bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of the Chick Embryo in Relation to Its Food Supply
Authors: Byerly T. C. 
Published: April 2021

ABSTRACT
The rate of growth of the chick embryo depends upon an inherent growth rate, probably identical for all breeds. This rate is modified during incubation in direct proportion to a function of egg size. The increments in wet weight of the embryo are proportional to a function of the weight of the yolk sac, from the time of establishment of the circulation to the time of the changes preparatory to hatching. Both function and proportionality are probably identical for all breeds of chicken, regardless of egg size.
The growth in weight of the allantois and the yolk sac have been measured quantitatively for the first time. The weight of the allantois in eggs of different sizes is roughly proportional to the two-thirds power of egg weight after the first three or four days of its growth. During the initial period of its development the relative size is apparently independent of breed, egg size, or embryo weight. The yolk-sac weight in eggs of different sizes is roughly proportional to the circumference of the yolk after a similar initial period of independent growth.
Inclusion of the living material in the embryonic membranes in calculations of the rate of physiological processes of the embryo indicates that they are probably of the same order of magnitude throughout the incubation period rather than of sharply decreasing magnitude as supposed by some previous workers.
Factors Involved in the Production of Annual Zones on the Scales of the Rainbow Trout (Salmo Irideus). II
Authors: Bhatia D. 
Published: April 2021

ABSTRACT
Rainbow trout fed uniformly does not exhibit any periodic zones on its scales whether the temperature is normal or high or low. At both high and low temperatures (17° C. and 4° C.) fish fed abundantly show on their scales a peripheral band of comparatively broad rings, and fish starved show a peripheral band of narrow rings. Bands of broad and narrow rings, resembling the so-called “annual zones,” could be produced on the scales by altering the food supplies of the fish irrespective of the temperature of the medium. Variations in temperature have no direct effect on the production of the periodic rings on the fish scales.
The Growth of the Pituitary Body in the Female Rabbit
Authors: Allanson Marjorie 
Published: April 2021

ABSTRACTIn order to determine the relation of pituitary weight to body weight in the female rabbit, data were collected from 48 female rabbits. These data appear to fall on a straight line when the logarithm of the pituitary weight is plotted against the logarithm of cleaned body weight, and a straight line was fitted using the formula y = axk. The value of the constant k was found to be 0 · 61. From the data from 31 male rabbits a straight line was obtained by the same formula. The value of the constant k was found to be 0 · 57 as compared with the value 0 · 55 obtained by Robb for male rabbits. The growth rate of the pituitary does not show any marked difference after puberty in male and female rabbits as has been recorded for the rat (Hatai). Ten female rabbits were killed at varying periods after copulation and the relation of pituitary weight to body weight examined. No change in the relative size of the pituitary was detectable by the methods used, and it is concluded that any change in weight of the pituitary following copulation, if it occurs, must be slight.
Studies on the Nutrition of Blow-Fly Larvae
Authors: Hobson R. P. 
Published: April 2021

ABSTRACT
The intestinal flora of Lucilia larvae consists mainly of non-lactose-fermenting, gram-negative bacilli which do not liquefy gelatine. Proteolytic organisms are not present in the gut in significant numbers, but they occur in blown meat. A method of rearing larvae aseptically is described. The eggs are sterilised by treatment with c 1 per cent, mercuric chloride solution and the larvae reared on heated brain mush, sterility being tested by inoculating aerobic and anaerobic media. The absence of symbionts transmitted inside the egg has been concluded from an examination of stained smears and sections of “sterile” larvae. When larvae are reared aseptically on sterilised brain, the reaction of the gut contents is normal, tryptase is present in the intestine and excreta, and the growth rate is almost the same as in the presence of bacteria. It is, therefore, concluded that micro-organisms play no part in intestinal digestion. Sterile larvae excrete ammonia, but the amount is insufficient to make the food alkaline until the third or fourth day of larval growth. With infected cultures the reaction is distinctly alkaline on the second day. The ammonifying bacilli isolated from normal larvae are probably responsible for the rapid appearance of ammonia in blown meat.
The Utilisation of Proteoses by Chicken Heart Fibroblasts Growing in vitro
Authors: Willmer E. N. , Kendal L. P. 
Published: April 2021

ABSTRACT
The growth of chicken heart fibroblasts in physiological saline media, e.g. Tyrode, is not materially increased by the addition of pure proteoses. In the presence of plasma, the addition of proteoses causes increased growth of the tissues, probably owing to the slow digestion of the proteoses to utilisable amino acids by the enzymes of the plasma. If small quantities of embryo extract are also present in the plasma, then the beneficial effect of the proteoses on the rate of growth is very greatly increased. A thermostable substance has been separated from Witte’s peptone, and from fibrin digests, which is capable of stimulating cells to increased activity and division. The activity of this substance is not dependent on the presence of plasma. The effective agent is associated with, or is actually, a heteroproteose, and its action is probably not to supply nitrogen, but rather to stimulate the cells in some other way. It is present in certain preparations of proteoses and partly accounts for their activity. Suggestions are put forward to account for the manner in which the various media described affect the rate of growth of the cells.
Iodine Compounds and Fertilisation
Authors: Carter G. S. 
Published: April 2021

ABSTRACT
The results given in the previous papers of this series (1930, 1931 a, b, 1932 a, b) have shown that thyroxine, and, to a much smaller extent, certain related iodine compounds, resemble the egg secretions of E. esculentus and E. miliaris in their action upon the eggs and sperm of these species and that this resemblance extends to several distinct phenomena. The conclusion has been reached that the secretions contain a substance which is not only similar to thyroxine in its physiological action but is also chemically related to it. Further, the evidence has led to the conclusion that this substance is the component of the secretions which is essential to the activation of the egg, and is therefore the fertilizin of Lillie (1914).
Experiments with the Stipes of Fucus and Laminaria
Authors: Delf(Mrs Percy Smith) E. Marion 
Published: April 2021

ABSTRACT
Marine algae may be briefly characterised as either intertidal or totally submerged forms.
The intertidal algae have a dual existence : they are land plants at low tide and aquatics when covered by the sea. The proportion of time spent in the aerial or aquatic medium must vary with the position on the shore and the factors influencing tidal periodicity. The more exposed plants must have a tolerance for various light intensities and for a wide range of conditions affecting water loss ; and they must also, if fixed to the substrate, be able to withstand more or less violent movements of the water. These movements may be partly due to currents and partly to waves, frequently reinforced by wind.
Currents are said to have little influence on littoral plants, but wave action is certainly an important factor, influencing the mechanical stresses and strains to which the plants are subjected. These stresses differ from those to which land plants are exposed in being predominantly a series of intermittent pulls or jerks, applied to plants with little initial rigidity and great flexibility.
Some Aspects of Chemical Changes During Insect Metamorphosis
Authors: Evans Alterbury Coulston 
Published: April 2021

ABSTRACT
The changes in carbohydrate content, fatty acid content, and nitrogen distribution are described in detail during the metamorphosis from larva to adult in the sheep blow-fly, Lucilia sericata Meigan.
Carbohydrate decreases rapidly until the thirteenth day, after which it remains constant. Glycogen is present.
The fatty acid content decreases rapidly until the ninth day. A synthesis of fatty acid now occurs, reaching a maximum on the fourteenth day, after which a decrease sets in until emergence of the adult. The amount of saturated fatty acid present remains constant, the unsaturated fatty acids only being utilised.
The course of histolysis and histogenesis is reflected in the nitrogen distribution curves. The initial decrease in insoluble protein correlated with a rise in peptone is associated with the formation of the hard chitinous puparium. Continued decrease of the insoluble protein accompanied by a fall in peptone and an increase of soluble protein continues until histogenesis of the imaginal thoracic muscles commences. The insoluble protein now abruptly rises and the soluble protein shows a corresponding decrease. Formation of excretory-N occurs mainly during histolysis.
Duration of Testis Activity of Sturnus Vulgaris in Relation to Type of Illumination1
Authors: Bissonnette Thomas Hume , Robert Wadlund Arthur Pehr 
Published: April 2021

ABSTRACT
Between January 24th and April 22nd, 32 male starlings, with females, were subjected to (a) no added light (controls), (b) 1-7 foot candles of filtered red light together with the total light from a General Electric Company’ s “sunlamp” at about 3 ft. distance, approximating to midsummer mid-day sunlight, and (c) 1-7 foot candles of filtered red light, after dark for 6 hours, in addition to a 912 hours constant daily daylight period (about 18 min. reduction from the daylight period in nature at the beginning of the experiment). Samples from (a), (b) and (c) groups were killed for study after 18, 25, 32 and 60 days, and from (c) group also at 88 days. Testes of controls (a) underwent a slight regression, remained smaller than at the first killing, and did not increase in germ-cell or other gonadal activity. Testes of birds in (c) group were slower to reach their maximum size and spermatogenesis (60 days) than were those from (b) group (32 days), with their more intense light and approximately double the amount of red rays. Both sets of birds failed to maintain their maximum size and spermatogenesis, though the more slowly reacting (c) group maintained it longer than did the (b) group. The reaction differences are such as to indicate that differences in light intensity and amount of red rays caused the observed differences in relative length of the phases of the sexual cycle and, particularly, in the length of periods of maximum testis size and activity rather than any specific action of ultra-violet rays or excess of green light. Even on the highly stimulating exposures to light used, the duration of maximum spermatogenic activity was limited and varied with different birds, with different exposures to light, and with different types of light, and the consequent rates of germ-cell activity. The duration of any phase of the sexual cycle bore an inverse relation to the effectiveness of the stimulating exposure to light, which, in turn, depended on the daily period, intensity, wave-length and rate of change of illumination. Alternative modes of causation of these phenomena and the probable mediation of the anterior lobe of the hypophysis in the reactions are discussed.
Studies on the Nutrition of Blow-Fly Larvae
Authors: Hobson R. P. 
Published: April 2021

ABSTRACT
Investigation of the feeding of Lucilia larvae on meat suggested that the chief factors involved are mechanical maceration and the alkaline reaction which results in the first place from bacterial action. Larvae suck the fluid serum from acid muscle ; they ingest semi-liquid food only when the reaction is alkaline or the free liquid has been removed. Predigestion of the muscle substance is apparently not essential, as the crop contents often consist of insoluble protein. The proteolytic enzymes in the larval excreta, which include a collagenase, probably serve to digest the structural parts of muscle tissue.
Studies on the Nutrition of Blow-Fly Larvae
Authors: Hobson R. P. 
Published: April 2021

ABSTRACT
Lucilia larvae fail to grow at the usual rate when reared aseptically on sterile unheated muscle (guinea-pig). Infection with B. coli, a non-liquefying organism which does not form ammonia, restores normal growth. Adding yeast extract to muscle produces the same effect on larval growth as infection with bacteria. It is therefore concluded that muscle is deficient in a growth-promoting factor which is normally supplied by the natural flora ; also, that bacterial action is not essential for the liquefaction of the muscle. From preliminary experiments the growth factor does not appear to be identical with vitamin Bj or B2. Yeast extract which has been autoclaved at an alkaline reaction retains most of its activity and is not less potent than ox-liver extract. When larvae are reared aseptically on muscle, they feed at first on the serum owing to the persistence of the acid reaction. However, this does not explain their slow development since sterile larvae grow well on beef juice.
Iodine Compounds and Fertilisation
Authors: Carter G. S. 
Published: April 2021

ABSTRACT
In the earlier papers of this series (Carter, 1930-32) it has been shown that a compound which is related to thyroxine in chemical structure plays an essential part in the fertilisation of the gametes of Echinus esculentus and E. miliaris. Evidence has been brought forward that this substance is present in the ripe egg, being formed during the later stages of its ripening, and that it is concerned in the increase of chemical activity which occurs in the egg after fertilisation. It is probably identical with or closely related to Lillie’s fertilizin. It is also present in the egg secretions and in the ripe sperm. Further, the similarity between the effects produced by the secretions and by thyroxine on sperm which was not perfectly ripe (in the sense previously defined, 1931 a, p. 180), and the fact that the behaviour of such sperm in the presence of thyroxine became identical with that of ripe sperm led to the conclusion that this substance is formed within the sperm during the later stages of its ripening, as it is formed in the ripening of the egg.
Swimming Energetics of Striped Bass (Morone Saxatilis) and Bluefish (Pomatomus Saltatrix): Hydrodynamic Correlates of Locomotion and Gill Ventilation
Authors: Freadman M. A. 
Published: April 2021

ABSTRACT
Swimming patterns of striped bass and bluefish were monitored using a miniature accelerometer to record instantaneous acceleration and instantaneous deceleration during tail-thrusts over a wide range of swimming speeds. In addition, ventilatory excurrent flow patterns were visualized in swimming striped bass by injecting milk via a buccal catheter. Both species accomplish steady swimming with both symmetric and asymmetric thrusts; other transient swimming patterns were observed as well. Over the transition range from active branchial to ram gill ventilation, no measurable change in forward acceleration amplitude occurred with adoption of ram gill flow in both species; this can only occur if drag does not change over the ventilatory transition. From metabolic measurements and from implications about swimming drag deduced from acceleration amplitude, the cost of active ventilation just prior to adoption of ram gill ventilation was estimated to be 8-i % and 8-4% of total metabolism for striped bass and bluefish respectively. Ventilatory effluent flow patterns during cyclic ventilation in swimming striped bass induce substantial turbulence and probably boundary layer separation. Flow patterns during ram ventilation result in streamlined flow over most of the length of the fish. The results show that transfer from active to branchial to ram gill ventilation provides important hydrodynamic advantages to these fishes at cruising velocities.
Further Observations on the Serotonergic Cerebral Neurones of Helisoma (Mollusca, Gastropoda): The Case for Homology with the Metacerebral Giant Cells
Authors: Granzow Bonnie , Rowell C. H. Fraser 
Published: April 2021

ABSTRACT
A bilaterally symmetrical pair of serotonergic neurones in the cerebral ganglia of the snail Helisoma trivolvis has major features in common with the serotonergic cerebral cells of other gastropods, including those of Helix and Aplysia. The cells were found to receive a high level of inhibitory synaptic activity which is important in determining their firing level. In the cells of isolated cerebral ganglia, tonic inhibitory synaptic potentials, uniform in frequency and amplitude, occur continually at a rate of about 2/s. In the cells of cerebral ganglia left intact with the periphery and buccal ganglia, phasic inhibitory activity occurs in addition to the tonic activity. Phasic inhibitory input could be observed at regular intervals, correlated with feeding motor activity in the buccal ganglia. Other properties of these cells include: a linear relationship between membrane potential and current injected into the cell; communication between bilateral cells in about 50% of the preparations studied; and sodium-based somatic action potentials. Some of these properties of Helisoma SCCs are different from those of Helix and Aplysia. We propose that the Helisoma SCCs are homologous to those in other gastropods and that the differences observed are the result of evolutionary adaptation of the cells to different functional roles.
Studies on Water in Barnacle Muscle Fibres II. Role of ions and Organic Solutes in Swelling of Chemically-skinned Fibres
Authors: Clark M. E. , Hinke J. A. M. , Todd M. E. 
Published: April 2021

ABSTRACT
Single muscle fibres from the giant barnacle, Balanus nubilis, were chemically skinned (2 % Tween 20), then equilibrated for 40 h in salt solutions ranging in ionic strength from 0·025 to 0·6 m at pH 7·0. The water content of the fibres and the net charge on the myofilaments increased with increasing salt concentration. Cation accumulation in the fibres was about equal to anion exclusion at all salt concentrations. When an organic solute (trimethylamine oxide, glycine, alanine, serine, proline, or glycerol) in the concentration range from 0·1 to 0·6 m was added to the salt solution, cation accumulation increased and water content decreased. Myofilament architecture was disrupted when the fibres were equilibrated in high salt (&gt; 0·4 m) solutions and preserved when 0·5 M-triethylamine oxide was also added. The results are consistent with the view that organic solutes enhance the association between the fixed charge sites and their counterions. This hypothesis is examined quantitatively using the Oosawa relationship between the volume and the counterion association for cylindrical polyelectrolytes. The results illustrate that organic solutes can influence fibre volume in a way other than through osmo-regulation.
Vascular Resistance Responses of an Eel Tail Preparation: Alpha Constriction and Beta Dilation
Authors: Davie Peter S. 
Published: April 2021

ABSTRACT
An isolated, saline-perfused, eel tail preparation is described. This preparation was easily prepared and did not suffer from progressive deterioration, as indicated by stable baseline resistance with time and maintained responsiveness to drugs. Elevation of caudal venous pressure caused a reduction in resistance of about 10% per 0·5 kPa. Addition of 3% or 5% human serum to the perfusate increased baseline resistance and imparted a degree of autoregulation to the preparation. Full dose-response curves for the preparation’s resistance responses to adrenaline (AD), noradrenaline (NA), and isoprenaline are presented. AD and NA increased resistance, indicating the presence of alpha adrenergic receptors. AD was more potent than NA; the mean potency ratio was 2·78:1 ·00 (AD: NA). Isoprenaline decreased resistance, indicating beta adrenergic receptors. From the relative potencies of isoprenaline ≪ AD &lt; NA in stimulating these receptors, they are classified as beta two adrenergic receptors. The possible physiological functions of alpha and beta responses of the eel tail are discussed.
Thoracic Leg Control of Abdominal Extension in the Crayfish, Procambarus Clarkii
Authors: Page Charles H. 
Published: April 2021

ABSTRACT
Postural extensions of the abdomen of the crayfish, Procambarus clarkii, could be evoked by mechanical stimulation of a single thoracic leg. Movement of a single leg joint was sufficient to initiate an extension response. Vigorous abdominal extensions were initiated either by depression of the whole leg (WLD) or by flexion of the mero-carpal joint (MCF). Weaker extension responses were obtained by depression of the thoracic-coxal and coxo-basal joints. Similar stimulation of the chelipeds did not elicit an abdominal extension response.
Single-frame analysis of motion pictures of crayfish responding to WLD or MCF stimulation of a 2nd thoracic leg showed that the responses evoked by the two different stimulus situations were nearly identical. They differed principally in the responses of the leg located contralateral to the stimulated leg.
Movements of most of the cephalic, thoracic and abdominal appendages accompanied the abdominal extension response. Only the eyes remained stationary throughout the response. The mean values of the latencies for the initiation of appendage movement ranged from 125 to 204 ms; abdominal movement had a mean latency of about 220 ms.
The abdominal extension reflex resulted from the activity of the tonic superficial extensor muscles. The deep phasic extensor muscles were silent during the response. The mean latencies for the initiation of superficial extensor muscle activity by WLD and MCF stimulation were 53·7 and 50·0 ms respectively.
Activity of Excitor and Inhibitor Claw Motor Neurones During Habituation and Dishabituation of the Crayfish Defence Response
Authors: Hawkins R. D. , Bruner J. 
Published: April 2021

ABSTRACT
The activity of the opener excitor and inhibitor motor neurones was recorded during habituation and dishabituation of the defensive claw opening response in partially restrained crayfish (Astacus sp.). Claw opening evoked by brief tactile stimulation of the thorax undergoes habituation if the stimulation is repeated at 30 s or 1 min intervals. This habituation is accompanied by a progressive decrease in evoked excitor activity, while the activity of the inhibitor remains unchanged. The habituated claw opening response can be dishabituated by tactile stimulation of the claw or head, or by visual stimulation. Dishabituation is accompanied by both an increase in evoked excitor activity and a decrease in evoked inhibitor activity. Dishabituation is also accompanied by potentiation of claw opening: that is, the same number of excitor and inhibitor spikes produce greater claw opening following dishabituating stimulation. The potentiation of claw opening following dishabituation is due in part to post-tetanic potentiation (PTP) at the excitor neuromuscular junction. PTP was demonstrated with physiological parameters of stimulation in isolated claw preparations, and is of sufficient magnitude and duration to account for the observed potentiation. These results contradict the conclusion from an earlier study (see Schone, 1961) that habituation of the claw opening response is due to an increase in inhibitor activity. They also provide new evidence for a role in dishabituation of both disinhibition and PTP.