712 



COLOURLESS CORPUSCLES OF BLOOD. 



in which they seem to be identical with the corpuscles found 

 floating in Chyle and Lymph, they seem to be nearly homogeneous 



particles of pro- 

 Fig. 372. toplasmic sub- 



stance ; but in 

 their more ad- 

 vanced condi- 

 tion a dif- 

 ferentiation is 

 observa ble, 

 analogous to 

 that which 

 exists between 

 the Ectosarc 

 and Endosarc 

 of Rhizopods 

 (§ 325) ; and 

 the isolated 

 particles of the 

 latter are often 

 to be seen 

 executing an 

 active molecu- 

 lar movement 

 within the 

 former, which 

 continues when 

 they are dis- 

 charged by the 

 bursting of the 

 corpuscle, con- 

 sequent upon 

 the addition of 

 a solution of 

 potass. These 

 Corpuscles are 

 occasionally 

 seen to exhibit 

 very curious 

 changes of 

 form, which 

 remind us of those of the Amoeba (§ 331) ; a protrusion taking 

 place from some portion of the Ectosarc, the form of which 

 seems quite indeterminate ; and this being soon succeeded by 

 another from some different part, the first being either drawn-in 

 again, or remaining as it was. These changes have been observed, 

 not only in the Colourless corpuscles of the blood of various Verte- 

 brated animals, but also in the corpuscles floating in the circulating 



Comparative sizes of Blood-Corpuscles :— 1. Man ; 

 2. Elephant ; 3. Musk-Deer ; 4. Dromedary ; 5, Ostrich ; 

 6. Pigeon ; 7. Humming Bird ; 8. Crocodile ; 9. Python; 

 10. Proteus ; 11. Perch ; 12. Pike : 13. Shark. 



