280 PHYSIOLOGICAL BOTANY. PART II. 



certain time in the pericarp after they have been ga- 

 thered, in order that they may more completely elabo- 

 rate the provision there prepared for their use. When 

 thoroughly mature many seeds may be preserved for a 

 very great length of time, provided they are not exposed 

 to the influences of those causes which determine their 

 germination, viz : a certain elevation of temperature, 

 the presence of oxygen, and the influence of water. 

 There are some however which very soon lose the 

 faculty of germinating after they an- ripe, though they 

 may be preserved in a state fit for food for a long time. 

 The seeds of coffee, for instance, will not germinate 

 unless they are sown within the space of a few weeks 

 after they have become ripe. 



The fact that seeds retain their vitality for very 

 many years is well authenticated. De Candolle tells us 

 that a bag of seeds of the sensitive-plant gathered about 

 sixty years ago, has regularly supplied the Paris gar- 

 den with fresh plants every year since then. Young 

 plants have been raised from seeds of a French-bean 

 which were taken from the herbarium of Tournefort, 

 where they must have lain for more than a century. 

 These examples are remarkable exceptions to the more 

 general rule, that seeds 'cannot be artificially preserved 

 in a living state for many years together. It is cer- 

 tain that most of those found in ancient tombs, and 

 in the catacombs of Egypt, have entirely lost their 

 vitality ; and although recent accounts have been pub- 

 lished to the contrary, the fact does not seem to have 

 been thoroughly established, and may possibly have 

 been founded on some mistake, or perhaps imposition 

 practised upon the credulity of the traveller by the 

 cunning of the natives. M. Rifaud, a recent and labo- 

 rious investigator of the antiquities and natural history 

 of Egypt, brought to Europe a large collection of various 

 seeds, bulbs, and other parts of plants, which he had 

 found in the catacombs, and all of these were deprived 

 of any vegetating power. Many of them have pre- 

 served to a great extent the appearance of freshness. 



