Induction of parthenocarpy and a comparison of normal and parthenocarpic fruits was undertaken in order to determine the possible role of the embryo in the development of the fruit. There is at present a question as to whether the production of fruit is brought about as a result of growth substances from the polleni, the developing ovule, seeds, tissues of the ovary wall and placentae, or from some other region of the plant. These arguments have been reviewed by GUSTAFSON (9, 10, 11, 12), and it is believed that the data given below contribute further to the interpretation of this point. Materials and methodsThe Marglobe variety of Lycopersicum esculentum was grown under greenhouse conditionis, with a temperature range from approximately 70°-850 F., and the experimental work was carried out with seventy selected plants. One group received the treatment necessary for the production of parthenocarpic fruit; the second group was kept as a control.The seeds were planted October 6, and the seedlings were transplanted several times to secure a vigorous root system; they were kept under observation from that time until February 2, when the first treatment was applied.Indolebutyric acid in lanolin was prepared in the manner reported by OLESON (20), and used in concentrations of 0.5%o by weight. The flowers were emasculated, to prevent pollination, before the bud opened. Both the sepals and petals were removed with a minimum of trauma after the blossom opened in order to facilitate the application of the lanolin smear.Applications were initially made in several ways: on the stigma, on a horizontal cut at the base of the style, or at a cut through the ovary. Parthenocarpic fruits most nearly resembling the normal fruits were produced by the treatment of the cut at the base of the style as described by GUSTAFSON (9). This method of treatment was used throughout the remainder of the experiment. Following the application of the lanolin-indolebutyric acid mixture, the flowers were bagged with cellophane envelopes to prevent any contamination by pollen, although it has been reported that the pollen becomes inactivated when in contact with lanolin mixtures containing some growth-promoting substance. Treatments were continued on the blossoms as they opened through February and March.Beginning March 2, following the above treatment, flowers were cut below the abscission layer of the pedicel and collected at two-hour intervals for a period of twenty-four hours; further collections were made at 24-hour