"The pericarp is at first of a green color, and performs the same functions as the other green parts of plants, decomposing carbonic acid under the agency of light and liberating oxygen. Saussure asserts that all fruits, in a green state, are adequate to perform this process of deoxidation. As the pericarp advances to maturity, it either becomes dry or succulent. In the former case it changes into a brown or white color, and has a quantity of ligneous matter deposited in its substance, so as to acquire great hardness, where it is incapable of performing any process of vegetable life; in the latter it becomes fleshy in its texture, and assumes various bright tints. In fleshy fruits, however, there is frequently a deposition of ligneous cells in the endocarp, forming the stone of the fruit; and even in the pulpy matter of the sarcocarp, there are found isolated cells of a similar nature, as in some varieties of pear, where they cause a peculiar grittiness. The contents of the cells near the outside of succulent fruits are thickened by exhalation, and a process of endosmose goes on, by which the thinner contents of the inner cells pass outward, and thus cause swelling of the fruit. As the fruit advances to maturity, however, this exhalation diminishes, the water becoming free and entering into new combinations. In all pulpy fruits, which are not green, there are changes going on by which carbon is separated in combination with oxygen. * * * "Succulent fruits contain a large quantity of water along with cellulose or lignine, sugar, gummy matter or dextrine, albumen, coloring matter, various organic acids, as citric, malic and tartaric, combined with lime and alkaline substances, beside a pulpy gelatinous matter, which is converted by acids into pectine, whence pectic acid is formed by the action of albumen. Pectine is soluble in water, and exists in the pulp of fruits, as apples, gooseberries, currants, strawberries, etc. Pectic acid is said to consist of C.14, H.3, O.12 + H.O. It absorbs water, and is changed into a jelly-like matter, hence its use in making preserves. Each kind of fruit is flavored with a peculiar aromatic substance. Starch is rarely present in the pericarp of the fruit, although it occurs commonly in the seed. * * *