143 



CHAP. X. 



THE BLOOD. 



THE fluid into which the chyle and lymph are converted, is blood. 

 *' The blood is" a slightly alcaline fluid, of a red colour ; " of a 

 peculiar odour ; its taste is rather saline and nauseous ; its tem- 

 perature about 96 of Fahrenheit ; it is glutinous to the touch ; 

 its specific gravity, though different in different individuals, may 

 be generally estimated as 1050, water being 1000." Blood from 

 arteries is florid, and from veins of a dark red which the trans- 

 lucence of the venous coats renders bluish when seen through 

 them : and the specific gravity of the former is said by Dr. John 

 Davy to be 1049, and of the latter 1051. a " When fresh drawn 

 and received into a vessel, it exhibits the following appear- 

 ances b : 



" At first, especially while still warm, it emits a vapour 

 which," "if collected in a bell glass, forms drops resembling dew, 

 of a watery nature, but affording a nidorous smell, which is most 

 remarkable in the blood of carnivorous animals, is peculiar, and 

 truly animal. Much of this watery liquor still remains united 

 with the other parts of the blood, hereafter to be mentioned. 



" In the mean time the blood " " begins to separate into two 

 portions. A coagulum is first formed, from the surface of which 

 exudes, as it were, a fluid of a yellowish slightly red colour, 

 denominated serum : the more abundantly this exudes, the greater 

 is the contraction of the glutinous coagulum, which has received 

 the appellations of crassamentum ; and, from some resemblance 

 to the liver in colour and texture, of hepar sanguineum ; of pla- 

 centa ; and, from the circumstance of its being surrounded by 

 the serum, of insula." 



Some have thought that heat is evolved during its coagula- 



a Journal of Science and Arts, No. iv. 



b " J. Martin Butt, De spontanea sanguinis separatione. Edin. 1760. 8vo. 

 reprinted in Sandiford's Thesaurus, vol. ii. J. H. L. Bader, JExperimenta circa 

 sanguinem. Argent. 1788. Svo." 



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