THE 



AMERICAN NATURALIST 



THE EVOLUTION OF THE CELL 1 



BY THE LATE PROFESSOR E. A. MINCHIN, F.R.S. 



When addressing an audience of biologists it would be 

 superfluous to insist upon the importance of the study of 

 the cell and its activities. It is now recognized almost 

 universally that the minute corpuscles known by the some- 

 what unsuitable term " cells" are the vital units of which 

 the bodies of animals and plants are built up, and that all 

 distinctive vital processes— metabolism, growth and re- 

 production, sexual phenomena and heredity— reduce 

 themselves ultimately to activities taking place in, and 

 carried on by, the individual cells which build up the 

 body as a whole. Each cell must be regarded as a living, 

 individual organism which, however much it may be spe- 

 cialized for some particular function or form of vital ac- 

 tivity, is capable of maintaining its life and existence in a 

 suitable environment by carrying on all the necessary 

 processes of metabolism which are the essential and dis- 

 tinctive characteristics of living beings. In the case of 

 cells composing the complex body of the higher animals 

 and plants the cells are mutually interdependent, and, 

 with the exception of the mature germ-cells, can not main- 

 tain their existence apart from their fellows; that is to 

 say, the only natural 2 environment suitable for their con- 



^ i Address by the President to the Zoological Section of the 



