THE COLOURLESS BLOOD-CORPUSCLES. 



13 



to 



detect the 

 C 



0P- ' 



# 









factory somewhere. As to the number of corpuscles which daily decay, we have in 

 .some measure an index in the amount of bile-pigment and urine-pigment resulting 

 from the transformation of the liberated haemoglobin ( 20). 



9. COLOURLESS CORPUSCLES, BLOOD-PLATES, AND GRANULES. 



White Blood-Corpuscles. Blood, like many other tissues, contains a number of 

 cells or corpuscles which reach it from without ; the corpuscles vary somewhat in 

 form, and are called colourless or white biood-corpuscles, or "leucocytes" 

 (Hewson, 1770). Similar corpuscles are found in lymph, adenoid tissue, marrow 

 of bone, and as wandering cells or leucocytes in connective-tissue, and also between 

 glandular and epithelial cells. So that these corpuscles are by no means peculiar 

 to blood alone. They all consist of more or less spherical masses of protoplasm, 

 which is sticky, highly refractile, soft, capable of movement, and devoid of an 

 envelope (fig. 9). When they are quite fresh (A) it is difficult 

 nucleus, but after they have been 

 shed for some time, or after the ^ 



addition of water (B), or acetic 

 acid, the nucleus (which is usually 

 a compound one) appears ; acetic 

 acid clears up the perinuclear 

 protoplasm, and reveals the pres- 

 ence of the nuclei, of which the 

 number varies from one to four, 

 although generally three are found. 

 The subsequent addition of ma- 

 genta solution causes the nuclei to 

 stain deeply. Water makes the 

 contents more turbid, and causes 

 the corpuscles to swell up. One 

 or more nucleoli may be present 

 in the nucleus. The size of the 

 corpuscles varies from 4-13 fi. 

 and as a rule they are about 

 ^sV f an ^ ncn ^ n diameter ; in 

 the smallest forms the layer of 

 the protoplasm is extremely thin. 

 They all exhibit amceboid move- 

 ments which are very apparent 

 in the larger corpuscles, and were 

 discovered by Wharton Jones in 



the skate (1846), and by Davine in the corpuscles of man (1850). 

 describes three different forms in human blood : 



(1) The smallest, spherical forms, less than the red corpuscles, with one or two 

 nuclei, and a very small amount of protoplasm. 



(2) Spherical forms, the same size as the coloured blood-corpuscles. 



(3) The large amceboid corpuscles, with much protoplasm and distinctly evident 

 movements. 



[On examining human blood microscopically, more especially after the coloured blood-cor- 

 puscles have run into rouleaux, the colourless corpuscles may readily be detected, there being 

 usually three or four of them visible in the field at once. They adhere to the glass slide, for if 

 the cover-glass be moved, the coloured corpuscles readily glide over each other, while the 

 colourless can be seen still adhering to the slide.] 



[White Corpuscles of Newt's Blood. The characters of the colourless corpuscles are best 

 studied in a drop of newt's blood, which contains the following varieties : 



(1) The large finely granular corpuscle, which is about T ^ir of an inch in diameter, irregular 

 in outline, with line processes or pseudopodia, projecting from its surface. It rapidly changes 



Fig. 9. 

 human white blood-corpuscles, without any reagent ; 

 B, after the action of water ; C, after acetic acid ; 

 1), frog's corpuscles, changes of shape due to amce- 

 boid movement ; E, fibrils of fibrin from coagulated 

 blood ; F, elementary granules. 



Max Schultze 



