bluuebunny/crossref_metadata_2025_split huggingface dataset:
ARGINASE
Authors: BALDWIN ERNEST 
Published: January 2008

SummaryI. Arginase is a highly specific intracellular enzyme and requires that both the carboxyl and the guanidine groups shall be free if the substrate molecule is to be activated. The kinetics of arginase and its behaviour towards activators and inhibitors are very briefly discussed in the text.2. Arginase is abundantly present in the liver of ureotelic vertebrates; small amounts are present also in the kidney and testis, but little or none elsewhere. In uricotelic vertebrates it is mainly confined to the kidney.3. Male animals always contain about 50 per cent, more arginase than females; a sudden increase in the arginase content of the testis at puberty suggests a possible specific relation between sex and the distribution of arginase.4. Arginase is widely distributed among invertebrates, usually in small amounts. But the terrestrial gastropods contain as much of the enzyme as do the ureotelic vertebrates.5. The synthesis of urea by ureotelic vertebrates takes place by a cyclical mechanism involving arginase. This system is present in mammals, chelonian reptiles and Amphibia, but not in birds. It is very probably present in the elasmobranch fishes also, and the possibility that it is present in the teleosts remains open.6. Although arginase is not concerned in the production of uric acid by uricotelic vertebrates it does account for such urea as is excreted by these forms. Its main function in the birds is that of supplying ornithine for detoxication.7. Many invertebrates resemble the birds in possessing small amounts of arginase, which probably suffice to account for the urea which they excrete. In the terrestrial gastropods it is possible that metabolism is primarily ureotelic as in the mammals, but that urea is secondarily converted into uric acid as an adaptation to xerophilous life.8. Although many bacteria are capable of breaking down arginine they probably contain no arginase but only guanidinodesimidase. This enzyme appears to be absent from vertebrate tissues.9. Arginase is present early in embryonic life and is soon capable of discharging its adult function. But there exists a correlation between a high growth rate and a high content of arginase, phosphatase and nuclease, which suggests a specific association between arginase and the processes of growth.
THE INTERPRETATION OF THE FLOWER: A STUDY OF SOME ASPECTS OF MORPHOLOGICAL THOUGHT
Authors: ARBER AGNES 
Published: January 2008

SummaryIn the introduction to this study, the chief phases in the interpretation of the flower, from Goethe's day onwards, are briefly indicated in their historical sequence. Goethe's theory of the equivalence of the vegetative shoot to the flower, in the angiosperms, is then discussed and an attempt is made to evaluate the evidence for it. It is shown that this theory, if understood in a broad sense, harmonizes with the modern holistic trend in morphology. It is suggested that the flower is comparable with a vegetative shoot in a condition of permanent infantilism. Special emphasis is laid upon the inflorescence as offering, in some respects, an intermediate term between the vegetative shoot and the flower.After a brief consideration of bracts, sepals, petals and stamens, the Candollean theory of the carpel is discussed, and it is concluded that it has been peculiarly successful in providing a framework for the vast plexus of facts which it is its task to correlate. Some of the difficulties which have been felt in regard to this theory are considered, with special reference to recent work on the gynaeceum structure of the Papaveroideae. The stigma and “transmitting tissue” are then discussed, and it is concluded that there is nothing in the behaviour of this tissue which is out of harmony with the Candollean theory of the carpel.An attempt is made to arrive at a more precise notion of the meaning to be attached to correspondence, equivalence and homology, when these terms are used in connexion with Goethe's comparison of the vegetative and reproductive parts. It is suggested that these terms are best translated into the language of modern thought by the word parallelism, thus avoiding the use of Goethe's type concept, which cannot be safely employed unless its abstractness is constantly borne in mind.The nineteenth‐century phase, in which morphological ideas were lifted bodily into an historical setting, is then discussed, and emphasis is laid upon the danger of thus confusing two irreducible worlds of thought. Certain attempts which have been made to relate the flower of the angiosperm to the reproductive organs of plants of earlier geological periods are briefly criticized.In the concluding sections, attention is drawn to the current reaction against phylogenetic morphology, and in favour of the purely comparative morphology contemplated by Goethe. A slight sketch is given of Delpino and Troll's theories of the flower, in which “form” is considered as distinct from “organization”. Whether these views are accepted or not, the “Gestaltlehre” is at least an indication that the morphological ideas, which Goethe initiated before the end of the eighteenth century, may even to‐day suggest fresh approaches to the problem of the interpretation of the flower.
PROTEIN SYNTHESIS IN PLANTS
Authors: PETRIE A. H. K. 
Published: January 2008

SummaryThe final stages in the formation of protein, rather than the formation of amino‐acids, are discussed. The approach is physiological rather than biochemical. After reviewing the present state of knowledge of the structure of proteins various suggestions as to the substances used in the formation of the protein are considered. The evidence seems to be in favour of the formation by condensation of amino‐acids rather than by the polymerization of some simple unit. This leads to a consideration of the various seats of synthesis in the cell and to the mechanism by which the proteins are formed from their constituent parts. The article concludes with a discussion of the interrelation of nitrogen metabolism and respiration and of the factors governing amino‐acid formation and protein synthesis.
TIMBER DECAY*
Authors: CARTWRIGHT K. ST G. , FINDLAY W. P. K. 
Published: January 2008

SummaryAfter a brief historical introduction, attention is drawn to the importance of the correct sylviculturaj management of woodlands in the production of clear, disease‐free timber. Methods for the identification of the organisms which cause decay in timber are discussed, and the importance of pure culture methods is stressed. The principal contributions to the general descriptive work on timber decay in various countries are referred to, and it is pointed out how the usefulness of much of this work has been enhanced by the publication of books and monographs collating this scattered information. In a discussion of the physiology of wood‐rotting fungi the temperature relations and nutritional requirements, growth in relation to pH, and moisture content of the substratum are considered. The unsatisfactory state of present‐day knowledge of the enzymes of wood‐decaying fungi is mentioned. Recent work on the metabolic products of wood‐rotting fungi is referred to briefly. The effects of decay on the physical properties of wood are described, i.e. on the density, strength and optical properties, etc. The mechanical strength of timber, especially the toughness, may be appreciably affected in a very early stage of decay before any measurable loss in weight has occurred. The chemical changes brought about during the decomposition of wood are discussed. Rot of timber can be classified chemically into two main types: brown rots, in which only hydrolysis of cellulose and other polysaccharides occurs, and white rots, in which all the constituents of the wood, including the lignin, are attacked in varying degrees and in which oxidizing as well as hydrolysing enzymes are present. The effect of fungal attack on the microscopic structure of wood is described, and the theories put forward to explain the penetration of the cell walls by hyphae are critically examined. Methods of determining the natural resistance to decay of timber in the laboratory are referred to, and the basis of natural durability in wood is shown to lie mainly in the nature of the chemical ‘extractives’ present in the wood. Recent advances are described in the use of water‐soluble wood preservatives which become fixed in the wood by the addition of a chromate to the treating solution, and the establishment of a British Standard method of test and the use of field tests are noted. Finally, attention is drawn to the great lag in the application to practice of recent advances in the study of timber decay and its prevention.
TAXONOMIC PROBLEMS IN THE EUGLENINEAE
Authors: PRINGSHEIM E. G. 
Published: January 2008

SummaryThe Euglenineae form a well‐defined natural group comprising a great number of species, the subdivision of which into families is difficult to make.Among taxonomic features, the basic shape of the cell body is fusiform but often irregular and twisted, with periodical tapering towards the posterior end. It may be concealed by morphological aberrations. The metaboly of many species and the occurrence of dimensional varieties render the use of shape and size as specific features sometimes rather equivocal. Other features have to supplement them for the identification of the species.The shape of the nucleus is sometimes characteristic, but the structure of the plastidome and the presence or absence of pyrenoids are of much greater taxonomic importance. These features vary greatly in the species of Englena, while the other green genera have almost uniform chromatophores. By plastid and other characteristics Trachelomonas and Colacium are related to certain species of Euglena, while Phacus and Lepocinclis are nearer to others.The flagellar apparatus of the Euglenineae is tentatively considered as being composed of two flagellar units throughout the group, the length alone varying according to the genus. Eutreptia with two equal or more or less unequal flagella would be nearest to the hypothetical ancestral form. The other green genera would be derived from it by a further shortening of the minor flagellum. Its near convergence to the long active flagellum gives the impression of bifurcation. Distigma would be the apoplastidic counterpart of Eutreptia, Astasia that of Euglena. All green Euglenineae and some colourless ones have an eye‐spot and opposite to it a thickening of the active flagellum or flagella not found in the species without an eye‐spot.The striation of the periplast varies greatly, without correlation to the degree of cell metaboly. A first attempt at classifying the different types of metaboly is made. Envelopes differ from the periplast by being exudations of inorganic substances.While the distinction between the phototrophic and the saprotrophic Euglenineae seems gradually to disappear, the holozoic forms are more distantly derived. There are no indications as to their evolution, as no zootrophic green Euglenineae are known, and some are similar to saprotrophic forms. The entire class of the Euglenineae is rather uniform, and a rational and at the same time natural classification has not yet been attained.
DEVELOPMENTAL ANALYSIS OF SCYPHOMEDUSAE
Authors: BERRILL N. J. 
Published: January 2008

SummaryThe eggs of the scyphomedusae vary in size from 0–03 to 0–3 mm. diameter, a variation of a thousand‐fold in volume. Type of gastrulation is correlated fairly closely with egg size, the smallest eggs gastrulating by unipolar ingression, the largest by complete or partial invagination, while eggs of intermediate size gastrulate by a combined process of ingression and invagination. The nature of the subsequent development is equally correlated with egg size and type of gastrulation. The smallest become vermiform planula larvae incapable of constituting a polyp directly, the intermediate‐sized eggs form planulae which become polyps or scyphistomae, larger eggs may occasionally form actinula larvae and so form a polyp without having had an active planula existence, while the largest eggs develop directly into the ephyra‐medusa, omitting the scyphistoma stage entirely. In the case of the smallest, and of the smaller intermediate types, the blastula and planula stages have the capacity to grow as such without accompanying progress in differentiation. Budding may occur even at the planula stage.The scyphistoma develops four, sometimes six, gastric pouches, and forms tentacles from the rim of the oral disc, usually in the order 2, 4, 8, 12, 16, and by further addition of fours to attain sometimes as many as 32. It consists of a head and a stalk, though either part may be much the longer. Outgrowths from the body wall near the junction of head and stalk may form either pedal stolons for attachment, or buds. Buds may be liberated as free‐swimming pseudo‐planulae, may develop attached to the parent and then liberated, or may develop at the ends of long stolons. Buds of a statoblast function may be formed successively beneath the pedal disc. Tentacles of a fully grown scyphistoma may constrict off, move away as pseudo‐planulae and give rise to new polyps. There are regional differences in the capacity of pieces of the body wall to regenerate whole or partial polyps. Isolated endoderm has no capacity to reconstitute a polyp. Isolated ectoderm from any level can reconstitute a perfect whole.The type of strobilation depends upon the size and shape of the scyphistoma head or column. When the head is shallow and the stalk long, strobilation is usually monodisc, resulting in one, sometimes two ephyrae. When the head is large and more or less columnar, segmental constrictions appear, and strobilation is typically poly‐disc. Isolated segments of a polydisc strobila do not necessarily develop into ephyrae, but may reconstitute themselves into scyphistomae and become reattached as typical polyps. In polydisc forms at least, the initiation of strobilation depends upon the attainment of a large size, accumulation of food reserves, and a certain critical low temperature. Most ephyrae are liberated with eight lappets, but the first ephyra formed, that is, from the oral disc, usually has more than eight, while the last to be formed may have smaller numbers. The initial number, with their corresponding rhopalia, persists as the final number in the mature medusa.
THE HISTOCHEMISTRY OF LIPOIDS IN ANIMALS
Authors: CAIN A. J. 
Published: January 2008

Summary1. The available methods for histochemical analysis of lipoids having been reviewed, the following are regarded as valid for the substances or groups indicated: Sudan black: all liquid or grease‐like lipoids.Nile blue sulphate: ‘acidic’ lipoids (lipines, chromolipoids and free fatty acids) as against ‘neutral’ ones (hydrocarbons, triglycerides, higher alcohols, waxes, steroids, carotenoids, etc.).Fluorescence (without the addition of sulphuric acid): a rapidly fading green is due to vitamin A.Presence of spherocrystals: lipines, cholesteryl esters (and perhaps other sterol esters as well).Osmium tetroxide, primary blackening only: for active unsaturated bonds, most usually ethylenic linkages in fatty acid radicles and probably in carotenoids, but also for aldehyde groups (in plasmal), and for various other strong reducers which are not lipoid.Acid haematein test: phospholipines (possibly acetalphosphatides as well).Feulgen's plasmal test (not the Feulgen‐Verne test): acetalphosphatides by means of the aldehydes liberated from them.Schultz's method I (modification of Liebermann's reaction): cholesteryl group. Schultz's method II (modification of Lifschiitz's reaction): without a previous oxidation, for certain ill‐defined oxidation products of sterols, with a previous oxidation (by light and air, or by ferric compounds) for the cholesteryl group.Antimony trichloride, and glycerol dichlorhydrin: a transient blue or blue‐green is specific for carotenoids.2. Some of the above tests are subject to interference by certain rare substances; the plasmal test and Schultz's method I may possibly give positive results with certain toad poisons.3. The following tests are rejected as definitely invalid, insufficiently investigated, or superseded by more satisfactory techniques:Fischler's technique for fatty acids;Casanova's reaction;Ciaccio's methods I and II for ‘lipoids’The Smith‐Dietrich method for phospholipines;Romieu's method for lecithin;The Feulgen‐Verne technique for plasmal;Bennett's method for ketosteroids.
THE VERTICAL MIGRATION OF PLANKTONIC CRUSTACEA
Authors: CUSHING D. H. 
Published: January 2008

SummaryThere are four methods of analysing the vertical migration of plankton in the field: (a) One day and one night observation at the surface. (b) One day and one night observation at depths between surface and the bottom. (c) Observations at long time intervals at all depths during day and night. (d) Observations at short time intervals at all depths during day and night.The last method, using horizontal closing tow‐nets with flow meters at measured depths, shows that migration consists of four parts: (a) ascent from the day depth; (b) midnight sinking; (c) dawn rise; (d) descent to the day depth.This pattern has been shown to be modified by wind (or state of sea), rain, sun on a calm sea, extremes of temperature, age of the individual animal and possibly by phytoplankton concentrations.These different parts of migration have been examined in detail and linked together in a single and continuous process. Ascent in the evening and descent in the morning become the continuous change of day depth with the changing penetration of light; the midnight sinking is assumed to be due to a passive state in full darkness; the dawn rise is a return by the animals to the mean optimum light intensity for the population. This is supported by the fact that the order in time of arrival at the surface for some fresh‐water species is the same as the order in depth of these species in full daylight.Theoretical interpretations of migration are reviewed. It is argued that the most likely theory has as its basic assumption the idea of an optimum light intensity.Experiments on migration are divided into three parts: (a) those showing that randomly oriented movement can take place; (b) those showing that the speeds of individual animals can vary with varying light intensities; (c) those showing that animals in full darkness will move at minimal speeds or not at all.It is concluded that the vertical migration of planktonic Crustacea is mediated by the change in light penetration throughout the day. Animals aggregate in an optimum band of light intensity. They have the capacity of moving phototactically, i.e. moving at constant speed towards or away from light; they also have the capacity of moving photokinetically, i.e. moving at speeds that vary with varying light intensity. In full darkness they move probably at minimal speeds. Migration between periods of full darkness may be operated by phototaxis, photokinesis or by a combination of these mechanisms.
THE PHYLOGENETIC CLASSIFICATION OF THE ANGIOSPERMS
Authors: SPORNE K. R. 
Published: January 2008

SUMMARYThe ideal classification of a group of organisms is one which takes account of all that is known about the group. It should, therefore, include information about its evolution. There are two aspects of evolutionary theory, (1) that which concerns the past history of the group and which can only be known with certainty from the fossil record, (2) that which concerns present‐day organisms and is expressed in the differences between advanced and primitive types. As regards angiosperms, there is only faint hope that their history will ever be known in sufficient detail for it to be made the basis for a phylogenetic classification. The extent to which the second aspect of evolutionary theory can be incorporated into classification depends on the ability of botanists to assess relative advancement.The first step in deciding which organisms are primitive is to discover which characters are primitive. For this purpose, a number of doctrines have been employed, often without due consideration of their philosophical justification. The doctrines of ‘conservative regions’, of ‘recapitulation’, of ‘teratology’ and of ‘sequences’ are unreliable, since their application is entirely subjective; in the absence of evidence from some other source, it is impossible to judge whether they are appropriate to the structures concerned. The doctrine of’ association’ is unsatisfactory because of the assumptions which have to be made before it can be applied. The doctrine of ‘the basic ground plan’, if applied in the strict sense, is relatively unprofitable; if applied loosely it is dependent on subjective judgement and if applied in the ‘Gestalt’ sense leads only to figments of the imagination. The doctrine of ‘correlation’ has been applied with success to the evolution of secondary wood in dicotyledons and to other characters, both floral and vegetative. Its results are of value since the subjective element is reduced to a minimum and, by its means, it is possible to assess the relative advancement of present‐day taxa.There have been many attempts to represent in two dimensions the phylogenetic classification of the angiosperms, but most of these are at fault because of a misconception of the tree of evolution. The ideal representation is visualized as resembling a target whose concentric rings correspond with relative advancement. On this are disposed the various families in such a way that closely similar ones are close together within circles of affinity, while, at the same time, their radial position corresponds to their relative advancement. In this way the second of the two aspects of evolutionary theory is catered for, and the classification may, therefore, be described as a phylogenetic one. The history of the group, if it becomes known from the fossil record, may then be inserted as a tree of evolution in a plane (corresponding to evolutionary time) which is perpendicular to that of the present‐day classification.
THE SIZE, SHAPE AND DENSITY OF MARINE PHYTOPLANKTON CONCENTRATIONS
Authors: BAINBRIDGE RICHARD 
Published: January 2008

SUMMARYData concerning the size, shape and density of concentrations of marine phytoplankton are considered.It is shown that patches of many shapes may occur, but that those most frequently encountered are elliptical, having the major axis four times the minor.The patches vary in size in a continuous series from a few feet across to as much as 30 or 40 miles by 120 or 180 miles, but the mean seems about 10 by 40 miles.Very long narrow bands or streaks are common and should be distinguished from the patches considered above. They are only a few feet in width and may form a pattern superimposed on the latter.Diatoms at concentrations of 10 cells/mm.3 and flagellates at 50 cells/mm.3 may be found in all these patches. Much higher concentrations have been reported but more common ones are 0–5 cell/mm.3 of diatoms and 2–5 cells/mm.3 of flagellates.Some possible origins of this pattern of distribution are briefly discussed. It seems likely that two different mechanisms are involved: the long narrow bands or streaks resulting from the aggregation of dispersed organisms under the influence of wind‐induced water movements, and the larger patches resulting from spatially restricted upwelling of nutrient rich water into the photic zone.