“The soil in such a broken country is, of course, very diversified, ranging from a very light decomposed shale or sandstone to a heavy blue or chiefly yellow clay. “The rainy season begins in October, and continues until May or June. During this time the rains are copious and almost constant. During the succeeding two months there is scarcely a drop of rain, and during the next two there are only occasional showers. “Such are the conditions under which the Coca grows in this section. “When we come now to consider the methods of cultivation here adopted, we must be cautious about accepting them as the best, merely because they are generally followed here. It is to be remembered that the Bolivian system of agriculture has not received the attention that it should have had, and that it is very probable that reforms might be introduced in present methods. “Nor is it proper to proceed concerning Coca-culture without a few words concerning what is meant by the ‘best quality’ of Coca-leaves. To a manufacturing chemist the best quality would mean the quality that would yield the largest percentage of crystallizable cocaine, obtainable in the easiest manner, while the same Coca might be considered for domestic consumption as representing one of the lower grades. It is highly probable that the amount of cocaine forms no element in the Indian’s estimate of the quality of Coca, no more than the percentage of nicotine establishes the quality of a particular grade of tobacco. Coca-leaves are classed in general by the Indians as ‘hajas dulces’ (sweet leaves) and ‘hajas amargas’ (bitter leaves). The former are made sweet by the abundance of alkaloids other than cocaine. While it is true that a greater abundance of these alkaloids is usually accompanied by a larger percentage of cocaine also, yet the variation in the amount of the latter is not so great as in the former; so that while in the sweet leaves the bitter taste of the cocaine is masked by the presence of the other alkaloids, in the bitter leaves its flavour is the predominant one. The presence, then, of these _sweet alkaloids_, as we may call them, translating the simple and expressive term of the Indians, determines the domestic value of the Coca, and all that is known of the best methods of cultivation is based on the production of the highest percentage of these alkaloids.[25] Experience may determine that for manufacturing purposes a very different line of principles of culture should be followed.