S96 THE BLOOD, BY ALEXANDER ROLLETT. 



water, when the corpuscles have acquired a spherical form, comes 

 more prominently into view, and remains so as long as these 

 still retain their colour, but subsequently becomes less con- 

 spicuous, and after the long operation of large excess of water 

 appears smooth, distended, and less highly refractile. 



Especial attention should be directed to a structure which can 

 be easily demonstrated in the elliptical corpuscles after the 

 cautious addition of water (fig. 73). The stiU ellipsoidal cor- 

 puscle is bounded by a perfectly smooth contour line, but the 

 place of the nucleus sometimes cappears to be occupied by a 



Fig. 73. 



coloured spheroid; whilst in other cases numerous processes 

 radiate from this ball towards the contour line, becoming 

 pointed peripherically. The parts lying between the latter 

 and the coloured portion are homogeneous and colourless. 



According to Kneuttinger,* these forms are obtained when 

 fresh frog's blood, from which the fibrin has not been removed 

 is mingled with three or four times its volume of water, and 

 an examination shortly afterwards made of the gelatinous mass. 



If larger quantities of water be added and thoroughly com- 

 mingled with the blood, some of the corpuscles remain much 

 longer in the condition of coloured spheroids than others ; and 

 the inference has been not unreasonably drawn, that an essen- 

 tial difference exists amongst such corpuscles. 



b. Salts act very differently, according to their chemical 

 nature and their degree of concentration. Many metallic salts 

 occasion precipitates in the blood corpuscles similar to the acids 



* Zur Histologie des Blutes. Wiirzburg, 1865, p. 21. 



