270 



THE MICROSCOPE AND ITS REVELATIONS. 



FIG. 457. 



tains upwards of eighty millions of red corpuscles, and nearly a quarter 

 of a million of the colorless. 



666. The white or ' colorless ' corpuscles are more readily distin- 

 guished in the blood of Reptiles than in that of Man; being in the for- 

 mer case of much smaller size, as well as having a circular outline (Fig. 

 455, c); whilst in the latter their size and contour are so nearly the 

 same, that, as the red corpuscles themselves, when seen in a single layer, 

 have but a very pale hue, the deficiency of color does not sensibly mark 

 their difference of nature. The proportion of white to red corpuscles 

 being scarcely ever greater (in a healthy Man) than 1 to 250, and often 

 as low as from one-half to one-quarter of that ratio, there are seldom 



many of them to be seen in the field 

 at once; and these may be recog- 

 nized rather by their isolation than 

 their color, especially if the glass 

 cover be moved a little on the slide, 

 so as to cause the red corpuscles to 

 become aggregated into rows and 

 irregular masses. It is remarkable 

 that, notwithstanding the great 

 variations in the sizes of the red cor- 

 puscles indifferent species of Verte- 

 brated animals, the size of the white 

 is extremely constant throughout, 

 their diameter being seldom much 

 greater or less than l-3000th of an 

 inch in the warm-blooded classes, and 

 1 -2500th in Reptiles. Their ordin- 

 ary form is globular; but their aspect 

 is subject to considerable variations, 

 which seem to depend in great part 

 upon their phase of development. 

 Thus, in their early state, in which 

 they seem to be identical with the 

 corpuscles found floating in chyle 

 and lymph, they seem to be nearly 

 homogeneous particles of protoplas- 

 mic substance; but in their more 

 advanced condition, according to Dr. 

 Klein, their substance consists of a 

 comparative sizes of Red Biood-corpuscies: reticulation of very fine contractile 



1. Man ^2. Elephant; 3. Musk-Deer; 4. Drome- protoplasmic fibres, termed the *in- 



tra-cellular network;' in the meshes 

 of which a hyaline interstitial mate- 

 rial is included; and which is contin- 

 uous with a similar network that can be discerned in the substance of 

 the single or double nucleus, when this comes into view after the with- 

 drawal of these corpuscles from the body. In their living state, how- 

 ever, whilst circulating in the vessels, the white corpuscles, although 

 clearly distinguishable in the slow- moving stratum in contact with their 

 walls (the red corpuscles rushing rapidly through the centre of the tube), 

 do not usually show a distinct nucleus. This may be readily brought 

 into view by treating the corpuscles with water, which causes them to 

 swell up, become granular, and at last disintegrate, with the emission of 



