THE IMPERMEABILITY OF SEEDS 6i 



It is to Professor Ewart of the University of Melbourne The investi- 

 that we are indebted for a most important contribution to our Prof^Ewart. 

 knowledge of seed-longevity and of the impermeability of the 

 seed-coverings. If the author had had the leisure to extend 

 the explanatory portion of his memoir, it would have ranked 

 as one of the most extensive records of investigations con- 

 cerned with seeds since De Candolle published his Geographic 

 botanique rather over half a century ago, Dr Gola and Mr 

 Crocker, as far as the dates of publication are concerned, were 

 his predecessors in the field ; but it would be probably more 

 correct to say that they were contemporaries in their labours. 

 Professor Ewart, like Dr Gola, discusses the distribution of 

 impermeability in seeds, and, like Mr Crocker, he considers 

 the relation between longevity and impermeability. But on 

 this point the two investigators in America and Australia seem 

 to diverge widely, Mr Crocker holding that '' delayed ger- 

 mination is generally related to seed-coat characters rather than 

 to the so-called dormancy of protoplasm," whilst Professor 

 Ewart considers that longevity depends not on the seed-coats, 

 but on the staying power of the protoplasm. The difference, 

 however, is more apparent than real, since Professor Ewart 

 evidently regards the impermeable covering as an adaptation 

 for ensuring the long life of the seed in the soil ; and at 

 all events it would seem likely there is enough common 

 ground on which to base a theory that would reconcile both 

 the views. 



In this memoir on " The Longevity of Seeds," which was 

 published in the Proceedings of the Royal Society of Victoria for 

 1908, he deals with the seeds of about 2500 species of 

 plants. In addition to the results of his own work, which 

 involved the employment of nearly 3000 tests. Professor Ewart 

 incorporates in his table, which in itself occupies 176 pages, 

 all the previous records relating to the subject that he could 

 find. Yet, in spite of the great importance of this contribution 

 to knowledge, one is conscious of missing much in the 22 

 pages that are alone devoted to the summarising of results, 



