The bark yielded by this tree is named Quina amarilla1, Cascarilla de Loxa, and Cascarilla amarilla; but it is not the Calisaya, the yellow bark of the shops, which is not brought from Carthagena, but from ports in the Pacific Ocean. The genuine yellow bark is the Calisaya arrollada of the Spaniards, the synonymes of which are Calisaya de plancha, de Quito, de Lima.2 It is brought to this country in chests, containing about 90 lbs. to 100 lbs. each; and consists of pieces about eight or ten inches or more in length, some quilled, but the greater part flat.3 The quilled pieces are less rolled and much thicker than the quilled pale bark; and the epidermis, which is of a tawny, greyish-brown colour, and covered with flat and stringy lichens, is more rough and chopped, easily separating, and often as thick as the bark itself, which is about one eighth of an inch; while the interior is of a yellow colour, passing to orange. The flat pieces are generally without any epidermis, and considerably thicker than the quilled, and of the same yellow hue without and within.

Both are mixed in the same chest The epidermis yields a dark-red powder, which is tasteless and inert.

1 Yellow bark; but the adjective signifies both yellow and pale or wan. The name appears to be used in contradistinction to naranjada, orange-colour, which is applied to the first officinal species. Additional synonymes:

Cascarilla delgada.

-------------palo bianco.

Quina amarilla de Bogota.

2 The name Calisaya is that of a province producing this bark, in the most southern part of Peru, in the Intendencia de la Paz. There are three varieties of Calisaya known in South American commerce : 1. Calisaya, arrollada, rolled Calisaya; 2. Calisaya de plancha, flat Calisaya; 3. Calisaya de Santa Fe, which is also a thick, flat bark.-MSS. of Dr. Devoti.

3 These are distinguished in commerce by the terms with coat and without coat.

Qualities.-Yellow bark has nearly the same odour in decoction as the pale; the taste is more bitter, but less austere, and it does not afford any astringent feeling to the tongue when chewed. The internal colour is golden cinnamon, or subdued orange-yellow, becoming when moistened a lively orange. The fracture is woody and fibrous, presenting, when examined by a lens, the appearance of parallel, longitudinal, needle-like fibres, with a dry agglomerated powder in the interstices, of a yellow colour. It is easily reduced to fine powder, and the powder preserves the colour of the bark, but is brighter. Guibourt has proposed the following method of distinguishing this bark when in quill from red bark. Pulverize a little of the bark, and triturate the powder in a porcelain mortar with water, and filter; then to the filtered fluid add some crystals of pure sulphate of soda: a white precipitate will be thrown down if the specimen be true yellow bark. The sediment,, which the infusion lets fall in cooling, is of a brighter colour than the dry powder.

The filtered aqueous infusion has a pale golden hue, with a shade of red; is clearer, and seemingly less mucilaginous, than the former : it has all the bitterness of the bark; reddens litmus paper, and precipitates solution of galls; but the precipitate does not fall so instantaneously as in the infusion of the former species. With solution of gelatine a pinkish yellow precipitate is produced: acetate of lead throws down a precipitate; and tartarized antimony, one more copious than that which the pale bark affords. A solution of sulphate of iron changes its colour to a bluish green, and, after many hours, gives a precipitate of the same hue. The ethereal tincture has a golden colour, affords resin when evaporated, and is affected by the same re-agents as that of the pale cinchona; but the water on which it is evaporated is less highly coloured. The alcoholic tincture appears to be in every respect the same as that afforded by the pale bark. It seems to agree in most of its properties with the first species examined by Vauquelin; which he states was brought to Spain in 1788, and, owing to its having been used for the royal family, got the name of royal cinchona.

Yellow bark owes its febrifuge properties to an alkali which has been termed Quina, and which can be separated by a process similar to that employed for obtaining cinchonia. Quina separates from the alcoholic solution in a viscid state, and when dried in the open air, in a moderate heat, becomes brown and brittle. Thiel procured from the flat bark 2.3 per cent. of. Quina, and 0.08 of Cinchonia : Michaelis procured no Cinchonia, but 3.7 per cent, of Quina from the flat, and 2.0 from the quilled: Von Santen, 2.0 of Quina from the flat, with a trace of Cinchonia: Witstock obtained 3.0 per cent. of sulphate of Quina, and 0.12 of Cin-chonia.1 When properly prepared Quina is white, bitter, insoluble in water, but very soluble in ether. Its proximate principles are 75.76 of carbon, 7.52 hydrogen, 8.11 nitrogen, and 8.61 of oxygen2: or 20 eq. of Carbon = 122.4 + 12 Hydrogen = 12 + 1 Nitrogen = 14.15+2 Oxygen =16, making its equivalent 154.5.

All the cinchonas are mountainous trees, growing seldom lower than 975 toises above the level of the sea. Those are richest in the alkaloids which are found in the most elevated situations: the Cinchonas of Peru are generally the richest in Cinchonia; those of Bolivia and La Paz in Quina. Those species, the corolla of which is downy and pink, furnish the largest quantity of the alkaloids : those which have smooth and white corollas, the smallest quantity. No inference can be drawn from the smooth or downy character of the leaves.3

The goodness of all the species of Cinchona depends on the proper age of the branches that are barked. The bark-collectors (cascarilleros) decide on the maturity of these in the following manner: - They strip off from each branch a small piece of bark; and if it immediately redden on the inner side, they consider it sufficiently mature; but should the colour not appear in three or four minutes, it is rejected as being not yet in season.4 As the trees frequently die after being barked, and no new ones are planted, there is reason for fearing that this valuable drug may ere long be lost to Europe.