SENESCENCE, DECADENCE, AND DEATH 441 



to an end, but the life of the germ-plasm persists in its 

 descendants in a succession of ever-changing forms for 

 which one can see no end so long as the physical condi- 

 tion of our planet continues to afford such conditions of 

 temperature and moisture as are compatible with life 

 as we know it. 



The death of the soma and the succeeding retrogressive 

 and analytic changes it undergoes must not be inter- 

 preted as loss. The greater part of the surface of the 

 earth is covered by a layer of matter composed of the 

 products of organic decomposition which is continually 

 utilized by new living things. As one living organism 

 dies and disintegrates, others of different kind arise from 

 its remains, so that the organic compounds are per- 

 petually undergoing cyclical integration and disinte- 

 gration, in which available material is worked over and 

 over again with ever new results by new organisms aris- 

 ing through the energy of the immortal germ-plasm. 



REFERENCES. 



CHARLES SEDGWICK MINOT: "The Problem of Age, Growth, and 

 Death: A Study of Cytomorphosis Based on Lectures 

 at the Lowell Institute," N. Y., 1908. 



ELIK METCHNIKOFP: "The Nature of Man," translated by I. C. 

 Mitchell, N. Y., 1903. "Etudes Biologiques sur la 

 Veilleuses," Annales d. Tlnst. Pasteur, xv., xvi., 1901- 

 1902. 



