RIPENING AND PRESERVING FRUITS. 277 



be an increased supply of sap for that which remains. In 

 this way, peaches, nectarines, apricots, etc., are rendered 

 larger and better flaA r ored. When the fruiting is checked 

 for one season, there is an accumulation of nutritive mat- 

 ter which has a beneficial effect upon the subsequent crop. 

 " The pericarp is at first of a green color, and performs 

 the same functions as the other green parts of plants, de- 

 composing carbonic acid under the agency of light and 

 liberating oxygen. Saussure asserts that all fruits, in a 

 green state, are adequate to perform this process of deox- 

 idation. As the pericarp advances to maturity, it either 

 becomes dry or succulent. In the former case it changes 

 into a brown or white color, and has a quantity of ligneous 

 matter deposited in its substance, so as to acquire great 

 hardness, where it is incapable of performing any process 

 of vegetable life ; in the latter it becomes fleshy in its 

 texture, and assumes various bright tints. In fleshy 

 fruits, however, there is frequently a deposition of ligneous 

 cells in the endocarp, forming the stone of the fruit; and 

 even in the pulpy matter of the sarcocarp, there are found 

 isolated cells of a similar nature, as in some varieties of 

 pear, where they cause a peculiar grittiness. The con- 

 tents of the cells near the outside of succulent fruits are 

 thickened by exhalation, and a process of endosmose goes 

 on, by which the thinner contents of the inner cells pass 

 outward, and thus cause swelling of the fruit. As the 

 fruit advances to maturity, however, this exhalation di- 

 minishes, the water becoming free and entering into new 

 combinations. In all pulpy fruits, which are not green, 

 there are changes going on by which carbon is separated 

 in combination with oxygen. 



