290 SACCHARINE FERMENTATION PRODUCED 



Then, if the difference of black tea should be 

 found to be due to the elaboration and fermentation 

 of a saccharine principle, the reason becomes 

 obvious, why leaves gathered during bright weather, 

 and even in mid-clay, should be more suitable for 

 this purpose than when collected during cloudy 

 or rainy weather. Liebig states, that during the 

 absence of solar light and heat, whether by night or 

 day, the leaves form acids, which during bright 

 sunshine and heat are converted into starch, gum, 

 and sugar. Thus in southern climes grapes contain 

 more saccharine matter, and those of northern 

 ones more acids. 



Tea leaves gathered after heavy and long con- 

 tinuous rains, being exuberant in aqueous juices, 

 are not in a state to favour the elaboration of this 

 principle ; as we know by fruits, which under 

 similar circumstances do not ripen. The juices of 

 the leaves being too watery, they readily run into 

 the putrefactive fermentation. Thus it is obvious 

 why it may be beneficial under circumstances of 

 exuberant moisture to expose the leaves of black 

 tea to fire, as practised in China, to hasten evapora- 

 tion, in order to bring them quickly into that state 

 of relative moisture which favours the elaboration 



the leaves are yet moist, if found necessary. But it has been 

 shown, that not only the saccharine principle, but also the red 

 colouring matter of the leaf and infusion may be diminished and 

 even altogether destroyed, by a small excess of heat in the 

 process of roasting and drying. In such cases, the leaves turn 

 yellow, and the infusion is as light as green tea. 



