xxxii THE BLOOD. 



in venous than arterial blood ; and it is much greater in the blood of the 



splenic and hepatic veins than in venous blood generally. They are destitute 



of colour, finely granulated on the surface, and specifically lighter than the 



red corpuscles. The large corpuscles are less distinctly granular than the 



small. Water has little effect on them ; acetic acid brings speedily into 



view a nucleus, which frequently presents a reddish tint (Virchow and 



Kb'lliker), consisting sometimes of one, but more commonly of two, three, 



or four, large clear granules (fig. xvm. , 2 3 ). The 



Fig. XVIII. number of apparent nuclei is said by Mr. Wharton 



/rim Jones to depend upon the strength of the acetic acid 



^ employed ; if the acid be much diluted, only one is 



* * seen ; if strong acid be used, the nucleus breaks up 



V) (jo) into three or four nuclear-looking particles. Under 



the action of the acid the circumferential part of the 



Fig. XVIII PALE cor P usc l e becomes clear of granules and pellucid, and 



CORPUSCLES' OF Hu- swells up by imbibition with a regular and well- 

 MAN BLOOD ; MAGNI- defined outline, which has teen taken for the indi- 

 FIED ABOUT 500 DiA- cat i on O f a f ne envelope, but conclusive evidence 

 on this point is wanting. The clear substance is 

 1 natural aspect; 2 evei)tua i ly dissolved, the nucleus remaining, 

 and 3, acted on by weak m . * 



acetic acid, which brings The P ale corpuscles frequently undergo curious 

 into view the single or changes of shape, sending out processes into which 

 composite nucleus. the granules enter, and retracting them again ; in 



short, exhibiting phenomena which have been aptly 

 compared to the movements of an amoeba. 



Albuminous granules and molecules of a fatty nature occur in the blood 

 in varying numbers ; sometimes very scantily, or not at all, but the latter 

 sometimes in vast numbers so as to give the serum a turbid, milky 

 appearance. These are probably derived directly from the chyle (its 

 "molecular base"), and they are especially seen in the blood of herbivora, 

 in sucking animals, and in pregnant women. 



' Occasional elements. Besides the foregoing, the blood occasionally presents 

 the following constituents : (1) bodies like cells, enclosing blood-corpuscles, 

 noticed by Ecker and Kolliker in the blood of the spleen and hepatic 

 vessels, and elsewhere. (2) Pigmentous granule-cells. (3) Pale, fine-granular, 

 roundish aggregations, in the splenic blood. (4) Peculiar bodies, three or 

 four times larger than the pale corpuscles, but in other respects resembling 

 them. (5) Caudate, pale, or pigmentous cells. (6) Fibrinous coagula. 



Liquor Sanguinis, or Plasma. This is the pale clear fluid in which the 

 corpuscles are naturally immersed. Its great character is its strong ten- 

 dency to coagulate when the blood is withdrawn from the circulating current, 

 and on this account it is difficult to procure it free from the corpuscles. 

 Nevertheless, by filtering the slowly coagulable blood of the frog, as was 

 first practised by Miiller, the large corpuscles are retained by the filter, 

 while the liquor sanguinis comes through in perfectly clear and colourless 

 drops, which, while yet clinging to the funnel, or after they have fallen 

 into the recipient, separate into a pellucid glassy film of fibrin, and an 

 equally transparent diffluent serum. When human blood is drawn in in- 

 flammatory diseases, as well as in some other conditions of the system, the 

 red particles separate from the liquor sanguinis before coagulation, and 

 leave the upper part of the liquid clear. In this case, however, the plasma 

 is still mixed with the pale corpuscles, which, being light, accumulate at the 

 top. On coagulation taking place in these circumstances, the upper part of 



