The following harvests are called _mitta_ ("time" or "season"), and take place three times and even four times in the year. The most abundant harvest takes place in March, immediately after the rains; the worst at the end of June, called the _mitta de San Juan_. The third, called _mitta de Santos_, is in October or November. With plenty of watering, forty days suffice to cover the plants with leaves afresh. It is necessary to weed the ground very carefully, especially while the plants are young, and the harvest is gathered by women and children. The green leaves, called _matu_, are deposited in a piece of cloth which each picker carries, and are then spread out in the drying-yard, called _matu-cancha_, and carefully dried in the sun. The dried leaf is called _coca_. The drying-yard is formed of slate-flags, called _pizarra_; and, when the leaves are thoroughly dry, they are sewn up in _cestos_ or sacks made of banana-leaves, of twenty pounds each, strengthened by an exterior covering of _bayeta_ or cloth.[320] They are also packed in _tambores_ of fifty pounds each, pressed tightly down. Dr. Poeppig reckoned the profits of a coca-farm to be forty-five per cent. The harvest is greatest in a hot moist situation; but the leaf generally considered the best flavoured by consumers, grows in drier parts, on the sides of hills. The greatest care is required in the drying; for too much sun causes the leaves to dry up and lose their flavour, while, if packed up moist, they become fetid. They are generally exposed to the sun in thin layers. Acosta says that in his time the trade in coca at Potosi was worth 500,000 dollars annually; and that in 1583 the Indians consumed 100,000 _cestos_ of coca, worth 2-1/2 dollars each in Cuzco, and 4 dollars in Potosi. In 1591[321] an excise of 5 per cent. was imposed on coca; and in the years 1746 and 1750 this duty yielded 800 and 500 dollars respectively, from Caravaya alone. Between 1785 and 1795 the coca traffic was calculated at 1,207,430 dollars in the Peruvian viceroyalty; and, including that of Buenos Ayres, 2,641,487 dollars. In the district of Sandia, in Caravaya, there are two kinds of coca, that of Ypara and that of Hatun-yunca, which has a larger leaf. The yield is 45,000 cestos a year. In the yungus of La Paz, in Bolivia, the yield is about 400,000 cestos. The coca-trade is a government monopoly in Bolivia, the state reserving the right of purchasing from the grower, and reselling to the consumer. This right is generally farmed out to the highest bidder. In 1850 the coca-duty yielded 200,000 dollars to the Bolivian revenue.