20 
RESEARCHES ON THE MANUFACTURE 
colouring matters, salts, etc, and perhaps also to acids and 
acid salts, as Wiesner assumes. Now it is quite certain that 
an alteration ot colour soon takes place, when the contact 
of chlorophyll granule with an acid sap is favoured by press¬ 
ing and crushing of the leaves, as in the case of the prepara¬ 
tion of black tea. Hence, the alteration of colours can not 
be calculated as a decisive proof of fermentation. A more 
certain measure for fermentation is, perhaps, the observation 
of temperature. I observed in the above trial an increase 
from 20 to 26.°6C, in the specimen with withered leaves, 
and only 20-22 1 C. in the steamed leaves. It is hardly neces¬ 
sary to add that the infusion of the former had a reddish 
brown colour, while that of the latter shewed a yellowish 
tint. Hence, it is highly probable that the fermentation might 
be caused by a living organism. Of course many experi¬ 
ments must be made before bringing forward the above con¬ 
jecture as indubitable truth. Of the nature of fermentation 
I know not with certainty, but it is highly probable that it is 
of an acid nature, since according to the manufacturer, over¬ 
fermented tea has a sour taste. Indeed, I have found a 
minute quantity of a volatile acid in the black tea prepared 
by myself for analysis, but I could not identify its nature 
because of the small quantity. 
As to the practice of fermenting the leaves, there are two 
systems adopted in this country. The first system consists 
in making the twisted leaves into balls with a diameter of 
3-4 sun , arranging many such balls, side by side, in a 
shallow bamboo tray, covering them with white cloth, and 
placing them in a sunny place. The second system is to 
spread the leaves in a bamboo tray, and press them together. 
They are also then covered with white cloth and put in the 
sunshine. It is of vital importance to ferment the leaves to the 
proper extent. By under-fermentation the raw flavour is not 
i This might partly be attributed to the large quantity of water in the 
steamed leaves. 
