nishida lived up to his reputation in the field, being incredibly knowledgeable not only about the primates he studied, but about the forest as a whole and all of the flora and fauna therein. not satisfied with bookish knowledge, he personally tasted each and every new leaf or fruit that he saw his chimpanzees consume - the ultimate act of identification with one's subjects. one major advance in the study of chimpanzee habits came when nishida discovered that wild chimpanzees consume aspilia leaves. these leaves have no known nutritional value, and are in fact not digested. the chimpanzees consume them very slowly, mostly in the morning, swallowing the leaves without chewing. together with richard wrangham, the first western primatologist to set foot in mahale, in 1971, nishida published his observations of potentially medicinal use of plants by wild chimpanzees, thus founding the new field of zoopharmacognosy (i.e., self-medication by animals ingesting plants, insects, or soils).