ATTENDED WITH EVOLUTION OF OXYGEN. 6? 



the acids is accompanied with the smallest separa- 

 tion of oxygen ; that the amount of oxygen set free 

 increases with the production of the so-named 

 neutral substances, and reaches its maximum in the 

 formation of the oils. Fruits remain acid in cold 

 summers ; while the most numerous trees under the 

 tropics are those which produce oils, caoutchouc, 

 and other substances, containing very little oxygen. 

 The action of sunshine and influence of heat, upon 

 the ripening of fruit, is thus in a certain measure 

 represented by the numbers above cited. 



The green resinous principle of the leaf dimi- 

 nishes in quantity, while oxygen is absorbed, when 

 fruits are ripened in the dark; red and yellow 

 colouring matters are formed ; tartaric, citric, and 

 tannic acids disappear, and are replaced by sugar, 

 amylin, or gum. 6 eq. Tartaric Add) by absorb- 

 ing 6 eq. oxygen from the air, form Grape 

 Sugar, with the separation of 12 eq. carbonic 

 acid. 1 eq. Tannic Avid, by absorbing 8 eq. 

 oxygen from the air, and 4 eq. water form 1 eq. 

 of Amylin, or starch, with separation of 6 eq. 

 carbonic acid. 



We can explain, in a similar manner, the forma- 

 tion of all the component substances of plants, 

 which contain no nitrogen, whether they are pro- 

 duced from carbonic acid and water, with separation 

 of oxygen, or by the conversion of one substance 

 into the other, by the assimilation of oxygen and 

 separation of carbonic acid. We do not know in 



F2 



