Till; r,|.>n|t, I.VMl'll. AX1> HlST(>[.n<;y n\-' T11K VKSSKI.S. 263 



b. The corpuscles are of two kinds, colourless and coloured. 



i i ) The colourless or white corpuscles are subspherical masses of 

 protoplasm, endowed with the power of spontaneous motion. They 

 are much fewer than the red corpuscles, though the proportion of 

 white to red varies considerably. Three chief varieties of colourless 

 corpuscles can be distinguished, all of which are true cell forms, 

 and behave like other cells with staining or other reagents. They 

 have no cell-wall, but are simply nucleated masses of protoplasm. 

 These corpuscles possess the power of passing through the walls 

 of the blood-vessels, and are then known as migratory cells ; such 

 migratorv cells can be found in nearly all tissues, but more espe- 

 cially in the connective-tissues, 



o. Ordinal 1 v large colourless corpuscles are large transparent 

 masses of protoplasm containing one or two nuclei, rarely three 

 or more. The cell contains few granules, and usually has one or 

 more vacuoles or clear spaces containing fluid. 



/3. Granular corpuscles are less numerous than the foregoing, but 

 larger, and are distinguished by the numerous large dark granules 

 which they contain. The processes such a corpuscle sends out are 

 hyaline. 



y. Smaller corpuscles also occur varying much in form: they may 

 consist of a nucleus with a very small amount of hyaline or granu- 

 lar protoplasm, or of several nuclei with an extremely small amount 

 of protoplasm. 



(2) The coloured corpuscles arc much more numerous than the 

 colourless corpuscles ; each is a bi-concave, oval disc, about 

 0-0255 mm. in length, and 0-017 mm - ^ n breadth (Gulliver) 1 

 (R. temporaria. 0-0235 and 0-0145 mm - respectively). Each cor- 

 puscle possesses an oval nucleus (Hewson) 2 , which projects into 

 either concave surface of the whole corpuscle. These corpuscles 

 do not possess the power of spontaneous movement; and have no 

 cell-wall. The corpuscles are of a reddish -yellow colour, and 

 give the blood its characteristic hue. The colouring matter is 

 haemoglobin, and when separated it crystallizes in prisms (Preyer). 

 The corpuscles show a well-marked intracellular and intranuclear 

 network.] 



1 Gulliver, Proc. Zool. Soc. London, 1845, Vol. XIII, p. 93 seq. 

 - Hewson, Phil. Trans. 1773, Vol. LXIII. p. 310 seq. 



