CORPUSCLES. 



19 



consist of a transparent colourless fluid, named the "lymph of the 

 blood," " liquor sanguinis," or " plasma," and minute solid particles or 

 corpuscles immersed in it. These corpuscles are of two kinds, the 

 coloured and the colourless : the former are by far the more abundant, 

 and have been long known as " the red particles," or " globules," of 

 the blood ; the " colourless," " white," or " pale corpuscles," on the 

 other hand, being fewer in number and less conspicuous, were later in 

 being generally recognised. When blood is drawn from the vessels, the 

 liquor sanguinis separates into two parts ; — into fibrin, which becomes 

 solid, and a pale yellowish liquid named serum. The fibrin in solidify- 

 ing involves the corpuscles and forms a red consistent mass, named tlie 

 clot or crassnmenfum of the blood, from which the serum gradually 

 separates. The relation between the above-mentioned constituents of 

 the blood in the liquid and the coagulated states may be represented by 

 the subjoined scheme : — 



/Corpuscles 



Liquid) 

 blood 1 



Liquor sanguinis 



f" Fibrin 



iSermn 



I Clot ^ 



hCoagrilated blood. 



E-ed Corpuscles. — These arc not spherical, as the name " globules," 

 by which they have been so gene- 

 rally designated, would seem to 

 imply, but flattened or disk- 

 shaped. Those of the human 

 blood (fig. 10 and fig. 12 a) have 

 a nearly circular outline, like a 

 piece of coin, and most of them 

 also present a shallow cup-like 

 depression or dimple on both sur- 

 fjices ; their usual figure is, there- 

 fore, that of biconcave disks. 

 Their magnitude differs somewhat 

 even in the same drop of blood, 

 and it has been variously assigned 

 by authors; but the prevalent 

 size may be stated at from 3-5'ooth 

 to 3V0 o^h of an inch in diame- 

 ter, and about one-fourth of that 

 in thickness. 



In mammiferous animals gene- 

 rall}-, the red corpuscles are shaped 

 as in man, except in the camel 

 tribe, in which they have an ellip- 

 tical outline. In birds, reptiles, 

 and most fishes, they are oval 

 disks with a central elevation on 

 both surfaces (fig. ]2, B, from 

 the frog), the height and ex- 

 tent of which, as well as the proportionate length and breadth of 



Blood as seen os the 

 Magnified aboit 1200 



DiAMETEKS. 



c, c, crenate red corpuscies ; p, a finely 

 granular, (j, a coarsely granular pale cor- 

 puscle. Both exhibit two or three vacuoles, 

 iu g, a nucleus also is visible. 



c 2 



