Zur Ermittlung der Farben grösster Buntkraft

Summary In experiments with a sufficiently great number of observers, using our spectral colour integrator, it has been shown thatone colour containing a maximum of chromatic power (chroma) can be chosen out of a series of optimal colours continuously changeable from white over the fullcolour to black. The determination of such maximal colours, differing in hue, shows their position between fullcolour and spectral colour in the mixing metric colour solid. Their relation to maximal properties of scalemetrically defined chromatic power functions is discussed.     

Interspecific diversity and uniformity of flower colour patterns as cues for learned discrimination and innate detection of flowers

The colour patterns of angiosperm flowers visited by bees and hoverflies were shown to provide a dual signalling system, giving the flower-visitors visual orientation cues for the initial detection of flowers, as well as for learned discrimination. Pollinators show an innate response to interspecifically uniform colour signals, which enable them to detect flowers and to orient towards the site of reward. Interspecifically diverse colour signals provide pollinators with cues for learned discrimination between flowers of different species.     

The statesman and the ophthalmologist: Gladstone and Magnus on the evolution of human colour vision, one small episode of the nineteenth-century Darwinian debate

Among the numerous nineteenth-century sorties into particular aspects of the Darwinian debate are two 1877 publications. The first, Die Geschichtliche Entwickelung des Farbensinnes, was a treatise on the evolutionary development of human colour vision by Hugo Magnus, an obscure German ophthalmologist. The other, The Colour-Sense, was an article by William Ewart Gladstone, the great British statesman. Magnus, working from linguistic science and optical physiology, developed the theory that humankind had passed through successive stages of colour recognition, from none to full perception, brightest colours first. Gladstone supported the theory with data from his studies of Homeric colour words, placing Homer at a very early stage. Their theory was not accepted. It assumed colour vocabulary to be an index of colour recognition, and too little was known about the nature or age of early man. The present study intends to follow this particular episode as an excellent example of the scholarship, argumentation, and limited scientific knowledge of the time, as applied to human evolution.     

Correlations between the neurobiology of colour vision and the psycholinguistics of colour naming.

Neurobiological experiments demonstrate that colour sensation is perceived by the brain by processes which, in principle, follow the opponent colour pairs scheme proposed by Hering in 1874. Tests on colour naming in various European, Asian and Central American languages have shown that the opponent scheme is also reflected in psycholinguistics. The linguistic evolution of colour terms proposed by Berlin and Kay (1969) is correlated directly with the ontogenetic development of language in children as elucidated by Jakobson (1941). Colour vision is therefore a suitable field for interdisciplinary investigations of brain processes and linguistics.     

Correlations between the neurobiology of colour vision and the psycholinguistics of colour naming

Summary Neurobiological experiments demonstrate that colour sensation is perceived by the brain by processes which, in principle, follow the opponent colour pairs scheme proposed by Hering in 1874. Tests on colour naming in various European, Asian and Central American languages have shown that the opponent scheme is also reflected in psycholinguistics. The linguistic evolution of colour terms proposed by Berlin and Kay (1969) is correlated directly with the ontogenetic development of language in children as elucidated by Jakobson (1941). Colour vision is therefore a suitable field for interdisciplinary investigations of brain processes and linguistics.Dedicated to Prof. Roman Jakobson, Cambridge, Mass.Acknowledgment. I thank Prof. Roman Jakobson, Harvard University and M.I.T., Cambridge (Mass.) and Prof. Elmar Holenstein, Ruhr-Universität, Bochum, Germany (formerly University of Zurich, Switzerland) for many stimulating discussions.     

A new type of interaction between spore colour mutants ofAspergillus niger

Summary A new white-spored mutant of the imperfect fungusA. niger is described. Behind the heterokaryotic heads formed with non-allelic spore colour mutants, it shows as a result of crossfeeding a uniform change of colour of the conidial heads in a band up to 4–5 mm deep. This mutation with pleiotropic effects on colour and crossfeeding occurs relatively frequently inA. niger, although it has not been reported previously.Acknowledgment. Thanks are due to Dr A. J. Clutterbuck (Department of Genetics, University of Glasgow, Glasgow) for helpful comments on this work.     

Man's strategy in domestication — a synthesis of new research trends

Summary The minimum brain size possible in the relevant wild species and certain colour types which, because of alterations in the neurotransmitter system caused by the respective colour genes, are related to behavioural traits diverging from the wild animal's norm appear to be first-rate bases for domestication either separately or in combination.     

A flexible model of technological diffusion incorporating economic factors with an application to the spread of colour television ownership in the UK

In this paper a new encompassing flexible diffusion model of the epidemic type is proposed and its properties explored. Economic factors are incorporated directly into the model. The new model allows freer interaction between exogenous and endogenous factors in the diffusion process than existing models of this type. The model is applied to the diffusion of colour television ownership in the UK and outperforms the existing models in the literature. The exogenous factors are shown to play a more dominant role in the diffusion of colour television in the UK than existing models allow.     

Spurenelemente einiger schweizerischer Ophiolithe,Radiolarite und Mergel

Summary The trace element content of a few Swiss ophiolites, radiolarian cherts and marls has been determined by means of spectrographic methods.Field observations, microscopical and spectrographical data lead to the conclusion that the colour of green cherts in certain areas is due to the supply of clastic peridotite- and serpentine-particles originating from a syn-temporaneous ultrabasic igneous body.     

Unilateral change in color produced by ablation of the eyestalk of the crustacean Processa edulis (Decapoda, Natantia)]

A difference of expansion of erythrophores is observed between the left and right side of P. edulis after the removal of only one Eyestalk. It is the first time, in the Crustacea, that experiments lead to the conclusion that a sympathetic-like constrictor nervous action can exist in colour-change control; colour changes are particularly fast in this species.     

The genetic and evolutionary basis of colour variation in vertebrates

Variation in pigmentation is one of the most conspicuous phenotypic traits in vertebrates. Although mammals show less variation in body pigmentation than other vertebrate groups, the genetics of colour determination and variation is best understood for them. More than 150 genes have been identified that influence pigmentation, and in many cases, the cause for variation in pigmentation has been identified down to the underlying nucleotide changes. These studies show that while some genes are often responsible for deviating pigmentation, similar or almost identical phenotypes even in the same species may be due to mutations in different genes. In this review we will first discuss the current knowledge about the genes and their functions underlying the biochemical pathways that determine pigmentation and then give examples where the mutations responsible for colour variation have been determined. Finally, we will discuss potential evolutionary causes for and consequences of differences in pigmentation between individuals.     

Zur Kenntnis der «Keller-Reaktion» und ihre Anwendung zur spektrophotometrischen Bestimmung von Indolen

Summary A spectrophotometric method suitable for quantitative estimation of indole compounds is described. The correlation is discussed between this colour test, derived from the ?Keller-reaction?, and the ?Hopkins-Cole-reaction?.      

The Challenge of Colour: Eighteenth-Century Botanists and the Hand-Colouring of Illustrations

Colourful plant images are often taken as the icon of natural history illustration. However, so far, little attention has been paid to the question of how this beautiful colouring was achieved. At a case study of the eighteenth-century Nuremberg doctor and botanist, Christoph Jacob Trew, the process of how illustrations were hand-coloured, who was involved in this work, and how the colouring was supervised and evaluated is reconstructed, mostly based on Trew's correspondence with the engraver and publisher of his books, Johann Jacob Haid in Augsburg. Furthermore, the question of standardizing colours, their uses and their recipes is discussed at two examples of the same time period: the colour charts of the Bauer brothers, arguably the most renowned botanical draughtsmen of the period, and the colour tables by the Regensburg naturalist, Jacob Christian Schaeffer. Hand-colouring botanical illustrations, it is argued, was far from a straightforward task but confronted botanists and their employees with a plethora of practical and methodological problems, to which different solutions were developed in the course of time. Analysing these problems and solutions reveals some new and interesting aspects of the practices of eighteenth-century botany and of the production of scientific illustrations in general.     

Autonomic response of the fish to pyrogen

Summary Lipopolysaccharide (LPS) applied to the anterior brainstem of the carp caused lightening of body colour. This indicates that an increase in set point temperature is responsible for increased cutaneous autonomic activity following LPS-administration.We express thanks to Dr S. Kanoh, National Institute of Hygenie Sciences, Osaka, Japan, for suppling the LPS.     

Orientation ofPapilio demoleus larvae to coloured solutions

Summary The present work compares the taxis ofPapilio demoleus larvae to different coloured solutions. The larval positive taxis, i.e., attraction, is maximum for yellow colour and declines with the increase or decrease in the wavelength of maximum light transmission. Red and bluish-green colours repel the larvae.     

A Companion to the History of Science

Snell's law of refraction did not affect the study of optics until twenty‐five years after its publication in 1637 and by then its universality threatened to break down already. Two optical phenomena—colour dispersion and strange refraction—were discovered that did not conform to the sine law. In the early 1670s, Isaac Newton and Christiaan Huygens respectively investigated these phenomena. They tried to describe the irregular behaviour of light rays mathematically and to reconcile it with ordinary refraction. This paper discusses their investigations and aims at throwing new light on the history of seventeenth‐century optics. Both initially approached the problem in a mathematical way in which they built on Descartes' analysis of refraction. This is surprising because it contradicts their earlier dismissal of Descartes' account and it does not fit our picture of them as mathematical physicists. By looking more closely at their early investigations it becomes clear that Newton and Huygens first had to develop the approach to optics of their later writings. After Descartes placed the issue of the physical nature of light rays on the scientific agenda in 1637, they recognized its purport in their struggles with colour dispersion and strange refraction. It was at this point that their physical optics evolved from the traditional geometrical optics with which they had started.     

Optic lobe neurosecretory cells of an Indian spiderCryptophora sp. (Areinidae)

Summary In all the 3 pairs of optic lobes ofCryptophora sp. there are small groups of monopolar PF^– neurosecretory cells which take on a green colour by PF technique and red by Azan. Their function is unknown, but they may be involved with photoperiodically controlled activity rhythms.We wish to express our thanks to Prof. U.S. Srivastava for providing working facilities and valuable suggestions.     

3-OH-Kynurenine content and ommochrome formation in the developing compound eye ofEphestia kühniella

Summary The eye color ofEphestia kühniella is primarily determined by the ommochromes xanthommatin and ommin. The pigmentation, an important part of eye differentiation, occurs mainly during the pupal stage. Comparative studies on eye colour mutants indicate that a first step in ommochrome synthesis is the binding of the precursor 3-OH-kynurenine to developing pigment granules. Both xanthommatin and ommin are present from the early beginning of eye differentiation, and exhibit different developmental profiles.