bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the Phase Difference Between Particle Motion Components of Sound By Teleosts
Authors: Van Den Berg A. V. 
Published: April 2021

ABSTRACT
The hypothesis that fish may remove 180° ambiguities concerning the sound source direction by a timing analysis between particle motion components is addressed. Analysis of the phase difference ψ (w, v) between the horizontal (v) and the vertical (w) components of the particle velocity of sound signals by teleost fish is investigated by cardiac conditioning. Standing wave sound stimuli (90 Hz) are used with ψ (w, v) = + or – 90° and equal amplitudes of v and w. The water particles move along circular trajectories for such stimuli: however, the direction of revolution is reversed in the two stimuli. These stimuli were discriminated by one whiting, one catfish and several cod, indicating that these teleosts are able to discriminate signals on a pure timing cue. If the w/v ratio is lowered, the cod can discriminate the resulting elliptical motions on the direction of revolution down to a w/v ratio of –12 dB. Moreover, down to the same w/v ratio the cod discriminates an elliptical particle motion signal from a pure translatory particle motion signal. At this level, the threshold signal-to-noise ratio for the w component is exceeded by 9 dB. Apparently phase analysis can be limited by ‘cross talk’ between horizontal and vertical particle motion detectors. The results are discussed with respect to models of directional hearing by fish.
Partitioning of Regulatory Sites in Bufo Marinus During Hypercapnia
Authors: Tufts Bruce L. , Toews Daniel P. 
Published: April 2021

ABSTRACT
Ureters were cannulated in specimens of Bufo marinus (L.) in order to partition the regulatory contributions of the kidney and skin. The in vivo roles of the kidney, skin and internal calcareous deposits in the response of these animals to chronic hypercapnia were then evaluated.
There was no compensatory adjustment by the skin and only a minimal regulatory response by the kidney. Major adjustments which have been attributed to combined skin and urinary tract in previous studies must therefore come from the urinary bladder. Removal of the bladder as a regulatory site in these animals completely eliminated the compensatory elevation of HCO3− in the extracellular fluid. Mobilization of internal calcareous deposits as a source of HCO3− was found to contribute 50% of the compensatory response of these animals during hypercapnia.
Cholinergic and Monoaminergic Mechanisms Associated with Control of Bioluminescence in the Ctenophore Mnemiopsis Leidyi
Authors: Anctil Michel 
Published: April 2021

ABSTRACT
The effects of cholinergic and monoaminergic drugs and blocking agents on luminescence responses of the comb-jelly Mnemiopsis leidyi were investigated, using isolated strips of meridional cells. Catecholamines elicited dose-dependent flash activity and adrenalin was the most patent. The adrenalin response was abolished by propranolol (0·1 mmol l−1), but not phentolamine. Reserpine (0·1mmol l−1) suppressed the flash response to electrical stimulation without affecting the adrenalin response. Acetylcholine (ACh) elicited flash activity which was propagated along the meridional canals. Eserine (0·01 mmol l−1) potentiated the flash response to either ACh or electrical stimulation. Tubocurarine reduced or abolished responses to either ACh or electrical stimulation. Atropine elicited intense flash activity and potentiated the response to electrical stimulation, but failed to block the ACh response. Prolonged exposure of meridional canals to serotonin (5-HT) depressed or abolished flash responses to ACh, adrenalin and electrical stimulation. The ACh flash response was abolished by propranolol but the response to adrenalin was not altered by tubocurarine. It is concluded that nicotinic cholinergic and beta-adrenergic mechanisms are interrelated and indirectly involved in excitation of luminescence in Mnemiopsis.
The Effect of Sewage on Brown Trout (Salmo Trutta L.)
Authors: Longwell J. , Pentelow F. T. K. 
Published: April 2021

ABSTRACT
Fresh undiluted sewage contains unstable substances which are directly toxic to fish. Sewage which has been kept for 1 or 2 days and stirred in an open tank at 180 C. is more toxic than fresh sewage, possibly owing to the production of other toxic substances. It has also been shown that the biochemical oxygen demand is directly proportional to the “strength” of the sewage which is closely related to toxicity. Consequently a large biochemical oxygen demand of fresh sewage indicates a certain degree of toxicity.
It appears that when fresh sewage is discharged into a river in concentrations up to 10 per cent, of the river water, it has no directly toxic effect on fish. A river can purify a certain proportion of sewage effluent without becoming seriously deoxygenated. In one river with which we are acquainted a sewage effluent forms about 3·7 per cent, of the river flow at normal summer levels. The dissolved oxygen content of the river during the period it was under observation never fell below 60 per cent, of the saturation value, and such a mixture of sewage and water would have no directly injurious effect on fish. If, however, the proportion of sewage is increased, then the river will become more deoxygenated and eventually at a certain ratio of sewage to river water the toxicity will become more apparent, partly owing to the oxygen depletion. This condition is of course readily produced in a small river. The final stage will be attained when the quantity of sewage is sufficient to remove all the dissolved oxygen of the water. When there is a belt of deoxygenated water, sewage will decompose under anaerobic conditions and sulphide will be formed. As it has been shown that this substance is directly toxic to trout in small concentrations, 0-3 part per 100,000 being rapidly fatal, the fish are exposed to a definite poison as well as the danger of asphyxiation. In a slow-flowing river below a sewage works, mud is deposited on the river bed. Anaerobic conditions can exist in this mud although the supernatant water is fully oxygenated and any sulphate present may be reduced to sulphide which will be washed downstream when the river is in flood.
It may therefore be concluded that in a river where there is a plentiful supply of oxygen, sewage in moderate quantity has no directly harmful effect on fish unless it is in a septic condition and contains sulphide. When sewage is discharged into a slow-flowing river, mud banks will be formed which may have the necessary anaerobic conditions for the production of sulphide. These, during floods, may be harmful to fish before they are oxidised. There remains the possibility that, although the fish are not directly affected, their food and spawning grounds may suffer from the pollution. This possibility has not been overlooked, but the data on these points are not yet complete.
Studies in Reptilian Colour Response
Authors: Zoond A. , Bokenham N. A. H. 
Published: April 2021

ABSTRACT
In a recent paper (Zoond and Eyre, 1934) the responses of blind and normal chameleons on different backgrounds and with strong and weak illumination were described. Starting with animals adapted to darkness (maximum pallor) colour indices, recorded at intervals of 2 min., were plotted. The time curves thus obtained demonstrated the following facts: (a) In strong light on a black background the animals darken rapidly, and attain a maximum intensity after about 4 min.(b) Blind animals under the same conditions behave in a similar way.(c) In strong light, on a white background, intact chameleons darken perceptibly during the first 2 min. and then slowly become paler, but they never attain a pallor as extreme as in total darkness.(d) Blind animals under the same conditions darken in much the same way as they do on a black background.(e) In weak light, on a black background, intact chameleons darken quite as intensely as in strong light, but blind animals under these conditions remain pale.(f) On a white background, in weak light, the intact animals become slowly dark, the blind animals remain relatively pale.
Studies on Living Protoplasm
Authors: Harris J. E. 
Published: April 2021

ABSTRACT
In recent years many attempts have been made to determine the absolute coefficient of viscosity of “protoplasm.” The values for this constant obtained by different workers differ widely, and while it is probable that the protoplasm from different sources is never the same in its composition, and cannot be expected to be constant in its viscosity, many sources of error in such determinations have not been sufficiently appreciated. One of the most serious of these, the presence of powerful currents in the protoplasm, forms the subject of this communication.
On the Utilisation of Oxygen by My A Arenaria
Authors: Van Dam L. 
Published: April 2021

ABSTRACT
A study of the rather scarce and widely scattered literature concerning the respiratory exchange of Lamellibranchia shows that even under constant external conditions the oxygen intake of a given specimen is extremely variable. This phenomenon was observed by Mitchell (1912) and Galtshoff and Whipple (1930) in Ostrea, by Weinland (1918) in Anodonta, by Collip (1921) in Mya, by Bruce (1926) and Bouxin (1931) in Mytilus.
Pro-Vitamin A in the Food of Whales
Authors: Drummond J. C. , Macwalter R. J. 
Published: April 2021

ABSTRACT
The origin of the large reserves of vitamin A which may be found in certain tissues, particularly the livers, of fish has been the subject of considerable study. In the case of some species (e.g. cod and halibut) an examination of the food has shown that the concentrations of vitamin A and its acknowledged precursor carotene are curiously small (Drummond and Hilditch, 1930; Lovern and Sharp, 1933). This striking fact has even led to the suggestion that some fish possess the power to synthesise vitamin A from unknown precursors. Alternatively, it seems not improbable that although the food may itself contain but slight traces of vitamin A, the retention of the latter by the liver might in time lead to an accumulation sufficient to account for the large reserves which are encountered.
The Nerve-Net of the Actinozoa
Authors: Pantin C. F. A. 
Published: April 2021

ABSTRACTPolarity exists in Calliactis, particularly in the tentacles. In these, there is a centripetal polarity of anatomical origin, but there is in addition a physiological polarity running centrifugally. More stimuli are required to facilitate a conducting path centrally from a point on the tentacle than in the reverse direction. Polarity may originate by the development of differential facilitation rates. In some individuals, a kind of after-discharge is observed. A series of one or more extra contractions follows the primary response to a stimulus. Though these appear only after a stimulus has been given they are only indirectly caused by it. Their presence or absence cannot be predicted and seems to bear no relation to the strength of the stimulus. They introduce an arbitrary element into the otherwise singularly regular relation between stimulus and response. Several possible sources for the phenomenon are considered, including synaptic junctions between conducting units of the nerve net, but there are difficulties in accepting any of them. The nerve net of Calliactis possesses many of the properties of the nervous systems of more highly organised animals. The danger is pointed out of employing the unique skeletal neuromuscular system of the Vertebrata as the standard by which the nervous arrangement of other phyla are to be compared.
The Toxic Action of Heavy Metal Salts on the Three-Spined Stickleback (Gastrosteus Aculeatus)
Authors: Erichsen Jones J. R. 
Published: April 2021

ABSTRACT
The observations and conclusions of Carpenter (1927, 1930) regarding the toxic effect of heavy metal salts on the minnow (Leuciscus phoxinus) are shown to apply equally well to the three-spined stickleback (Gastrosteus aculeatus). It is shown that in the case of heavy metal salts the toxic effect of hypertonic solutions is due chiefly to the metallic cation, the toxicity of the anion being relatively small, while in the case of hypotonic solutions the toxicity is due entirely or almost entirely to the cation. Nevertheless, in equimolar concentrations, different salts of the same metal do not have equal or approximately equal toxicity. At the same molar concentration the sulphates of heavy metals are much less toxic than the nitrates or chlorides. This is not due to difference of pH. This difference in toxicity is shown to be closely related to difference in relative electrical conductivity; the toxicity of nitrate, chloride and sulphate is determined, not by the normality alone, but by the product of the normality and conductance ratio. It is concluded that the factors responsible for the lower electrical conductivity of the sulphate also lower the chemical activity of the sulphate so that the toxicity falls in proportion to the conductivity.
The Vapour Pressures of the Blood of Arthropods from Swift and Still Fresh Waters
Authors: Fox H. Munro , Baldes E. J. 
Published: April 2021

ABSTRACT
It has been shown that the oxygen consumption of caddis larvae and mayfly nymphs from swift streams is considerably greater than that of comparable species from still waters, and that within one species of isopod Crustacea, Asellus aquaticus, individuals from swift water consume more oxygen than those from slow water (Fox and Simmonds, 1933; Fox, Simmonds and Washbourn, 1935).
It has also been shown that the oxygen consumption of fresh-water Crustacea is greater than that of their marine relatives (Fox and Simmonds, 1933). Now, in marine invertebrates, the osmotic pressure of the blood is close to that of sea water, whereas in fresh-water invertebrates the difference between the osmotic pressures of blood and water is great. In fresh water compared with marine Crustacea, then, a higher oxygen consumption goes together with a considerable inequality between internal and external osmotic pressures.
Effects of Infra-Red Light on Subsequent Cleavage of the Eggs of Urechis Caupo
Authors: Nelson Clarence , Brooks S. C. 
Published: April 2021

ABSTRACT
We have recently reported (Nelson and Brooks, 1933) that infra-red light of wavelengths of approximately 1μ, interfered with successful formation of fertilisation membranes by subsequently inseminated eggs of Urechis caupo and two species of Strongylocentrotus. We now show that this injury is still traceable in the rate of cleavage of the fertilised eggs of Urechis, but that gradual recovery, or some process which simulated it, takes place both before and after insemination.
The Photoreceptors of Lampreys
Authors: Young J. Z. 
Published: April 2021

ABSTRACT
The tail of larval and adult L. planeri and adult L. fluviatilis contains a photoreceptive mechanism involving an initial short sensitization period, and a latent period. The impulses initiated by the photochemical change are carried in the lateral line nerves, as is shown by the facts that section of these nerves abolishes the response, whereas section of the spinal cord does not do so. Motor responses are only occasionally seen after illumination of parts of the body other than the tail. These responses are apparently due to direct stimulation of the spinal cord, and can be regularly elicited if the pigment protecting the latter be removed. Motor responses may follow illumination of the head, either of larvae or adults, but only after illumination periods much longer than are necessary to obtain a response from the tail. The responses play a part in the normal behaviour of the animals by assisting them to bury themselves completely in the mud. The stimulus of illumination of the tail simply initiates swimming movements, and there is no orientation of the animal with reference to the direction of the light. This is confirmed by the observation that, following illumination of the tail from one side, the first movement of the head may be either towards or away from the side stimulated. Further, after section of one lateral line nerve only no forced movements occur on illumination. The reaction may thus be described as a photokinesis, and does not involve any true topotaxis, its effect is to prevent the animal remaining in any illuminated area.
An Oil-Soluble Neurohumour in the Catfish Ameiurus
Authors: Parker G. H. 
Published: April 2021

ABSTRACT
The skin and fins of Ameiurus, irrespective of their original state, take on the dark coloration (dispersion of melanophore pigment) whenever they are triturated. Hence oil extracts can be made from these parts only in the dark condition. Olive oil extracts from the skin and fins of dark Ameiurus when injected under the skin of light-tinted individuals induce the formation of temporary dark splotches in an otherwise light skin. These splotches result from the dispersion of pigment in the melanophores, both epidermal and dermal, in the region of the injection. On the spontaneous disappearance of these splotches, which ordinarily occurs a few days after their formation, the melanophore pigment reassumes its concentrated state. Newly formed dark splotches in Ameiurus may be obliterated by an injection of adrenalin and will return spontaneously after the adrenalin has disappeared. From these several tests it is concluded that the nervous factor in the dispersion of the melanophore pigment of Ameiurus is an oil-soluble neurohumour of local activity. Ether extractions, hot and cold, yielded residues that were only slightly active in darkening the skin of the catfish. No effective oil extracts could be obtained from the dark skins and fins of Fundulus heteroclitus probably because of the inaccessibility of the tissues to the oil.
The Photoreceptors of Lampreys
Authors: Young J. Z. 
Published: April 2021

ABSTRACT
Illumination of the dorsal region of the head of an ammocoete larva is followed by movements of the animal, but only after exposure for longer periods than are necessary to elicit responses from the tail. Since this reaction persists unaffected after removal of the pineal and paired eyes, it is concluded that it is produced by the direct effect of light on some tissue in the brain. Larval and adult L. planeri show very pronounced daily rhythms of colour change, becoming pale at night and dark during the daytime. Continuous artificial illumination of the animals produces maximal darkening and stops the diurnal rhythm. When animals are left in total darkness the diurnal changes usually persist, though diminished in extent; sometimes the melanophores come to rest in the expanded phase. Since section or faradic stimulation of spinal nerves is not followed by local changes in the melanophores, it is concluded that these are not under nervous control. After removal of either the whole pituitary complex or its pars nervosa and intermedia the animals become maximally pale, and remain so indefinitely in spite of changes of illumination. Injection of extracts of mammalian posterior pituitary lobe causes darkening of such hypophysectomised lampreys. Pituitrin was also found to be capable of maintaining the expansion of isolated melanophores. After removal of the pineal complex from ammocoetes the rhythms of colour change were interrupted, the melanophores remaining in the expanded phase under all conditions of illumination. Removal of the pineal of adult L. planeri disturbed the colour rhythm, which was then completely abolished if the paired eyes were also removed. Thus the paling of an ammocoete when it passes from light to darkness is probably due to the inhibition of posterior pituitary secretion by nervous impulses set up by the change of illumination of the pineal complex.
The Effect of Hypophysectomy on the Reproductive Organs of the Male Guinea-Pig
Authors: Allanson M. , Hill R. T. , McPhail M. K. 
Published: April 2021

ABSTRACT
Atrophic changes in the testes and accessory organs following hypophysectomy have now been described in a number of mammals, but not as yet in the guinea-pig. McPhail and Parkes (1933), in describing a method of removing the pituitary in guinea-pigs, noted that regression of the testes occurred but gave no details. Pencharz and Lyons (1934) have described the effects of hypophysectomy on the pregnant female, while Selye, Collip and Thomson (1934) record the operation on a single pregnant female.
The Nerve Net of the Actinozoa
Authors: Pantin C. F. A. 
Published: April 2021

ABSTRACT
The relation of the “staircase “effects in the vertebrate heart, in the bell of Medusae and in the sphincter of Calliactis is discussed. Whereas in the heart the effect is due to an intrinsic increase of contractility of the whole contractile tissue, evidence is brought to show that the staircase in Calliactis and in Medusae depends upon neuromuscular facilitation by which each stimulus in a series reaches more and more individual muscle fibres. The relation of different types of contraction in coelenterate muscle is discussed. It is shown how this depends upon the relation of the stimulation interval necessary for a facilitated response and the duration of a complete contraction and relaxation of the muscle. If these are about equal the step-like contraction of the sphincter of Calliactis results ; if the facilitation interval is long a staircase similar to that of a Medusa bell is produced ; if the duration of the twitch is relatively long a smooth contraction as in the mesenteric muscle of Calliactis is produced.
Photo-Electric Records of the Colour Change in Fundulus Heteroclitus
Authors: Hill A. V. , Parkinson J. L. , Solandt D. Y. 
Published: April 2021

ABSTRACT
The colour change in Fundulus is produced by an alteration in the size of its chromatophores, caused by impulses in special nerve fibres running to them. According to Parker (1934 a, b, and elsewhere) the nerves produce their effects not directly, but by chemical transmitters (“neurohumors”) of some kind. The movements of the chromatophores are very rapid, although they are not, as in the cuttlefish and squid, due to muscle fibres pulling the chromatophores out, or allowing them to relax elastically.
Tissue Intracellular Acid-Base Status and the Fate of Lactate After Exhaustive Exercise in the Rainbow Trout
Authors: Milligan C. Louise , Wood Chris M. 
Published: April 2021

ABSTRACT
Exhaustive ‘burst-type’ exercise in the rainbow trout resulted in a severe acidosis in the white muscle, with pHi dropping from 7·21 to a low of 6·62, as measured by DMO distribution. An accumulation of lactate and pyruvate, depletions of glycogen, ATP and CP stores, and a fluid shift from the extracellular fluid to the intracellular fluid of white muscle were associated with the acidosis. The proton load was in excess of the lactate load by an amount equivalent to the drop in ATP, suggesting that there was an uncoupling of ATP hydrolysis and glycolysis. Initially, lactate was cleared more quickly than protons from the muscle, a difference that was reflected in the blood. It is suggested that during the early period of recovery (0–4 h), the bulk of the lactate was oxidized in situ, restoring pHi to a point compatible with glyconeogenesis. At that time, lactate and H+ were used as substrates for in situ glyconeogenesis, which was complete by 24 h. During this time, lactate and H+ disappearance could account for about 75 % of the glycogen resynthesized. The liver and heart showed an accumulation of lactate, and it is postulated that this occurred as a result of uptake from the blood. Associated with the lactate load in these tissues was a metabolic alkalosis. Except for an apparent acidosis immediately after exercise, the acid-base status of the brain was not appreciably affected. Despite the extracellular acidosis, red cell pHi remained nearly constant.