AMCEBA. 



15 



ing the particles of food ingested by the amoeha. This pro- 

 teus-animalcule is neither provided with mouth nor anus. The 

 food can be taken in and expelled at any part of the body. 

 This process can easily be watched if particles of indigo are 

 placed in the water surrounding an amoeba : a speck of indigo 

 will be found to be drawn to the protozoon by the pseudo- 

 podium, and then it can be watched gradually sinking into the 

 protoplasm until it reaches tlie endosarc, where it remains 

 whilst the substance (if an organism) is digested, the waste part 

 being expelled through any part of the animal. The food con- 



i. Large specimen, showing structure, ii. A smaller specimen in process of division, 

 iii. Later stage of ii. a and n, nucleus ; h and cy, contractile vacuoles ; yi\ lood 

 vacuoles ; jPsu, pseudopodia. 



gists of organisms still smaller than the amcebse are themselves. 

 Amceba reproduces by the primitive method of " fission " or 

 division. The nucleus of the amceba divides into two (fig. 2, 

 ii. and iii., a), and one of these nuclei, surrounded by part of the 

 original protoplasm, breaks off and floats away ; thus one amceba 

 becomes two. This division may go on until one amceba has 

 given rise to hundreds. But by degrees each amoeba becomes 

 smaller and smaller, and they would eventually die out. To 

 counteract this, what is known as " rejuvenescence " takes place. 

 Eejuvenescence is the union or conjugation of two amoebse, 



