I.—THE LOXA REGION, AND ITS CROWN BARKS.
The region around Loxa, on the southern frontier of the modern republic of Ecuador, is the original home of the Chinchona, and nearly in the centre of its latitudinal range of growth. On the lofty grass-covered slopes of the Andes, around the little town of Loxa, and in the sheltered ravines and dense forests, those precious trees were found which first made known to the world the healing virtues of Peruvian bark. They were most plentifully met with in the forests of Uritusinga, Rumisitana, Cajanuma, Boqueron, Villonaco, and Monje, all within short distances of Loxa.
Linnæus had named these trees Chinchona officinalis; but when Humboldt and Bonpland examined them, the discovery of other species yielding medicinal bark had rendered the name inappropriate, and they very properly re-christened them, after the distinguished Frenchman who had originally described them, Chinchona Condaminea. Humboldt says that they grow on mica slate and gneiss, from 6000 to 8000 feet above the sea, with a mean temperature between 60° and 65° Fahr. In his time the tree was cut down in its first flowering season, or in the fourth or seventh of its age, according as it had sprung from a vigorous root-shoot, or from a seed. He describes the luxuriance of the vegetation to be such that the younger trees, only six inches in diameter, often attain from fifty-three to sixty-four English feet in height. "This beautiful tree," he continues, "which is adorned with leaves above five inches long and two broad, growing in dense forests, seems always to aspire to rise above its neighbours. As its upper branches wave to and fro in the wind, their red and shining foliage produces a strange and peculiar effect, recognisable from a great distance."[36] It varies much in the shape of the leaves, according to the altitude at which it grows, and bark-collectors themselves would be deceived if they did not know the tree by the glands, so long unobserved by botanists. The C. Condaminea described by Humboldt is the same as the C. Uritusinga of Pavon. It once yielded great quantities of thick trunk bark, but, owing to reckless felling through a course of years, it is now almost exterminated, and its bark is rarely met with in commerce. The distinguished botanist Don Francisco Caldas examined the chinchona forests of Loxa after Humboldt, between 1803 and 1809. He says that the famous quina-tree of Loxa grows in the forests of Uritusinga and Cajanuma, at a height of from 6200 to 8200 feet above the sea, in a temperature of 41° to 72° Fahr.; but that it is only found between the rivers Zamora and Cachiyacu.[37] He describes the tree as from thirty to forty-eight feet high, with three or more stems growing from the same root; the leaves as lanceolate, shining on both sides, with veins a rosy colour, a short and tender pubescence on the under side when young, and when past maturity a bright scarlet colour; the bark black when exposed to the sun and wind, a brownish colour when closed in by other trees, and always covered with lichens;[38] and the rock on which the trees grow, a micaceous schist.
Don Francisco José de Caldas, a native of New Granada, was one of the most eminent scientific men that South America has yet produced. He was associated with Mutis in the botanical expedition of New Granada; he explored the chinchona region as far as Loxa; and thus takes his place as one of those to whom we are indebted for throwing light on the nature of the trees yielding Peruvian bark. Caldas was born at Popayan in the year 1770; and, from early youth, devoted himself to the pursuits of science with untiring energy, especially studying botany, mathematics, meteorology, and physical geography. He constructed his own barometer and sextant, and, ignorant of the methods adopted in Europe, he discovered the way of ascertaining altitudes by a boiling-point thermometer. He has left many memoirs on botanical and other subjects behind him, and his style is always animated, clear, and interesting; but many of the productions of this remarkable man are still in manuscript,[39] and others are lost to us for ever. Above all, it is to be regretted that his botanical chart of the chinchona genus, which he promised in one of his memoirs, has never seen the light. After the declaration of independence Caldas was nominated by the Congress at Bogota to publish the works of his friend the botanist Mutis. When the brutal Spanish General Morillo entered Bogota in June 1816, he perpetrated a series of savage massacres, in which more than 600 of the most distinguished men in the country fell victims. Among them was Caldas, who was shot through the back on the 30th of October 1816.[40]
The Spanish botanists Ruiz and Pavon also examined the chinchona-trees of Loxa; and the latter described two species, C. Uritusinga, named from the mountain on which it was once most abundant, and C. Chahuarguera, so called from a fancied resemblance of the bark to a pair of breeches (huara in Quichua) made from the fibre of the American aloe (chahuar). To these the botanist Tafalla added the C. crispa. These three species are all included in Humboldt's C. Condaminea, which is readily known by the little pits, bordered with hairs, at the axils of the veins on the under side of the leaf. It would appear that at one period of growth these little pits or scrobicules are wanting, but when the plant is in full vigour they are markedly prominent. The C. Chahuarguera[41] is described by Pavon as growing from eighteen to twenty-four feet in height; although now the trees, which yield the Loxa bark of commerce, do not attain a height of more than four to nine feet. It is met with on the grassy open crests of mountain ridges, in light sandy soil interspersed with rocks, amongst shrubs and young plants. The barks of Loxa were called crown barks, because they were reserved for the exclusive use of the royal pharmacy at Madrid; and they originally sold at Panama for five and six dollars, and at Seville for twelve dollars the pound; but in later times they were much adulterated, and the price fell to one dollar the pound.
The C. Chahuarguera is the rusty crown bark of commerce,[42] and the C. crispa is the quina fina de Loxa or crespilla negra of the natives. A parcel of it has quite recently sold at a higher price than Calisaya quills. With this rusty crown bark are mixed larger quills particularly rich in the alkaloid called chinchonidine.[43] The C. Uritusinga grew to the height of a lofty forest tree, but it is now nearly exterminated. The leaves assume a red colour before they fall, acquiring the most beautiful tints, and the tree is one of the finest in those forests.[44] It is said that there is a great difference in the bark, according as it is grown on the sides of mountains most exposed to the morning or evening sun; and its position is believed to have a great influence on the quality of its alkaloids. The usual yield of the large quills is 3.5 to 3.6 per cent.[45]
The bark-collectors of Loxa are said to show some little forethought, a quality which is entirely wanting in most of their fraternity. To save the trees they occasionally cut off the whole of the bark, with the exception of one long strip, which gradually replaces its loss; and the second cutting is called cascarilla resecada. This practice was in use in the days of the botanist Ruiz, who protested against it, and declared that it was very injurious to the trees, many having been destroyed by it.[46] Later accounts, however, show that the bark-collectors of Loxa are as thoughtlessly destructive as those in other parts of South America. They often pull up the roots, while the annual burning of the slopes, and the continual cropping of the young shoots by cattle, assist the work of destruction.[47]
It is, therefore, well that the C. Chahuarguera and C. Uritusinga, the earliest known and among the most valuable of the chinchona-trees, should have been saved from extinction by timely introduction into India.
The annual export of Loxa bark, from the port of Payta, is from 800 to 1000 cwts.