TRANSACTIONS OF THE SECTIONS, 61 
value in reference to the examination of the tea of commerce and the detection of 
adulteration. 
Some time ago Professor Zéller read before the. Physico-Medical Society of Erlan- 
gen a paper on the chemical investigation of. a Himalaya tea.(Repertorium fiir 
Pharmacie, Band xx. Heft 8),. which. possessed. peculiar value, -from the cireum- 
stance that the specimen examined might he. regarded as consisting of genuine tea 
without any foreign admixture, having. been received from the growers by the late 
Baron von Liebig. Professor, Zéller’s investigations confirmed the correctness of 
observations which he had formerly. made respecting the influence which the age 
of the leaves of plants exercised. on the. composition of the.ash—that while young 
leaves are found to be rich in potash and phosphoric acid, and. poor in lime and 
silica, the amount of lime and silica in. the ash increases.with the age of the plant. 
As the best qualities of tea are known.to consist (as.will.be shown below) merely 
of the very young shoots of the plant, the estimation of the amount of potash, phos- 
phoric acid, lime, and silica may be usefully, as he suggested, employed in 
enabling us to judge of the quality of a specimen of tea. 
The richness of the tea-ash in potash and phosphoric acid, showing that the tea 
had been prepared from young leaves, suggested that the amount of matters in the 
leaves soluble in water, and of nitrogen, and also probably of theine, would be large. 
These anticipations were confirmed by the investigations. The extract obtained by 
treating the leaves with boiling water weighed 36°38 per cent., and the nitrogen 5°38 
per cent., while the theine amounted to 4°95 per cent. of the air-dried leaves. 
Some time ago the author had an opportunity of submitting to examination 
specimens of tea grown in Cachar, under the superintendence of Samuel Davidson, 
Ksq., and also a specimen of fine Cachar tea forwarded to him from the same district 
by Dr. Joseph Nelson. . Mr. Davidson’s specimens were taken from the fields in 
August, and were carefully enclosed in tinfoil, and may -therefore be regarded as 
representing genuine, unmixed specimens of Indian tea. Mr. Davidson also kindly 
supplied the following history of the crop from which the specimens were taken :— 
“The leaves were taken from plants in their seventh season, and consisted of the 
young shoots from which tea is manufactured, viz. the bud, and first, second, and 
third leaves down the stem. In none of the samples were there old leaves or actual 
wood. A shoot with this number of leaves is usually the growth of about twelve 
days after the bud has got started to grow. The indigenous sample is from the 
variety of the plant which was originally found growing wild in the jungles of these 
districts, _ The author thinks that it is the true Thea viridis. It 1s a very large- 
growing plant, almost.a tree, and its. leaves. when full-grown are very large and 
succulent. It yields hy far the best quality of.tea. ..The other sample was from a 
hybrid plant. This is supposed to bea. true hybrid -between the indigenous and 
China varieties, and certainly partakes very much of. the peculiarities of both 
varieties. The China plant is the variety, which is probably the correct Thea Bohca 
originally imported direct from China... It is a. miserable, small-growing, stunted 
plant compared to the indigenous, the full-grown leaves being only about 2 inches 
long, and the tea is inferior. The hybrid gives a good strong tea, and is a hardier 
plant than the indigenous, and so. is. very much liked, but the more closely it 
approaches to the indigenous it is the more highly prized.” The specimens received 
by the author had been merely dried in heated rooms. The produce of the crop 
was estimated at 400 Ibs. of dried tea per English acre. It is so seldom that we 
are able to oblain any precise account of the history of the specimens of tea and 
. other foreign productions which have been submitted to chemical examination, that 
Mr. Davidson’s report possesses especial importance. 
100 parts of each variety of the tea gaye the following results :— 
Indigenous. Hybrid. 
MMOIBbULC.. Sects asin ination Ree a mia nee Ake 16:06 16:20 
Oi fT Cosh LTD ETS) BRS IOI Ce re ete 7881 73:98 
MAVPITIEAT INMUUCIAY. ate ote crease iain ete le’ sistas clout crannies 5:13 4°82 
100-00 100-00 
Nitrogen in the dried tea... . cc. cs eee eee 4:74 2°81 
