The Spanish Government interfered with the cultivation from more worthy motives, and _mitas_ of Indians, for the purpose of collecting coca-leaves, were forbidden in 1569, owing to the reputed unhealthiness of the valleys.[318] Finally Don Francisco Toledo, viceroy of Peru, permitted the cultivation with voluntary labour, on condition that the Indians were well paid, and that care was taken of their healths. This most prolific of Peruvian legislators issued no less than seventy _ordenanzas_ on this subject alone, between the years 1570 and 1574. Coca has always been one of the most valuable articles of commerce in Peru, and it is used by about 8,000,000 of the human race. The coca-plant (_Erythoxylon coca_)[319] is cultivated between 5000 and 6000 feet above the level of the sea, in the warm valleys of the eastern slopes of the Andes, where almost the only variation of climate is from wet to dry, where frost is unknown, and where it rains more or less every month in the year. It is a shrub from four to six feet high, with lichens, called _lacco_ in Quichua, usually growing on the older trunks. The branches are straight and alternate; leaves alternate and entire, in form and size like tea-leaves; flowers solitary with a small yellowish-white corolla in five petals, ten filaments the length of the corolla, anthers heart-shaped, and three pistils. Sowing is commenced in December and January, when the rains begin, which continue until April. The seeds are spread on the surface of the soil in a small nursery or raising-ground called _almaciga_, over which there is generally a thatch roof (_huasichi_). At the end of about a fortnight they come up; the young plants being continually watered, and protected from the sun by the _huasichi_. The following year they are transplanted to a soil specially prepared by thorough weeding, and breaking up the clods very fine by hand; often in terraces only affording room for a single row of plants, up the sides of the mountains, which are kept up by small stone walls. The plants are generally placed in square holes called _aspi_, a foot deep, with stones on the sides to prevent the earth from falling in. Three or four are planted in each hole, and grow up together. In Caravaya and Bolivia the soil in which the coca grows is composed of a blackish clay, formed from the decomposition of the schists, which form the principal geological features of the mountains. On level ground the plants are placed in furrows called _uachos_, separated by little walls of earth _umachas_, at the foot of each of which a row of plants is placed; but this is a modern innovation, the terrace cultivation being the most ancient. At the end of eighteen months the plants yield their first harvest, and continue to yield for upwards of forty years. The first harvest is called _quita calzon_, and the leaves are then picked very carefully, one by one, to avoid disturbing the roots of the young tender plants.