476 THE UNIVERSE. 



Among these the cotyledons occupy the first place. They 

 are usually fleshy, sometimes foliaceous, organs which pre- 

 pare for the little plant, issuing from the egg, nourishment 

 appropriate to its delicacy till it can itself take up its food 

 from the soil. There are usually only one or two. 



When the cotyledons are little developed their alimentary 

 function is intrusted to another organ, the perisperm. This, 

 which Gartner compared very rightly to the albumen of 

 the egg, varies a good deal as to its volume and consistence. 

 In the cocoa-palm it is in part milky. Our bread is made 

 from the farinaceous perisperm of the wheat ; our coffee is 

 only the same part from the horny seed of the coffee-tree 

 of Arabia. 



Plants are known, the perisperm of which is of a firm- 

 ness much surpassing that of the coffee-tree. Such is the 

 case with the seeds of the Corozo, in which this structure is 

 as white and hard as ivory ; owing to this fact different ob- 

 jects are made from it in trade which are put forward as 

 being fabricated from this substance. This peculiarity has 

 procured for the Corozo palm the name of the elephant-plant 

 (Phytelephas), and for its fruit, cargoes of which are brought 

 to France, that of vegetable ivory. 



It was Leuwenhoeck who first of all noticed that the seed 

 contains the young plant in miniature, traced out in the 

 midst of its envelopes, and only waiting for favoring cir- 

 cumstances to expand its leaves and flowers. Thus, look- 

 ing philosophically at the subject, we may say that certain 

 plants are viviparous. There are even some in which the 

 impatience of the embryo is so great that, in order to reach 

 the air and light more quickly, it precipitately escapes from 

 its egg while this still adheres to the mother. 



