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The prospect of observing solar neutrinos by means of the inverse beta, process 'Cl(v, e )"Ar induced us to place the apparatus previously described' in a mine and make a preliminary search.This experiment served to place an upper limit on the flux of extraterrestrial neutrinos. These results will be reported, and a discussion will be given of the possibility of extending the sensitivity of the method to a degree capable of measuring the solar neutrino flux calculated by Bahcall in the preceding paper.The apparatus consists of two 500-gallon tanks of perchlorethy1. ene, C,C14, equipped with agitators and an auxiliary system for purging with helium. It is located in a limestone mine 2300 feet below the surface' (1800 meters of water equivalent shielding, m. w. e. On the other hand, if one wants to measure the solar neutrino flux by this method one must use a much larger amount of C,C14, so that the expected "Ar production rate is well above the background of the counter, 0. 2 count per day. Using

Tanks containing 200 and 3900 liters of carbon tetrachloride were irradiated outside of the shield of the Brookhaven reactor in an attempt to induce the reaction Cl 37 (J>,e~)A 37 with fission product antineutrinos. The experiments serve to place an upper limit on the antineutrino capture cross section for the reaction of 2X10" 42 cm 2 per atom. Cosmic-ray-induced A 37 was observed and the production rate measured at 14 100 feet altitude and sea level. Measurements with the 3900-liter container shielded from cosmic rays with 19 feet of earth permit placing an upper limit on the neutrino flux from the sun. * Research carried out under the auspices of the U. S. Atomic Energy Commission. 1 The experiments are reviewed by H. R. Crane, Revs. Modern

In an earlier report (1), it was suggested from cross circulation experiments that a humoral agent provides the immediate stimulus for aldosterone production. It was proposed that this humoral substance be called the aldosterone-stimulating hormone (ASH). The present experiments were designed to determine the locus of secretion of ASH. Specific regions or organs which might be the source of ASH were removed and, subsequently, attempts were made to stimulate aldosterone secretion by bleeding. A positive response to bleeding in the absence of ACTH has been considered as presumptive evidence for secretion of ASH. It is important that studies be conducted in hypophysectomized dogs since bleeding (2, 3) stimulates release of ACTH which promotes increased aldosterone secretion. Bleeding was used as a stimulus because it is a simple and effective means of increasing aldosterone production.Studies were made in normal dogs to establish the magnitude of the response in aldosterone secretion to bleeding. In view of the marked fall in aldosterone secretion following hypophysectomy, the possibility was examined that ASH is secreted by the anterior pituitary. Since a response in aldosterone secretion to acute blood loss was obtained in hypophysectomized dogs, the effects of decapitation and subsequent bleeding were next determined. Finally, the effects of bleeding on aldosterone secretion were observed in hepatectomized-hypophysectomized dogs and in nephrectomized-hypophysectomized animals, and * This investigation was aided in part by Grant A-1944 from the National Institutes of Health, Bethesda, Md. Preliminary report made during the discussion period at a symposium on aldosterone at the First International Congress of Endocrinology in Copenhagen, Denmark, July 21, 1960. the effects of saline extracts of kidney and of liver on aldosterone secretion have been studied. METHODSThe animals were lightly anesthetized with sodium pentobarbital and maintained on a demand pneophore at a pressure of 10 to 15 cm water. The response to bleeding was measured 1 hour after acute hemorrhage, unless otherwise indicated. Bleeding was accomplished by removal of 250 to 300 ml of blood from the femoral vein of 15 to 20-kg dogs, with one exception; in the last experiment in which the simple hypophysectomized and nephrectomized-hypophysectomized dogs were studied alternately, 16 ml of blood per kg of body weight was removed. An infusion of norepinephrine (100 ,ug per ml) in 5 per cent glucose was used to support all decapitated and hepatectomized dogs; also, in some of the hypophysectomized and nephrectomized-hypophysectomized dogs, support was necessary. Arterial blood pressure was measured continuously with a Statham strain gauge and a Sanborn recording system. The rate of norepinephrine infusion was varied in an attempt to achieve a constant adrenal blood flow throughout the experiment. Adrenal vein blood was collected by techniques described previously (4).Hypophysectomy was performed by the oral approach (5). The procedure for decapitati...

While twin concordances for schizophrenia have been used to estimate heritability and to develop genetic models, concordances in subtypes of monozygotic (MZ) twins can also be used to investigate the influence of prenatal development in the etiology of mental illness. We used within-pair variability and mirroring of fingerprints to estimate retrospectively the placentation status of concordant and discordant MZ twins. The results indicate that concordant MZ pairs were more likely to have been monochorionic (MC) and to have shared a single placenta, whereas discordant MZ pairs appear more likely to have been dichorionic (DC) with separate placentas. Pairwise concordances for MZ twins without MC markers averaged 10.7 percent. In contrast, concordances for MZ twins with one or more MC markers averaged 60 percent. This suggests that simple MZ concordance rates may overestimate schizophrenia heritability and that prenatal development may also be important in the etiology of schizophrenia. Because MC (but not DC) twins usually share fetal blood circulation and hence are likely to share infections, these results are consistent with the hypothesis that fetal infections may be a significant etiological factor in schizophrenia.

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