242 OP THE BLOOD: 



undergo constant change alike in their form and relative position. The 

 size of these white corpuscles is remarkably uniform in the different classes 

 of the animal kingdom, being seldom much greater or less than -g-oVgth 

 of an inch in the warm-blooded Vertebrata, and ^-joo^ 1 f an ^ nca ^ n 

 Reptiles. 



2. A second kind of colorless Corpuscle in the blood of the Newt has 

 been described by Dr. Klein, 1 under the term Granular corpuscles. These 

 are larger but less numerous than the others, and are characterized by the 

 large dark granules they contain. 



FIG. 109. 



A granular corpuscle of the Newt, showing changes assumed in fifteen minutes. 



Their movements are much more active than the former variety, but other- 

 wise present a close general resemblance to them. 



3. Besides the ordinary colorless corpuscles and the granular corpuscles, 

 other kinds 2 are observable, which have been divided into, a, small, well- 

 defined bodies resembling nuclei, b, large corpuscles consisting of finely gran- 

 ular protoplasm, with jagged outline, containing three or four distinct nuclei, 

 c, still larger irregularly-shaped masses of finely granular protoplasm inclos- 

 ing from five to twenty nuclear-like bodies. The human colorless corpuscles 

 are smaller than those of the newt, present less variety in aspect, and are 

 less active in their movements. They are either quite pale, or they contain 

 a variable number of dark granules. The Colorless corpuscles possess a 

 higher refractive power than the red ; from which they are further distin- 

 guished by their greater firmness, their inferior elasticity, their softly shaded 

 and granular aspect, and the absence of any disposition to adhere to each 

 other ; so that, when a drop of fresh blood is placed between two strips of 

 glass, and these are gently moved over one another, the white corpuscles 

 may be at once recognized by their solitariness, in the midst of the rows 

 and irregular masses formed by the aggregation of the red. This is still 

 better seen in inflammatory blood, in which the Red corpuscles have a 

 peculiar tendency to adhere to one another, so that the distinctness of the 

 White is more marked. Colorless corpuscles may be readily distinguished 

 in the blood circulating through the small vessels of the Frog's foot; and it 

 is then observable that they occupy the exterior of the current, where the 

 motion of the fluid is slow, whilst the red corpuscles move rapidly through 

 the centre of the tube (Fig. 110). The colorless corpuscles, indeed, often 

 show a disposition to adhere to the walls of the vessels; which is manifestly 

 increased on the application of an irritant. Hence the idea naturally arises, 

 that (to use the words of Mr. Whartou Jones) "there is some reciprocal re- 

 lation between the colorless corpuscles and the parts outside the vessels, in 

 the process of nutrition." On the addition of distilled water the white cor- 

 puscles swell up, become globular, and cease to move; one or several nuclei 



pusclc, pamphlet, 18712, some of the phenomena, he has observed lend countenance 

 to tin.' theory that tlie white corpuscles of Man possess n eel I- \vnll dotted with minute 

 pores, which permit delicate threads of the soft protoplasm to he extruded. The 

 pseudopodia, he thinks, are invested to near their tip by the external cell-wall. 



1 Handbook for the Physiological Laboratory, 1873, p. 5. 



2 See Gulliver, Med. Times, i, 18G3, p. 207 ; Nedsvetski, Centralblatt, 1873, p. 147. 



