A large quantity of a kind of alabaster or gypsum is brought down from the northward in large junks to Canton; it is called in the Chinese language _Shek, oo_, and is used by them, as well as by Europeans, in a pulverized state, as a dentifrice: it is also employed and highly esteemed by the Chinese as a _tisan_, for the purpose of allaying the ardent thirst in fevers, and is considered by them _nourishing_ as well as cooling. It is pulverized and used in the adulteration of powdered sugar-candy, to which it bears in appearance a very close resemblance; indeed, it is (except by the taste) not easy to distinguish one from the other. Dr. Cox presented me with a specimen in spirits of a very venomous snake, which is not uncommon in China; this one had some time since bitten a Chinese servant in the Dutch Hong, and occasioned his death in a few hours. The head of the reptile in this specimen had been cut off by the Chinese who first arrived to the assistance of the wounded man, who having bruised it, had applied it as a poultice to the bitten part; from which a query may arise, whether the poison mingled with the mashed head, being applied to the bitten part, may not have served to hasten the fatal termination. This venomous reptile is called _white and black snake_, from its colours; by the Chinese, _Pak, y, hak_, (pak signifying white, and hak, black). The largest size it has been seen to attain, has been three feet. The colour of the reptile is a bluish white, with black, circular, broad rings, around the body. The head (which I had an opportunity of examining in another and unmutilated specimen) was broad, flattened, with ten broad scales upon the upper and lateral parts; and around the body, from one extremity to the other, there were forty-nine circular rings. The length of my specimen is nearly three feet.