CHAP, i.] BLOOD. 39 



In carrying on these amoeboid movements the corpuscle may 

 transform itself from a spherical mass into a thin flat irregular 

 plate ; and when this occurs there may be seen at times in the midst 

 of the extended finely granular mass or cell body, a smaller body 

 of different aspect and refractive power, the nucleus. The normal 

 presence of a nucleus in the white corpuscle may also be shewn by 

 treating the corpuscle with dilute acetic acid which swells up and 

 renders more transparent the cell body but makes the nucleus more 

 refractive and more sharply defined, and so more conspicuous, or 

 by the use of staining reagents, the majority of which stain the 

 nucleus more readily and more deeply than the cell body. In what 

 perhaps may be considered a typical white corpuscle, the nucleus 

 is a spherical mass about 23 /u, in diameter, but it varies in size 

 in different corpuscles, and not unfrequently is irregular in form, at 

 least after the action of reagents. It occasionally appears as if 

 about to divide into fragments, and sometimes a corpuscle may 

 contain two or even more (then generally small) nuclei. Though 

 staining readily with staining reagents, the nucleus of an ordinary 

 white corpuscle does not shew the nuclear network which is so 

 characteristic, as we shall see, of the nuclei of many cells, and which 

 in these is the part of the nucleus which especially stains ; in the 

 closely allied lymph corpuscles, to which we shall have immediately 

 to refer, a nuclear network is present. 



The cell body of the white corpuscle may be taken as a good 

 example of what we have called undifferentiated protoplasm. Opti- 

 cally it consists of a uniformly transparent but somewhat refractive 

 material or basis, in which are imbedded minute particles, generally 

 spherical in form, and in which sometimes occur minute vacuoles 

 filled with fluid ; it is rarely if ever that any distinct network, like 

 that which is sometimes observed in other cells, can be seen in the 

 cell body of a white corpuscle whether stained or no. The im- 

 bedded particles are generally very small, and for the most part 

 distributed uniformly over the cell body giving it the finely granular 

 aspect spoken of above ; sometimes however the particles are rela- 

 tively large, making the corpuscle coarsely granular, the coarse 

 granules being frequently confined to one or another part of the 

 cell body. These particles or granules whether coarse or fine vary 

 in nature ; some of them, as shewn by their greater refractive power, 

 their staining with osmic acid, and their solution by solvents of 

 fat, are fatty in nature ; others may similarly be shewn by their 

 reactions to be proteid in nature. 



The material in which these granules are imbedded, and which 

 forms the greater part of the cell body, has no special optical 

 features ; so far as can be ascertained it appears under the micro- 

 scope to be homogeneous, no definite structure can be detected in 

 it. It must be borne in mind that the whole corpuscle consists 

 largely of water, the total solid matter amounting to not much 

 more than 10 per cent. The transparent material of the cell body 



