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‘Unting is all that's worth living for – all time is lost wot is not spent in ‘unting – it is like the hair we breathe – if we have it not we die – it's the sport of kings. The most vital possessions of the plant are the chloroplasts in the cells of its leaves. Through these, the organism can convert, for its own purposes, a fraction of the solar energy that falls upon it. Sunlight is remarkably uniform in its intensity, and a plant has little to gain by moving about. It can thus afford a relatively stationary existence, the only motion being that required to reach regions beyond the shade of its immediate environment and its competitors. Because they have no chloroplast-bearing cells, animals have paid the penalty of having to develop several specialized functions in order to satisfy their energy requirements. They must have a means of locomotion and feeding, and some form of coordination of these faculties, however primitive, is needed. And as insurance against the unsuccessful forage, they should be able to store digested energy. Moreover, unless an animal is so small that the normal process of diffusion is adequate, it must have a circulatory system to distribute dissolved gases and chemical compounds to its various parts. [ABSTRACT FROM AUTHOR]

Twist ye, twine ye! even so Mingle shades of joy and woe, Hope and fear, and peace and strife, In the thread of human life. All molecules in a living organism serve a purpose, and we cannot say that a particular type is more important than any other. Nevertheless, it would be difficult to identify substances that play more varied and central roles than do the biopolymers. They contribute to the mechanical structure, and in the animal kingdom they provide the means of motion. They facilitate transport of smaller chemical units and mediate the chemical interaction between molecules, the biopolymers that serve this catalytic function being the proteins known as enzymes. There are biopolymers that form the immunological system and others that are involved in the mechanism of tissue differentiation. With so many functions to be fulfilled, we should expect to find many different types of these ubiquitous molecules, and this is certainly the case. It is believed, for example, that there are several hundred distinct enzymes within each cell of a higher organism such as a mammal. Even the task of perpetuating and translating the genetic message is entrusted to biopolymers. The body of a typical mammal is mostly water – about 65% by weight in fact – but of the solid components no group is better represented than the proteins; they make up about 15% of the total weight. [ABSTRACT FROM AUTHOR]

How vainly men themselves amaze To win the palm, the oak, or bays; And their uncessant labours see Crown'd from some single herb or tree, Whose short and narrow verged shade Does prudently their toils upbraid; While all flowers and all trees do close To weave the garlands of repose. The common aims of plants and animals are the conversion of energy to their own purposes and the perpetuation of their species. All energy in the solar system ultimately comes from the Sun as light emission, and organisms that can use this source directly belong to one of the autotrophic groups, which are independent of outside sources of organic substances. These direct solar energy converters, or phototrophs, are almost exclusively plants, the rare exceptions being found among the bacteria. An example of this latter esoteric group is Halobacterium halobium. But not all plants are autotrophic. A major division, or phylum, of the plant kingdom are the mycophyta, or fungi, which include mushrooms, moulds and yeasts. These heterotrophs are all either saprophytes, obtaining nutriment in solution from the decaying tissues of plants or animals, or parasites. The latter group are important agents of disease, mainly in other plants but occasionally in animals. We will not be concerned here with such plants, and neither will we consider all phototrophic plants. The algae, which are simple photosynthetic plants, were formerly classified as belonging to a single taxonomic division. [ABSTRACT FROM AUTHOR]

What! will the line stretch out to the crack of doom? When Lewis Carroll's Walrus suggested that the time had come ‘to talk of many things; of shoes and ships and sealing wax, of cabbages and kings’, the intention was to reel off an impressively incongruous list of items. In point of fact, however, he was merely reciting an inventory of materials all of which are at least partly composed of polymers. And the list was by no means exhaustive, for he could have gone on to add paper and paint, rubber and rope, fur and flax, and wood and wool, and so on. The polymer domain is a veritable pot-pourri which displays greater variety than is seen in any other class of substances. Of all materials used by Man, those based on polymer molecules have been around longest. Wood, for example, was pressed into service long before metals were being smelted, and wood is composed of cellulose, lignin and resins, all of which are natural organic polymers. Nevertheless, an adequate knowledge of polymer structure and properties has been acquired only during recent decades. The reason for the delay lies in the fact that these molecules are frequently very large and complex compared with anything encountered in metals and ceramics. Analysis of such huge aggregates of atoms, with molecular weights frequently running into the hundreds of thousands, has required the sophistication of modern instrumentation, and polymer science is still a relatively young discipline. [ABSTRACT FROM AUTHOR]

Like harmony in music; there is a dark inscrutable workmanship that reconciles discordant elements, makes them cling together in one society. The products of the glass maker are often aesthetically pleasing, but it would be unfair to claim that glass is intrinsically more attractive than any other type of material. Rather, by its presence in the family of materials, glass extends the range of useful properties and artistic qualities. As has transpired only recently, glass also extends the range of atomic structures in condensed matter, through its unique lack of order. Indeed, it is this atomic-level attribute, rather than the traditional ones of transparency and brittleness, which is now acknowledged as the defining characteristic of this type of material. Oxide glasses such as the common silicate varieties have been in use for at least 4000 years. Glass beads, dating from about 2500 BC, have been found in Egypt and other parts of the Near East, although exploitation of the plasticity of hot glass is more recent. These oxide materials so dominated the scene that the existence of the glassy state was believed to be intimately connected with the presence of covalent bonds. Glass has long been known to be a supercooled liquid, and covalent bonding was regarded as a prerequisite if crystallization was to be avoided. These attitudes underwent radical revision in the 1960s. With the production of metallic examples, it was suddenly realized that a glass need not be transparent, brittle, or insulating. [ABSTRACT FROM AUTHOR]

All nature is but art unknown to thee, All chance, direction which thou canst not see; All discord, harmony not understood; All partial evil, universal good; And, spite of pride, in erring reason's spite, One truth is clear, Whatever is, is right. The bonding between atoms is governed by the structure of the atoms themselves, and because all atoms of a given element are identical, we might expect the atomic arrangement in a crystal to be regular. Crystals, and indeed solids in general, were believed to be perfect for many years after the atomic structure of matter had become generally accepted. There are now so many common phenomena whose very existence is the result of a lack of perfection that it seems surprising that the concept of crystal defects developed only recently. The idea emerged in several different guises, and there was an important precursor which, although not specifically related to crystals, played a major role in heralding the new era. The first person to delve into the realm of imperfection was Alan Griffith, in 1920, following studies of the strengths of glass rods and fibres. He found that when the diameter decreases to about 10 μm, the strength of a fibre becomes markedly higher than that of a relatively thick rod. Assuming that such thin fibres must be free of the flaws that plague thicker specimens, Griffith analyzed the energy balance at idealized cracks and its dependence on applied stress. [ABSTRACT FROM AUTHOR]

The force of nature could no farther go; to make a third she join'd the former two. Most substances are mixtures of two or more elements, and chemical compounds are found to have definite compositions. They are also found to consist of molecules, which are the smallest particles that can exist in the free state and still retain the characteristics of the substance. Thus the chemical formula for water is always H2O, indicating that its molecules contain two hydrogen atoms and one oxygen. (The subscript 1 is not written explicitly; H2O implies H2O1.) The formula H2O2, in which the relative proportions of hydrogen and oxygen are different from those in water, belongs to a different chemical compound, the common bleaching agent hydrogen peroxide. Similarly, sodium chloride, also known as common salt, has the formula NaCl, and not Na2Cl or NaCl3. This shows that the forces that hold atoms together in groups must have certain characteristics which determine the rules of combination. The occurrence of chemical reactions reveals that the forces can be overcome, allowing the atoms to move apart and establish bonds with other atoms. A simple example of such an event is the reaction Zn + 2HCl → ZnCl2 + H2 in which the addition of hydrochloric acid to zinc produces zinc chloride and hydrogen, which is liberated as a gas. This demonstrates that the binding forces between zinc and chlorine atoms are stronger than those which hold hydrogen to chlorine. [ABSTRACT FROM AUTHOR]

INTRODUCTION The scientific revolution of the seventeenth century has long been a centre of interest for historians of science. Traditionally, a major topic within it was astronomy, the ideal science on account of its being objective, intellectual, based on the senses, uncontaminated with contemporary unscientific things and pointing firmly to the future. This image – and the name ‘scientific revolution’ itself – are now seen to be constructions of recent historians, but the name has stuck and we are still invited to see science in the seventeenth century and celebrate its earliest exponents. But to many observers at the time, the new doctrines were a pernicious heresy spread by men who had betrayed the old traditions of learning and piety. The new doctrines were also a minority opinion, promulgated by a handful of people limited largely to two European countries, England and Holland. Elsewhere, the men with the greatest vocational need for philosophy were the physicians, whose use of it is the subject of this book. When and if they finally absorbed the new doctrines, it was not until well into the eighteenth century, which makes a European ‘scientific revolution’ a thing of the Enlightenment. It is only recently that the role of medicine in these changes has begun to be appreciated. There are several things we should note. First, as we have seen, the doctors had a practical use for natural philosophy and treated it as professional knowledge. [ABSTRACT FROM AUTHOR]

INTRODUCTION Few histories of medicine are without an evolutionary approach. Histories adopting this approach are not now generally ‘whiggish’, but they invariably give much attention to signposts indicating the direction of the road and bearing legends such as ‘mechanism’ or ‘circulation’. Many of these directional milestones are clustered in England and the United Provinces of Holland, and, even in the seventeenth century, medical mechanism could be seen by a major figure in Paris as so much modern Dutch nonsense. But as we have seen, Learned and Rational Doctors were successful in the familiar territory of traditional natural philosophy where they did not need signposts or milestones. This was mostly the case in Catholic countries such as Italy and Spain, and we have glanced at some probable religious reasons for this. In Spain in particular, the universities were happy to do without the new doctrines from England and Holland, and viewed with suspicion the instrument of their dissemination, the tertulia, which were private associations. In 1700 the rector of the University of Seville wrote to his counterpart in Osuna urging the destruction of a tertulia.These organisations co-operated, he said, with the object of destroying the Aristotelianism and Galenism of the schools. There were also political and economic circumstances that seem to bear on the matter. The economic centre of gravity of Europe was moving north. [ABSTRACT FROM AUTHOR]