bluuebunny/crossref_metadata_2025_split huggingface dataset:
Of the Movement of Worms
Authors: Chapman Garth 
Published: April 2021

ABSTRACT
Four aspects of the functioning of a fluid-filled cylindrical animal have been examined, viz.: (I) the role of the body fluid as a skeleton for the interaction of the longitudinal and circular muscles of which the animal must be composed; (2) the measurement of the maximum thrust which the animal can exert by measurement of its internal hydrostatic pressure; (3) the application of the force to the substratum and the part played by friction; (4) the relation between the changes in dimensions of the animal and the working length of the muscles.
Under (1) the necessity for a longitudinal and circular construction has been shown and the necessity for a closed system emphasized.
Under (2) the pressure exerted on the body fluid by the contraction of the longitudinal and circular muscles is discussed, and from their cross-sectional areas it is shown to be probable that when contracting maximally in Lumbricus they are not balanced, but that the longitudinals are about ten times as strong as the circulars.
Under (3) it is shown that the strength of an animal as measured by its internal hydrostatic pressure is sufficient to account for its customary activities. Use which may be made of the longitudinals during burrowing is pointed out.
Under (4) it is shown to be mechanically sound for burrowing animals of cylindrical form to be ‘fat’, but that a ‘thin’ animal is more efficient at progression.
The Effect of Pituitrin Injection on the Water Balance of Bufo Regularis Reuss
Authors: Ewer R. F. 
Published: April 2021

ABSTRACT
A method of cannulating the cloaca of Anura is described. Using this method it is found that in Bufo regular is the increase in body water which follows pituitrin injection is the result of an increased rate of water uptake, together with a diminished urine flow. The excess water is mostly retained in the lymph spaces, while the water content of the tissues of the body increases very little. The bearing of these results on the problem of the identification of the substance or substances which elicit the amphibian water balance effect, and the biological significance of the organization of the anuran lymphatic system are discussed.
The Physiology of Sea-Urchin Spermatozoa
Authors: Rothschild Lord , Tuft P. H. 
Published: April 2021

ABSTRACT
When a suspension of sea-urchin semen in sea water is diluted, the total O2 consumed and the rate of O2 uptake per spermatozoon are greater than before dilution. This is the Dilution Effect, first described by Gray (1928a). A further investigation of this phenomenon has been made, using the semen of Echinus esculentus. The form of the O2 uptake-time curve of such suspensions varies according to the ratio semen : sea water. In very dense suspensions d⩾5 × 109 sperm/ml.), the apparent low O2 uptake per unit quantity of spermatozoa is mainly due to inadequate O2 saturation of the lower layers of the suspension, in which the spermatozoa are virtually unable to respire. Such suspensions are not suitable for experiments in Warburg or Barcroft manometers. In dense suspensions (4 × 108 &lt; d ⩽ 109 sperm/ml.) the Dilution Effect was observed when sea water was added to the suspension, in such proportions that the sperm density was only reduced by a factor of 1·14. No Dilution Effect occurred when isotonic ‘Analar’ NaCl was added in the same proportions. On the basis of the small dilution involved, and the negative results with ‘Analar’ NaCl, it is concluded that the Dilution Effect is not exclusively due to the sperm having more space to move after dilution and therefore being able to expend more energy. The Dilution Effect occurs when isotonic ‘Analar’ NaCl containing 1 p.p.m. CuCl2 is added to a dense sperm suspension, in the above proportions. Stimulation of O2 uptake is proportional, over certain limits, to the amount of CuCl2 added. Both CuCl, ZnCl2, and to a lesser extent CuSO4, have similar effects. In a particular experiment, egg-water and Cu salts were about equally efficacious in increasing the O2 uptake of a sperm suspension. The characteristic decline in the O2 uptake of dense suspensions can be partly reversed by the addition of Cu salts. In dilute suspensions (d⩽4 × 108 sperm/ml.), there is no Dilution Effect when sea water or CuCl2 are added in the above proportions. On the other hand, the decline in O2 uptake can be partly arrested by the addition of Cu salts. Diethyldithiocarbamate markedly inhibits the O2 uptake of unwashed seaurchin spermatozoa diluted with sea water. The inhibition does not take place in the presence of added CuCl2. Cu may therefore have a catalytic function in the metabolism of sea-urchin semen. The possibility that Cu lack is responsible for the reduced O2 uptake of spermatozoa in dense suspensions is considered.
A Note On the Copper Content of Sea-Urchin Semen and Sea Water
Authors: Barnes H. , Rothschild Lord 
Published: April 2021

ABSTRACT
The copper content of semen, seminal plasma and coelomic fluid of Echinus esculentus has been determined. The average figures for sea-urchins examined immediately after collection were : semen, 1·33μg/ml.; seminal plasma, 0·50μg/ml.; coelomic fluid, 0·07μg./ml. The accuracy of the method of estimation was ± 0·08μg. Cu/ml. original sample, which means that the amount of Cu in coelomic fluid is not significant. This figure for coelomic fluid is considerably lower than that obtained by Webb (1937) in the only previous examination. The copper content of sea water (surface, off Keppel Pier, Millport) was 0·0064μg./ml.
Studies On Regional Specificity Within the Organization Centre of Urodeles
Authors: Waddington C. H. , Yao T. 
Published: April 2021

ABSTRACT
In young gastrulae of Triton alpestris the median part of the organization centre immediately in front of the blastopore was excised and replaced after reversal of its anterior-posterior axis. Completely normal embryos developed in many cases, but in others there was some degree of microcephaly or spina bifida. Similar normal embryos can develop after exchange of the anterior and posterior regions of the organizer, either with normal or reversed orientation. The spina bifida which frequently appears is a consequence of the impediment offered by the graft to the normal gastrulation movements. Microcephaly may also result if the presence of the graft prevents the proper development of the anterior part of the archenteron roof. It may also be caused when the posterior organizer region is brought into the anterior region, if the host fails to convert it into anterior material. This occurs the more frequently the older the grafted posterior material is. Even at the end of gastrulation (slit yolk-plug stage) the regional character of the archenteron roof is not finally determined. A fairly normal embryo (with over-thick mesoderm) may develop if an extra archenteron roof is added with reversed orientation between the normal archenteron roof and the presumptive neural plate. The determination of the regional structure of the archenteron roof and the neural plate is discussed. Attention is drawn to the spatio-temporal factors involved in the production and diffusion of the evocator with the dynamic system of the gastrulating egg.
The Physiology of Carbon Dioxide Transport in Insect Blood
Authors: Levenbook L. 
Published: April 2021

ABSTRACT
The pH of the blood of the third instar Gastrophilus larva is 6 ·64 at 38° C. with a pH-temperature coefficient of −0-007 Per 1° C. rise in temperature. The total CO2 content of the blood varies from 40·6 to 131·4 vol. % with an average of 72·4 vol. %. The CO2 content of the tissues minus the cuticle is very close to, and follows the variations in, the CO2 content of the blood. The CO2 tension in the blood is from 300 to 500 mm. Hg. From 30 to 50% of the CO2 is in solution, the rest in the form of bicarbonate. Carbamate formation does not occur in the blood. The ‘apparent’ dissociation constant for carbonic acid, , has a value of 6 ·08 (S.D. ±0 ·06) at 38° C. and 6 ·19 (S.D. ±0 ·13) at 16 ° C. CO2 dissociation curves have been drawn for 38 and 16 ° C. The slope of the curves indicates that the whole of the CO2 is given off at zero CO2 tension, and that the blood is adapted for functioning at high CO2 tensions.
The Physiology of Carbon Dioxide Transport in Insect Blood
Authors: Levenbook L. , Clark A. M. 
Published: April 2021

ABSTRACT
In a previous paper (Levenbook, 1950) it has been demonstrated that carbon dioxide transport in the blood of the larva of Gastrophilus intestinalis de Geer (Diptera) occurs largely in the form of bicarbonate. It is highly probable that this also applies to most other insects. The quantity of bicarbonate present is a function of both the available base and the carbonic acid concentration, the latter in turn being directly proportional to the amount of gaseous CO2 existing in the blood. Wigglesworth (1939) has pointed out that except where the tracheolar endings are intracellular, the final gas transport between the tracheoles and the respiring tissues is through the insect’s blood. Accordingly it is of interest to determine whether or not insect blood possesses any special properties peculiar to this function of transporting carbon dioxide between the cells and the tracheoles.
The Physiology of Carbon Dioxide Transport in Insect Blood
Authors: Levenbook L. 
Published: April 2021

ABSTRACT
One of the primary attributes of the internal medium of any organism is that it should maintain its normal hydrogen-ion concentration within certain rather narrow limits. Throughout life and, for different reasons, even after death, there is a continuous tendency for this pH to be depressed on account of the liberation into the blood of certain predominantly acidic metabolites, together with respiratory carbon dioxide. Although insects appear to support a wider range of pH change than do mammals, if their blood were insufficiently well buffered, its reaction would soon become outside the limits compatible with life.
Flight Recorders. A Technique for the Study of Bird Navigation
Authors: Wilkinson D. H. 
Published: April 2021

ABSTRACT
Experiments on the homing ability of birds usually take the form of displacing a bird from its home, releasing it at a known time, observing its behaviour until out of sight and then noting the time when it returns, if at all, to its home. If the interval between release and return is that appropriate to direct flight from release point to home the interpretation is obvious; the bird has flown more-or-less straight home. If, as is more usual, the interval is considerably greater than the direct flight time the question arises as to whether the bird has been flying all the time or whether some substantial fraction of the time has been spent in other ways such as resting and feeding. It is of importance to be able to answer this question: a theory of bird homing based on methodical or random search would demand a considerable time spent actually on the wing, while a theory which postulates some genuine navigational ability on the part of the bird would admit of considerable resting periods and a time actually in the air no bigger than the direct flight time. The time spent in flying is, then, a vital datum which is lacking in conventional homing experiments.
Nitrogenous Excretion of Amphipods and Isopods
Authors: Dresel Elisabeth I. B. , Moyle Vivien 
Published: April 2021

ABSTRACT
The nitrogen excretion of eleven species of amphipods and isopods, including marine, fresh-water and terrestrial forms, has been studied. All species are essentially ammonotelic, since more than 50% of the total soluble N.P.N. of the excreta was present in the form of ammonia throughout. The level of nitrogen excretion is appreciably lower in the terrestrial species than in any of the others, indicating that, in this group, adaptation to terrestrial conditions has been attended by a general suppression of nitrogen metabolism rather than by a transformation of ammonia to other, less toxic products. Some 5-10% of the total soluble N.P.N. was present as urea in the case of the fresh-water amphipod, Gammarus pulex, and as uric acid in the terrestrial isopods as well as the fresh-water isopod, Asellus aquaticus. It is suggested that these minor excretory components might originate from purines as a result of the loss of one or more of the uricolytic enzymes. In association with the excretion of uric acid some retention of this insoluble compound usually occurs, and it was found that among the terrestrial species the amount so stored parallels the degree of morphological and physiological adaptation to terrestrial conditions. The greatest accumulation of uric acid was, however, observed in the fresh-water species, A. aquaticus, and although such a storage cannot necessarily be taken as evidence for a partially uricogenic metabolism, this possibility must be borne in mind.
Refinements in Polarized Light Microscopy
Authors: Swann M. M. , Mitchison J. M. 
Published: April 2021

ABSTRACT
Various measures to increase the sensitivity of the polarizing microscope for visual observation are discussed. These include choice of polarizing apparatus, reducing condenser and objective aperture, reducing lamp iris, blooming lenses, use of mica plate compensators and use of bright light sources. By such means as these it is possible to detect retardations down to 0.28 A., or 1/20,000th of a wave-length. A photographic method for measuring retardations down to the same limit in small biological objects, is also described.
We are deeply indebted to Mr E. W. Taylor of Messrs Cooke, Troughton and Simms Ltd., for his great help in fitting our microscope with double Polaroids and a graduated compensator mount, as well as for blooming our lenses and making special low retardation mica plate compensators. We are also indebted to Dr L. E. R. Picken and Dr A. F. Hallimond for helpful suggestions at various stages of the work.
An Electron Diffraction Study of the Crystalline Structure of the Lipids in the Pupal Exuviae of Calliphora Erythrocephala
Authors: Hurst H. 
Published: April 2021

ABSTRACT
Electron diffraction techniques have been extensively used for the direct crystallographic examination of thin films of fatty materials, but they have hitherto not been applied to the study of natural membranes. These techniques provide more information than diffraction of X-rays about the atomic and molecular organization of surface structures. X-ray diffraction methods have been used successfully by Fraenkel & Rudall (1940, 1947) for elucidating the molecular organization of the chitin and protein components of the bulk cuticle framework in blowfly larvae ; but the thin lipid-rich epicuticle constitutes a small proportion of the entire cuticle, and would not contribute effectively to the observed diffraction patterns.
Studies on Haemovanadin. III. Some Physiological Properties of Haemovanadin, The Vanadium Compound of the Blood of Phallusia Mamillata Cuv*
Authors: Califano Luigi , Boeri Enzo 
Published: April 2021

ABSTRACT
It has been known since 1911 (Henze) that the blood of Phallusia mamillata Cuv. contains vanadium, which is found in special cells, called vanadocytes by Webb (1939). Webb estimated that the vanadocytes constitute about 60% of the blood cells and the blood cell volume amounts to between 1 and 2% of the total blood volume. It was found by Henze that the inner medium of the vanadocytes is very acid, due to free sulphuric acid which is present in a concentration of about 3%. According to Webb, the vanadium content of the animal amounts to about 0-15% of the dry weight of the body, and three-quarters of the total amount of vanadium is present in the blood, 15 % in the gut and associated viscera and 10% in the mantle and branchial sac.
The Diurnal Variations in the Tissue Glycogen Content and Their Relation to Mitotic Activity in the Adult Male Mouse
Authors: Bullough W. S. , Eisa E. A. 
Published: April 2021

ABSTRACT
A description is given of the hour-to-hour variation in the liver glycogen content in adult male mice, and it is shown that the concentration is highest while the animals are asleep and lowest while they are awake. A similar cycle is also described in the glycogen content of the skin. Histologically it is shown that a high proportion of the skin glycogen lies in the cytoplasm of the epidermal cells, and that during sleep both the epidermal glycogen content and the epidermal mitotis rate increase considerably. The skin glycogen content and the epidermal mitotic activity also show a marked increase after a subcutaneous injection of 20 mg. starch, while they are both abnormally depressed after two injections of unit insulin. These results, together with others previously reported, are in agreement with the theory that at the onset of sleep glucose is deposited from the blood into the tissues where it appears in the form of glycogen. Since it is known that glucose, or glycogen, is a critical substance affecting mitotic activity in the adult mouse, it is logical to find that an increase in the epidermal glycogen content is accompanied by a greatly increased mitosis rate. On waking, the reverse process takes place, glycogen being withdrawn as glucose into the blood and mitotic activity falling to a low level.
Changes in the Behaviour of Honey-Beesfollowing Their Recovery From Anaesthesia
Authors: Ribbands C. R. 
Published: April 2021

ABSTRACT
Chloroform anaesthesia did not impair the memory, change the foraging behaviour, or reduce the longevity of the treated bees; chloroform is therefore a satisfactory anaesthetic for use in experiments on bee behaviour. Carbon dioxide anaesthesia did not impair the memory of treated bees, but it did induce a permanent change in their behaviour. Their pollen-collecting tendencies were either eliminated or suffered very marked reduction. Experiments with foraging bees of known age indicated that the carbon dioxide treatments had no direct effect on longevity. Treatment of recently emerged bees with carbon dioxide eliminated all or most of their brood-rearing and wax-secreting activities and caused them to forage at an early age. Foraging life is more hazardous than life within the hive, and therefore the expectation of life of these carbon-dioxide treated bees was less than that of the controls. The effects of nitrogen anaesthesia were similar to those obtained with carbon dioxide. The factor common to both treatments is oxygen lack. The theoretical and practicable possibilities of these results are discussed.
Central Nervous Function and Changes in Brain Metabolite Concentration
Authors: Chance M. R. A. , Yaxley D. C. 
Published: April 2021

ABSTRACT
The content of glycogen and lactate in mouse brain has been estimated after a new extraction procedure which has been demonstrated to involve only a slight loss in amount of these two metabolites in comparison with extraction following freezing in situ. Five different methods of precipitating convulsions produced increases in the amount of lactate concentration at both subconvulsive and convulsive levels, but glycogen increased appreciably only when these methods produced a convulsion. It is concluded that glycogen increase in the mouse brain is specifically related to the occurrence of epileptic discharge in the brain. This increase has been shown to occur in all parts of the brain, though in varying degrees. Previous studies on these brain metabolites are discussed in the light of these results.
A New Micro-Respirometer with Automatic Setting and Recording Apparatus
Authors: Tuft Peter 
Published: April 2021

ABSTRACT
The instrument was designed to measure the O2 uptake of living material which consumes between 0·01 and 5·0 μl. O2/hr. Its accuracy is + 0·001 μ1., and it has the following advantages over other micro-respirometers of similar sensitivity.
The Hatching Mechanism of Muscid Eggs (Diptera)
Authors: Davies Lewis 
Published: April 2021

ABSTRACT
Certain Muscid eggs are shown to change their shape almost simultaneously with changes in the relative humidity of the air in their immediate vicinity. Evidence is produced that these shape changes are caused by the effect of humidity on the chorion. The net effect of the shape changes appears to be the setting up of increasing strain in the chorion, making it progressively easier for the larvae to rupture their shells, with increasing humidity. These shape changes therefore provide an explanation for certain well-known humidity effects on the hatching of Muscid eggs.
The Development of Motor Responses in the Stomach of the Foetal Sheep
Authors: Duncan D. L. , Phillipson A. T. 
Published: April 2021

ABSTRACT
Knowledge of the movement of the gut in the mammalian foetus is mainly derived from observations on small laboratory animals. Yanase (1907) made a systematic study of pre-natal intestinal movement in the guinea-pig, and observed that the appearance of peristalsis coincided with the time of development of the longitudinal muscle of the gut, at about the 27th day of gestation. At the stage when circular muscle alone was present, he was able to elicit only local constriction by mechanical or faradic stimulation. Foetal gastric movement was observed in the rabbit (Tani, 1927) and in the cat by Friedman (1934), Windle & Bishop (1939), and Becker & Windle (1941). The last-named described rhythmic and persistent gastric peristalsis in cat foetuses of 35–40 days. Becker, Windle, Barth & Schultz (1940) found that thorotrast injected into the amniotic sac of the guinea-pig circulated through the alimentary tract of the foetus from the 42nd day onwards; and human foetal swallowing is said to occur from the fifth month (Windle, 1940). While there is evidence, therefore, that alimentary tract movement commences in pre-natal life, nothing is known of the factors controlling the onset of movement or of the nature of the individual movements.
Fermentation in the Rumen of the Sheep
Authors: Gray F. V. , Pilgrim A. F. , Weller R. A. 
Published: April 2021

ABSTRACT
It is now generally accepted that the fermentation of carbohydrates in the rumen gives rise to the formation of large amounts of the lower volatile fatty acids ; but the fact that these acids are absorbed in considerable amounts and at different rates from the rumen into the blood stream has made it clear that in vitro studies of the fermentation processes are necessary in order to ascertain the actual quantities in which they are made available to the ruminant.