OXYGEN. 73 



not being exhaled, remains to give the acid 

 taste fruits, under such circumstances invaria- 

 bly possess. 



That such is the result oT the absence of light 

 and heat will be obvious, if it is considered of 

 what the 'analysis of sugar consists, viz. car- 

 bon 43 parts and water 67 parts; thus, if 

 plants, from the absence of that cause which 

 enables them to assimilate their carbon and 

 dispose of their oxygen, are unable to do so, 

 the results must be as is found they are, that 

 under such circumstances the acid taste must 

 predominate over the sweet; and in corrobo- 

 ration of this view it may be noticed that the 

 sugar cane, the plant of all others which yields 

 the greatest amount of carbon, can only be pro- 

 fitably cultivated in the tropics, where a burn- 

 ing sun and unclouded sky enable it to assimi- 

 late a sufficient quantity of ^carbon to produce 

 its due supply of sugar. 



That the cultivation of the beet root in 

 France is no argument against this view of the 

 subject, can be satisfactorily proved from the 

 circumstance that the moment the protective 

 duties which long existed in France for the 

 protection of the home manufacture were 

 abolished, that moment the manufacture from 

 beet root ceased, thus proving that a given 

 quantity of labour in Europe could not pro- 

 duce the same quantity of sugar as in the 

 tropics, simply because the climate is not 

 sufficiently clear to facilitate the assimilating 

 of a sufficient quantity of carbon. 



There are several classes of plants which 



