Ill] IN VARIOUS ORGANISMS 161 



some call it) to succeed another, whether at special epochs in a 

 lifetime, or as often as winter gives place to spring*. 

 20 



Days 

 Fig. 33. Growth of Lupine: daily increments. 



45 50 

 days 



Fig. 34. Growth in weight of a mouse. After W. Ostwald. 



In the accompanying curve of weight of the mouge (Fig. 34) we 

 see a slackening of the rate of growth when the mouse is about a 

 fortnight old, at which epoch it opens its eyes, and is weaned soon 



* W. PfefiFer, Pflanzenphysiologie, 1881, Bd. ii, p. 78; A. Bennett, On the rate 

 of growth of the flower-stalk of Vallisneria spiralis and of Hyacinthus, Trans. Linn. 

 Soc. (2), I, Botany, pp. 133, 139, 1880; cited by G. Backman, Das Wachstums- 



