238 THE EVOLUTION OF SEX. 



SUMMARY. 



1. The essential fact in reproduction is the separation of part of the 

 parent organism to start a fresh life. 



2. Reproduction begins with rupture, — a katabolic crisis. 



3. Cell-division, which sometimes sums up, and is always associated 

 with, the act of reproduction, occurs at a katabolic crisis. 



4. The gradations between discontinuous asexual multiplication and 

 ordinary sexual reproduction, show a lessening of the sacrifice ; but all de- 

 mand a disruption, or a katabolic preponderance. 



5. From first to last reproduction is linked to death. 



6. Environmental conditions of a katabolic character favour sexual re- 

 production. 



7. General conclusion, — a relative preponderance of katabolism neces- 

 sitates reproduction. 



LITERATURE. 



Geddes, p. — Theory of Growth, Reproduction, Sex, and Heredity. Proc. 



Roy. Soc. Edin. 1886. 

 MECKEL. — Generelle Morphologic. 1866. 

 Spencer. — Principles of Biolog}^ 1866. 

 Semper. — Animal Life. Int. Sci. Series. 1881. 

 Thomson. — " Synthetic Summary of the Influence of the Environment 



upon the Organism." Proc. Roy. Phys. Soc. Edin. 1887. 



