bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE PHYSIOLOGY OF HIBERNATION
Authors: GORER. P. A. 
Published: January 2008

Summary.1. It is stated that hibernation is but one manifestation of a property very widely spread amongst living organisms, i.e. that of withdrawing from an unfavourable environment. It is urged that comparison of hibernation with other analogous conditions would be valuable. Evidence is given that somatic changes occurring for various unknown reasons may cause the assumption of lethargy at an unusual time. Therefore somatic changes are as important in determining the cause of hibernation as environmental changes.2. The metabolism of hibernating animals, which is the lowest metabolism required to maintain the existence of protoplasm, is discussed. The various values obtained in connection with the respiratory exchange are mentioned. It is pointed out that the chief points of contention concern themselves with the possible effects of temperature on the solubility of CO2. From experiments covering long periods it is urged that the observed phenomena cannot be explained in this way. The adaptation to changes in temperature is discussed to a certain extent.3. The governor of metabolism amongst the higher animals apart from the nervous system is the endocrine system. The value of various histological findings, and of various injections, is discussed. It is pointed out that lack of structural modification does not necessarily eliminate the possibility of functional modification. Special attention is paid to the importance of the pituitary.4. The effects of varying concentrations of water on the metabolic processes are discussed. It is also indicated how the water content can modify the behaviour of an animal, and that a reduction of it may have opposite effects in various cases.5. Observations are given which demonstrate the remarkable adaptivity, and primitive structure, of the nervous system of hibernating mammals. Particular stress is given to the comparatively slight effects of decerebration on the heat regulative and postural reactions of such animals.6. The various internal and external stimuli tending to terminate lethargy are mentioned, as well as the phenomena connected with the actual return to activity. Emphasis is laid on the need of direct calorimetry to elucidate this problem in the mammalia.
SOME BIOLOGICAL ASPECTS OF THE POPULATION PROBLEM
Authors: HOGBEN LANCELOT 
Published: January 2008

Summary1. The logistic curve which Pearl has applied to the growth of populations of the fruit fly is the law of an experiment carried out under certain restrictions. The assumptions from which the law can be deduced are assumptions whose biological significance is problematical. Their sociological relevance is obscure. There is no sound reason to believe that the decline in European birth‐rate is the expression of a universal law governing the growth of populations. No known biological data conflict with the view that the declining fertility of European communities is a phenomenon sui generis.2. Occupational, statistics from all countries where the birth‐rate has fallen indicate a differential decline. To estimate the genetic significance of differential fertility existing methods are inadequate, and new methods for the detection of genetic differences in social behaviour are required. There are some indications that differential fertility is an ephemeral feature of present‐day conditions because the decline of the birth‐rate is extending to the labouring classes. On this view civilisation appears to be faced with the alternative of devising new incentives to parent‐hood or facing extinction through a progressive decline of population.3. There is insufficient reason to believe that improvement in infant welfare has significantly diminished the expectation of life in the later age groups—or that it is likely to do so in the immediate future.
RECENT PROGRESS IN THE CHEMISTRY OF MUSCULAR CONTRACTION
Authors: EGGLETON PHILIP 
Published: January 2008

Summary.I. In the last few years it has been found that:(a) A large proportion of the acid‐soluble phosphate originally classed as “inorganic” is actually combined with creatine (creatinephosphoric acid, phosphocreatine, phosphagen).(b) Most of the organic phosphate hydrolysed by the muscle enzymes during autolysis (the fraction hitherto known as “lactacidogen”) is adenosinetriphosphoric acid (adenylpyrophosphate).(c) There is no hexosediphosphoric ester in normal muscles, but a small amount of a hexosemonophosphoric ester. To this the name lactacidogen is now applied.2. Concerning the chemical events accompanying activity of a muscle, two discoveries in particular have greatly altered their interpretation:(a) It is found that the production of lactic acid occurs partly, and in some cases entirely, after the activity has ceased.(b) The production of lactic acid does not occur at all in muscles suitably poisoned with fluoride or iodoacetate. In such muscles the energy production is proportional to the extent of the accompanying phosphagen breakdown and is limited by the amount of phosphagen in reserve.3. Arising out of these and other considerations discussed in the text, a reasonable working hypothesis of muscular contraction is that the thermal and mechanical energy released in activity comes from the (exothermic) breakdown of phosphagen During the subsequent recovery period this phosphagen is resynthesised, the necessary energy being derived:(a) In the absence of oxygen; from the conversion of glycogen to lactic acid. Restitution in this case is only complete in muscles which have used up nearly all their reserve of phosphagen. There seems to be no alternative to the glycolysis mechanism as an anaerobic source of energy.(b) In the presence of oxygen, from the combustion probably of any available foodstuff, though carbohydrate seems to be the material used for choice by skeletal muscles.4. Other directions in which rapid advance has been made in recent years are:(a) The isolation of the constituent parts of the ferment system responsible for the glycolytic process in muscle.(b) The perfection of a delicate and rapid method of measuring the vapour pressure of muscles. One of the immediate results of the application of this technique has been the demonstration that the catabolic changes so far studied in connection with muscular activity do not account for all the osmotic pressure change. There must remain reactions of quite considerable extent so far undiscovered.
THE DIGESTION OF WOOD BY INSECTS AND THE SUPPOSED ROLE OF MICRO‐ORGANISMS
Authors: MANSOUR K. , MANSOUR‐BEK J. J. 
Published: January 2008

Summary

The relation between certain insects and the intracellular micro‐organisms they harbour is obscure and cannot be described as symbiotic for the following reasons:

Sterile mycetomes are known to occur in some species closely related to others with heavily infected mycetomes.
Defloration experiments have been carried out successfully without any harmful effect to the host insect.

Intracellular micro‐organisms in xylophagous insects cannot be considered as playing an important role in the digestion of wood for the following reasons:

In weevils with wood‐eating habits which have intracellular micro‐organisms, the latter only pass into the lumen of the gut of their host during the adult stage when the insect is not feeding on wood.
Some wood‐eating species of insects harbour intracellular micro‐organisms, while closely related species with similar feeding habits are free from these.
The intracellular micro‐organisms of some wood‐eating forms have been cultivated in vitro and found to be unable to break down cellulose.

The relatively high content in nitrogenous substances of different kinds of wood, and the general occurrence of proteolytic enzymes in insects, make the assumption that intracellular micro‐organisms fix atmospheric nitrogen for the use of their host superfluous.
The extracellular intestinal micro‐organisms of certain lamellicorn larvae and of some termites play no role in breaking down cellulose for the use of their host. They are utilised as a direct food source. Such insects are therefore better referred to as micro‐organism‐feeders.
True wood‐eating insects derive the necessary carbohydrates from the wood they live on through the activity of their own enzymes. The enzyme complex in such insects has been found to vary from species to species.
The carbohydrate components of wood vary in quantity in different kinds of wood.
Some true wood‐eating forms depend upon starch and soluble sugars for their source of carbohydrates. Such insects have no cellulase and can consequently only live in kinds of wood comparatively rich in starch and sugars.
Other true wood‐eating forms secrete cellulase and are therefore able to live in kinds of wood comparatively poor in starch and soluble sugars.
The occurrence of hemicellulase has been demonstrated only in a very few cases and the value of the hemicelluloses as food for wood‐eating insects has not been thoroughly investigated.
THE GENETICAL CONCEPTION OF THE SPECIES
Authors: HARLAND SYDNEY CROSS 
Published: January 2008

Summary.1. Previous work on the behaviour of genes in interspecific crosses is discussed, and it is concluded that allelomorphic relationships exist between the genes of crossable species whether these are in the same genus or in reputedly different genera2. Genetical experiments on interspecific hybrids in six species of the genus Gossypium enable the following main conclusions to be drawn:(a) Although allelomorphic relationships exist throughout the six species in respect of all genes examined, cases of identity (apparent or real) are practically confined to recessive genes only. Geographical isolation over a long period of time has resulted in the production of new alleles at most loci. These may be termed “species alleles”. Species endemic in the Galapagos and Hawaiian Islands are characterised by species alleles not found in mainland species.(b) The introduction of genes from one species into another indicates that species differ not only in the mode of distribution of alleles functioning as main genes, but also in the modifier complexes accompanying such alleles. The degree to which modifier complexes differ in species is of primary importance from a taxonomic point of view.(c) The bearing of experiments with the “Crinkled” mutant on the Fisher theory of dominance is discussed. It is shown that a number of normal alleles of crinkled exist, which are distinguishable only by their dominance potency, that the dominance relation is due to the interaction of a normal allele of specific potency with a modifier complex to which it is precisely adjusted, and that the genes constituting the dominance modifier complex have been preserved not because of their function as modifiers of initially disadvantageous heterozygotes, but because of their selective value on their own account. It is believed, however, that on the appearance of the crinkled mutant, selection probably ensued in favour of alleles with greater dominance potency, i.e. that the “Haldane effect” has been operative.(d) Examples are given of three different ways in which homologous characters can be genetically constructed in the genus Gossypium. It is pointed out that the conception of continuous change with time in the genetical architecture of an organ is probably of profound evolutionary significance.3. The Darwinian process of evolution by natural selection, involving mere gene substitution, has probably been the main mechanism involved in the profound changes induced in the genus Gossypium through geographical isolation.
THE SPECIFICITY AND COLLABORATION OF DIGESTIVE ENZYMES IN METAZOA
Authors: VONK H. J. 
Published: January 2008

Summary

The identity of the digestive enzymes found in vertebrates and invertebrates has been discussed.

For the proteases the conclusion is reached that in the vertebrates as well as in the invertebrates (as far as investigated) the protein molecule is attacked by at least four different enzymes, a proteinase, carboxypolypeptidase, aminopolypeptidase and dipeptidase, which can be separated by adsorption. (Recent researches have, moreover, demonstrated the presence of a separate protaminase in the former trypsin of vertebrates.) The proteinase of Maia squinado has the same specificity and properties as the vertebrate trypsin. In the midgut gland of Helix a cathepsin is present. Further investigations must verify the distribution of these enzymes for other groups. In the vertebrates the action of these enzymes is preceded by that of pepsin (stomach), working in a strongly acid medium. This pepsin is nowhere found in invertebrates.The nature and distribution of the proteases seems to be the same for all the classes of vertebrates. It is doubtful whether the enterokinases of the vertebrates are entirely identical.The amylases of vertebrates are, as far as is known, α‐amylases. They need activation by salts (chiefly sodium chloride). The amylases of invertebrates resemble those of vertebrates. An inulase is not found in vertebrates, but is present in some invertebrates. Cellulase and hemicellulase (it is doubtful whether they are identical or not) are also lacking in the vertebrates, but are present in some invertebrates. The properties of these enzymes have been fully treated.The disaccharases of vertebrates are saccharase, maltase and lactase. Of these, maltase is the most common in the invertebrates, occurring together with amylase (though its separation has not yet been carried out). Some invertebrates, especially Helix pomatia, are able to hydrolyse many more sugars (also tri‐ and tetrasaccharides) than the vertebrates can do. These disaccharases are still awaiting further investigation.The fat‐ and ester‐splitting digestive enzymes of invertebrates have more the character of esterases than of lipases (or an intermediate character), whereas in the vertebrates the reverse is the case.

The differences in localization of the vertebrate and invertebrate digestive enzymes have been discussed.

It has been pointed out that in the vertebrates the digestive enzymes occur in chains and attack the food successively, whereas in invertebrates almost all the enzymes meet in the place where the digestion is performed and attack the food simultaneously. Through this localization the action of the pepsin of the vertebrates becomes possible, for which a medium with strongly acid reaction is required, and moreover the organism is protected against inundation with cleavage products.Only in fishes (and probably amphibia) among the vertebrates is no pronounced chain of carbohydrases present, but amylase and maltase are chiefly found together in the pancreas.
SOIL CONDITIONS AND THE ROOT‐INFECTING FUNGI
Authors: GARRETT S. D. 
Published: January 2008

SummaryAn examination has been made of papers published during the last 15 years on soil‐borne fungus diseases of plants, with especial reference to the influence of soil conditions on infection.In reviewing the ecology of the root‐infecting fungi, a distinction has been made, following Reinking, betweensoil inhabitantsandsoil invaders.Thesoil inhabitantsare considered to be primitive or unspecialized parasites with a wide host range; these fungi are distributed throughout the soil, and their parasitism appears to be incidental to their saprophytic existence as members of the general soil microflora.Thesoil invaders, to which class the majority of the root‐infecting fungi seem to belong, are more highly specialized parasites; the presence of such fungi in the soil is generally closely associated with that of their host plants. In the continued absence of a host plant, such fungi die out in the soil, owing to their inability to compete with the soil saprophytes for an existence on non‐living organic matter. This close association between thesoil invadersand their host plants thus seems to be enforced by the competition of the general soil microflora.The influence of soil conditions upon a number of soil‐borne fungus diseases has been tabulated and discussed under the headings of soil moisture content, texture, organic matter, reaction and chemical composition. The relation of soil temperature to soil‐borne diseases has already been reviewed at length by L. R. Joneset al.(1926) and has therefore not been further considered here.
THE EXPANSION OF TAXONOMY WITH SPECIAL REFERENCE TO SPERMATOPHYTA
Authors: TURRILL W. B. 
Published: January 2008

SummaryAn attempt is made, within a limited space, to indicate the importance of taxonomy, especially of the Spermatophyta, to the more recently developed branches of biology, and to show that these in turn are reacting on taxonomy. Certain basic logical problems are discussed and a via media between extreme lines of development is suggested. The interactions between taxonomy and cytology, genetics, ecology, palaeontology, phylogeny, biometrics, and physiology are discussed briefly with a few selected examples. Practical suggestions for improving taxonomic methods and for increasing co‐operation between different branches of biology are made in various places throughout the text. Lastly, proposals are made that in practice should lead gradually and some way towards an “omega” or perfected taxonomy, which, idealistically, should be a completed classification of all biological knowledge.
PALAEONTOLOGICAL EVIDENCE BEARING ON HUMAN EVOLUTION
Authors: CLARK W. E. LE GROS 
Published: January 2008

SummaryPalaeontological evidence bearing on the evolutionary origin of the Hominidae is provided by dryopithecine fossils of Miocene and Pliocene date. These fossils consist almost entirely of jaws and teeth. They indicate that, while the dentition of Dyropithecus was essentially simian in its general characters, in certain features, notably the cusp‐pattern and proportions of the molars, it showed some significant approach to a human type of dentition. In certain allied genera, this approach is still further emphasized by the conformation of the dental arcade. The fact that in some species of these fossil apes the characteristic specializations of modem anthropoid apes were already evident in incipient form suggests that the divergence of the evolutionary line leading to the Hominidae from that which culminated in the modem genera of anthropoid apes must probably be referred to the beginning of Miocene times.More recent fossil apes from South Africa, even though they themselves may not bear any ancestral relation to man, emphasize the evolutionary potentialities of the Dryopithecinae for development in the direction of the Hominidae. However, a considerable gap still exists between the dryopithecine apes and the earliest known representatives of the Hominidae, a gap which can only be filled by further palaeon‐tological discoveries, with particular reference to the skull and limb characters of the former.The accession of new palaeontological material of the Pithecanthropus group (including those fossils which have been referred to the genus Sinanthropus) has served to emphasize its hominid status. It is important to note that, despite many primitive features of the skull, brain and dentition, the limb bones of the Pithecanthropus group are closely comparable with those of modem man. It becomes clear that if the modem characters of the human limbs had already been acquired so early as the beginning of Pleistocene times, the point of divergence of the Hominidae from the Simiidae must have been correspondingly more remote.The Pithecanthropus group almost certainly provided the basis for the develop‐nent of later types of man. Of these, one is represented by the rather specialized Neanderthal type of later Mousterian date. That this is to be regarded as an aberrant line is indicated by the fact that fossil human remains of early Mousterian and pre‐Mousterian date were less distinctively “Neanderthaloid”, and more akin in their anatomical features to Homo sapiens. There seems little doubt that these fossils represent, as a group, the direct ancestors of modem man.
THE ANTIHORMONES
Authors: COLLIP J. B. , SELYE H. , THOMSON D. L. 
Published: January 2008

SummaryAfter a short review of the history of antihormones, the antigonadotrophic and antithyrotrophic hormones have been discussed in detail because these are the best known members of this group. The possible existence of other antihormones, especially of antigrowth hormone, antiprolactin, antiketogenic, anticortin, anti‐thyroid hormone, etc. has also been considered.In view of the fact that many of the relevant publications have appeared in foreign languages and in journals not readily accessible to the general public, we tried to make this review as complete as possible. We felt that in the present state of our knowledge, an unbiased presentation of all the available data which may throw light on the theoretical interpretation and practical evaluation of the antihormones would prove of more value to the reader than an elaborate discussion of theories and personal views, most of which would after all have to be based on impressions rather than on knowledge.The most important facts which, as our survey shows, are now definitely established are the following:1. The blood of animals chronically treated with gonadotrophic or thyrotrophic preparations acquires the ability to neutralize the action of such preparations in other animals.2. The antihormones are specific in so far as, for instance, antigonadotrophic hormone does not antagonize the action of the thyrotrophic hormone and vice versa.3. The blood of an animal rendered immune to a certain type of a gonadotrophic preparation, though very active in neutralizing the action of this preparation, may be relatively inactive with regard to other gonadotrophic extracts. Similar examples of extract specificity have been observed concerning the antithyrotrophic hormone.4. Neither the presence of the effector organ (the gonads in the case of the gonadotrophic and the thyroid in the case of the thyrotrophic hormone) nor that of the hypophysis is essential for antihormone formation.5. There is little or no evidence that chemically pure hormone preparations such as the oestrogens, adrenaline, etc., may form antihormones in the true sense of the word, although the sensitivity of the organism to such preparations may decrease after prolonged treatment, In summarizing the essence of this survey, the authors emphasize, however, that the fact that pretreatment with certain hormones will cause the appearance in the blood of principles antagonistic to these hormones may be regarded as established beyond doubt. It is felt that the much‐debated question, whether these principles are hormones or antibodies, cannot be answered with certainty as yet; and even if we knew more about them the answer would largely depend on our definition of these two types of active principles.
HEARING IN INSECTS
Authors: PUMPHREY R. J. 
Published: January 2008

Summary1. The difficulties attending precise definition of auditory organs are discussed and a sketch of the early work on insect hearing is given.2. A brief account is given of the nature of sound and of the physical conditions which different types of auditory receptor must fulfil.3. The tympanic organs of insects, though undoubtedly of independent origin in the different groups of insects in which they occur, are shown to have a common structural plan; and the implications of this fact are discussed.4. An account is given of the important experimental work of Regen which first conclusively established the auditory function of tympanic organs in Orthoptera, and of subsequent work upon these organs in fulfil., Lepidoptera and Hemiptera.5. Experimental work indicating that tympanic organs may mediate a qualitative discrimination between different sounds is reviewed, and a tentative explanation of these observations is submitted.