buds along with them: whereas the leaves of parts that have received no material injury, and where the vital energy acts with due power, either fall off spontaneously, or are detached by the slightest touch. Plants of hot countries, kept in our stoves, exhibit the same phænomenon when transplanted or otherwise injured, even though not naturally deciduous.
So when fruits are thoroughly ripened, they become, with respect to the parent plant, dead substances, and, however strongly attached before, are then thrown off as extraneous bodies. Their stalks fade or wither, though the life of the adjoining branch continues unimpaired, and a line of separation is soon drawn. In a poor soil, or unfavourable climate, a bunch or spike which should naturally consist of a considerable number of flowers, bears perhaps not half so many. Its upper part very early withers, the vital principle ceases to act at the point beyond which it could not continue to act with effect, and all its energy is directed to perfect what lies within the compass of its resources. This is evident in Lathyrus odo-
