6 THE BIOLOGY OF THE SEASONS 



(katabolism), the other a more autonomic winding-up or 

 construction (anabolism). 



But without going further into interpretations, which 

 remain uncertain, we may say that all physiologists are 

 agreed about the fact, that there is in all living a twofold 

 process of waste and repair, of discharge and restitution, of 

 activity and recuperation. And it is the preponderance 

 now of the one, and again of the other, that constitutes 

 the fundamental rhythm of life. As it is said in Ecclesi- 

 astes iii. : "To everything a season ... a time to break 

 down and a time to build up ... a time to cast away 

 stones and a time to gather stones together ... a time 

 to get and a time to lose ... a time to keep and a time 

 to cast away." 



Besides the alternation of predominant anabolism and 

 predominant katabolism, though ultimately dependent on 

 it, there are numerous periodicities in the life of organ- 

 isms. The growth of the embryo is sometimes markedly 

 periodic. Thus Dr. A. Fischel says of duck-embryos, 

 that " the growth of the whole length of the embryo as 

 well as that of the several regions of the body is periodic." 

 It is said of some very simple organisms that they can 

 continue to move only as long as a certain substance 

 within them holds out ; when that is used up there is no 

 movement possible until after a period of nutrition. They 

 have to be re-charged. So in nerve-cell and muscle-cell, 

 wonderful engines as they are, there is a necessary limita- 

 tion to the output. Rest must alternate with work. We 

 see a similarly fundamental periodicity in the see-saw 

 between nutrition and reproduction, between vegetating 

 and flowering. " A time to embrace, and a time to refrain 

 from embracing." 



Our point is that living creatures are inherently pre- 

 disposed to be rhythmic, and that on this predisposition 



