bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galvanotropic Reactions ofPolycelis nigrain Relation to Inherent Electrical Polarity
Authors: Robertson J. Armitage 
Published: April 2021

ABSTRACTIt occurred to the author that it was possible that some relation might be found to exist between the reactions of animals to stimuli and their physiological polarity and symmetry relations. It was necessary to use as stimulus some form of energy that was both continuous in action and controlled in direction. Light, though much used in experiments on animal reactions, would here prove unsuitable because of the variable nature of the responses called forth, and because a number of conditions alter the sign of phototropic response. Electrical current was chosen, and, since Planarians are animals in which physiological polarity is known to exist, and on which much work has been done, Polycelis nigra was used as the subject of experiment.
The Effect on Plants of Radiations From A Quartz Mercury Vapour Lamp
Authors: Delf E. M. , Ritson K. , Westbrook A. 
Published: April 2021

ABSTRACT
A number of plants grown in the full daylight of a greenhouse have been exposed daily to the radiations of an Ulviarc mercury vapour lamp for very short time intervals, varying from 10 minutes to 30 seconds in the different experiments. Stunting and other formal and formative effects were seen with intervals of 1 minute and upwards. Exposures of 30 seconds on seedlings of Trifolium six weeks old appear to have no stunting effect and a favourable after-effect. Exposures of 2 minutes given to plants of Voandzeia receiving natural illumination for 7 hours or 5 hours daily have a more serious effect than when given to a plant receiving a 12-hour day.
The Qualitative and Quantitative Effects of Food on the Growth of A Soil Amoeba (Hartmanella Hyalina)
Authors: Cutler D. Ward , Crump L. M. 
Published: April 2021

ABSTRACT
Among the free-living protozoa, excluding those forms which contain chlorophyll, two types of nutrition are found, holozoic and saprozoic; in the soil commonwealth there is an ample food supply for the saprozoic forms without reference to the other members of the micro-organic population, but the holozoic species present a different problem, since in the great majority of cases their food consists of the bacteria or other smaller organisms which occur with them in the soil solution. The idea that a normally holozoic animal might be induced to become saprozoic arose with the introduction of a suitable pure-culture technique. Among the earlier workers Beijerinck (1896), Frosch (1897) and Tsujitani (1898) all obtained “pure mixed cultures” of amoebae, and record their failure to grow these except in the presence of bacteria or yeasts, though Tsujitani was able to grow his amoebae with bacteria killed by heating them to 65 ° or 70 ° C. ; later Mouton (1902) records that an amoeba, a form obtained from soil, would not grow except in the presence of living bacteria, and Oehler (1916, 1924), who has perhaps worked more in this field than any other observer, has experienced great difficulty in obtaining any protozoan growth in cultures which do not contain bacteria or yeasts, either dead or alive, though successful growth was obtained in the case of Colpoda by feeding the culture with ground-up fish or powdered egg albumen. It further appears from Oehler’s work that, while the holozoic ciliates and flagellates are practically omnivorous provided that the food is supplied to them alive and of a suitable size, the amoebae tend to be very much more fastidious in their acceptance of food. All these writers seem to have been impressed by the enormous amount of bacterial food that a successful culture of protozoa can consume, and a quantitative study of this problem by Cutler and Crump (1924) showed that in the case of Colpidium colpoda in pure mixed culture the reproductive rate varied from 0·0 to 5·3 in 24 hours according as the number of bacteria per individual ciliate varied from 250 to 1,024,000; similar results have been obtained by Vieweger (1923)1, (1924).
On the Tropisms of Some Freshwater Planarians
Authors: Carpenter Kathleen E. 
Published: April 2021

ABSTRACT
The behaviour of Planarians belonging to a variety of species has been shown by a number of workers to depend largely upon the action of external stimuli—mechanical, chemical, light, heat, contact, etc.—inducing responses usually described as “tropisms,” which, while subject to some slight individual variation, remain on the whole constant in character for stimuli of the given degree of intensity. Observations have been made on reactions of this type in certain species occurring within the Aberystwyth district of Cardiganshire (Carpenter, 1926, 1927), with the special object of determining how far, if at all, such responses may assist in determining the peculiar ecological distribution of the species in question; the results seem worthy of a brief separate consideration, as they show that there may be considerable diversity of reaction between even closely allied species.
Studies on Calcium Metabolism
Authors: McIsaac P. 
Published: April 2021

ABSTRACT
Since the appearance of the works of Weiske, Voit, Forster, and others of later years, numerous attempts have been made to determine the various factors involved in calcium metabolism. Patterson carried out feeding experiments on rabbits and on himself and found that even a dietary deficient in calcium induced no loss of calcium in the blood. Moreover, with a fixed diet the urinary calcium varied but slightly, the variations being parallel with total amounts of urine excreted. One of his conclusions was that the greater the volume of urine excreted the greater was the mass of salts eliminated.
Studies on Calcium Metabolism
Authors: McIsaac P. 
Published: April 2021

ABSTRACT
Several years ago Reach (1912) made comparisons of the amount of calcium that could be recovered from ashing of the entire bodies of male and female white mice. He worked with normal and gonadectomised males and females and obtained higher percentages of CaO from both groups of females (1·283 normal, 1·275 ovariotomised), and lower percentages from both groups of males (1·180 and 1·005). Reach accordingly arrived at the conclusion that “here we have a secondary sexual character—the ♀♀ of these animals are richer in Ca than the ♂♂.” More recently Hammett (1923) working on the femur and humerus of rats earlier thyro-parathyroidectomised at a hundred days found the amount of Ca in the males unchanged but slightly less than normal in the females, thereby suggesting some difference in the calcium metabolism of the sexes. Riddle and Honeywell (1925) undertook the study of calcium metabolism in relation to sex in the pigeon. They worked on blood serum, employing the method of Kramer and Tisdall (1921), and obtained two determinations from each bird at intervals of ten days. They obtained a sex-dimorphism, the males as a group showing a lower and the females a higher Ca content. They state, however, that only on a basis of sex had they found a consistent grouping of values.
The Effect of A Temperature Gradient on the Early Development of the Frog
Authors: Dean I. L. , Shaw M. E. , Tazelaar M. A. 
Published: April 2021

ABSTRACT
The present paper is an account of experiments carried out under the direction of Professor Julian S. Huxley, in April and May, 1927, in an attempt to amplify and extend similar experiments done by the latter in the spring of 1926 (Huxley, 1926). The object of these experiments was to ascertain what effects a steep apico-basal temperature gradient has on the developing frog’s egg. The present experiments were carried out on a larger scale, their range being widened to include the effects of both apico-basal and lateral temperature gradients on later embryonic stages. The apparatus was improved, making it possible to use a steeper temperature gradient and so obtain more striking results. Some of the results have been embodied in a general paper (Huxley, 1927).
The Effect of Egg-Secretions on the Activity of Spermatozoa
Authors: Gray J. 
Published: April 2021

ABSTRACT
Egg-secretions increase the rate at which the spermatozoa of E. esculentus absorb oxygen by about 300 per cent. Similar secretions may exert little or no effect on the respiratory level of the spermatozoa of E. miliaris. This difference between the species corresponds to the difference visible in the effect of the secretions on the mechanical activity of the two types of sperm. In the presence of egg-secretions the respiratory activity remains constant at a high level for at least 1 hour, whereas in the absence of secretions the level falls to about 30 per cent, of its original value in the same period of time. This effect is observed in both E. esculentus and E. miliaris.
An Experimental Study on the Effect of Thyroxin Upon Sexual Differentiation in the Fowl
Authors: Greenwood A. W. , Chaudhuri A. C. 
Published: April 2021

ABSTRACT
An attempt was made to determine in the developing fowl embryo whether injections of thyroxin into the incubating egg would lead to a modification of the processes of sexual differentiation. The injections into the air space were made during the 3rd day of incubation, that is, at a time before the differentiation of the gonads in the two sexes can be demonstrated. Of the 190 eggs injected with thyroxin, 39 embryos survived of which 12 were markedly affected, reduced size of embryos being regarded as an indication of a marked hyperthyroidism which has resulted in an increase in the metabolic rate. No effect on the processes of sexual differentiation in either sex was found. The effect of the injections was not apparent before the 1 ith day. It will be attempted in a further series of experiments to determine whether this is a specific reaction of the thyroxin or whether it is due to mechanical hindrances to the absorption of the thyroxin into the foetal circulation until a considerable time after the injection. These experiments can not at present lead to any definite conclusion as to the relation between increased metabolism and the processes of sexual differentiation.
Inhibition of Pacemaker Systems in the Hydroid Tubularia
Authors: Josephson R. K. , Uhrich J. 
Published: April 2021

ABSTRACT
Of the three conducting systems known in the stalk of Tubularia—the slow system (SS), the triggering system (TS), and the distal opener system (DOS)—the SS can be eliminated as being necessarily involved in the pacemaker system inhibition seen during continued stalk stimulation because its threshold is higher than the minimal stimulus strength required for inhibition. The TS can also be eliminated as the inhibitory pathway because (1) separating a polyp from a colony and hence from a source of continued input along the TS does not result in an increase in the spontaneous activity of the polyp above that of appropriate controls, and (2) distal tentacle stimulation which activates the DOS but not the TS is more inhibitory than is stalk stimulation which excites both the TS and the DOS. The inhibitory pathway is apparently the DOS or, less likely, a yet unidentified conducting system in the stalk. Inhibitory stimulation suppresses both single pulses and bursts in the NP pacemaker system and it is likely that the HP pacemaker system is also inhibited. The greater the background level of spontaneous activity the greater is the effectiveness of inhibitory stimulation. The period of inhibition lasts for a few seconds after each stimulus.
Aspects of the Physiology of Terrestrial Life in Amphibious Fishes
Authors: Gordon Malcolm S. , Boetius Inge , Evans David H. , McCarthy Rosemary , Oglesby Larry C. 
Published: April 2021

ABSTRACT
Bony fishes which could spend periods of time out of water, but which lacked special anatomical modifications for survival out of water, were probably involved in the early stages of the evolution of terrestrial life in the vertebrates. The rhipidistian crossopterygians were apparently the group ancestral to all higher vertebrates (Romer, 1966; Schmalhausen, 1968), but they are unavailable for study of possible physiological adaptations to life on the land. One way we may obtain some idea of the possible range of physiological adaptations which might have been possessed by these ancestral forms is to make comparative studies of pertinent aspects of the physiology of living amphibious fishes. We define amphibious fishes as those which spend periods of time out of water, on or above the ground surface, as normal parts of their life-histories. The most relevant forms are those lacking specialized accessory respiratory organs.
Urine Formation by the Malpighian Tubules of Calliphora
Authors: Berridge M. J. 
Published: April 2021

ABSTRACT
The ability of chloride and phosphate to support urine formation has been studied under different conditions. When sulphate is used as a balancing anion, rate of urine formation is linearly related to the external chloride or phosphate concentration. Tubules can concentrate phosphate in the urine by a mechanism which is independent of other anions. Phosphate U/P declines with an increase in external phosphate concentration. In the absence of phosphate, chloride is slightly concentrated in the urine. Chloride U/P is reduced by phosphate but unaffected by sulphate. When an extensive series of anions was tested, rate of urine production was related to the size of the anions. Phosphate was the only exception because despite its large size it supported the highest rate of urine production. Arsenate competitively inhibits phosphate transport, resulting in an augmentation of chloride transport. Copper, however, blocks urine formation in the presence of chloride but not in the presence of phosphate. The experiments indicate two separate mechanisms for anion transport. Anions such as chloride probably pass through pores with an estimated radius of 3·6 Å., whereas phosphate is transported by a carrier.
The Physiology of the Antennal Gland of Carcinus Maenas (L.) III. Glucose Reabsorption
Authors: Binns R. 
Published: April 2021

ABSTRACT
Glucose is actively reabsorbed by the antennal gland. In 100% sea water there is a blood threshold concentration of approximately 150 mg.%. This does not indicate the maximum rate of glucose reabsorption. Below the threshold, reabsorption is not always complete, but may be if carbohydrate sources are limited or absent. The threshold level depends on the rate at which fluid passes through the antennal gland, an increase in urine production rate being correlated with a reduction in the glucose threshold. Phloridzin inhibits reabsorption and glucose U/B ratios approach unity, indicating that glucose is filtered passively into the antennal gland.
Visual Thresholds and Spectral Sensitivity of Flatfish Larvae
Authors: Blaxter J. H. S. 
Published: April 2021

ABSTRACT
Plaice and sole larvae have a pure-cone retina and no retinomotor responses. Observations on the extinction of phototactic and light-dependent feeding behaviour, using both white and coloured light, enabled visual thresholds and spectral sensitivity to be determined. Visual threshold decreased (that is, sensitivity increased) with age. The values for extinction of negative phototaxis ranged from 10−4−10−6 m.c. Sole larvae could feed in the dark from the early post-hatching stage, plaice larvae only at metamorphosis. Thus light intensity thresholds for feeding were only determinable in younger plaice larvae. The values ranged from 10°−10−2 m.c. The spectral sensitivity curves were plateau-like and photopic in nature. Thus the larval cones have spectral properties similar to those of adult teleosts. The differences in threshold obtained by the two techniques are probably a measure of the extent of recruitment of high-threshold cones required for image formation in feeding. No evidence of a dermal light sense was found.
The Circadian Rhythm of Flight Activity in the Mosquito Aedes Aegypti (L.): The Phase-Setting Effects of Light-on and Light-Off
Authors: Taylor B. , Jones M. D. R. 
Published: April 2021

ABSTRACT
The circadian flight-activity of individual, sugar-fed Aedes aegypti females has been studied, using the flight-sound as an indicator of activity. The activity appears to be controlled by an endogenous rhythm with a period of 22–24 hr-in constant dark and about 26 hr. in constant light. Both light-on and light-off have phase-setting effects. Under favourable conditions, peaks of activity occur 13–14 hr. after light-on and 22–23 hr. after light-off. Both these peaks persist in constant dark following an LD 4:20 regime. The total amount of flight-activity is correlated with the duration of light (70 lux) in the 24 hr. period.
A Study of the Instantaneous Air Velocities in a Plane behind the Wings of Certain Diptera Flying in a Wind Tunnel
Authors: Wood James 
Published: April 2021

ABSTRACT
The variations in several kinematic parameters of Calliphora erythrocephala were studied on flies flying in a wind tunnel. Variation was equally pronounced at both the and bottom of the wingstroke. The wakes of Calliphora erythrocephala and Phormia regina flying in moving air exhibited extremely low turbulence, while considerable turbulence indicative of stall was present in the wakes of flies flying in still air. The air velocities recorded as functions of time in the wakes of both Phormia and Calliphora are consistent with most lift being produced in the downstroke, with the first part of the upstroke also contributing to the production of lift.
Characteristics of Transmission Failure in the Squid Stellate Ganglion: A Study of A Simple Habituating System
Authors: Horn G. , Wright M. J. 
Published: April 2021

ABSTRACT
When certain vertebrate and invertebrate interneurones are repeatedly stimulated through the sense organs, or by electric shocks delivered to sensory nerves, their response gradually fails. Typically the stimulus is delivered once every few seconds and the response consists of action potentials (e.g. Bell, Buendia, Sierra & Segundo, 1964; Horn & Hill, 1964, 1966; Horridge, Scholes, Shaw & Tunstall, 1965; Horn & Rowell, 1968) or excitatory postsynaptic potentials (Bruner & Tauc, 1966; Spencer, Thompson & Neilson, 1966; Segundo, Takenaka & Encabo, 1967 a). The physiological basis of this response decrement is not known though synaptic depression, desensitization of the postsynaptic membrane, accumulation of potassium ions in the extracellular clefts and build up of pre-and postsynaptic inhibition have all at one time or another been invoked.
Mechanisms for the Control of Body Temperature in the Moth, Hyalophora Cecropia
Authors: Hanegan James L. , Heath James E. 
Published: April 2021

ABSTRACT
Thoracic temperature in the moth, Hyalophora cecropia, is correlated with gross patterns of behaviour. The animal warms up to a minimum of 34·8 °C body temperature before initiating flight. The rate of warm-up is linear and the duration of the warm-up period increases with decreasing air temperature. Thoracic temperature at the initiation of flight and during maintained flight remain constant at any given air temperature, however, decreases 0·25 °C per °C gradient as air temperature is decreased. Distribution of the maximum and minimum thoracic temperatures during active periods indicate that the animal maintains its body temperature within a favourable range. The animal uses behavioural mechanisms to maintain the thoracic temperature within this range when the body temperature reaches the limits, 33·4 and 37·8 °C. The minimum thoracic temperature for flight (34·8 °C) and the shade-seeking temperature (38·5 °C) correspond closely to the limits predicted from the maximumminimum distribution of thoracic temperatures. The theoretical minimum and maximum rates of oxygen consumption were calculated from cooling curves and warm-up curves. Both rates increase when the gradient between body temperature and air temperature increases (air temperature is lowered, body temperature remains relatively constant). Directly measured rates of oxygen consumption in flying animals increase as air temperature decreases. These values fall within the calculated maximum and minimum in all cases. Oxygen consumption measured in torpid animals indicates a normal poikilo-thermic response, increasing with increased air temperature. The Q10 for this response is 2·25 over the range 20–30 °C. A model for the regulation of body temperature in active moths is discussed.
Detour Experiments with Split-Brain Octopuses
Authors: Wells M. J. 
Published: April 2021

ABSTRACT
Octopuses will move out of sight of their prey and make detours through a maze to get crabs that are initially visible but not directly accessible to them. Successful detours are made without training, and performance shows little change with practice. Longitudinal division of the vertical and subvertical lobes and/or of the superior and inferior frontal lobes does not affect performance. Extension of the cut downwards to include the optic commissures produces animals that sometimes perform quite normally, and at other times vacillate, apparently unable to prevent the onset of incompatible responses arising from visual inputs to the two sides of the body. If the optic nerves are cut on once side such animals perform normally. In the intact octopus conflict between the two sides must be avoided by exchange of information through the optic commissures, or though structures closely associated with these. This situation is compared with that found in training experiments involving visual discrimination. In detours the information acquired through one eye modifies the behaviour of both sides of the body for a few minutes. Its availability is not changed by prior removal of the superior frontal and/or vertical lobes. Following unilateral training involving visual discrimination, responses arising as a result of visual inputs to either side of the body are modified for many weeks, but only provided that the superior frontal-vertical lobe system remains intact. If this system is split the untrained side remains naive. It is concluded that the long and short-term storage of representations of objects seen must be different in kind and that the establishment of long-lasting bilateral traces involves structures that are not essential for the side-to-side distribution of information in the short-term situation. This state of affairs is compared with the situation in touch learning, where there seems to be no functional equivalent of the optic commissures. Long-term bilateral traces are established as a result of unilateral training but the effect takes an hour or more to spread to the untrained side.
The Influence of the Diuretic Hormone On the Process of Urine Secretion by the Malpighian Tubules of Carausius Morosus
Authors: Pilcher Diana E. M. 
Published: April 2021

ABSTRACT
The rate of urine secretion and the trans-wall potential have been measured in single, isolated Malpighian tubules in media of varying ionic composition. Potassium, present as the only monovalent cation in a saline, is able to support urine secretion at a higher rate than sodium. In the absence of sodium, the rate of urine secretion depends upon the concentration of potassium, but is enhanced in the presence of sodium, especially at low potassium concentrations. The replacement of part or all of the anions normally present in saline by sulphate results in a reduction in rate of urine secretion and a rise in trans-wall potential. Neither the rate of urine secretion nor the trans-wall potential is affected by ouabain, but both are reduced by 2,4-dinitrophenol. The ionic composition of the urine remains unchanged by the addition of diuretic hormone to the medium surrounding the tubule, but the rate of urine secretion and the trans-wall potential are increased. It is suggested that the diuretic hormone acts by stimulating active potassium transport.