bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Kinematics and Dynamics of Ciliary Fluid Systems
Authors: Miller C. E. 
Published: April 2021

ABSTRACT
The difficulties of directly applying the methods of Newtonian mechanics to solve the problem of mucus flow in the mammalian trachea are discussed. In order to circumvent these difficulties, a sophisticated model of the mucociliary system, called the circular rheociliometer, was constructed. A brief account is given of the model and the homomorphic relation it has to the mucociliary system of mammal. Kinematic experiments are described in which observations on the model are compared with observations on the mucociliary system of the cat’s trachea. A coefficient of energy, which is the ratio of energy loss in the fluid to the kinetic energy supplied by the cilia, is developed. The coefficient of energy is plotted against the Reynolds number for the model and for the cat’s trachea. It is shown that both sets of data fall within the same range of Reynolds numbers. Based on other kinematic and dynamic similarities, which are shown to exist between the two systems, a hypothetical mechanical exemplar of the mucociliary system is derived.
A Comparative Study of Central Blood Pressures in Five Amphibians
Authors: Shelton G. , Jones D. R. 
Published: April 2021

ABSTRACT
The temporal relationships of blood pressures recorded from the ventricle, conus and arterial arches are identical in Rana, Bufo and Xenopus. Pressure levels in the arterial arches are very similar in all the species. The pulse in the ventricle is large and the pressure falls to zero during diastole. Continued conus contraction after ventricular relaxation causes a divergence of pres-sure in the two chambers. Divergence between conus and arterial pressures follows as the conus relaxes. Pressure gradients between the various recording sites during forward movement of the blood is small. Theoretical considerations show that pressure-flow relationships approximate to the formula of Poiseuille. They also pro-duce no evidence for substantial pressure gradients during blood ejection. Blood pressures recorded in Salamandra are significantly lower than in the anurans. The systemic and pulmocutaneous pulses are identical, unlike the condition in anura where the pulmocutaneous pulse is almost invariably the larger. In all other respects the pressure relationships in Salamandra are identical to those in anurans.
The Sensitivity of Housefly Photoreceptors in the Mid-Ultraviolet and the Limits of the Visible Spectrum
Authors: Goldsmith Timothy H. , Fernandez Hector R. 
Published: April 2021

ABSTRACT
In experiments published in his book of 1882, Sir John Lubbock demonstrated that removal of the ultraviolet (u.v.) wavelengths decreased the effectiveness of natural sunlight in stimulating ants to carry their pupae into the dark. An apparently high sensitivity to near-ultraviolet light was subsequently shown in studies of phototaxis in bees (Bertholf, 1931a, b; Heintz, 1959) and flies (Bertholf, 1932; Cameron, 1938). More recently electrophysiological techniques have been employed to study selective adaptation of the retinal action potential (Walther & Dodt, 1959; Goldsmith, 1960) and the spectral responses of single retinular cells (Autrum & Burkhardt, 1960; Autrum & von Zwehl, 1962, 1964; Burkhardt, 1962; Autrum, 1965). This work demonstrates that honeybees (Apis) have u.v. receptors with peak sensitivity at 340 nm. and the cockroach (Periplaneta) at ∼ 350 nm. The photoreceptors of flies (Calliphora) show two maxima, one of which lies at about 350 nm. The peaks are less well defined, but u.v. receptors maximal at about 350 nm. also seem to be present in Coleoptera, Lepidoptera (Hasselmann, 1962) and probably Odonata (Ruck, 1965). These peaks are not due to secondary excitation of the visual pigments through fluorescence of accessory pigment for (1) both bees and flies are phototactically several times more sensitive to the 365 nm. mercury line than to any longer wavelengths (Bertholf, 1931a, b, 1932; Cameron, 1938); (2) in flies the u.v. maxima seen in the retinal action potential are higher than the peaks in the visible region of the spectrum (Walther & Dodt, 1959; Burkhardt, 1962); and (3) bees can be trained to discriminate u.v. from all other wavelengths or mixtures of wavelengths (e.g. Daumer, 1956).
Effect of Season and Sex on the Photopic Spectral Sensitivity of the Three-Spined Stickleback
Authors: Cronly-Dillon John , Sharma Sansar C. 
Published: April 2021

ABSTRACT
It is now almost two decades since Tinbergen and his associates (Tinbergen, 1951 ; Tinbergen & van Iersel, 1947; van Iersel, 1953) identified the relevant features of visual displays which trigger sexual and parental behaviour in the three-spined stickleback. Specifically, they showed that during the breeding season, when the female’s abdomen is swollen with eggs, the latter serves as a visual sign stimulus which triggers appropriate sexual behaviour in the sensitized male. In addition, the red colouring which the belly of the male acquires during this period was found to elicit, in other sensitized males, the complex behaviour patterns which characterize the defence of territory in this species.
The Effects of Pituitrin and of Narcosis on Water-Regulation in Larval and Meta-Morphosed Amblystoma
Authors: Bělehradek J. , Huxley J. S. 
Published: April 2021

ABSTRACT
Injection of post-pituitary extract to larval and adult Amblystoma individuals leads to an increased water-intake, followed by a decrease in water-content of the body, the decrease being greater than the preliminary increase. Repeated injections cause decreases of body-weight of over 35 per cent. This effect runs parallel with the chromatophore effect. No change in oxygen consumption could be detected, even with long continued injection. Both larval and metamorphosed Amblystoma lose weight (by loss of water) when narcotised in a solution of amytal 1 : 3000 ; the loss is greater in larval specimens; the decrease is followed, in metamorphosed animals, by a slight net increase. Both the pituitary effect and the amytal effect develop considerably more quickly in larval than in metamorphosed Amblystoma. The mechanism regulating the water-equilibrium of the body in Amblystoma passes, during metamorphosis, from a relatively imperfect state in the larval stage to a more efficient condition in adult individuals.
A Study of Arginase Content in the Fowl With Special Reference to Sex
Authors: Chaudhuri A. C. 
Published: April 2021

ABSTRACT
The enzyme arginase which occurs in various organs of different animals was first discovered by Kossel and Dakin (1904) in the mammalian liver. Clementi (1916, 1918, 1922) found arginase in the liver of mammals, amphibians and fishes and the turtle, but he did not find any in the liver of birds and of the majority of reptiles. He found the enzyme to be present in the kidney of birds. Hunter and Dauphinee (1924) found a considerable amount of arginase in the liver of mammals and fishes. They also established the presence of arginase in the kidney of mammals and fishes, but usually in an amount smaller than that present in the liver. In the organs of fishes other than the liver, heart and kidney, the distribution of arginase appeared to be variable. In mammals these workers did not find arginase in any organs except the liver and the kidney, while in birds they could find it only in the kidney.
The Effect of the Injection of Alcohol Into the Male Mouse Upon the Secondary Sex Ratio Among the Offspring
Authors: Chaudhuri A. C. 
Published: April 2021

ABSTRACT
Bluhm (1921) found that in the mouse the injection of alcohol into the male parent was followed by a remarkable rise in the sex ratio among the offspring. The results of Danforth (1926), who administered alcohol in the form of vapour, confirmed this finding, as did those of Parkes and Bellerby (1926). MacDowell and Lord (1926) and Crew (1926) found that severe exposure of the male to alcohol fumes was not followed by any disturbance of the secondary sex ratio. In view of this disparity, it was suggested to me by Dr Crew that the difference in results might possibly be but a reflection of the difference in the method of exhibiting the alcohol and that it would be a profitable study actually to repeat Bluhm’s work, using her technique.
Studies on Calcium Metabolism
Authors: McIsaac P. 
Published: April 2021

ABSTRACT
It was thought to be of interest to determine the relation that exists between the serum-calcium content of mother and offspring in the rabbit. Comparatively little work has been done on the calcium content of maternal and foetal blood and that which has been done is more or less recent and is concerned with cattle and man. Robinson and Huffman (1926) found that the blood of the cow at calving had a lower calcium content than that of the calf, and that the tendency in the case of the calf was for the calcium to decrease during the first week of the calf’s life. In the case of the mother there is a drop in calcium at the end of pregnancy, but after calving there is an immediate rise, which continues for several days. Hellmuth (1925), working on man, found that the calcium content was always 20–30 per cent, higher in the foetal than in the maternal blood. H. A. and H. I. Mattil (1922), also working on human blood, found on the other hand that at birth the infant’s and mother’s blood were identical in calcium content, and during several months after birth the calcium in the infant’s blood increased, reaching a variable maximum, often double that at birth. Thereafter there was a gradual decrease. Harding (1925) in his review of metabolism in pregnancy states that Ca, P, Na and K appear to be higher in foetal than in maternal blood.
On The Occurrence of Haemoglobin and of Erythrocytes in the Perivisceral Fluid of A Holothurian
Authors: Hogben Lancelot , Van Der Lingen J. 
Published: April 2021

ABSTRACT
On examining specimens of Cucumaria frauenfeldi, it was found by one of us that a red fluid exuded from the body cavity when punctured. C. frauenfeldi (Ludwig), kindly identified for us by Dr Barnard of the South African Museum, is a common representative of the Holothuroidea in the littoral fauna of the Cape Peninsula, especially abundant in rock pools at Sea Point, near Cape Town. It is dark brown in colour and about 112 to 3 inches in length. On cutting through the integument, a densely coloured fluid of a port wine red or scarlet tint exudes. A few seconds after shedding the pigment is seen to be concentrated in flocculent masses which rapidly sediment leaving the supernatant liquor colourless. It can be dispersed again by vigorous shaking, and if then transferred to a test-tube connected with a pump capable of giving a high vacuum, it changes colour from scarlet to a reddish purple on removal of air. On readmitting the latter, and shaking once more, the scarlet colour reappears, thus indicating that the colouring matter itself is a reversibly oxidisable pigment, in all probability one of the family of haemoglobins, a conclusion confirmed, as will be seen later, by spectroscopic examination.
The Effect of Electrolytes on the Muscle of the Fore-Gut of Dytiscus Marginalis, with Special Reference to the Action of Potassium
Authors: Hobson A. D. 
Published: April 2021

ABSTRACT
The muscle of the isolated fore-gut of Dytiscus marginalis will maintain rhythmic contractions for long periods when suspended in a medium of the composition NaCl 0·161 M : KC1 0·003 M : CaCl2 0·002 M at a pH of about 7·2. In the presence of normal concentrations of sodium, alterations in the potassium and calcium concentrations cause changes in the muscle essentially similar to those already described by Hogben and by Wells in the crustacean heart. Rhythmic contractions can be maintained for extended periods in mixtures of potassium and calcium chlorides alone. In potassium-calcium mixtures the tone is always high, but the contractions are normal in form and the muscle reacts in the normal manner to changes in the K/Ca ratio. The optimum K/Ca ratio is extraordinarily low, having a value of about 0·4. The tone of the muscle is dependent, not only on the absolute concentration of potassium and calcium but also on the K/Ca ratio.
Active Transport of Potassium by the Cecropia Midgut
Authors: Wood J. L. , Farrand P. S. , Harvey W. R. 
Published: April 2021

ABSTRACT
The potential profile recorded as a microelectrode is advanced from the blood side through the isolated midgut of Hyalophora cecropia consists of negative plateaus followed by a large positive step to the full midgut potential. Oxygen deprivation diminishes both the positive step and the midgut potential ; the negative plateaus are not affected. Changes in the potassium concentration in the blood-side solution affect both the negative plateaus and the midgut potential; the large positive step remains about the same. From these results it is concluded that the positive step is probably produced by the electrogenic potassium pump and that the negative steps are due to a potassium equilibrium potential. The discrete and independent nature of the negative and positive potentials argues that there are two barriers separating a ‘midgut’ compartment from the two bathing solutions. It is inferred that the epithelial cells are the site of the profile negativity and therefore that they constitute the ‘midgut’ compartment. This interpretation implies that the potassium equilibrium potential appears across the basal cell membranes and that electrogenic pump potential appears across the apical plasma membranes of the epithelial cells. The most conservative interpretation of these results is that the electrogenic potassium pump is located somewhere in or on the apical plasma membrane of the epithelial cells.
Kinetic Studies of the Flagellar Movement of Sea-Urchin Spermatozoa
Authors: J. Holwill M. E. 
Published: April 2021

ABSTRACT
The movements of intact and glycerinated spermatozoa from two species of sea-urchin were examined in the range of temperature between.5 and 30° C. The variations of the frequency of the glycerinated spermatozoa with changing pH, dielectric constant and ionic strength were examined. From the temperature studies values for activation entropies and enthalpies were obtained that pertain to the chemical reaction which limits the frequency. Within the limits of experimental error the activation parameters are identical for the intact spermatozoa and for the glycerinated model of the same species. The results are consistent with the hypothesis that the rate-limiting reaction is the breakdown of an enzyme-substrate complex. The pH studies suggest that neither the acidic nor the basic part of the enzyme is involved in complex formation but that both participate in the breakdown of the complex. The results obtained from the studies of dielectric constant are interpreted in terms of a model for the breakdown of the enzyme-substrate complex involving the separation of several spherical charges. The studies of pH and ionic strength suggest that both 14S and 30S dynein participate in the mechano-chemical process responsible for bending the flagellum.
Water Balance in the Eggs of the Atlantic Salmon Salmo Salar
Authors: Potts W. T. W. , Rudy P. P. 
Published: April 2021

ABSTRACT
The rate of exchange of tritiated water across the vitelline membrane of the eggs of the Atlantic salmon has been examined under various conditions. In eggs shed into isosmotic saline the rate constant of exchange is about 0·3−0·4/hr. When eggs are shed into distilled water or isosmotic glucose rate constants as high as 0·8−1·0/hr. occur for short periods but the rate of exchange declines rapidly. Low concentrations of sodium and more especially of calcium ions delay both the phase of rapid exchange and the phase of declining permeability. The rate of formation of perivitelline fluid is greatest during the period of high permeability.
Locomotion and Coelomic Pressure in Lumbricus Terrestris L
Authors: Seymour M. K. 
Published: April 2021

ABSTRACT
Crawling movement and burrowing of Lumbricus terrestris (L.) have been studied by continuous recording of internal pressure, direct observation and analysis of cine film. Frequency of locomotory waves is from 5 to 20 per min. Timing of protrusion of setae and of backward slip of points d’appui in locomotion have been observed and recorded. In normal locomotion elongation of segments by contraction of the circular muscles gives rise to a discrete pressure pulse; shortening, by contraction of the longitudinal muscles, may or may not do so, depending on the position of the segment in the worm and the relative extent of contraction of the longitudinal and circular muscles. Consideration of crawling and burrowing pressure records emphasizes the importance of (a) the circular muscles in extension of the head end in crawling and in initial penetration of the soil, and (b) the longitudinal muscles during burrowing, in dilating the burrow and drawing in more posterior segments Mean pressures at circular and longitudinal muscle contraction are 12 and 7 cm. H2O respectively. The highest pressure recorded was 75 cm. H2O and accompanied violent squirming with evident contraction of all the body wall muscles. Resting pressures, shown in the absence of organized movement, are low (mean 0-26 cm. H2O). In both resting and crawling negative pressures sometimes occur and these are considered in relation to the inherent stiffness of the body wall and to the septate condition. Tension in the longitudinal and circular muscle layers of a worm developing 75 cm. H2O internal pressure are calculated to be 265 and 1323 g./cm.2 respectively, demonstrating in this example that, relative to the circulars, the longitudinal muscles are understressed by a factor of 5. Mean locomotory L.M. and C.M. peak values yield tension values of only 25 and 212 g./cm.2 respectively, and these are clearly well within the worm’s capacity.
The Oxygen Consumption of Octopus Cyanea
Authors: Maginniss L. A. , Wells M. J. 
Published: April 2021

ABSTRACT
There is now a considerable literature on the brain and behaviour of Octopus (for reviews see Wells, 1966; Young, 1964). Most of the accounts relate to the mediterranean Octopus vulgaris and most are concerned with this animal’s behaviour in training experiments and with the effect of brain lesions on learning. These experiments have been made with octopuses of a variety of sizes, ranging from 500 g. (early experiments by Boycott & Young, 1950−55; see reviews cited above) through a ‘normal’ experimental range of 200−400 g. down to the 15−40 g. animals used in experiments dealing with statocyst removal and recognition of the orientation of objects in the visual field (Rowell & Wells, 1961 ; Wells, 1960).
Observations on the Function and Physiological Properties of a Fast Paramyosin Muscle—The Notochord Of Amphioxus (Branchiostoma Lanceolatum)
Authors: Guthrie D. M. , Banks J. R. 
Published: April 2021

ABSTRACT
Measurements of tension and pressure from the isolated notochord during electrical stimulation indicate that the notochord of Amphioxus is a muscular organ. Muscular contraction increases the stiffness of the notochord and the pressure increase suggests that it behaves as a hydrostatic skeleton. The mechanical responses of the muscles accord fairly well with the known characteristics of other paramyosin muscles, although they are rather faster than the paramyosin muscles of most molluscs. The muscular response appears to make its greatest contribution to notochordal stiffness at the small angles of bending associated with fast swimming. Notochordal activation is preceded by a giant fibre potential. The collagen of the notochordal sheath appears to be rather more extensible than vertebrate collagen, but there is a material, probably in the elastica interna, with similar properties to elastin. The characteristics of the lancelet notochord emphasize rather than detract from the importance of its phylogenetic position.
Discharge Patterns of Coxal Levator and Depressor Motoneurones of the Cockroach, Periplaneta Americana
Authors: Pearson K. G. , Iles J. F. 
Published: April 2021

ABSTRACT
Observation of movements of the metathoracic legs of the cockroach before and after section of peripheral nerves allowed identification of muscles involved in flexion and extension of the femur. Extracellular recordings from the nerves to these coxal muscles show that during rhythmic leg movements bursts of activity in a number of levator motor axons were strongly reciprocal and generally non-overlapping with those of a slow depressor motor axon. These reciprocal patterns persisted after removal of all sensory input from the legs. The durations of levator bursts were relatively constant compared to those of the depressor, corresponding to the behavioural observations on leg protraction time. The pattern was asymmetric: levator bursts could be generated without depressor activity, but never the reverse. No evidence was found for inhibitory collateral pathways between antagonisti motoneurones. It is proposed that levator motoneurones are driven by a group of bursting interneurones which simultaneously inhibit the ongoing depressor activity.
A Study of the Effect of Temperature Changes On the Respiratory Pumps of the Rainbow Trout
Authors: Hughes G. M. , Roberts J. L. 
Published: April 2021

ABSTRACT
The pumping mechanism maintaining water flow across the gills has been investigated in the trout using pressure transducers and ciné analysis (Hughes & Shelton, 1957, 1958). It was shown that the mechanism could be considered as being made up of a buccal pressure pump and opercular suction pumps, the two being separated functionally by the gill resistance. In this species, Salmo gairdneri, the relative contribution of the two pumps appeared more or less equal, as judged by the areas of the corresponding phases of the differential pressure across the gills. Further studies of the respiratory pumps with special reference to their muscular basis were made using electromyography (Ballintijn & Hughes, 1965) and emphasized the many couplings between the two pumps. Although several studies have been made on the influence of environmental changes on gas exchange (Randall, Holeton & Stevens, 1967), no detailed account has been published on the modifications that occur in gill ventilation mechanisms and interactions with cardiac cycles when trout are subjected to stress. The present series of experiments forms part of such a study in which electrocardiograms were obtained simultaneously with electrical recordings from parts of the respiratory neurones in the medulla, from some respiratory muscles, and with pressure recordings from the buccal and opercular cavities. All were carried out during subjection of rainbow trout to warming thermal stress. A preliminary report of this work has already been given (Roberts & Hughes, 1967).
Respiratory Function of the Swim-Bladders of the Primitive Fish Polypterus Senegalus
Authors: Magid A. M. Abdel , Vokac Z. , El Din Ahmed Nasr 
Published: April 2021

ABSTRACT
The respiratory function of the swim-bladders of Polypterus senegalus was investigated. Experiments were carried out in tap water with an oxygen tension of about 140 mm. Hg. Both swim-bladders were cannulated through the body-walls of the unrestricted fish. Gas samples were analysed for their oxygen and carbon dioxide content before and after the fish visited the surface. A sharp increase in oxygen and a decrease in carbon dioxide tension was always observed after inhalation. This proves that atmospheric air is actually inspired into the bladders. After inspiration, the amount of oxygen in the bladders decreased rapidly. This shows that oxygen is taken up by the blood, even when the oxygen content of the water is normal. Inspiration of air is preceded by expiration which, on the average, reduces the volume of the bladders to about 40%. The uneven distribution of inhaled air in the right bladder is shown to be due to anatomical configuration.