"Dr. Bronson said that we were in the centre of the region which produces the celebrated _Chinchona_, or Peruvian bark, which has such a great reputation in curing fevers. It takes its name from the Countess of Chinchon, who was cured of intermittent fever by its use at Lima, about the middle of the seventeenth century. It was then taken to Europe, and the knowledge of it was spread through the civilized world." "Quinine is produced from this bark, is it not?" Frank inquired, when Fred read the note quoted above. "Yes," replied the latter, "quinine is an alkaloid, made from Peruvian bark, and was discovered in 1820. There are several other alkaloids in the bark, but none are as important as the one you have just mentioned. Any doctor can tell you of its qualities, and a great many people who are not doctors are familiar with its uses. "No traveller will venture into a malarious region without a good supply of quinine, and in some countries it is almost as important to have it as to be provided with food." Having answered Frank's interrogatory, Fred continued with his observations upon the trees that produce the valuable bark. "There are no less than twenty-one varieties of trees producing the bark from which quinine is made," said Fred, "but some of the most valuable of them are extinct, owing to the reckless way in which they have been stripped. The trees grow on the slopes of the Andes, in Peru, Ecuador, and other countries; they have been successfully transplanted to India, Java, Algeria, and the United States; and the future supply of quinine for a feverish world will probably come from other countries than South America. "The _cascarilleros_, or bark-collectors, are obliged to go far into the forests in search of trees, and they suffer many hardships and privations in pursuing their industry. The best of the trees have been destroyed; we asked if we could see one, and were told we must make a journey of several days to do so, as none now grow in the neighborhood of Guaranda. A gentleman who lives in Quito told us he had seen a chinchona tree sixty feet high, and six feet in circumference; it yielded two thousand pounds of green bark, or about one thousand pounds when dry. Another tree that he saw gave three thousand dollars' worth of quinine; but such trees are rare. [Illustration: AMONG THE LAVA BEDS.] "We left Guaranda very early in the morning," Fred continued, "and when we jumped into our saddles we could hardly see where they were. There is a ridge to cross, after getting out of the valley of the Chimbo, which it is desirable to pass in the forenoon, as the wind blows violently there after the sun has passed the meridian, though it is quiet enough in the morning. We crossed the ridge, with the great mountain rising before us, and then descended to another valley to the city of Ambato, which has nothing in particular to recommend it. [Illustration: VIEW OF COTOPAXI.]