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SUMMARY Purpose: The role of sharps and spikes, interictal epileptiform discharges (IEDs), in guiding epilepsy surgery in children remains controversial, particularly with intracranial electroencephalography (IEEG). Although ictal recording is the mainstay of localizing epileptic networks for surgical resection, current practice dictates removing regions generating frequent IEDs if they are near the ictal onset zone. Indeed, past studies suggest an inconsistent relationship between IED and seizure-onset location, although these studies were based upon relatively short EEG epochs. Methods: We employ a previously validated, computerized spike detector to measure and localize IED activity over prolonged, representative segments of IEEG recorded from 19 children with intractable, mostly extratemporal lobe epilepsy. Approximately 8 h of IEEG, randomly selected 30-min segments of continuous interictal IEEG per patient, were analyzed over all intracranial electrode contacts. Results: When spike frequency was averaged over the 16-time segments, electrodes with the highest mean spike frequency were found to be within the seizure-onset region in 11 of 19 patients. There was significant variability between individual 30-min segments in these patients, indicating that large statistical samples of interictal activity were required for improved localization. Low-voltage fast EEG at seizure onset was the only clinical factor predicting IED localization to the seizure-onset region. Conclusions: Our data suggest that automated IED detection over multiple representative samples of IEEG may be of utility in planning epilepsy surgery for children with intractable epilepsy. Further research is required to better determine which patients may benefit from this technique a priori.

MCGAHAN, MERRITT W. (United Fruit Co., Norwood, Mass.) Studies on the seed of banana. I. Anatomy of the seed and embryo of Musa balbisiana. Amer. Jour. Bot. 48(3): 230-238. Illus. 1961. -The seed coat of Musa balbisiana Colla consists of a relatively thick outer integument and a 2-cell-layered inner integument. The entire seed coat is selerified, but routine tests for lignin are negative. Within the outer integument there is a zone of unusual sclereids tentatively termed "multiluminate." Between the inner integument and the remnants of the nucellus is a cuticle 10-12,u thick. The micropylar plug and collar are typical of the genus. The chalazal mass is an annular region of gelatinous cells. The mature embryo is comprised of a massive cotyledon, an epicotyl with 1 leaf primordium, a primary root primordium, and several adventitious root primordia. Procambium is well developed, but no mature vascular elements are present in the

IN THE STUDIES on the photoperiodic responses of plants, there has been no detailed study made of the vascular ontogeny in the plants used. It is felt that such studies would not only increase the understanding of these responses, but would also contribute to the understanding of plant development in general. Of the several plants that have been used quite extensively in studies on photoperiodism, Xanthium has proven to be one of the most responsive (Bonner and Bonner, 1948; Hamner and Bonner, 1938; Mann, 1940; Withrow and Withrow, 1943.) Xanthium chinense Mill. (Millspaugh and Sherff, 1919) was selected for this study as a representative of this physiologically interesting group and as a starting point for further comparative studies in this genus. The literature on vascular differentiation was reviewed in 1943 (Esau, 1943b) and more recently by Esau (1953b) and Philipson (1949). A consideration of the most pertinent papers will be made in the discussion of the results of this study. MATERIALS AND METHODS.-Plants of Xanthium chinense were collected in the vicinity of Davis, California, during the spring and summer of 1950 and 1951. The apical 1 cm. or more was removed and killed and fixed in Craf III (Sass, 1940). Dehydration was accomplished by the alcoholxylene method or by the tertiary butyl alcohol method. The latter technique caused less hardening and made sectioning easier. The material was embedded in Fisher's Tissuemat and sections were cut at 7-l10i. Heidenhain's hematoxylin, safranin and fast green were used as a triple-stain combination. Fast green stained the thickened walls of young sieve tubes and thus facilitated their identification. Three shoots, cut in serial transverse sections, were analyzed in detail. Twentv-two other shoots, cut in serial transverse or longitudinal sections, were used to confirm or substantiate the data presented here. Some of the data were obtained from fresh material sectioned by hand and stained with phloroglucinol and hydrochloric acid. While the exact chronological age of these plants is not known, the stage of development as indicated by the number of leaves is noted in the appropriate places. The oldest (ontogenetically) plants used