ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 241 



176. Besides the red corpuscles of the blood there are others which 

 possess no color, and may have an altogether different function. These are 

 known as the White or Colorless corpuscles (b, Figs. 107, 108, 109). From 



FIG. 107. 



the researches of Dr. Klein on the blood of the Newt, there appears to be 

 three varieties of white corpuscles in this animal. 



1. The first is the common large colorless corpuscle. These, when examined 

 immediately after they have escaped from a bloodvessel, are round and 

 transparent, with a smooth surface. A few minute granules are scattered 

 through their substance (b, Fig. 105). If means be taken to maintain the 

 temperature of the microscope stage at about 100 Fahr., and to prevent 

 evaporation (as with a Strieker's warmed stage), 1 the surface may be ob- 

 served to become rough and prickly, one or two nuclei characterized by 

 their duller aspect, and some perfectly clear spaces or vacuolce, which are 

 believed to be clear spaces filled with fluid, make their appearance, and the 

 whole corpuscle undergoes slow but continuous and most remarkable changes 

 of form, closely resembling those of some of the lower organisms, and hence 

 termed amoeboid. These were first observed by Mr. Wharton Jones.' 2 Sev- 

 eral such alterations of form are represented in the adjoining cut. 



FIG. 108. 



a, Common white corpuscle, soon after its withdrawal from the vessels. 



6, The surface become prickly, c, Protrusion of larger processes, and apparition of nuclei. 



\ 



The tips of the processes are usually rather more transparent and hyaline 

 than the rest of the corpuscle, and a current seeming to carry some of the 

 fine granules and one or more of the nuclei sets into them and urges them 

 to further protrusion. Movements of locomotion as well as of mere change 

 of form are thus effected, and after straying over the field of the microscope 

 for some time the movements either become more and more feeble until they 

 cease altogether, or the corpuscle may gather itself together again and re- 

 sume its original nearly spherical form. 3 Both the nuclei and the vacuolse 



run into rouleaus if they arc rvholly submerged in a fluid that will wet them, because 

 then a cohesive equilibruim is established ; but they can again be made to do so by 

 wetting them with some liquid that is immiscible with the one in which they are 

 submerged. 



1 See Strieker's Human and Comp. Histology, New Syd. Soc. Translation, 1870. 



2 Phil. Trans., 1846, pp. 64, 71, 90, etc. 



3 According to Dr. Kichardson, Report on the Structure of the White Blood-Cor- 



