en. xxvi.] COLOURLESS BLOOD-CORPUSCLES. 419 



cytes. A fourth variety of leucocyte is the hyaline corpuscle, in 

 the protoplasm of which there are no granules. They have a single 

 nucleus. Very rarely basophile cells (i.e., cells whose granules 

 have an affinity for basic aniline dyes like methylene blue) are 

 found. The nucleus of all these varieties of cells is basophile. 



Amosboid Movement. The remarkable property of the 

 colourless corpuscles of spontaneously changing their shape was 

 first demonstrated by Wharton Jones in the blood of the skate. 

 If a drop of blood is examined with a high power of the micro- 



Healthy bacillus j^ ^^ Healthy bacillus ' 



\- Partially digested bacillus 



Healthy bacillus \ 



--. Nucleus 



....Bacillus in leucocyte 

 Partially diKeMted^euoorytp-.-^^^g^^^^^jtoaidiy digested leucoejte 



Foreign matter 



Nuclei vaeuulaU-d \g) A ^W " "*M" 



Foreign matter - gf IWV r rtirf * of forei ^ mattcr 



V j/\~'2l\ Particles of foreign matter 



Leucocytes { i:::::.^!^ Particles of toreiga matter 



Fig. 351. Macrophages containing bacilli and other structures supposed to be under- 

 going digestion. (Ruffer.) 



scope, under conditions by which loss of moisture is prevented, 

 and at the same time the temperature is maintained by a warm 

 stage at about that of the body, 37 C. (98*5 F.), the colourless 

 corpuscles will be observed slowly to alter their shapes, and to 

 send out processes at various parts of their circumference. The 

 amoeboid movement, which can be demonstrated in human colour- 

 less blood-corpuscles, can be more readily seen in newt's blood. 



The full consideration of amoeboid movement is given on p. 13. 

 An interesting variety of amoeboid movement is that which leads 

 to the ingestion of foreign particles. This gives to the leucocytes 

 their power of taking in and digesting bacilli (phagocytosis). The 



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