ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 235 



bum en, Corpuscles, and Saline matter. In the circulating blood, they are 

 thus combined : 



Fibrin, ) 



Albumen, > In solution, forming Liquor Sanguinis. 



Salts, j 



Corpuscles, suspended in Liquor Sanguinis. 



But in coagulated blood, they are combined as follows : 



Fibrin, "l Forming Crassamentum, or Clot, which, however, al- 

 Corpusc;les, j ways contains more or less serum in its meshes. 



Albumen, \ Rema j n j ng j n solution, forming Serum. 



Oil l LI? j 



The change from the one condition to the other is due to the fibrillation of 

 the fibrin; which usually takes place so speedily as to involve the Corpus- 

 cles floating in the "liquor sauguiuis," before they have time to subside ; 

 although, under various conditions hereafter to be described, it may occur 

 in such a manner that the clot, or a portion of it, is left colorless. 



173. The Red Corpuscles of the Blood (commonly but erroneously termed 

 "globules") are minute, nearly transparent, yellowish bodies, of a flattened 

 or discoidal form, which, in Man, as in most of the Mammalia, have a dis- 

 tinctly-circular outline (Figs. 101, 102). In the disks of Human blood, 

 when this is examined in its natural condition, the sides are somewhat con- 

 cave; and there is a bright spot in the centre, which has been regarded by 

 many as indicating the existence of a nucleus; though it is really nothing 

 else than an effect of refraction, and may be exchanged for a dark one by 

 slightly altering the focus of the Microscope (Fig. 101). The Corpuscles of 

 Man and Mammalia seem to be homogeneous masses of germinal matter, 

 soft, elastic, transparent, and structureless, refracting light singly, and hav- 

 ing a specific gravity of about 1088. The appearances of a proper cell-wall 

 and nucleus which they present when subjected to the action of certain 

 reagents 1 are probably deceptive, and arise either from physical or chemical 

 changes occurring on their surface or in their substance. Mr. Wharton Jones, 

 from considerations connected with their 



development, regards them as free nu- FIG. 101. 



clei, though they certainly possess neither 

 the physical nor chemical characters of 

 nuclei, but are very energetically acted 

 on by numberless reagents, which are 

 quite powerless on the nuclei of the red 

 corpuscles of the blood of Birds, Rep- 

 tiles or Fishes. Mr. Gulliver considers 

 them to be peculiar bodies without any 

 known homologues in the blood of these 

 pyrenjematous vertebrates. The form Red Corpuscles of Human" Blood : repre- 



Ot the Ked Corpuscles IS very much al- 8en ted at a, as they are seen when rather be- 

 tered by Various reagents. Thus if they y0 nd the focus of the microscope ; and at 6, as 



be treated with water, they first become they appear when within the focus, 

 flat, and then double-convex, so that the 



central spot disappears; and by a continuance of the same process, they 

 at last become globular, and so attenuated that a diffusion of their substance 



1 Strong arguments have recently been adduced by Dr. J. G. Richardson of Phila- 

 delphia (On the Cellular Structure of the Red Blood-corpuscle, Pamphlet, 1870), to 

 show that the red corpuscles of the Menobranchtts or Proteus (Batrac/iia), are truly 

 cellular. On division the contents escaped, and the cell-wall collapsed, and crystals 

 were frequently found in the interior, over which the cell-wall appeared to be stretched 

 like a tent over a tent-pole. 



