No. 593] THE EVOLUTION OF THE CELL 283 



As regards the application of the term unicellular or 

 non-cellular to the Protozoa, it is evident that if the evo- 

 lution of living beings had never proceeded beyond the 

 stage of the Protista, and if no multicellular organisms 

 had ever been evolved, the term cell could then never 

 have been invented by an intelligent being studying other 

 living beings, supposing for an instant the possibility of 

 such intelligence existing apart from a mammalian brain. 

 So long as the Protozoa are studied entirely by themselves, 

 without reference to any other forms of life, they may be 

 termed non-cellular in the sense that they are not com- 

 posed of cells. It is only when they are compared with 

 multicellular organisms that the term unicellular becomes 

 applicable on the ground of the homology already dis- 

 cussed between the Protozoon and the body-cell of the 

 Metazoon. 



