166 ON THE FRUIT OF DIOSPYROS VIRGINIAN A. 
the plant ; but as the fruit ripens the lignin is converted 
into sugar, 20 parts of lignin producing 21 parts of sugar. 
The lignin which was missing in the last experiment would 
produce 13| grains of sugar. In experiment fourth, the 
sugar was about one-fifth of the persimmon employed. In 
experiment third, it was rather more than one-ninth. Judg- 
ing, then, from this experiment, one might suppose that in 
experiment fourth the sugar would be rather more than S2 
grains, instead of which it weighed 113 grains ; 13^ grains 
were produced from the lignin, making, when added to 82, 
95 grains; the other IS grains might have been formed 
from the two-fifths of tannin which was not formed into 
apotheme. The dried fruit strongly resembles the date in 
its taste, but an insoluble substance is very plainly per- 
ceived. 
It seems to be a general opinion that a frost is necessary 
to perfect the fruit of the persimmon; the opinion, however, 
is not entirely correct; for in the West Indies the persimmon 
tree bears two crops, and both are ripened without the 
aid of frost, and I have in one instance seen the fruit per- 
fectly ripe some days before any frost was felt. It is cer- 
tain, however, that the cold has considerable influence in 
rendering them edible. An experiment was made in order 
to ascertain the cause of this. A tincture of kino was sub- 
jected to the action of the atmosphere on a cold frosty night : 
in the course of a few hours it was found to be almost en- 
tirely converted into an apotheme ; but a portion of the 
tincture enclosed in a bottle and exposed to the cold, did 
not undergo any alteration in its character ; so that it ap- 
pears that the atmosphere, and not the temperature, effects 
this change. The persimmons which remain on the trees 
are not near so fine as those which fall to the ground, and 
indeed in many instances the fruit remains on the trees 
till the return of spring, and is then found to be quite 
astringent. It appears probable, then, that the cold acts by 
destroying the connection between the calyx and the stem 
