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ON THE MODE OF PREPARING THE EXTRACT OF PERV- vIAN BARK IN THE KINGDOM OF PERU.

To the Editor of the Commercial and Agricultural Magazine.

SIR» Liſbon, 1/2 Fune, 1800,

My friend, Dr. Hipólito Ruiz at Madrid, having lately publifhed and com- municated to me ſome intereſting obſervations on the mode in which the ex- trat of Peruvian Bark, or Cinchona, is prepared in Peru, of freſh bark, juſt taken from the tree,and on its ſuperior medicinal powers, I have taken the earlieſt opportunity of incloſing thèm to you; truſting that you will not find them unworthy of a place in your bigbly intereſting and inſtruêtive Magazine. Lamy,&c

J. PATTEN.

N the mountain of Huánaco, in the kingdom of Peru, frcm whence a great many arobes* of the‘extra& of. Peruvian bark, or Cinchona, have already been exported, made of freſh bark, juſt taken from the tree; it is prepared in this manner 5 that common water is poured upon a given guantity of bark, in the proportion of four parts of water to one part of bark, which infuſion is left tó ſtand forty hours, the bark having been previouſly broken into ſmall pieces; at the expiration of that time, it 1s boiled by a flow fire, and when half of the liguor is evaporated, the remainder is poured of into an earthen veilet. Upon the reſidue of the ſame bark, half the quantity of water is poured, which was made ufe of before, and boiled by a moder- ate fire, until the liquor is half evaporated; then this ſecond liquor is mixed with the firſt, and poured into an earthen veſſel, where it is left to ſettle for the ſpace of twenty hours; the clear liquor is then poured off, añd boiled down to the conſiſtence of honey. Itis afterwards poured into another veſſel, ſmaller than the former, to give it, by a ſmall fire, the conſiſtence of a con- ſervé, taking care to ſtir it conſtantly with a wooden ſpattle, leſt it ſhould ſtick to the bottom and ſides of the veſſel and be burned. In this fate it is put in a glafs or earthen veſſel, but more generally, in tin caniſters, or 1n boxes, made of the wood of Cinchona, and as ſoon as it is cold, the veſſels are cloſed with the utmoſt care, to prevent the humidity of the air from penetrating to the extract,

Many manufadurers of the extra ftrain the liquor through double baize, and boil it to the conſiſtence of a conſerve, without paying much attention to the dregs having well ſettled. But, in conſequence of this operation, the extract remains im- pure and thick, and is uſually burnt, becauſe at the leaſt careleſs- nefs in ſtirring the liquor, when it has already attained the con- fiſtence of a conſerve, the terreſtrious and heterogeneous parts, which paſſed through the ftrainers, ſink to the bottom of the

veſſel, and, ſticking to it, they eaſily burn, and communicate

* An arobe contains thirty-two pints Spank meaſaure-