COLOURLESS CORPUSCLES OF THE BLOOD. 



213 



Dilute alcohol may bring to view one or two nucleoli within the nucleus of 

 the amphibian red corpuscle (Ranvier, Stirling). In other respects also this struc- 

 ture resembles the nucleus of an ordinary cell, for it contains a network traversing 

 its interior (fig. 246), which is, however, very close, and produces under moderate 

 powers of the microscope a somewhat granular effect. It is 

 doubtful whether the nucleus of the adult corpuscle can undergo 

 division, although in the young state the division of the nucleus, 

 followed or accompanied by that of the corpuscle, has frequently 

 been observed. 



COLOURLESS CORPUSCLES OP THE BLOOD. 



Fig. 246. COLOURED 



CORPUSCLE OP SALA- 

 MANDER, SHOWING 

 INTRA-NUCLEAR NET- 

 WORK (Flemming). 



General characters. The white, pale, or colourless 

 corpuscles (leucocytes) are few in number as compared with the 

 red, and both on this account and because of their want of 

 colour, they are not at first easily recognised in a microscopic 

 preparation of blood. Their form is very various, but when the blood is first drawn 

 they are rounded or spheroidal. Measured in this condition they are found to be 

 about -jTsVo-kh f an inch ('01 mm. = 10 /*) in diameter. They are specifically 

 lighter than the red corpuscles. 



The white corpuscle may be taken as the type of a free animal cell. It is a 

 minute protoplasmic structure inclosing one or more nuclei. The protoplasm, being 

 to all appearance unaltered from its primitive condition, and unenclosed in a 

 definite cell-wall, is capable of exhibiting in a high degree the amoeboid movements 



Fig. 247. THREE AMOEBOID WHITE CORPUSCLES or THE NEWT, KILLED BY INSTANTANEOUS APPLICATION 



OF STEAM. (E. A. S.) 



a, a coarsely granular cell ; b, c, finely granular cells, with vacuolated protoplasm. 

 Fig. 248. AN AMCEBOID WHITE CORPUSCLE OP THE NEWT. Highly magnified. (E. A. S.) 



and other phenomena which depend upon the possession of contractility : these have 

 been already sufficiently described (pp. 174 to 179). The white blood-corpuscles are 

 apt to take into their interior minute solid particles that have been introduced into 

 the blood (fig. 204) ; this property has served in the hands of Cohnheim and others 

 as a means of detecting escaped white corpuscles in tissues which are wholly extra- 

 vascular, such as the cornea. Some of the colourless corpuscles have in their 

 protoplasm a number of comparatively coarse round granules (fig. 239, ff, fig. 247, a) 

 which are generally grouped together round the nucleus. These corpuscles are often 

 distinguished from the more common paler variety (fig. 239, p, fig. 247, i, c) as the 

 coarsely granular cells (eosinophile-cells of Ehrlich), but it is not known how they 

 are different in nature, origin, or destination. 



Corpuscles, coarsely granular and finely granular, are sometimes met with, which 

 are much smaller than the ordinary pale cells, consisting chiefly of a spheroidal 



