REJUVENESCENCE BY CONJUGATION 71 



or another represents a phenomenon universal in animals and 

 plants. It is, therefore, one of the fundamental properties of 

 living things (see page 15). It is usually associated with re- 



FIRST MATURATION DIVISION OF MICRONUCLEUS 



SECOND AND THIRD 

 DIVISION OF MICRONUCLEUS 



THREE SOMATIC DIVISIONS OF FERTILIZED NUCLEUS 



FERTILIZATION 



TWO CONSECUTIVE DIVISIONS 

 GIVING FOUR NORMAL CELLS 



FIG. 30. Diagram of the consecutive stages in conjugation of Paramecium 



caudatum . 



production but reproduction may go on without it, as in the 

 case of division, spore formation, etc., of the protozoa, or budding 

 in Hydra and plants, or parthenogenesis in insects. Strictly 

 speaking therefore it is not a process of reproduction but a 



