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This paper is concerned with a problem which has puzzled me for many years. The Greek philosophers of the Ionian tradition, from Anaximander to Epicurus, are commonly called specially ‘scientific,’ in contrast with the Italian tradition started by Pythagoras. Why is it, then, that their systems are cast in the form of dogmatic pronouncements? It is not only that they describe, with complete confidence, matters beyond the reach of observation, such as the origin of the world; but when they come to matters of detail, they make assertions which could have been upset by a little careful observation or by the simplest experiment.It has been argued—by Burnet, for instance—that this dogmatism may be only apparent. Our evidence is fragmentary, and comes largely from manuals compiled much later by men whose object was to discredit science for reaching contradictory conclusions, and by no means to record the methods employed to reach those conclusions. W. A. Heidel, too, thought that, if we possessed the philosophers' notebooks, we should find that their results were obtained by methods akin to those of modern science, though with less awareness of the need for caution in experimental tests. Behind these arguments lies the assumption that the questions they asked themselves, the motives prompting their inquiries, and the quarter to which they looked for the sources of knowledge, were the same then as now.

MEASURES to control schistosomiasis (bilharziasis) aimed at either the molluscan vector or the trematode's larval stages might be enhanced by a better understanding of the intricacies of how miracidia and cercariae find and penetrate hosts. Previous work from our laboratory identified chemicals from mammalian skin that initiated penetration responses by Schistosoma mansonicercariae1. Other earlier studies implicated amino acids and additional compounds as attractants of S. mansonimiracidia to the molluscan host, but did not show that these substances were derived from the snail2. Subsequently, based on Neuhaus'3and C. A. Wright's4indications that snails release substances into water that stimulate miracidia, several investigators5–8have confirmed that snails ‘condition’ water making it stimulatory or attractive to miracidia. Wright and Ronald9recently demonstrated that water conditioned by the snail Lymnaea palustrisattracted miracidia of the rodent blood fluke, Schistosomatium douthitti, and that this snail-conditioned water (SCW) contained amino acids. Here we show that Biomphalaria glabrata, the molluscan vector of S. mansoni, the important parasite of humans, contributes amino acids to the aqueous environment, and that these, and possibly other substances elicit chemotactic and chemokinetic responses by miracidia of this parasite.

WHEN dissolved in water, the natural slimes of most of the fishes we have tested have a remarkable capacity to decrease greatly the friction of water when flowing in the turbulent state. In one species, a dilute solution of its slime was found to reduce the friction of water by as much as 65.9%; reductions of 57% to 63% were frequently obtained with the slimes of other species. These measurements have led us to the view that the slimes of many (but not all) fishes assist in locomotion by reducing the drag or resistance which water offers to their bodies.

The ionization potentials of the methyl amines down to 20 eV binding energy, have been determined by photoelectron spectroscopy, and are compared with those predicted by i.n.d.o.-l.c.a.o.-s.c.f. theory. The first ionization potential for each compound refers to the removal of an electron from the lone pair, and is shown to be the one most affected by the inclusion of one center repulsion integrals in the i.n.d.o. calculations.

Scanning electron microscopy of the antennae of Ostrinia nubilalis (Hübner) moths was used to compare morphological classes and numbers of external sensilla typical of the sexes. These observations are correlated with previous studies of sex pheromone receptor sensilla in Bombyx mori L. for assessment of the physical apparatus responsible for sex pheromone detection in the corn borer. Sensillar classes found on antennae of both male and female corn borers include sensilla styloconica, sensilla chaetica, sensilla coeloconica, sensilla auricillica, sensilla basiconica, and sensilla trichodea. The sensilla trichodea are further subdivided into two distinct types (designated A and B) on criteria of surface substructure and length. Sensilla trichodea are more numerous on the antennae of male moths than on those of females, with the excess surface area of Type A sensilla trichodea estimated at 100% greater in the males. Estimates of numerical totals and distribution along the antennal flagelluni are compared for the sensilla trichodea types for both sexes. The other sensilla of male and female corn borer moths also have been compared with respect to location on the antennae and relative frequency. Complete descriptions of sensillar and antennal morphology as observed with this technique are included.

GAMMA radiation, which has previously been shown to prevent sprouting in potatoes1, onions2and carrots3, has now been found to prevent the sprouting of stored mangolds (Beta vulgaris). Recently harvested mangolds of the variety Orange Globe, from which the leaves had been removed leaving 2 in. of leaf-stalk, were irradiated in batches of five with a cobalt-60 source giving a dose-rate of 100 rads per min. After treatment on November 7, 1956, the mangolds were bedded in damp sand in an unheated building. On April 8, 1957, the mean lengths of the sprouts were 5.7, 3.2, 1.5, 0.0, 0.0 and 0.0 in. on the batches given 0, 5,000, 10,000, 20,000, 30,000 and 40,000 rads, respectively. Some of the aphid species that transmit viruses of sugar beet and mangold crops survive through the winter in clamps and multiply in the spring on the developing sprouts of mangolds4. This experiment was part of a programme of research to find a method of preventing the aphid vectors from over-wintering in this way.