64 THE BIOLOGY OF THE SEASONS 



of Death help to loosen the bonds of birth rotting away 

 the hard husks. 



The fermentation which goes on in seeds and seedlings, 

 making hard reserve material available for transport and 

 transformation, brings home to us the fundamental unity 

 of vital processes. There is a close resemblance between 

 digestive fermentations in animals, which make the solid 

 food diffusible, and the fermentations in plants. The list 

 of chemical substances known to be common to plants 

 and animals is enormous, and it includes a number of 

 digestive ferments. 



Thus the diastase which Professor Vines and others have 

 proved to be present in every green leaf is comparable to 

 the ptyalin in our salivary secretion. Both change starch 

 into sugar. A diastatic ferment certainly occurs in many 

 seeds, bringing about the same change, and various ob- 

 servers have found a peptic ferment like that in our 

 stomachs, turning proteids into peptones. And Professor 

 J. Reynolds Green found a ferment like that of the animal 

 pancreas in the seeds of the Lupin. 



There is, however, great discrepancy among chemical 

 physiologists in regard to these peptic ferments in seeds, 

 and we cannot enter into the very difficult questions 

 involved. Suffice it to say that there is often much stored 

 proteid in seeds more than there is for a time in the 

 young plant. In some way this condensed reserve 

 material is made available. There is no doubt that seed- 

 lings have a peptic ferment which acts in the presence 

 of an organic acid, but its presence remains doubtful in 

 many seeds where some sort of digestion must go on. 

 Perhaps the protoplasm of the seed sometimes does its 

 own fermenting of reserve material, without the aid of 

 any specialised ferment. 



The rapidity of growth that follows germination in a 



