may not be on hand. Inasmuch as the common names of the plants lead to many mistakes and much confusion, it is indispensable to acquaint one's self with the description of the plant and be sure that the actual product conforms in all respect to the description. For this purpose it is well to obtain flowering specimens and bearing this fact in mind I have been careful to indicate the flowering season of each plant. By making excursions to the towns of San Mateo and Angono I have obtained an abundance of whatever I sought and at the same time have learned by taking with the mountaineers and "curanderos," what uses they make of their plants. The "curanderos" know a great deal concerning these uses, but become very reticent as soon as questioned about them. Whether it is dread of ridicule or fear that silences them, the fact remains that is no easy matter to glean any useful facts from them. And yet by tact and friendliness one may elicit much more information from them than first impressions would lead one to hope.
Leaves should be gathered when fully developed, rejecting the old, dried and worm-eaten ones.
The best time to gather bark is one month before the period of inflorescence, when it is rich in sap. The flowers are best gathered when about half expanded. The fruit is gathered green or ripe according to the active principle sought. The seeds should always be mature.
Not all parts of the plants are equally provided with the active principle which may be localized in the roots or the flower; or distinct principles may exist in different parts of the same plant. Therefore the part indicated, and only that part should be employed.
In the root the active substance usually resides in the bark, sometimes in the parenchyma that envelopes the woody tissue and rarely in the woody tissue itself, as, for example, in "rhubarb" and "pareira brava."