bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centres for Tactile and Visual Learning in the Brain of Octopus
Authors: Wells M. J. 
Published: April 2021

ABSTRACT
Octopuses were trained to stop reacting to visual and tactile stimuli normally eliciting positive responses, and to make visual and tactile discriminations. The effect on performance of removal of parts from the brain was observed. It appears that Octopus has two learning systems, one in the inferior frontal and subfrontal lobes, dealing with tactile discrimination on a basis of the proportion of sense organs excited, the other in the optic lobes, handling visual discrimination on a basis of the pattern of sense organs excited. The vertical lobe plays a part in learning by either system, and is to some extent a store for both tactile and visual memories.
Studies on Salt and Water Balance in Caddis Larvae (Trichoptera)
Authors: Sutcliffe D. W. 
Published: April 2021

ABSTRACT
Two freshwater caddis larvae, L. stigma and A. nervosa, drink and regurgitate large quantities of salt water at frequent intervals. Drinking is not controlled, and larvae may drink an amount equivalent to 50 % of the body weight per day. The gut wall is adversely affected by salt water and exosmosis occurs across the gut wall. L. affinis larvae drink only small quantities of salt water. Drinking is strictly controlled, and the intake is roughly equivalent to 3–7 % of the body weight per day over a wide range of external salt concentrations. The gut wall is not affected by high salt concentrations ; regurgitation and exosmosis do not normally occur. In the freshwater caddises the rate of rectal fluid production is approximately equivalent to 7 % of the body weight per day. Rectal fluid is not produced at high external salt concentrations. L. affinis larvae continue to produce rectal fluid at very high external salt concentrations. The daily output is probably roughly equivalent to the daily intake of salt water by drinking. The osmoregulatory mechanism in L. affinis larvae and other salt-water insects is discussed. It is suggested that controlled drinking forms an important part of this mechanism, together with the ability of the gut wall to withstand exposure to high salt concentrations and the ability to elaborate rectal fluid hyper-osmotic to the external medium.
Kidney Function in the Crab-Eating Frog (Rana Cancrivora)
Authors: Schmidt-Nielsen Knut , Lee Ping 
Published: April 2021

ABSTRACT
A study has been made of kidney function in the crab-eating frog, Rana cancrivora, of south-east Asia. This frog can live in full-strength sea water; in such concentrated media its blood is slightly hypertonic to the medium, and a considerable part of the osmotic concentration is due to urea. In concentrated media the excretion of urea is greatly diminished. This is not due to active tubular reabsorption of urea, but primarily to a low urine flow caused by increased tubular reabsorption of water and reduced glomerular filtration. In concentrated media, as compared with dilute media, only a few percent of the filtered urea appears in the urine. Osmoregulation of the crab-eating frog in sea water resembles that of elasmobranchs except in that there is no evidence of active tubular reabsorption of urea in the frog.
Desquamation in Actinophrys: Induction and Inhibition
Authors: Kitching J. A. 
Published: April 2021

ABSTRACT
The ‘skin’ raised by Actinophrys sol in response to bovine plasma albumin is thicker and more coherent in higher concentrations of the protein, and imprisons the Actinophrys for longer. Escape from thick skins is effected by the swelling of vacuoles, after the manner used by various Protozoa in excystment. Some limited power of further desquamation is recovered after an interval of one day. Desquamation can occur at all pH values from 5·4 to 9·0. However, skins are not formed in the more alkaline solutions at low concentrations of plasma albumin. Gelatin and ribonuclease are active in provoking desquamation. Egg albumin is less effective. Various amino acids proved entirely ineffective. Various inorganic salts failed to cause desquamation. Desquamation in response to bovine plasma albumin was visibly inhibited by the presence of MgSO4, MgCl, and (to some extent) by salts of Sr and Ca. A competition between Mg and the protein for active sites is suggested. A mixture of MgSO4 and serum albumin provoke a temporary spreading and lobulation of the bases of the axopods. In solutions of MgSO4 or bovine plasma albumin, separate individuals of Actinophrys tend to fuse together in ‘plasmogamy’. The various observations are tentatively interpreted primarily in terms of a surface reaction, although it is likely that the mechanisms of response are complicated.
The Imaginal Ecdysis of Blowflies. Detection of the Blood-Borne Darkening Factor and Determination of Some of Its Properties
Authors: Cottrell C. B. 
Published: April 2021

ABSTRACT
At the imaginal ecdysis of Calliphora erythrocephala (Meigen) the initiation of normal hardening and darkening is brought about by the release into the blood of an active factor (Cottrell, 1962b). The darkening factor can be detected in fly blood by injecting it into flies decapitated at the moment of emergence. Blood taken from flies at the moment of emergence or 24 hr. after expansion produces little or no reaction, although blood taken between 3 min. and 10 hr. after emergence shows darkening activity. However, extracts of other tissues and many chemicals will also induce darkening though probably unspecifically through damage effects. The assay can therefore be used certainly only for detecting activity in fly blood. The blood-borne darkening factor of blowflies will withstand boiling for 10 min. or drying at 120° C. for 20 min., but it does not retain its activity when kept in solution at room temperature for more than 24 hr. It is non-dialysable, relatively insoluble in organic solvents and is inactivated by ethyl alcohol and the bacterial protease subtilisin. It is probably proteinaceous and is certainly not tyrosine or any of the phenolic compounds at present thought to act as the precursors of the tanning agent. The blood-borne factor of different blowflies (Calliphora, Sarcophaga and Lucilia) is not species-specific and there is some inconclusive evidence that a similar factor is present at the ecdysis of Schistocerca.
Spiracle Control in Adult Dragonflies (Odonata)
Authors: Miller P. L. 
Published: April 2021

ABSTRACT
Spiracle activity is described in four species of adult dragonfly (Anisoptera) at rest, in flight and during recovery from flight. The closer muscle of spiracle 2 reacts directly to locally applied carbon dioxide. In one species this results in maintained opening of the valve, and in the other three in movements synchronized with abdominal ventilation. Neither reaction involves a change in the patterns of nerve impulses in the motor nerve to the closer muscle. Conditions of partial anoxia have no direct action on the spiracle but they reduce the frequency of impulses in the motor nerve, thereby increasing the sensitivity of the closer muscle to carbon dioxide. A central inhibitory reflex accounts for spiracle opening at the start of flight. Various stimuli are described which excite this reflex. Rhythmically-firing ventilation centres are confined to the abdomen, but the brain and thoracic ganglia exert a considerable influence over ventilation. In species whose thoracic spiracles are at times synchronized with ventilation, volleys of impulses ascend the cord and regularly superimpose a burst at high frequency (and in one species a subsequent brief inhibition) on the otherwise constant firing of the spiracle motor neurones. In the presence of carbon dioxide these bring about synchronized movements. Synchronized spiracle movements probably give rise to a one-way airstream in tracheae which pass axially up through the flight muscles and then posteriorly along the abdomen. In some species the stream may pass in the reverse direction. Among thirty-five species of dragonfly examined in Uganda synchronized movements of the thoracic spiracles are found in all species active during the day; in five species which are active only during crepuscular periods they are absent. The possibility is discussed that these movements are important for cooling as well as for respiration.
The Effect of Light On the Shadow Reaction of the Sea Urchin, Diadema Setosum (Leske)
Authors: Yoshida M. 
Published: April 2021

ABSTRACT
As is mentioned by Mortensen (1940), sea urchins which belong to the genus Diadema react to shadow by spine movements. Since the work of Millott (1954) these responses have been extensively studied on an Atlantic species, D. antillarum. In preliminary experiments on a Japanese species, D. setosum, some of the important findings in the Atlantic species, such as the part played by radial nerves in the reflex (Millott, 1954), the photosensitivity of the nervous elements (Yoshida & Millott, 1959) and the inhibitory effect of light on the reaction (Millott & Yoshida, 1960 a, b), were confirmed. This made it possible to base the work on the Japanese species on what has been found in D. antillarum.
Some Effects of the Ionic Composition of the Extracellular Fluid On the Electrical Activity of the Cockroach Abdominal Nerve Cord
Authors: Treherne J. E. 
Published: April 2021

ABSTRACT
Irrigation of abdominal ganglia of Periplaneta Americana with salines containing excess potassium ions resulted in the development of a reversible conduction block. Removal of portions of the cellular and fibrous nerve sheath produced an accelerated potassium depolarization as described by Twarog & Roeder (1956). Elevation of the cation concentrations to correspond to the extracellular levels resulted in delayed conduction block in desheathed preparations irrigated with highpotassium saline. At 70 mM./l. K the rate of depolarization was delayed to approximately half that of intact ganglia. At extremely high potassium concentrations this effect became relatively small. It is suggested that the enhanced rates of potassium depolarization obtained in desheathed preparations partly result from the changed ionic composition of the extracellular fluid resulting from the desheathing procedure. The possible additional factors involved in the desheathing procedure are discussed. 50 mM./l. acetylcholine had little effect on the synaptic transmission in intact terminal abdominal ganglia but caused rapid loss of conduction in desheathed preparations. Injection of equivalent amounts of acetylcholine beneath the nerve sheath did not cause rapid conduction block, and it is suggested that the effects of desheathing are not necessarily caused by the removal of a relatively impermeable superficial diffusion barrier.
Bifunctional Muscles in the Thorax of Grasshoppers
Authors: Wilson Donald M. 
Published: April 2021

ABSTRACT
Recording electrical activity of certain dorso-ventral muscles in the thorax of grasshoppers has shown that the same muscles and (in at least one muscle) the same motor units may be used to move either the wings or the legs. The anatomical connexions are such that muscles which are antagonists with respect to the wings are synergists with respect to the legs, and vice versa. These muscles, which operate in a nearly perfectly repeating, fixed pattern during flight, show complete independence during manœuvres involving the legs and it is concluded that the flight pattern is not due to a fixed set of connexions between the motor neurons.
A Working Model for Demonstrating the Mosaic Theory of the Compound Eye
Authors: Altenburg Edgar 
Published: April 2021

ABSTRACT
A working model of the compound eye can be constructed by the parallel arrangement of numerous tubes (e.g. straws) packed in a container. Lenses are not a necessary part of the model.
The defining power of the model depends upon the number of tubes per unit area—the greater their number, the more detailed is the image formed by the model.
The manner in which the model works would indicate that the image formed by the compound eye is a mosaic, or patchwork ; and that lenses take no primary part in image formation by a compound eye, but are merely accessory structures which bring about an increase in the amount of light that strikes the retina.
The Testis and Thyroid in a Hen-Feathered Silver-Grey Dorking Cock
Authors: Buchanan Gwynneth 
Published: April 2021

ABSTRACTA case is described of an apparently normal silver Dorking cock becoming hen-feathered.The endocrine glands of this bird were examined, and the testes and thyroid found to be distinctly abnormal.The testes showed large masses of “luteal” cells, encapsuled fibrosed masses, abnormal spermatogenesis and non-functioning tubules.The thyroid showed myxoedematous and cystic conditions with an apparent attempt at compensation in the functioning tubules, and on the whole the appearance of an under-functioning gland.The glands of two fertile Sebright bantams were examined.The testes were normal, without “luteal” cells ; the thyroid was small, relatively rich in connective and poor in glandular tissue, with small secreting vesicles and poor blood supply, suggesting that the Sebright thyroid is subnormal in activity.The evidence suggests that an under-functioning thyroid, either pathologically induced or apparently healthy, may be a controlling factor in hen-feathering, either by acting in combination with the gonad secretion, or by altering it.The hypothesis is put forward that the thyroid and gonad act antagonistically in this respect; and a suggestion is made by which the condition of the plumage may be represented as the algebraic sum of the influence of the two glands.
The Energy-Sources in Ontogenesis
Authors: Needham Joseph 
Published: April 2021

ABSTRACT
The uric acid content of the hen’s egg has been investigated from the fourth to the twentieth day of incubation. There is a period of intensive uric acid production from the seventh to the eleventh day. After that point the excretion of uric acid fails to keep pace with the growth and differentiation of the embryo. The point of maximum intensity of uric acid production occurs two days later than the point of maximum intensity in the production of urea. From the fourth to the seventh day more urea is present than uric acid, and more is excreted, but by the tenth day the adult relationship is attained, in which 95 per cent. of the total nitrogen excreted is uric acid. The maximum intensity of protein combustion is attained between the eighth and the ninth days. It is pointed out that this occurs midway between the periods when carbohydrate and fat are respectively the predominant energy-sources. The protein used as a source of energy belongs entirely to the coagulable fraction; ovomucoid is not employed for this purpose. The protein nitrogen lost by combustion during development amounts to 7.5 per cent. of the total protein nitrogen present at the beginning, and to 3.0 per cent. of the total foodstuff burnt. The R.Q. for each day of incubation has been calculated on the basis of chemical analyses of fat, protein, and carbohydrate, and agrees as well as can be expected at present with those experimentally determined by Bohr and Hasselbalch, and by Lussanna. Further evidence has been collected from the literature indicating that in embryogenesis there is a succession of sources of energy, carbohydrate preceding protein, and protein preceding fat. Injection experiments and other considerations lead to the conclusion that factors located in the embryo decide what the embryo shall make use of as a source of energy. It does not, for instance, combust protein because its supply of available carbohydrate has been exhausted.
A Comparison Between the Dissociation of the Haemocyanins of Helix and Crustacea
Authors: Hogben Lancelot T. , Pinhey Kathleen F. 
Published: April 2021

ABSTRACT
The effect of increasing temperature upon the dissociation curve of Helix is similar qualitatively to that which has been recorded in the case of haemoglobin and crustacean haemocyanin. The value of Q per n gram molecules of oxygen is about 8000 calories. That is, it is of the same order of magnitude as the value for crustacean haemocyanin, but in all probability significantly less. The effect of increase of hydrogen-ion concentration upon the haemocyanin of Helix pomatia is remarkably slight as compared with its effect on crustacean haemocyanin. At low tensions no effect is detectable. Comparing the 50 per cent, and 75 per cent, saturation points, it is seen, that, as with crustacean haemocyanin, increasing hydrogen-ion concentration at first diminishes, but beyond a certain point increases, affinity for oxygen. The curves obtained on the acid side of this point are not identical in shape with the curves obtained on the alkaline side. The significance of this fact in relation to previous observations on crustacean haemo-cyanin, and to Rona and Ÿllpo’s experiments on haemoglobin, is discussed in the text. The behaviour of the haemocyanin of Helix as compared with that of crustacean haemocyanin in relation to the presence of neutral chlorides of the alkaline and alkaline earth metals is even more different. In alkaline medium, the addition of neutral chlorides to the serum depresses the dissociation curve ; at a point on the acid side of the critical pH referred to in section 2, addition of salts was not found to exert any detectable influence.
The Lethal Action of Soluble Metallic Salts on Fishes
Authors: Carpenter Kathleen E. 
Published: April 2021

ABSTRACTThe work of several years on the fauna of streams polluted by lead-mining(1. 2, 3) has revealed the fact that the destruction of fish-life in such streams is neither a matter of starvation nor emigration for lack of food, nor of spawn-destruction, but is a direct consequence of the action of lead-salts in solution (probably as the sulphate) upon the fishes themselves. Further, experiments both in the field (using fish cages in the polluted streams) and in the laboratory (using filtrates of the flood waters and chemical solutions) have clearly demonstrated that one part of lead in three millions of water may be lethal to minnows, sticklebacks and trout. It seemed worth while, therefore, to investigate the physiological nature of the reaction in order to discover whether it followed the normal course of a toxic reaction.
Caudal Fin and Body Movement in the Propulsion of Some Fish
Authors: Bainbridge Richard 
Published: April 2021

ABSTRACT
Observations made on bream, goldfish and dace swimming in the ‘Fish Wheel’ apparatus are described. These include: An account of the complex changes in curvature of the caudal fin during different phases of the normal locomotory cycle. Measurements of this curvature and of the angles of attack associated with it are given. An account of changes in area of the caudal fin during the cycle of lateral oscillation. Detailed measurements of these changes, which may involve a 30 % increase in height or a 20 % increase in area, are given. An account of the varying speed of transverse movement of the caudal fin under various conditions and the relationship of this to the changes in area and amount of bending. Details of the way this transverse speed may be asymmetrically distributed relative to the axis of progression of the fish are given. An account of the extent of the lateral propulsive movements in other parts of the body. These are markedly different in the different species studied. Measurements of the wave length of this movement and of the rate of progression of the wave down the body are given. It is concluded that the fish has active control over the speed, the amount of bending and the area of the caudal fin during transverse movement. The bending of the fin and its changes in area are considered to be directed to the end of smoothing out and making more uniform what would otherwise be an intermittent thrust from the oscillating tail region. Some assessment is made of the proportion of the total thrust contributed by the caudal fin. This is found to vary considerably, according to the form of the lateral propulsive movements of the whole body, from a value of 45% for the bream to 84% for the dace.
The Action of Moulting Hormone and Juvenile Hormone at the Cellular Level in Rhodnius Prolixus
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
In the course of a discussion on the mode of action of growth hormones in insects (Wigglesworth, 1957 a) a preliminary account was given of the cytological changes brought about by the moulting hormone in certain selected tissues. Further work, with the use of improved methods, has substantiated many of these earlier results; others require revision.
Excretion in the Blood-Sucking Bug, Rhodnius Prolixus Stål
Authors: Maddrell S. H. P. 
Published: April 2021

ABSTRACT
The mechanism underlying diuresis in Rhodnius has been investigated. An isolated preparation of the Malpighian tubules of a 5th-instar larva is described. The rate of secretion by such a preparation, isolated in a drop of haemolymph, is at first high but soon falls to a low level. It can be restored by the addition of haemolymph taken from an insect during diuresis. It has been shown that diuresis is promoted by some substance, presumably a neurohormone, which can be extracted from the posterior neurosecretory cells of the fused ganglionic mass situated in the mesothorax.
Studies On the Glomerular Filtration Rate of Rainbow Trout (Salmo Gairdneri)*
Authors: Holmes W. N. , Mcbean R. L. 
Published: April 2021

ABSTRACT
Variations in the glomerular filtration rate (G.F.R.) and the renal tubular reabsorption of water are probably important factors in the homoiostatic mechanisms-associated with the euryhalinity of the rainbow trout (Salmo gairdneri). The observed reduction in urine flow after the adaptation of rainbow trout to sea water can be largely accounted for on the basis of the reduced G.F.R. Intraperitoneal injections of mammalian preparations of vasopressin, oxytocin and vasopressin/oxytocin into freshwater trout significantly increased the G.F.R. The intraperitoneal injection of aldosterone into freshwater fish had no detectable effect on G.F.R. The similar administration of corticosterone significantly reduced the G.F.R. to 73 % of the intact freshwater control value.
The Reaction of Fish to Moving Backgrounds
Authors: Harden Jones F. R. 
Published: April 2021

ABSTRACT
An apparatus is described to study the response of fish to moving backgrounds. Observations were made on pike, three-spined sticklebacks, trout, perch and roach; cod, whiting, whiting-pout, smelt, herring, armed bullhead, lesser weaver, plaice, dabs, soles and dogfish. Pike followed a moving background equivalent to a water current of 0.03 cm./sec. Pike were the best and most consistent performers among the freshwater species, followed by the three-spined stickleback, trout, roach and perch. The marine species fell into two groups. The cod, whiting, whiting-pout, smelt, and herring responded to background movements equivalent to water currents of 1-2 cm./sec. The other fish failed to respond to movements equivalent to currents up to 24 cm./sec. and it is thought that this may have been due to contact with the bottom. The fish that orientated to a moving background also responded kinetically. Cod, whiting, and whiting-pout gained on the background (swam upstream) at rotational speeds equivalent to water currents less than 1 fish lengthlsec., but started to lag behind at speeds equivalent to currents faster than 1-2 L/sec., although the fish were shown to be capable of swimming fast enough to keep pace with the background. Herring gained on the background up to rotational speeds equivalent to water currents of 3-4 fish lengths/sec. The results are discussed in relation to the contranatant theory of fish migration.