Wien, für ihre Hilfe bei der Isolierung und Strukturaufklarung von Gentiobiosyl-Adynerin. P. Bauer dankt dem Deutschen Akademischen Austauschdienst für em Forschungsstipendium an der Universitat Wien.Abstract: Three extracts from English or common ivy, Hedera helix, were prepared and tested for their anthelminthic activity both in vitro and in vivo. Saponic complex 60% (CS 60), purified saponic complex 90 % (CSP 90) and alpha hederin were evaluated in vitro using the trematodes Fasciola. hepatica and Dicrocoelium spp. These same extracts were assayed for their effects on Dicrocoelium in naturally infected sheep. After an exposure of 24 hours in vitro both Fasciola and Dicrocoeliwn were killed by a-hederin at concentrations of 0.005 and 0.001 mg/mI respectively. When sheep naturally infected with Dicrocoelium were treated p. o. with CS 60 and CSP 90 the worms were eliminated after three doses, one of 500 and two of 800 mg/kg. Alpha hederin was deemed slightly less efficacious at these concentrations. When compared with two reference compounds the authors conclude that these extracts show considerable promise. They also appear to be well tolerated by the sheep.

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

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A cytological study of Venturia inaequalis has revealed that only one meiosis occurs in the ascus, and that the haploid number of chromosomes is seven. Most asci originate through typical hooks, but in a number of perithecia these croziers are absent, and large budding cells give rise to small ascus-shaped structures. Variations in nuclear stainability were observed among perithecia at the same stage of maturity. Attempts were made to characterize the seven chromosomes.