourth part of its weight, of a bitter faline tafte, eafily 

 inflammable, and burning with a blueifh flame. The 

 exficcated blood is not foluble in acid or alkaline li- 

 quors, but gives fome tinge to water and to fpirits of 

 wine ; and is more powerfully acted on by dulcified 

 fpirit of nitre. Recent blood is coagulated by the 

 mineral acids, and by moft of the combinations of 

 them with earthy and metallic bodies. With vegetable 

 acids, and with foiutions of neutral falts, it mingles 

 equally without coagulation. Alkalies, both fixed and - 

 volatile, render it more fluid, and preferve it from 

 coagulating. Blood by ciiftiliation affords the fame 

 refults as other animal matters. Six pounds of human 

 blood diftiiled to drynefs, with a gentle heat, were re- 

 duced 



