60 



THE DAWN OF LIFE. 



is clear or transparent^ and more dense than tlie inner 

 mass, wliicli seems granular. It lias at one end a 

 curious vesicle wliicli can be seen gradually to expand 

 and become filled with a clear drop of liquid, and then 

 suddenly to contract and expel the contained fluid 

 through a series of pores in the adjacent part of the 

 outer wall. This is the so-called pulsating vesicle, and 

 is an organ both of circulation and excretion. In 

 another part of the body may be seen the nucleus, 



Fig. 12. Amceba. Fm. 13. Actinophrys. 



From criginal sketches. 



which is a little cell capable, at certain times, of pro- 

 ducingv by its division new individuals. Food when 

 taken in through the wall of the body forms little 

 pellets, which become surrounded by a digestive liquid 

 exuded from the enclosing mass into rounded cavities 

 or extemporised stomachs. Minute granules are seen 

 to circulate in the gelatinous interior, and may be 

 substitutes for blood-cells, and the outer layer of the 



