VIII. 



THE PROTEUS ANIMALCULE (Amoeba) AND THE 

 COLOURLESS BLOOD CORPUSCLE. 



Amoebce are minute organisms of very variable size which 

 occur in stagnant water, in mud, in damp earth and else- 

 where, and are frequently to be obtained by infusing any 

 animal matter in water and allowing it to evaporate while 

 exposed to direct sunlight. Parasitic Amoeba are known to 

 exist. 



The Amoeba has the appearance of a particle of jelly, 

 which is more or less granular and fluid in its central 

 parts, but usually becomes clear and transparent, and of 

 a firmer consistency, towards its periphery. Sometimes 

 Amcebce are found having a spherical form and encased 

 in a structureless sac, and in this encysted state they ex- 

 hibit no movements. More commonly, they present in- 

 cessant and frequently rapid changes of form, whence the 

 name of "Proteus Animalcule" given to them by the older 

 observers ; and these changes of form are usually accom- 

 panied by a shifting of position, the Amoeba creeping about 

 with considerable activity and, in most cases, with no con- 

 stancy of direction. 



The changes of form, and the movements, are effected 



M. 24 



