The humidity of the atmosphere, and the action of the sun, succeeding each other in constant alternation, and being always sufficient for the development of plants, an almost perpetual succession of vegetation ensues; for no sooner is one plant gone than another begins to arise in its place. The trees are covered perpetually with green leaves, and adorned with sweet-smelling flowers, or laden with tropical fruits in every stage of development. This province was said to be the most populous in America. It possessed a number of towns with populations varying from ten to thirty thousand. The people of _Quito_ had, fortunately for themselves, escaped the lot of labouring in the mines; since those which this district possessed were too poor to pay the expenses of working them. They must have been poor indeed, since the Spaniards consented to relinquish a mode of acquiring riches which cost them nothing but the blood of their slaves. Freed from this source of labour, the inhabitants of _Quito_ were more usefully employed in manufactures, the produce of which was exchanged for wine and oil, and other commodities which were foreign to this elevated region. Notwithstanding, however, its natural advantages, _Quito_, in the latter part of last century, had sunk into an extreme degree of poverty. This province possessed, in quinine, one production which has been ever since its discovery of the highest value to the human race, and which formed, in the colonial period, the sole article of export. The only precious portion of the _quinquina_ tree is its bark, which requires no other preparation for its use than being dried. At one time the _quinquina_ was supposed to be peculiar to the territory of _Loxa_, the finest quality being produced on the mountain of _Caganuma_. Later researches, however, prove that the same tree exists at _Riobamba_, at _Cuenca_, and at _Bogotá_. Europe is indebted for the introduction of this most precious article to the Jesuits, who made its invaluable qualities known at Rome in the year 1639. In the following year its use was established in Spain by Juan de Vega, physician to the Vice-Queen of _Peru_, its price being a hundred crowns a pound. The price which the invaluable article commanded and deserved, led, as a matter of course, to adulteration; and even the distant inhabitants of _Loxa_, being unable to supply the demand for genuine _quinquina_, filled up the void by a mixture of the bark of other trees. This proceeding, however, rebounded on themselves, since it deprived their special product of its unique reputation; whilst, at the same time, it led to a more diligent search for the same plant elsewhere. The natives of the region which furnished _quinquina_ were in the habit of using a simple infusion of the bark in cases of fever, before they were taught by M. Joseph _de_ Jussieu to produce the extract. * * * * * [Sidenote: 1728.] [Sidenote: 1731.]