Chap, i.] BLOOD. 37 



what may be called the normal or resting spherical shape is 

 variously changed (we shall study these amoeboid movements 

 later on), and in other respects ; but at present we will deal with 

 those features only which they have in common, and speak of 

 the white corpuscle as if all were alike. 



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

 example of what we have called undifferentiated protoplasm. 

 It may perhaps be best considered as consisting of a uniformly 

 transparent but somewhat refractive material forming the ground 

 substance or basis, in which occur vacuoles of varying size but 

 all for the most part ininute, and in which are imbedded particles 

 also of varying size but also for the most part minute. Some 

 maintain that the ground substance exists in the form of a net- 

 work, the interstices of which are rilled up either with fluid or 

 with some material different in nature from that of which the 

 bars of the network are composed ; but without entering into the 

 discussion of a debated question, we may say that the evidence 

 for the natural existence of such a network is not convincing. 

 The imbedded particles are in some cases extremely small, and 

 for the most part distributed uniformly over the cell body, giving 

 it the finely granular or even hyaline aspect spoken of above ; in 

 other cases however the particles are relatively large and obvi- 

 ously discrete, making the corpuscle coarsely granular, the coarse 

 granules being sometimes confined to one or another part of the 

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

 in nature: they behave differently towards various staining and 

 other reagents. Some of them, as shewn by their greater refrac- 

 tive 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 ; and in certain cases 

 some of the granules are carbohydrate 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 

 must therefore be in a condition which we may call semifluid, or 

 semisolid, without being called upon to define what we exactly 

 mean by these terms. This approach to fluidity appears to be 

 connected with the great mobility of the cell body as shewn in its 

 amoeboid movements. 



§ 29. When we submit to chemical examination a sufficient 

 mass of white corpuscles separated out from the blood by special 

 means and obtained tolerably free from red corpuscles and plasma 

 (or apply to the white blood corpuscles the chemical results 

 obtained from the more easily procured lymph corpuscles, which 



