NATURAL HISTORY OF THE CINCHONAS. 
29 
November he journeyed towards the South, gained the Rio 
Grande, and crossed the country of the Cordillera, as far as 
Tarija, where he arrived in January 1846, — a laborious 
journey, the object of which was to determine with correct- 
ness the southern limit of the district of the cinchonas. M. 
Weddell gave the name of Cinchona lustra lis to a species 
which he discovered, like a distant sentry, at this extreme 
point, near to the nineteenth parallel of south latitude. In 
the month of August following he visited some of the large 
towns of Bolivia. At Cochamba a curious phase of his ex- 
pedition began. He traversed near there the great chain of 
the Andes, purposing to reach La Paz, where the cinchona 
commerce is carried on to the greatest extent. The Andes 
present, at this part, a long and fine series of natural steps, 
by which the traveller gradually descends, passing succes- 
sively in review all the varieties of climate, and all the cor- 
responding shades of vegetation. The different species of 
cinchona are rapidly presented to observation. Almost im 
mediately on his entering the province of Enquisivare he 
had the opportunity of studying the trees which produce the 
Calisaya bark, the most valuable of all the species in conse- 
quence of the large proportion of quinine which it contains. 
He gave to this tree previously unknown, the name of Cin- 
chona Calisaya. At Palca he learned that there was recently 
discovered, on the borders of the Rio Ayopaya,an immense 
forest of cinchonas which no one had yet explored. But it 
was in the province of Yungas, the richest and most fertil e of 
the provinces of Bolivia, that he obtained the most precise in- 
formation of the mode of procuring, preparing, selling, and 
adulterating the barks which he wished to study. 
In 1817, after the rainy season, M. Weddell resumed the 
road of the great Cordillera. The town of Strata, or Es- 
quibel, situated on the eastern side of the Andes, and at the 
foot of one of its highest peaks, is considered one of the most 
prolific sources of the Bolivian cinchonas; but is, in fact, 
only a simple point of transit for theproducts of the valleys 
/ 
