AMOEBOID LIFE. 143 



sule, which immediately hardens, and in a state of repose 

 assumes the form of a spherical cell surrounded by a pro- 

 tecting membrane. The one-celled Amoeba obtains its 

 food, either by absorbing dissolved substances directly from 

 the water by imbibition, or by pressing into itself solid 

 particles of foreign matter with which it comes into contact. 

 The latter operation can be observed at any time if it is 

 made to eat. If finely pulverized colouring matter, such as 

 carmine or indigo, is placed in the water in very small 

 quantities, the soft body of the Amoeba can be seen to 

 assimilate these particles of colouring matter, over which 

 the soft substance of the cell flows together. The Amoeba 

 can take food in this way at any point of the surface of its 

 body, although it possesses no special organs for taking in 

 and digesting nutritive matter, no true mouth or stomach. 

 By means of this assimilation of nutriment and dissolving 

 the particles in its protoplasm, the Amoeba grows; and, 

 after it has reached a certain size by this process, it begins 

 to reproduce. This occurs in the simplest way, by division. 

 The enclosed nucleus first separates into two pieces. Then 

 the protoplasm distributes itself between the two new 

 nuclei, and the whole cell parts into two similar cells, in 

 consequence of the growth of the protoplasm round the two 

 nuclei. This is the usual method of propagation ; the 

 nucleus first divides into two halves, which separate from 

 each other, and act as centres of attraction to the surround- 

 ing cell-substance or protoplasm (Fig. 8). 



Though the Amoeba is, therefore, only a simple cell, it 

 shows itself capable of performing all the functions of a 

 many-celled organism. It moves itself by creeping, it feels, 

 it feeds, it reproduces its kind. Some species of Amoebae 



