Part 6: Environmental Current and Fields — The Natural Background

BIOELECTRICITY AND ELECTROTHERAPY TOWARDS A NEW PARADIGM?

Part 6: Environmental Current and Fields The Natural Background ROBERT A CHARMAN MCSP DipTP Senior Teacher. Cardiff School of Phywtherapy

Introduction PART 5 of this series considered the experimental and therapeutic claims made for the application of specific currents and fields t o cells and tissues. This article discusses the influence of Earth's electric and magnetic fields upon living systems and the possible role of these fields in the origin of life. Part 7 will concentrate upon the possible effects and health hazards of environmental man-made electromagnetic fields. Earth's Fields and Biological Sensitivity All life has originated and evolved in a flux of natural electric and magnetic fields and the last forty years have seen a revolution in scientific discovery and understanding of biological sensitivity t o them (for reviews see Barnothy, 1964, 1969; Burr, 1972; Anderson, 1983; Becker and Marino, 1982; Becker and Selden, 1985; Kirschrink et a/, 1985; Marino, 1988; Smith and Best, 1989). Trees, Plants and Earth's Fields As part of his forty years of research into the electrical patterns of life Burr, former emeritus professor of anatomy at Yale University, maintained a continuous record of voltage changes in t w o trees, some 40 miles apart, over many years (Burr, 1972). Two electrodes were inserted into the trunk of each tree, one 4 f t above the other and both instrumented for continuous trace recordings. He found that tree trunk potentials fluctuated, and even reversed, with fluctuating atmospheric electric fields, and that there were day and night cycles, 14%-day lunar cycles (when the moon is in alternating conjunction and opposite to the sun), and voltage swings induced by magnetic storms following sunspot eruptions. Figure 1 shows the close correlation between air, earth, maple tree and elm tree potentials recorded over one ordinary day. When the maple tree died, its trunk

Fig 1: A typical day's record of electrical potential difference in the air, earth, maple tree and elm tree (after Burr, 1972)

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still retained a potential but the responsive fluctuations faded away. The absolute potential range was 0-500 mV with an average 30-50 mV fluctuation over a basic potential [Markson, 1967). For more than twenty years Lund, w h o was professor of physiology and director of the Institute of Marine Science at the University of Texas, measured surface potentials and current flows on trees, plants, algae and seaweed, correlating their changes w i t h growth, weather and disease (Lund, 1947). Although the equipment was not as sensitive as modern electronics, and was subject t o artifact, it showed consistent correlation between polarities, potentials and the state of the plant. (Each of them also measured potentials in animals and Burr, in particular, correlated changes in human tissue potentials w i t h disease, finding, for example, consistent polarity changes in benign and malignant gynaecological disorders. Benign tumours, such as fibroids, were positive in relation t o an electrode placed on the abdominal wall, and active malignant growths were consistently negative.) As a result of their meticulous research, both Lund and Burr independently postulated a biologically generated 'bio-electric' or 'electrodynamic' DC field as an intrinsic organiser of growth and structure. Plants are electrically polarised w i t h the growth tips, or crowns, negative relative t o the trunk or stalk base (Goldsworthy, 1986). This creates microamp/cm2 current flows which transport auxins (plant growth hormones) from the growth tips, where they are manufactured, towards the base. Differential auxin concentration gradients co-ordinate plant shape and growth (Goldsworthy, 1986). Research by Goldsworthy and colleagues found that callus plant tissue cultures (callus is the healing 'scar tissue' of plants) showed more vigorous root and shoot growth if made negative relative t o the growth medium. Figure 2 summarises the electric and magnetic fields which interact over the surface of Earth. The relatively stable magnetic field probably has the most important background influence on living systems. The Geomagnetic Field The Earth's magnetic field permeates everything (fig 3) and many creatures of land, sea and air possess, and use, a magnetotactic sense (Anderson, 1983; Downer, 1988). The trackless ocean, for example, is not tractless t o marine

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Physiotherapy, January 1991, vol77, no 7

Solar radiation 1,400 W/m2 ionosphere I

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Fig 2: Life's natural electromagnetic environment. Natural radioactivity, incoming cosmic radiation and breaking water droplets, give the air an electric charge of positive or negative ions. The Earth's magnetic field permeates all things. Thunderstorms cause dramatic changes in atmospheric polarity with violent electrical discharges. Coupled resonances between the Earth's core and the ionosphere (Schumann waves) overlap EEG frequencies (slightly adapted from Smith and Best, 1989)

Fig 3: The Earth's magnetic field. A 3,000 km thick outer core of molten metal swirls around the 2,000 km diameter solid metal core generating massive circular electric currents. These, in turn, generate an enormously powerful magnetic field. The whole acts, in effect, like a huge 8,000 km long bar magnet. Lines of force (magnetic flux) leave the south-seeking pole and radiate through the 3,000 km thick rock mantle into space and return through the north-seeking pole

life that can sense and follow the map of magnetic linc contours within its depths. Nor is it trackless when the sarnc sense can follow the electric currents generated by thc sliding friction of huge volumes of warm and cold wate streaming past each other, over thousands of kilometres from continent t o continent. For marine life the sensing of magnetic flux is probabll a conscious sense which is integrated with the other senses Many fish, for example, sharks and rays, have electro Physiotherapy, January 1991, vol77, no 1

receptors in their snouts. These can detect induced voltage gradients as low as 0.01 pV/cm across their head when swimming across the magnetic field and cutting the 'lines of force'. The faster the s w i m speed the greater the rate of magnetic flux cutting across the head and the greater the induced voltage. At 100 cm/sec (36 km per hour) the induced gradient would be about 0.4 pV/cm (Blakemore eta/, 1988). The same receptors can detect the pulsing currents created by the muscle activity of potential prey and follow the flurry of pulses when it is attempting t o escape. Some fish generate a head-to-tail electric halo around themselves, analogous t o the field shape of a bar magnet, and swim w i th a straight body, using their electroreceptors t o sense the presence of fish, food and sea floor contours through' deformation of the field. For land and air species magnetic sensitivity seems t o be a subliminal back-up sense which operates only when the dominant cues of sight, hearing, taste and smell are masked or silent during foraging and homing. Darkness, cloud and fog would be typical circumstances. The magnetotactic sense is thought to be centred upon minute magnetite iron ore (lodestone)deposits (Blakemore, 1975; Blakemoreetal, 1988). These deposits consist of millions of magnetite crystal domains, arranged in tiny straight chains and embedded in densely innervated connective tissue. The whole is presumed t o act like a magnetic dipole: that is, it will produce a slight mechanical torque as it follows the angle of dip of the magnetic 'lines of force' t o earth. This torque is sensed by contact sensors and presumably relayed t o a 'mapping and location' centre in the brain, possibly the hippocampus. (Some mud dwelling bacteria possess an internal magnetite crystal chain, or magnetosome, in their cytoplasm. They use the torque for purposeful swimming down the magnetic lines of dip to the mud against the random buffeting of particles in the water ( BIa ke m o re, 19 7 5).) Such magnetite deposits have, for example, been located by magnetometers in the skulls of pigeons, buntings, migratory robins, sparrows, salamanders, sea turtles, yellowfin tuna, dolphins, whales and even woodmice. They have also been found in the abdomens of north-south migratory Monarch butterflies, honey bees and queen termites. The orientation of bee dances in the hive includes a magnetic line component t o indicate direction of food. Queen termites align themselves east-west, at right angles t o the Earth's field. This orientation somehow guides some termite species to build their mounds in a north-south alignment, so that the morning and evening sun warms the sides, but the heat of the midday sun is concentrated upon the narrow crest. Human Magnetic Sense Evidence for a subliminal magnetic sense in humans beings seems strong (Baker, 1980a, b; 1985a, b). So is the evidence for a magnetite deposit in the ethmoid bone of the human skull (Baker, 1985a). Experiments have included taking groups of blindfolded volunteers on winding journeys and then asking them to point towards home base. Often, but not always, more arms pointed homeward than elsewhere (fig 4a overleaf). When laterally mounted electromagnetic coils, in PVC helmets, have been actuated by the experimentor t o make a central helmet compass needle point either right or left, this has consistently altered the direction of arm pointing by 90' to the home line in unsuspecting volunteers (fig 4b). Similar results have been obtained when non-blindfolded students were taken for an exploratory walk through a 9

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Units of Magnetic Flux Used in this Series

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Fig 4a: Each dot is one blindfolded student's estimate of the 'home' direction. Arrows show the mean angle for each set of estimates. Subjects were often confused when unmasked

In the centimetre-gram-second system the gauss (G)is the unit of magnetic field density. The geomagnetic field at the Earth's surface is between 0.35 G and 0.7 G, often rounded up either t o 0.5 G or 1 G. In gaussian subunits it is often expressed in milligauss (mG) or gammas. That is, h a n d G respectively. In the metre-kilogram-second Systeme International (SI) system the unit is the tesla (TI. One tesla = 10,000gauss. Tesla subunits for small fields are microtesla (pTI and nanotesla (nTI. That is, sk%, and d m = T respectively. So 100 pT, or 10,000 nT = 1 G. As the t w o systems are used interchangeably concerning the Earth's field i t might be helpful t o express Earth's magnetic field, as the smaller rounded figure, in these comparative units as follows:

0.5 gauss ( G ) 500 milligauss (mG) 500,000 gammas

Tesla TI 50 microtesla (50 pT) 500,000 nanotesla (lo5nT)

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Fig 4b: The influenceof a changed magnetic field through the head on sense of direction during blindfold displacement. Each dot is one person's estimate of 'home' direction. L-helmets and R-helmets indicate on which side of the head the magnet was active (from Baker, 1980b)

wooded area unknown t o them. Those with dummy coils tended t o point towards base, while those with activated right or left fields pointed with appropriate deviation. These findings have been contested (Kirschrink et a/, 1985) and the issue remains unresolved but suggestive of a human magnetic sense. Dowsing Dowsing has a centuries-old history of 'water divining' and a large volume of anecdotal stories t o support the claim of a 'dowsing sense'. The traditional forked t w i g tends, nowadays, t o be replaced by t w o horizontally-held metal rods, one in each hand. These are said t o twist and swing at the point where the dowser walks over buried mineral veins, metal pipes, water pipes, building remains, oil deposits, wells, underground 'streams' and the like. Many scientific field trials, where dowsers have searched for hidden objects whose positions are known to the investigators, have been inconclusive with results close t o chance. In others, the results have been well above chance. In a review of claims and findings Williamson (19871, a geologist, felt that the overall experimental evidence indicated a subliminal sensitivity t o local magnetic gradient anomalies created by these underground artifacts. Two correspondents, commenting upon Williamson's article, found their scepticism overcome by personal experience in scientific circumstances (Younger, 1987; Skelcher, 1987). Another correspondent remained somewhat sarcastically unconvinced (Starling, 1987).

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The mechanical strength of 0.5 G is feeble. It is the force necessary to hold a compass needle pointing east-west against its magnetic tendency t o turn north-south. By comparison, a small door catch bar-magnet field is about 1,000 G.

Rocerd (1964) estimated that the threshold magnetic jradient necessary t o evoke a dowsing response is about 30-50 nT/m when walking at 1 m/s (see panel for magnetic inits). He used buried electromagnetic coils at different xrrents and estimated the field strengths required to obtain 3 dowsing response. Smith and Best (1989) point out that volt), or one millionth his would induce about 30 nV )f a nerve potential, in the dowser. I t may be that the body :an rnaximise sensitivity by 'integrating large numbers of ;ensing elements' as Williamson (1987) suggests. 3iological Clocks All plant and animal life exhibits rhythmic cycles of netabolic activity and behavioural pattens. The major :ycle is about 24 hours, known as the circadian or diurnal hythm, but vegetable metabolism also follows lunar rhythms Brown, 1962). For example beans, along w i t h many Ither seeds, imbibe most water at full moon (Brown and :how, 1973). These rhythms seem inherited and are, presumably, the ,esult of evolving in a rhythmically changing environment I f day and night solar radiation levels, temperature changes, i n d associated rainfall and humidity changes. The nteresting, and still unsolved, question is 'What sets the :lock(s)?' The question is important because the clock jetter, or Zeitgeber, mechanism is the key to the clock. n many cases the answer is changing daylight, either in ntensity or in length (photo-periodic), but this does not ?xplain how plants and animals, including humans, continue :o cycle over weeks and months in an experimentally Jnchanging environment - acting, in effect, as if they were ;till linked to the outside world. There is a certain lengthening :ycle drift over time, and a degiee of desynchronisation of, 'or example, core body temperature changes and sleeping/ Naking patterns. But life never becomes an unchanging :ontinuurn of activity in an unchanging environment. Wever (1973, 1974, 1985) isolated volunteers in self:ontained underground rooms for months at a time, 3nd found that greater desynchronisation occurred in dolunteers unknowingly living in magnetically shielded .ooms. Re-admitting the Earth's magnetism partly reversed the drift. Cycle re-synchronisation also occurred if a 10 Hz nagnetic pulse was passed across the room between m b e d d e d floor and ceiling coils energised by a battery at Physiotherapy, January 1991, vol77, no 7

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a low 2.5 V/m. Furthermore, intermittent pulse trains could re-set the body clocks at an artificial 23.5-hour cycle. The inference from these trials was that weak magnetic pulsations could entrain the biological clocks of the volunteers, although they were completely unaware of the pulses. The Effect of Geographical Location

Moving location can alter the timing of biological clocks without any ordinary cues. Oysters, for example, open and close their shells in feeding synchrony with the tides. Oysters placed in a nearby laboratory box keep time indefinitely w l t h their brethren on the beach, although no tide disturbs their calm waters. Move the same oysters a thousand miles inland however and, over several weeks, they will re-synchronise their shells t o open and close t o the tide time of their inland location, as if they were on a phantom shore (Brown, 1954). Brown concluded that the oyster clocks were slowly reset to the tide times of their new longitude by rhythmic changes in the Earth's magnetic field. These accompany the swing of the tides around the world. After thirty years of further research Brown, wh o was professor of endocrinology, Northwestern University, Evanston, Illinois, summarised the case for exogenous Zeitgeber mechanisms setting biological clocl
ifter magnetic storms than in quiet periods. Ravitz (1962) claimed that records of schizophrenic ind manic depressive patients showed both seasonal luctuations of symptoms and lunar cycles of psychotic pisodes. Tromp (1979) summarised biochemical assessi e n t s of blood chemistry changes w i t h meteorological latterns. The literature on the subject is considerable, icluding correlation of the stressful effects of the mistral nd Santa Anna winds w i t h high positive ion levels. Rotton and Kelly (1985), in their meta-analysis of the iterature, have been heavily critical of claimed lunar :orrelations and human disorders and the subject is one of ierce contention. The debate continues and has a long way o run. Geomagnetism and the Origin of Life

Generated by the giant dynamo currents of the Earth's nolten metal core the geomagnetic field curves outwards, )assing through rock, ocean and atmosphere into space. It acts, in effect, like a giant bar magnet t o which any obJect with magnetic susceptibility must respond. The 'lines of orce' or flux leave from the south pole and curve outwards o cross the equator and return into the north pole. Interactions of Earth's field w i t h the massive kiloampere :urrents of charged particles circulating in the ionosphere m d the magnetosphere at the edge of space creates l o w requency micropulsations along the magnetic flux back t o ?arth. These are, in effect, resonant frequencies oscillating 3cross the resonator cavity between the Earth's inner lynamo and the encircling charged layers high above. These xdsations range between 1-100 Hz and are termed Schumann waves. The frequency overlap between Schumann waves and brain waves (EEG) has led t o speculation that the latter have been entrained by the former 3ver the long span of evolution (Becker and Marino, 1982; 3ecker and Selden, 1985). It has also led Becker to a speculative theory of the origin of life, which is presented n the next section as it underlies the thinking of those w h o stress the importance of these fields. Earth and Life

The sun is about 5,000 million years old, the earth is about 4,500 million years old and life began between 3,500 and

Earth's Environment and Health It is a common belief that health is affected by 'the weather' and that the health of the general population is somehow linked t o weather cycles. It is not, however, so easy to prove, since the variables are enormous, and factor significance is often a matter of statistical interpretation. Friedman et a/ (1965) analysed the admission records of 28,000 psychiatric patients to Virginia state hospitals over a four-year period against the dates of 67 magnetic storms. They consistently found that significantly more patients were admitted just after the storms than when the geomagnetic field was stable. The same team found that standard behavioural assessments of 12 schizophrenic in-patients showed more marked behavioural changes some t w o days physiotherapy, January 199 1, vol77, no 7

amino acids formic acids urea, etc

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1985)

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1 1977 Sidney Harris Amencan Scientist Magazine

s Becker and Selden (1985) say 'a sort of crude consciousess and memory must be present from the first'. It must e structurally viable in a destructive environment. The inshielded chance linkage of fragile organic fragments in a ;oup seems an unlikely basis for life's beginning. According o the- separately expressed opinions of Cairns-Smith 1982, 1985) and Becker and Selden (19851, 'Life' as a ;elf-organising and self-replicating system need not have lad an organic beginning at all. There could have been a itage in which an inorganic structure was the protolife :hicken which laid the organic egg.

:ram Crystals t o

'I think you should be more explicit here in step two.'

3,800 million years ago (Wagoner and Goldsmith, 1983; Brooks, 1985). In a two-stage transition process inorganic chemical reactions became organic and organic chemistry somehow became life. The first stage has been duplicated in many laboratory experiments, following Miller's (1953) findings that continuous electrical spark discharge through gaseous simulations of the Earth's early atmosphere causes chemical reactions resulting in the formation of amino acids i n very small quantities. Carbon-based organic molecules, including mucleic acids and membrane forming phospholipid molecules, have been deposited in many test tube water traps since then (fig 51, but no life has emerged from the organic sludge. No matter what laboratory starter motor is fitted, the engine of life will neither splutter nor fire. Nor has it spluttered in the organic traces found in meteorites. They are merely mute evidence that the first stage transition can occur anywhere in the universe in the right chemical circumstances. Attempts to solve the origin of life have led many t o try and be 'more explicit here in step two' (fig 61, but no one has yet written the final formulae linking biological molecules t o life. Reviews of speculative scenarios of how 'Nature' did the 'inevitable' are many (Alberts e t a / , 1989; Shapiro, 1986; Scott, 1986; Cairns-Smith, 1982, 1985; Margulis and Sagan, 1987). The most popular scenario has been Darwin's 'little warm pond' or, as Becker and Selden (1985) call it, the 'warm soup and lightning' scenario, whereby catalytic polynucleotide templates were somehow in the right mix, in the right muddy concentrate, at the right time, for a 'lucky strike' breakthrough into self-replication. The odds against are in the 3 0 0 zeros category, and even the existence of the pre-biotic soup is now in doubt (Brooks, 1985). Entrance Requirements Life requires a surface film, separating 'self' from 'not self'. It needs ordered structure, stability of form through change, and the conversion of random energy into sequential reactions by enzymes. It requires mechanisms of information reception, recognition, storage and response so that 'meaning' is extracted from 'noise'. It must recognise

12

Cells

This scenario is a dry one, involving clays, crystals and ,olcanic eruptions, and a chemically dense atmosphere. The ierce energy of the sun is unchecked by an ozone layer, as he atmosphere has no oxygen, so the Earth receives the uII spectrum of ultraviolet photochemical activity. The major :hange of emphasis in this scenario is the possible lifelenerating role of intense electromagnetic energy pulsations iassing across the surface of Earth, between the Earth's :ore and the ionospheric layer, during the critical period of .ife's beginning. The encircling ionosphere lines the upper

Staggered formation

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boundary of the atmosphere. It is composed of a wide band of free electrons which are continually created by the ionisation of air molecules by incoming ultraviolet and X-ray energy from the sun. Becker and Selden's (1985) hypothesis is that semiconducting crystals such as silicon, which is the second most abundant element in the sand, rocks and clays of Earth's crust, fulfils Life's entrance qualifications. Figure 7 shows the tetrahedra lattice of feldspar (silicon and aluminium oxides) which is the major consistuent of igneous rock. It has a framework of negative charge enclosing large cavities containing Na + , K f and Ca + ions which neutralise the negatively charged framework. Semiconducting crystals display a range of piezoelectric and reverse piezoelectric effects, plus pyroelectric and photoelectric effects. Therefore the energy of mechanical

Physiotherapy, January 1991, vol77, no 7

vibration, electrical pulsation, heating and absorbed radiation can be converted to surface potentials and currents in crystalline lattices. Contaminant 'doping' considerably extends the range of crystal electronic properties. The proposed scenario is that orderly crystalline structures formed the template for an inner circuitry whereby repeated current patterns modified resistance characteristics to create a responsive information-receiving and storage system. As Becker says: 'Conditions on the young planet favoured forests of crystals. It was hot, and volcanoes were constantly firing new materials into the dark shell of turbulent gases.' Assuming a 'protolife' circuitry, what were the crystals responding to? And how did they form a template for organic 'life'? The Geomagnetic Resonator

Becker and Selden (1985) combined ideas from the research of Uffen (1963) and Cole and Graf (1974) on the possible interaction between Earth's metallic magnetic core and the surrounding ionosphere and magnetosphere belts at the edge of space t o suggest an answer. The larger, and denser, atmosphere of 4,500 million years ago pushed the t w o belts close together so that they acted, in effect, as one. This would have created t w o concentric spheres, consisting of the convex surface of earth facing the overlying concavity of the charged belts high above. Large, solar wind driven, current fluctuations in the outer magnetosphere would have induced huge currents in the inner adjacent ionosphere. The intense electric currents and magnetic fields of the Earth's metallic core coupled wit h the pulsing fields above t o become, in effect, an enormous electromagnetic resonator across the dielectric of rock mantle and atmosphere. The resonant pulse frequencies would have been in the extremely low frequency (ELF) range, ie from 1-200 Hz with a main frequency around 10 Hz. The circuitry within the crystalline lattice 'protolife' would have been driven by these pulsing discharges of enormous energy in self-modifying resonant frequencies. Both Becker and Selden (1985) and Cairns-Smith (1982) propose that colloidal mineral crystals were the first form of life, self-repairing and self-propagating in a sort of seeding process. Cairns-Smith has developed the concept in great detail, but does not follow the same line as Becker concerning the generative role of ELF pulsations. The continuously pulsing discharge of magnetic and electric energy through the supercharged atmosphere, combined with intense solar radiation, would have created chains of chemical reactions resulting in a rain of organic molecules on t o land and sea. A percentage of this organic fallout would have seeped into the protective crevices of active 'living' crystals. The combined effects of mineral-aided catalysis and primitive ribonucleic acid (RNA) catalysis resulted in the first faltering steps of organic template replication. This proposed formative stage would have been in intimate contact with the crystalline circuitry tuned t o the resonant frequencies of Earth's fields. The transition from organic molecular bricks t o RNA/DNA templating of a replicative structure and order was effected within these frequency fields, and sensitivity to them is now part of life's inheritance. This theory carries a possible explanation as to wh y the initial life forming process is no more. As the lightweight gases slowly escaped into space, and ammonia and methane became incorporated into organic compounds, the depth of the atmosphere decreased and the accompanying ionosphere separated from the high magnetosphere. The

iistance between the t w o resonant spheres became too ;hallow for dielectric sustained resonance w i t h the Earth's :ore, and the magnetosphere-induced ionospheric currents iecame weaker w i t h widening separation. As the pulsating mergy died away the 'spark of life' was slowly turned off. The giant resonator became a fading echo of its generative ieyday, but the echo has persisted across evolutionary time 3s a subtle Zeitgeber of biological clocks t o this day. Within the crystal rock lattices the processes of genetic nheritance, and the machinery of converting amino acids nto proteins, was slowly developed. A charged phospolipid nembrane enclosed the machinery and the 'genetic :akeover' (Cairns-Smith, 1982) from crystal life to organic ife was complete. The microscopic specks were washed, 3r blown, out of their crystalline crevices into sea and sunshine and a new world of the biosphere was born. This speculative scenario of Life's beginning, together with modern evidence of the subtle interaction of geomagnetic fields and organisms, underlies concerns about sensitivity to electromagnetic fields, and the possible ill-effects of exposure t o electromagnetic fields generated by recent technology. These concerns, and the evidence cited t o support them, will form the subject for part 7 on man-made environmental fields. REFERENCES Alberts, 6, Bray, 6, Lewis, J, Raff, M, Roberts, K and Watson, J D (1989). Molecular Biology of the Cell, 2nd edn, Garland Publishing Co, New York. Anderson, E W (1983). Animals as Navigators, Bodley Head, London. Baker, R R (1980a). 'Goal orientation in blindfolded human beings after long distance displacement: Possible involvement of a magnetic sense', Science, 210, 555. Baker, R R (1980b). 'A sense of magnetism', New Scientist, 87, 1219. Baker, R R (1985a). 'Magnetoreception in man and other primates' in: Kirschvink, J L et a/ (op citl. Baker, R R (1985b). 'Human navigation: A summary of American data and interpretations' in: Kirschvink, J L et al (op citl. Barnothy, M F (ed) (1964). Biological Effects of Magnetic Fields, Plenum Press, New York, vols I and II. Becker, R 0 and Marino, A A (1982). Electromagnetism and Life, State University of New York Press, Albany. Becker, R 0 and Selden, G (1985). The Body Electric: Electromagnetism and the foundation of life, V Morrow and Co, New York. Blakemore, R P (1975). 'Magnetotactic bacteria', Science, 201, 377, 4. Blakemore, R P, Blakemore, N A and Frankel, R B (1988). 'Bacterial biomagnetism and geomagnetic field detection !n organisms' in: Marino, A A (ed) Modern Bioelectricity, Marcel Dekker Inc, New York. Brooks, J (1985) Origins of Life: From the first moments of the universe to the beginning of life on Earth, Lion Publishing PLC, Tring, England. Brown, F A (1954). 'Persistent activity rhythms in the oyster', American Journal of Physiology, 178, 510. Brown, F A (1962). Biological Clocks, Heath Press, Boston, USA. Brown, F A (1983). 'The biological clock phenomenon: exogenous timing hypothesis', lnterdisciplinary Journal of Cycle Research, 14, 2, 137--162. Brown, F A and Chow, C S (1973). 'Lunar correlated variations in water uptake by bean seeds', Biology Bulletin, 45, 2 6 5 - 2 7 8 . Burr, H S (1972). Blueprint for Immortality: The electrical patterns of life, Neville Spearman, London. Cairns-Smith, A G (1982). Genetic Takeover: And the mineral origins of life, Cambridge University Press. Cairns-Smith, A G (19861. Seven Clues to the Origin of Life: A scientific detective story, Cambridge University Press. Cole, F E and Graf, E R (1974). 'Pre-Cambrian ELF and biogenesis' in: Persinger, M A (ed) ELF and VlF Electromagnetic Effects, Plenum Press, New York. Coveney, P and Highfield, R (1990). The Arrow of Time, W H Allen, London . Cremer-Bartels, G, Krause, K and Kuckle, H J (1983). 'Influence of low magnetic field strength variations on the retina and pineal gland of quails and humans', Graefe's Archives of Clinical and

Experimental Ophthalmology, 220, 232-248. Downer, J (1988). Supersense: Perception in the animal world, BBC Books, London (Book of BBC (1988) television series 'Supersense'). Friedman, H, Becker, R 0 and Bachman, C H (1985).'Psychiatric ward behaviour and geophysical parameters', Nature, 205,

Nature, 288, 607-608. Shapiro, R (1986).Origins: A sceptic's guide to the creation of life on earth, Heinemann, London. Shepherd, G M (1988).Neurobiology, 2nd edn, Oxford University Press. Skelcher, 5 W (1987).'Dowsing sense' (letter), New Scientist, 114,

Goldsworthy, A (1986). 'The electric compass of plants', New Scientist, 109, 1489, 22-23. Kirschrink, J L, Jones, D S and MacFadden, B J (eds) (1985). Magnetite Biomineralisation and Magnetoreception in Organisms. A new biomagnetism, Plenum Press, New York. Lund, E J (1947).Bioelectric Fields and Growth, University of Texas Press, Austin. Margulis, L and Sagan, D (1987).Microcosmos: Four billion years of microbial evolution, Allen and Unwin, London. Markson, R (1967). 'Tree potentials and external factors', MSc thesis in Meterorology, Pennsylvania State University. Shortened version in Burr, H S (1972). Blueprint for Immortality: Part 2. Selected Papers, Neville Spearman, London. Miller, S L (1953).'The production of amino acids under possible primitive earth conditions', Science, 117, 528. Ravitz, L J (1962).'History, measurement and applicability of periodic changes in the electromagnetic field in health and disease', Annals of the New York Academy of Sciences, 98, 4, 1144-1201. Rocard, Y 11964).'Actions of a very weak magnetic gradient: The reflex of the dowser' in: Barnothy M F (ed) Biological Effects of Magnetic Fields, Plenum Press, New York. Rotton, J and Kelly, I W (1985).'Much ado about the full moon: A meta-analysis of lunar-lunacy research', Psychological Bulletin, 97, 286-306. Scott, A (1986). The Creation of Life, Basil Blackwell, Oxford. Semm, P, Schnieder, T and Vollrath, L (1980).'Effects of an earthstrength magnetic field on electrical activity of pineal cells',

Smith, C W and Best, S (1989).Electromagnetic Man: Health and hazard in the electrical environment, J M Dent and Sons Ltd, London. Starling, E (1987). 'Dowsing sense' (letter), New Scientist, 114,

1050-52.

In Other Journals These current awareness lists aim to help readers keep up to date with articles of interest in overseas physiotherapy publications and those for other professions in the UK. They are not comprehensive and the full texts are not available from the Chartered Society - they should be found in medical libraries. The figures at the end of each line refer to the page numbers.

1556, 62.

1558, 81.

Tromp, S W (1979).Biometeorological Survey. Vol 7 7973-7978, Heyden and Sons, London. Uffen, R J (1963). 'Influences of the earth's core on the origin and evolution of life', Nature, 198, 143. Wagoner, R V and Goldsmith, D W (1983). Cosmic Horizons: Understanding the universe, W H Freeman and Co, San Francisco. Wever, R (1973). 'Human circadian rhythms under the intluence of weak electric fields and the different aspects of these studies', lnternational Journal of Biometeorology, 17, 220. Wever, R (1974). 'ELF effects on human circadian rhythms' in: Persinger, M A (ed) ELF and VLF Electromagnetic Field Effects, Plenum Press, New York. Wever, R (1985). 'Circadian rhythms of human subjects, in: Grandolfo, M, Michaelson, S M and Rindi, A (eds) Static and ELF Fields: Biological effects and dosimetry, Plenum Press, New York. Williamson, T (1987). 'A sense of direction for dowsers', New Scientist, 113, 1552, 40-43. Winfree, A T (1987). The Timing of Biological Clocks, Scientific American Books Inc, New York. Younger, P L (1987).'Dowsing sense' (letter), New Scientist, 114,

1556, 62.

Developmental Medicine and Child Neurology 1990, vol 32, no 9, September Light-gazing by visually impaired children. J E Jan, M Groenveld, A M Sykanda. 755-759. Cervical ausculation of suckle feeding in newborn infants. F L Vice, J M Heinz, G Guiriati et a/. 760-768. Multiple sclerosis in childhood: Contribution of serial MRI t o earlier diagnosis. M M Millner, F Ebner, E Justich, C Urban. 769-777. Control of isometric muscle activity in cerebral palsy. P D Neilson, N J O'Dwyer, J Nash. 778-788. Post-operative electromyographic function of tendon transfers in patients w i t h cerebral palsy. M M Hoffer, J Perry, G Melkonian.

789-791.

Scandinavian Journal of Rehabilitation Medicine 7990, vol 22, no 3 Two-point discrimination test. E Moberg. Key words: Testing of sensibility, surgical hand rehabilitation, tetraplegia, stroke. 127-1 34. Important predictors of the outcome of physical training in patients with intermittent claudication. S Rosfors, B B Arnetz, S Bygdeman et a/. Key words: Intermittent claudication, exercise therapy, ankle blood pressure, hormones, cognitive factors, prediction. 135-137. The effect of steering on the physiological energy cost of wheelchair propulsion. M Reid, A T Lawrie, J Hunter, P M Warren. Key words: Energy metabolism, exertion, oxygen consumption, wheelchairs.

139-143.

Detrusor pressure in cystometry compared t o physiological filling in patients w i t h a reflex urinary bladder after spinal cord injury. M Thyberg, A Spangberg, C Lassvik. Key words: Manometry, neurogenic bladder, pressure, spinal cord injuries - complications, urodynamics. 145-150. Respiratory function in chronic primary fibromyalgia. M Laurie, K Caidahl, G Johansson, B Blake. Key words: Chronic primary fibromylagia, dyspnoea, respiration, respiratory pressures, spirometry. 151-155. The hip joint: Forces needed for distraction and appearance of the vacuum phenomenon. I Arvidsson. Key words: Hip joint. separation, traction, vacuum phenomenon. 157-161. Individualised adaptation of clothes for impaired persons. G Kratz, I Soderback. Key words: Rehabilitation, occupational therapy, design, adapted clothes, disability. I63 -170.

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Hemiparetic forms of cerebral palsy in relation t o epilepsy and mental retardation. J Sussova, 2 Seidl, J Faber. 792-795. Progressive peripheral neuron degeneration in ataxia-telangiectasia: A n electrophysiological study in children. 0 Kwast, R Ignatowicz.

800-807.

Fukuyama congenital muscular dystrophy in t w o Australian female siblings. L M Stern, L Albertyn, J I Manson. 808-813.

No 11, November The incidence and natural history of scoliosis in Rett syndrome. G S Bassett, V T Tolo. 963-966. Cultural differences in family communication about Duchenne muscular dystrophy. C Fitzpatrick, C Berry. 967- 973. Deficits in reciprocal inhibition of children w i t h cerebral palsy as revealed by H-reflex testing. C T Leonard, T Moritani, H Hirschfeld, H Forssberg. 974-984.

No 12, December Instrumental gait analysis after selective dorsal rhizotomy. L D Cahan, J M Adams, J Perry, L M Beeler. 1037-43. Anterior versus posterior walkers: A gait analysis study. L Logan, K Byers-Hinckley, C C Ciccone. 1044-48. Siblings as change agents for promoting the functional status of children w i t h cerebral palsy. M J Craft, J A Lakin, R A Oppliger e t a / . 1049-57. Head shaking by visually impaired children: A voluntary neurovisual adaptation which can be confused with spasrnus nutans. J E Jan, M Groenveld, M B Connolly. 1061-66. Case report: Phobic anxiety and clumsiness in a ten-year-old girl. S Mukhopadhyay, P W Wilkinson. 1089-93.

Physiotherapy, January 1991, vol77, no 7