UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 6, No. 1, pp. 1-10 October 15, 1908 



CONTRIBUTIONS FROM THE LABORATORY 



OF THE 



MARINE BIOLOGICAL ASSOCIATION OF SAN DIEGO. 



XXIII. 



ON THE WEIGHT OF DEVELOPING EGOS. 



BY 



Wm. E. Ritter and Samuel E. Bailey. 



THE POSSIBLE SIGNIFICANCE OF SUCH 

 INVESTIGATIONS. 



Wm. E. Ritter. 



The term senescence has been applied to widely diverse 

 biological phenomena. Paleontologists in particular tell ns about 

 senescent species, physicians speak of conditions and diseases of 

 senility or senescence, protozoologists have recently had much to 

 say about a weakening in the successive generations of pure 

 cultures of unicellular animals; and the word also occurs not in- 

 frequently in connection with presumably normal tissues consti- 

 tuting the bodies of higher plants and animals. Is there any fact 

 in all these different realms that deserves a common designation 

 further than the fact that the longer organisms live the older they 

 become? Are there really phenomena relating to the limitations 

 and cessation of growth and development in departments of 

 biology so remote from one another that may be reduced to one 

 or a few common rules or principles? 



With a view to pushing this inquiry a step further along the 



