VIII spring and its Studies 153 



In the great majority of cases the embryo plant is fully 

 formed by the time the seeds are scattered in autumn. 

 Let us see what happens to the seed after it falls into the 

 ground. 



Every one has heard stories of " mummy wheat," which 

 after lying for many centuries in the tombs was still alive, 

 and germinated when sown ; or of the raspberry grown 

 from seed gathered among the ribs of a Roman soldier. 

 Although these stories are not justified by sufficiently care- 

 ful experiment, they express, in exaggeration, a fact char- 

 acteristic of most seeds, that in natural conditions they 

 remain for a time quiescent before they begin to germinate. 

 Throughout the winter their life is dormant, and if condi- 

 tions do not change — as notably through depth of burial — 

 the dormant period may be lengthened in a degree varying 

 with the species, and not yet sufficiently determined by 

 experiment, but certainly often extending to many years. 



This period of quiescence depends, however, only in part 

 upon external conditions, such as the depth or the frost- 

 bound hardness of the soil ; in part, too, upon the husks 

 which protect and imprison the embryo plant, and must be 

 softened before it can burst forth ; but also on internal 

 processes of fermentation, as the result of which the supply 

 of food becomes changed into more available form. In 

 fact, the process of digestion, which we recognised as an 

 apparently extraordinary thing in insectivorous plants, 

 occurs normally in the life of seeds. The stores of organic 

 substances — which make seeds important parts of our food 

 — are rendered soluble and ^ diffiasible before and during 

 germination. There is not only a diastatic ferment which 

 converts starchy material into sugar, but there are others, 

 such as that which Professor J. R. Green has so carefully 

 studied in the seeds of Lupin — a ferment which acts like 

 the pancreatic juice of animals, converting the proteids of 



