RHYTHMS IN PLANT LIFE 63 



all, this is not the way with the majority. For most there is 

 a period of quiescence which for some may be experiment- 

 ally shown to be imperative. That it is not purely adaptive 

 to the inhospitable state of the earth and the cold weather, is 

 proved by the fact that some seeds will not germinate at once 

 even in propitious conditions, and that others wait over 

 several years. This may be interpreted partly as an alterna- 

 tion of rest after activity just as the embryo hydra develops 

 for a while and then rests for six weeks ; partly as a conse- 

 quence of the firm protective husks and of the relatively 

 enormous quantity of capital or reserve products with which, 

 like a development-inhibiting legacy, so many seeds are 

 weighted ; and partly as adaptive to the seasons. 



The analogy between dormant seeds and dormant eggs 

 is far-reaching, and may be followed into details. Thus it 

 seems to be a necessary condition for the development of 

 some animals, such as the Phyllopod Crustaceans Apus and 

 Branchipus, that the ova should be subjected for a period to 

 desiccation. In many cases one of the conditions of the 

 survival of the animal egg is the possession of a firm pro- 

 tective shell, which is obviously comparable to the husk of 

 the seed, just as the yolk is to the seed's albumin. 



Noting as the main physical conditions warmth and 

 moisture we recognise as the chief facts in germination : 



(1) The insoaking of water, often through a specially 

 porous area, such as the brown mark or hilum at the base 

 of the bean ; 



(2) The reawakening of the protoplasm (and we must 

 remember how peculiarly thirsty for water plant-proto- 

 plasm is) ; 



(3) A fermenting process by which the hard stores in 

 the seed are rendered soluble and diffusible by a process 

 comparable to animal digestion ; and 



(4) The interesting way in which Bacteria the minions 



