SILOS, EKSILAGE AND SILAGE. 



53 



holism, and not comparable in efficiency or degree with 

 the action of the specific organisms of these fermenta- 

 tions. 



In the ripening of fruits we have illustrations of cell 

 metabolism that are of particular interest in this con- 

 nection. That the changes taking place in the fruit 

 cells in the process of ripening are not the result of 

 direct oxidation by free atmospheric oxygen, is shown 

 by the experiments of Lechartier and Bellamy,* and 

 Pasteur,! who found that carbonic acid was exhaled, 

 and alcohol formed in fruits placed in closed vessels, in 

 an atmosphere of carbonic acid. As no organized alco- 

 holic ferments could be found, this fermentation must 

 have been produced by the metabolism of the fruit cells 

 in the absence of free oxygen. In the maturation of 

 fruits, the cell metabolism is exceedingly complex, and 

 it cannot be formulated in definite chemical terms. 



Berard J gives the amount of lignine (characteristic 

 of wood tissue) and sugar, in 100 parts of fruits, at dif- 

 ferent stages of maturation, as follows : 



"The fruit, while still green, it may be remarked, 

 decomposes carbonic acid and emits oxygen, like the 

 leaves ; but when it ripens, this chemical action on the 

 atmosphere alters. In other words, carbonic acid is 

 given out, accompanied by a sensible rise in temper- 

 ature, while oxygen is absorbed. 



66 The fibrous and cellular tissues also diminish as the 



* Compt. rend., 69, p. 466, etc. 



t Compt. rend., 75, pp. 784= and 1054. Pasteur, Studies on Fermentation, p. 268. 

 t Brown's Manual of Botany, p. 4=70, refers to Ann. de Chim. et de Phys., Ser. 2, 

 XVI, p. 152. 



