378 THE BLOOD, BY ALEXANDEK EOLLETT. 



gives the impression of a rotating disc, with a thinner central 

 portion, caused by a fossa-like indentation of the surfaces and 

 a thickened border. A solid model of the blood corpuscle may 

 be represented by the revolution of the curve c c c (fig. 67) 

 around the axis a b. 



This form of blood corpuscle has also been termed the saucer- 

 shaped. If the observer has convinced himself of the varying 

 form of one and the same blood corpuscle, he will understand 



Fig. 67. 



Fig. 67. Diagrammatic section of one half of a blood corpuscle. 



how in every blood drop there are presented to his eye numbers 

 of such corpuscles standing on their edge. Nevertheless, the 

 number of those which are lying on their flat surfaces is always 

 much greater. 



Lateral views of the blood corpuscles are also very commonly 

 obtained on account of the adherence of the corpuscles in groups 

 to one another by their broad surfaces. Chain-like forms 

 are thus produced, which, when viewed laterally, resemble 

 rouleaux of coin (fig. 66, c). The cause of this formation 

 of rouleaux, which is frequent in fresh blood, has not as yet 

 been discovered. It does not occur within the vessels. It is 

 seen not only in freshly drawn blood, but also in blood which 

 has been immediately whipped, and thus freed from fibrin, 

 though it may afterwards have remained for some time at 

 rest* 



Besides the corpuscles just described, which are by far the 

 most abundant, M. Schultze-f constantly found in the blood of 



.* See Rollett, Wiener Akadem. Berichte, Band L, Abth. ii. ; p. 183. 

 t Archivfur Mikroskop. Anatomic, Band i., p. 35. 



