bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the Chemical Composition of Muscle Tissue
Authors: Robertson James D.
Published: April 2021

Methods of analysis of muscle are discussed, particularly in regard to ashing and extraction procedures for inorganic ions and the determination of chloride. imultaneous analyses have been made of blood and muscle for the following ions: Na, K, Ca, Mg, Cl, SO4, inorganic and total trichloracetic acid soluble P (inorganic and organic phosphates). In Myxine muscle the ions analysed make up 39-47% (average 42%) of the total osmotic concentration, assuming it to be that of the blood-serum: 491 mg. ions/kg. water content compared with 1181 mg. ions/kg. water in the serum. The latter is practically isosmotic with the surrounding sea water of 1208 mg. ions. Potassium and phosphate are the only ions higher in concentration in the muscle than in the serum, but the muscle concentration of sodium exceeds that of potassium. Low calcium concentrations of 1.8-2.2 mg. ions/kg. water in the muscle and 5.5-7.I mg. ions in the blood serum, compared with 11.1 mg. ions in the sea water, are correlated with the absence of a calcified skeleton. Muscle ions in Muraena come to 308 mg. ions/kg. water content, about 72% of the osmotic concentration of the plasma; the latter is about one-third that of the surrounding sea water. Potassium, calcium, magnesium and phosphate ions in muscle exceed their respective concentrations in the plasma, while the remaining sodium, chloride and sulphate ions are below the plasma values. Cation-anion balance of the analysed constituents of Myxine muscle is satisfactory, but there is a considerable anion deficit in Muraena muscle, probably made up in part by lactate and bicarbonate ions.
Studies on Sodium Balance in Gammarus Duebeni lilljeborg and G. Pulex Pulex (L.)
Authors: Shaw J. , Sutcliffe D. W.
Published: April 2021

The mechanisms of sodium balance in Gammarus duebeni and G. pulex, adapted to various external concentrations, were compared. G. duebeni could be adapted to live in 1 mM/1. NaCl solution and, in some cases, to concentrations down to 0·2 mM/1. G. pulex could survive in concentrations as low as 0·06 mM/1. The sodium loss rate in G. duebeni adapted to 2 % sea water was much higher than in G. pulex but was reduced to about the same level when the animals were adapted to low external concentrations. In both species there was a non-linear relationship between sodium influx and the external sodium concentration. In G. duebeni the uptake mechanism was saturated at an external concentration of about 10 mM/1., whereas in G. pulex saturation was reached at a much lower concentration. The maximum rate of uptake was greater in G. duebeni than in G. pulex. In both species adaptation to low concentrations involved a small increase in the sodium influx and a reduction in the loss rate. The most important factor in the superiority of G. pulex over G. duebeni in surviving at low external concentrations is the high affinity for sodium displayed by the uptake mechanism in G. pulex.
Water Relationships of Aphis Fabae Scop. During Tethered Flight
Authors: Cockbain A. J.
Published: April 2021

Water content varies from 64 to 73 % of the total body weight and 72−76 % of the fatless body weight of 24 hr. old unflown alatae of Aphis fabae. Water loss during flight may be attributed to evaporation and excretion. A mean of 0-07 mg. water is lost per aphid during a 6 hr. tethered flight at 25−26°C. and 57−82% R.H., corresponding to c. 9% body weight; at least 66% of the loss (c. 1 % body weight/hr.) is by evaporation. Excretion during flight is not affected by relative humidity differences over the range 41−75 % at 25−26°C., but the relative amounts of water lost during prolonged flight are inversely related to relative humidity, because of the effect of humidity on evaporation. Proportion of water in the body does not change significantly during tethered flight. Mean percentage water to total body weight increases from c. 68−69 % during 6 hr. ; mean percentage water to fatless body weight decreases from c. 74 to 73 %. Water loss is evidently not a limiting factor to flight in atmospheres of saturation deficit less than c. 23 mm. Hg.
Viability and Fecundity of Alate Alienicolae of Aphis Fabae Scop. After Flights to Exhaustion
Authors: Cockbain A. J.
Published: April 2021

Laboratory-reared 24 hr.-old alate alienicolae of A. fabae were flown for variable periods, but all to apparent exhaustion; their subsequent longevity and fecundity on broad beans, or their survival times during starvation, were compared with controls. Adult longevity, reproductive rate and capacity, and nymph viability were similar in exhausted and control aphids that settled on host plants after flight. Mean adult life was 31 days in exhausted aphids and 32 days in the controls. Both exhausted and control aphids produced an average of 84 larvae per adult. The only major difference noted between exhausted and control aphids that fed after flight was a reluctance, or inability, of exhausted aphids to fly on the following day. Exhausted aphids starved after flight lived for a significantly shorter time (mean of 30 hr.) than control aphids starved without flight (55 hr.). 28 % df the exhausted and 88 % of the control aphids could take-off on the next day. The results indicate that long migratory flights are unlikely to affect the reproductive potential of aphids, and that alate alienicolae of A. fabae, having settled on a suitable host after an exhaustive flight, are unlikely to fly again.
The Relationship Between Nutrition, Hormones and Reproduction in the Blowfly Calliphora Erythrocephala (Meig.)
Authors: Strangways-Dixon J.
Published: April 2021

Calliphora erythrocephala females will live on a sugar diet but will not reproduce unless protein-containing substances are also ingested. If fed protein without carbohydrate, they die. Isolated females were allowed to select from a carbohydrate (sucrose) solution and from a protein-containing solution (Marmite yeast extract in milk) which were contained in identical capillary tubes. The total volume of food ingested each day over a complete reproductive cycle was found to be fairly constant. Within this total, however, ‘protein’ and carbohydrate were selected in quantities which varied with different phases of the reproductive cycle. Thus during the early stages of egg growth, ‘protein’ was ingested in relatively large quantities, while during yolk formation ‘protein’ ingestion declined. Carbohydrate consumption, on the other hand, was relatively low during the early stages but increased during yolk formation. At oviposition the cycles started again. Carbohydrate ingestion of non-reproducing females (fed on sugar solution only) remained at a constantly low level. Selective feeding did not appear to be influenced by mating. Females were found to accept courting males on the day of the first oviposition but not before. This, of course, necessitated a mixed diet of carbohydrate and ‘protein’.
The Action and Composition of the Saliva of An Assassin Bug Platymeris Rhadamanthus Gaerst. (Hemiptera, Reduviidae)
Authors: Edwards John S.
Published: April 2021

The responses of whole insects, selected organs, and tissues to treatment with the saliva of an assassin bug Platymeris rhadamanthus are described. The excitability of muscle and nerve is rapidly abolished. In the general lysis that follows immobilization only cuticular and collagenous structures are spared. The disruption of lipid layers in the walls of nervous tissue is histologically demonstrable at an early stage. The saliva contains at least six proteins, and lacks mucoprotein or other mucoid substance. Three proteolytic fractions were recognized after starch-gel electrophoresis at pH 8·6, one of them forming the major component of the saliva. Attempts to locate a toxic fraction were unsuccessful. The alkaline endopeptidase activity of whole saliva characterized with an azocasein substrate closely resembles gut proteases of other insects examined with the same substrate. Hyaluronidase is present in the saliva and with protease acts as a spreading factor by breaking down the intercellular matrix. Lipase and esterase activity were not detected in the saliva, but gut-wall extracts were lipolytic. The saliva shows weak phospholipase activity. ATP-ase, and serotonin were not detected. The mode of action of assassin bug saliva as a venom and in external digestion is discussed. It is suggested that its toxicity is due to the disruption of phospholipid layers of the cell wall and is the first manifestation of general lysis during external digestion.
The Respiratory Centre in the Tench (Tinca Tinca L.)
Authors: Shelton G.
Published: April 2021

The medulla of the tench brain was searched systematically by means of needle electrodes for rhythmic bursts of action potential activity coinciding with the breathing movements. The neurones which produced these rhythmic bursts of activity were located in the grey matter, mainly beneath the IXth and Xth motor nuclei and in the region round the Vllth motor nucleus. This type of activity was also found in some of the neurones forming the Vth and Vllth motor nuclei. The respiratory neurones were not arranged in a discrete and homogenous nucleus anywhere in the medulla, but were scattered through the grey matter. The distribution was not uniform, the neurones tending to occur in very small groups. There was also a relatively higher density of respiratory neurones in the central, as compared with the more anterior and posterior, parts of the respiratory region. The possibility that variations may occur in the constitution of the respiratory centre, in different individuals and in the same individual at different times, is considered. The manner in which neurones of the respiratory centre function to produce the rhythmic activity is discussed. Localized destruction of active respiratory regions, over a wide area of the medulla in different fish, was never followed by a breakdown in the rhythmic movements. This is interpreted as evidence against the existence of a pacemaker and favouring the hypothesis that the rhythm is produced by a general reciprocal interaction of large numbers of respiratory neurones.
Sodium and Potassium Fluxes in the Abdominal Nerve Cord of the Cockroach, Periplaneta Americana L
Authors: Treherne J. E.
Published: April 2021

The influx of sodium and potassium ions into the central nervous system of Periplaneta americana has been studied by measuring the increase in radioactivity within the abdominal nerve cord following the injection of 24Na and 42K into the haemolymph. The calculated influx of sodium ions was approximately 320 mM./l. of nerve cord water/hr. and of potassium ions was 312 mM./l. of nerve cord water/hr. These values are very approximately equivalent to an influx per unit area of nerve cord surface of 13·9 × 10−12 M cm.−2 sec.−1 for sodium and 13·5 × 10−12 M cm.−2 sec.−1 for potassium jons. The relatively rapid influxes of these ions are discussed in relation to the postulated function of the nerve sheath as a diffusion barrier. It is suggested that a dynamic steady state rather than a static impermeability must exist across the sheath surrounding the central nervous system in this insect.
Osmotic and Ionic Changes in Blood and Muscle of Migrating Salmonids
Authors: Parry Gwyneth
Published: April 2021

Osmoregulation of the Atlantic salmon in fresh water and sea water, and during transfers from one salinity to another, has been studied by measuring the freezing-point and the levels of some inorganic ions in the blood plasma, and water content and ions in whole muscle. An increase in blood concentration of about 12 % follows the transfer of juvenile fish (smolts) from fresh water to sea water; and a fall of concentration of about 5 % follows the transfer of the adult fish from sea water to fresh water. Some changes in analyses of whole muscle indicate changes in the extracellular compartment during transfers from one salinity to another. Osmoregulatory powers of juvenile salmon (smolts) and fresh-run adults are good, but spent fish (kelts) returning from fresh water to sea water, osmoregulate with difficulty or not at all.
Territorial Behaviour in Barnacle Settlement
Authors: Crisp D. J.
Published: April 2021

An analysis of the natural pattern of settlement of barnacles, whether arranged along a groove or over a plane area, shows that later settlers tend to maintain a distance of about 2 mm. from earlier ones. This phenomenon in a sedentary form is analogous to territorial behaviour in active species. A method is described which gives average values for population density as a function of the distance from any reference individual. It is found that the reference individual lies in a trough of very low population density, and that the latter rises sharply a short distance away. The distance from the reference individual, at which the population density reaches the average value for the whole population, is defined as the territorial separation. The territorial separation is reduced, but not entirely eliminated, as the population density rises. The value of territorial separation is a little greater than the sum of the radius of the previously settled spat and the length of the cyprid, and is slightly smaller in species with smaller cyprids and spat. Cyprids settle at the periphery of the base of detached specimens rather than at the centre. Though strongly attracted to pits in the surface, cyprids continue to behave territorially within a pit, and avoid pits containing previously settled individuals. They settle readily in pits with only the bases of detached individuals present. Observations on settling cyprids show that after encountering settled barnacles they tend to remain and explore the surface. If they continue to encounter settled individuals at the time they are about to settle, the period of final searching is prolonged until they find a suitably vacant area. Territorial behaviour is probably an adaptation allowing the recently metamorphosed cyprid time to establish itself before it touches the growing edge of another barnacle.
The Structure and Function of the Prothoracic Spine of the Desert Locust, Schistocerca Gregaria Forskål
Authors: Fraser Rowell C. H.
Published: April 2021

The prothoracic sternal spine of Schistocerca is described. The second paired nerve innervates the sensilla of the sternum, coxae, and femora, and in subimaginal stages supplies chordotonal organs registering movement of the cervical membrane. Each nerve fibre serves the axons of several sensilla. When the sensilla are waxed, control of the legs is disturbed. When the prothoracic ganglion is isolated from the CNS stimulation of the sensilla produces complex, oriented, reflex cleaning movements by the legs. Recordings were made from nerve 2 and from the commissures. Co-ordination is mainly segmental; the signal in the commissures is much reduced. At normal levels of stimulation there is no activity in nerve 2 unless several sensilla are excited. Among related genera there is some correlation between manipulative ability and the number of sensilla on the spine. It is suggested that these sensilla contribute to the co-ordination of movements of the front legs.
The Central Nervous Control of Flight in A Locust
Authors: Wilson Donald M.
Published: April 2021

The co-ordination of the flight movements of Schistocerca gregaria Forskål was examined in order to determine the extent of central patterning and reflex control. Electrical recordings from wing sensory nerves showed many units which responded to wing movements of various kinds. During flight the sensory discharge was timed to certain phases of the wing-beat cycle. Surgical removal of the sources of timed input did not abolish patterned output, which resembled that during flight, but the frequency of cycling was considerably reduced. Either electrical stimulation of the nerve cord or continuous wind on the head could elicit the pattern. A multiplicity of oscillators in the flight control system was demonstrated. It is suggested that the basic co-ordination of flight is an inherent function of the central nervous system but that peripheral feedback loops influence the frequency of operation and details of pattern.
Repetitive Potentials Following Brief Electric Stimuli in a Hydroid
Authors: Josephson Robert K.
Published: April 2021

Electrical pulses (amplitude −0·05 to −15 mV.; duration 20−120 msec.) have been recorded from the stolon of Cordylophora lacustris following stimulation. These pulses are propagated with an average velocity of 2·7 cm./sec. at 22°C. Brief electric shocks of little more than threshold intensity can evoke bursts of pulses. The number of pulses in a burst increases with stimulus intensity, but the shape and size of individual pulses do not. Repetitive stimulation causes facilitation of both size of single pulses and number of pulses in a burst. Refractory period, if present, is variable. The minimum interval between two pulses is about 200 msec. Mechanical stimulation evokes pulses identical to those evoked by electrical stimulation. The greater the number of pulses recorded in the stolon near a polyp, the greater and faster is the contraction of that polyp. The number of pulses, but not their individual sizes, decreases with increasing distance from the point of stimulation. It is concluded that conduction in the stolon and the electrical pulses are due to nervous activity and that the conducting system is a network having intemeural junctions which sometimes require to be facilitated.
The Movements of Sodium Ions in the Isolated Abdominal Nerve Cord of the Cockroach, Periplaneta Americana
Authors: Treherne J. E.
Published: April 2021

The rate of loss of sodium ions from the abdominal nerve cord of Periplaneta has been determined by following the decline in radioactivity of 24Na-loaded nerve cords isolated in flowing Ringer solution. In all of the experiments there was an initial rapid exponential decline in radioactivity which eventually gave way to a second slower phase. The initial exponential extrusion of sodium ions was appreciably reduced by the presence of potassium cyanide and 2:4-dinitrophenol. The rate of sodium efflux was not reduced in sodium-free solutions, but was decreased in the absence of external potassium ions. It is concluded that sodium ions are extruded from the nerve cord by a metabolically maintained secretory mechanism which is also associated with the uptake of potassium ions.
Osmotic Regulation in the Crab-Eating Frog (Rana Cancrivora)
Authors: Gordon Malcolm S. , Schmidt-Nielsen Knut , Kelly Hamilton M.
Published: April 2021

The osmotic and ionic regulatory abilities of adults of the euryhaline crab-eating frog (Rana cancrivora) have been studied. Adult frogs tolerated environmental salinities as high as 28%,, at 30°C. Tadpoles of this form tolerated salinities as high as 39 % at the same temperature. Changes in body weight of frogs following transfers to different environmental salinities indicate both that the skin of this frog is permeable to water and that these animals do not swallow large volumes of external medium, even in high salinities. Above salinities of about 9 %, plasma Δrises with increasing environmental Δ. Plasma Δ is always higher than environmental Δ. Increases in plasma concentration above fresh-water levels are due partly to increased NaCl concentration (about 40%), partly to increased urea concentration (about 60%). Urea concentrations as high as 0·48 M (2·9%) have been measured. Urinary A parallels plasma Δ, but is always lower than plasma Δ. Considerable quantities of urea are lost via the urine, even though urinary urea levels are below plasma levels. Measurements of short-circuit current indicate that active uptake by the skin of inorganic ions continues in R. cancrivora acclimatized to high salinities. R. cancrivora is no less susceptible to water loss by evaporation from the skin than are other amphibians. In preference experiments R. cancrivora chooses salinities below 18 %, but shows no strong preference for a particular salinity. Similar observations on osmoregulatory mechanisms in a close relative of R. cancrivora, the tiger frog (R. tigerina), show that the latter species is similar to ordinary fresh-water frogs. The striking physiological convergence between R. cancrivora and the elasmobranch fishes is discussed, as are various possible implications of our data regarding nitrogen metabolism in tadpoles and kidney function in adult frogs.
The Swimming Response and Its Pacemaker System in the Anemone Stomphia Coccinea
Authors: Robson Elaine A.
Published: April 2021

The swimming behaviour of the anemone Stomphia coccinea Müller has been described by several authors (Stephenson, 1935; Yentsch & Pierce, 1955; Sund, 1958; Wilson, 1959; Hoyle, 1960; Robson, 1961). Specimens from the region of Puget Sound and the San Juan Islands respond to contact with certain starfish or to suitable electrical stimulation with a characteristic sequence of activity. They retract, re-expand, detach from the substratum, and display a series of abrupt bending movements which may continue for several minutes. An inert recovery period is followed by re-attachment to the substratum. The only species so far known to provoke this response are the starfish Hippasteria spinosa Verrill and Dermasterias imbricata Grube. The world distribution of the genus Hippasteria overlaps to some extent that of Stomphia, which is a widespread North European-Arctic form, but Dermasterias is strictly indigenous to the north-west American coast. Neither starfish seems to affect the anemone in any other way, and the significance of this particular response is difficult to understand.
The Mode of Excretion of Ammonia and Urea in Xenopus Laevis
Authors: Balinsky J. B. , Baldwin E.
Published: April 2021

Eighty-two single determinations of ammonia and urea excretion by Xenopus laevis indicated that the percentage of ammonia varied from 40 to 80%, with a mean value of 62%. Measurements of excretion on successive days after feeding showed that a large amount of ammonia was produced soon after feeding, but that ammonia excretion declined rapidly. Urea excretion, not so high initially, remained more or less constant until the third or fourth day, often exceeding ammonia excretion at that time. Thereafter, it also declined and the excretion of both substances reached a constant starvation level by the fifteenth day. Both ammonia and urea excretion were equally affected by temperature. The Q10’s were near 2 in the range 20–30° C., but greater in the range 10–20° C. At least 86% of ammonia, and 8r % of urea were excreted through the cloaca. The mean 24 hr. urine output of Xenopus at 20° C. was 23·6 ml. per 100 g. body weight. Although the blood ammonia concentration did not appear to be zero, the urine/blood concentration ratio of ammonia was greater than 100. The urine/blood concentration ratio of urea was not significantly different from unity, and constant over a very wide range of concentrations. The above result is interpreted to indicate passive glomerular filtration of urea, and little or no tubular reabsorption of water. It is suggested that ammonia is formed in the kidney, and actively secreted into the glomerular filtrate.
Visco-Elastic Properties of the Tunica Externa of the Swimbladder in Cyprinidae
Authors: Alexander R. McN.
Published: April 2021

The tunica externa of the anterior sac of the swimbladder in Cyprinidae is highly extensible, but a large part of its compliance is associated with retardation times greater than one second. The compliance is only partly reversible. The significance of these properties is discussed in relation to a possible high-pass frequency filter for the Weberian apparatus.
Pharmacological Studies on the Auditory Synapses in A Grasshopper
Authors: Suga Nobuo , Katsuki Yasuji
Published: April 2021

Picrotoxin, eserin, butyrylcholine and acetylcholine bring about increase of impulse discharges on the T large fibre in the cord. Picrotoxin gives conspicuous increase of impulse discharges in the response of the T large fibres to sound, while the excitatory effects of the latter three agents are not so conspicuous. Such effects can be explained on the assumption that picrotoxin inhibits the inhibitory synapses, so that the T large fibre is fully activated by both tympanic nerves, while the latter three agents activate both the excitatory and inhibitory fibres. GABA, γ-aminobutyrylcholine and D-tubocurarine act reversibly as inhibitors of the activity of the T large fibre. The response evoked in the T large fibre may be suppressed by the activities of the inhibitory interneurons activated by the tympanic nerve fibres. After the application of picrotoxin solution to the prothoracic ganglion the threshold of the T large fibre near to a sound source rises while that of the opposite side falls. The inhibitory effect seems to be eliminated by the drug action and the T large fibre is activated by both the ipsilateral and the contralateral excitatory fibres. The increased information about a source of sound which arises from the central inhibitory interaction is disturbed by the application of picrotoxin. The conclusion that the T large fibre has excitatory synapses with the tympanic nerves, and inhibitory synapses with the inhibitory interneurons activated by the tympanic neurons, has been confirmed pharmacologically. The inhibitory interneurons are activated not only by the natural activity of the tympanic nerve, but also by activity elicited electrically with square pulses.
The Cells Founding Aggregation Centres in the Slime Mould Polysphondylium Violaceum
Authors: Shaffer B. M.
Published: April 2021

In an ordinary agar-plate culture of the collective amoeba, or cellular slime mould, Polysphondylium violaceum, the solitary phase ends when compact and increasingly refractive cell clumps develop among the unoriented cells and secrete the chemotactic factor acrasin. Neighbouring cells may crawl towards them, either singly or aggregated in streams, which relay chemotactic and contact guidance centrifugally (Shaffer, 1957a, 1958). As already briefly reported (Shaffer, 1959), aggregation centres may be started by single, differentiated cells ; these have been called founders.
On the Regulation of Respiration in Reptiles
Authors: Nielsen Bodil
Published: April 2021

The chemical regulation of respiration in various species of reptiles has earlier been studied by Siefert (1896), Babak (1914a, b), v. Saalfeld (1934), Vos (1936), Boelaert (1941,1942), Randal, Stullken & Hiestand (1944), and B. Nielsen (1961). A survey of the literature was given by Vos (1936).

The present work deals with the effect of different concentrations of O2 in the inspiratory air on respiration of lizards. Further, the combined action of CO2 and different O2 percentages has been studied. Two species of lizard, Lacerta viridis and Tarentola mauretanica served as experimental animals.
The Response of the Ampullae of Lorenzini of Elasmobranchs to Electrical Stimulation
Authors: Murray R. W.
Published: April 2021

The ampullae of Lorenzini are sensitive to weak electrical stimuli which presumably cause currents to flow along the jelly-filled tubes of the sense organ. Increase of the resting frequency occurs when the tube-opening is made negative to the capsule, and inhibition when the opening is positive, with opposite after-effects in each case. Adaptation is three-quarters complete in about 5 sec. When the stimulus is applied as a voltage gradient in the water overlying the ampullae, the threshold for the most sensitive units is 1 μV./cm., which represents a current along the tube of less than 5 ×10−11 A. When the stimulus is applied as a current directly to the tube opening, the threshold for the most sensitive units is 4 ×10−10 A. Changes in the salinity of the water at the tube opening are also effective, the threshold being about 3 %. Dilution causes excitation, and concentration causes inhibition. The response is not due to the osmotic differences, and so probably results from potentials established at the jelly-water interface.
Studies on Chitin Synthesis in the Desert Locust
Authors: Candy D. J. , Kilby B. A.
Published: April 2021

In vivo studies on 5th instar and adult locusts revealed that chitin formation in thorax, abdomen, hind leg and wing was greatest during the first few days after moulting. Wing extracts were used for in vitro experiments, and evidence was obtained for the presence of the following enzymes: hexokinase, phosphohexose isomerase, glutamine transaminase, phosphoglucosamine transacetylase, acetyl coenzyme-A synthetase, phosphoacetylglucosamine mutase and uridine diphosphate N-acetyl-glucosamine pyrophosphorylase. The results are discussed, and a tentative scheme is presented for the biosynthesis of chitin in the wing of Schistocerca gregaria.
Evidence For the Intraocular Discrimination of Vertically And Horizontally Polarized Light by Octopus
Authors: Moody M. F.
Published: April 2021

Four groups of octopuses (6 animals in all) were trained to discriminate between vertically and horizontally plane-polarized light. Two different sources of polarized light were used: a torch, and a disk of polaroid backed by white plastic. Half the octopuses were trained using the former source, and half using the latter. With each polarized light source, discrimination could be based on a reflexion or scattering pattern, but the extra-ocular cues would be different for the two sources. After training, each octopus was shown, without reward or punishment, the polarized light source with which it was not trained. The aggregate score shows efficient transfer, and three of the four groups showed a significant preference for the new source when the plane of polarization was the same as that which they were trained to attack. It is concluded that the discrimination is not based on extra-ocular patterns, i.e. that the analysis of the polarized light occurs within the octopus’s eye.
Proprioceptive Reflexes In The Legs Of Carcinus Maenas (L.)
Authors: Bush B. M. H.
Published: April 2021

The reflex responses of the motor and inhibitor axons of the four distal muscles in the thoracic limbs of Carcinus maenas to passive movements of the dactylus and propus in the same limb are described.

Passive ‘opening’ (extension of the dactylus), both at steady speeds and in a stepwise manner, elicits a strong reflex discharge in the inhibitor axon specific to the opener muscle and in the ‘slow’ motor axon to the closer muscle. Passive ‘stretching’ (re-duction of the propus) evokes similar responses in the specific inhibitor axon of the stretcher muscle and in the ‘slow’ motor axon of the antagonistic bender muscle. Rapid opening (or stretching), in a fresh preparation, also excites the ‘fast’ motor axon of the closer (or bender) muscle. During passive closing or bending (propus pro-duction), the motor axon which innervates both opener and stretcher muscles discharges. No activity was observed in any of the branches of the ‘common inhibitor’. The frequencies of discharge of the two ‘slow’ motor axons and the two inhibitor axons during opening and stretching do not vary with displacement at constant speeds, at least within the range of speeds used (10–5oo° /sec.). Frequencies of 1060 impulses per second are common in these axons. The response frequency of the opener-stretcher motor axon during closing, however, and to a lesser extent during bending, increases with displacement at the lower speeds (10–100° /sec.). For all these axons, but in particular for the ‘slow’ motor axons and also the nhibitor axons, the frequency of discharge increases with speed of movement. The reflex responses to dactylus movement vary with the position of the propus, whether stretched, median or bent, in a way which indicates that the separate specific inhibitor axons to the opener and stretcher muscles do make independent action of these muscles possible, despite the fact that both muscles are supplied by one and the same motor axon. The reflex responses to opening and closing can be separately abolished by cutting the requisite one of the two groups of afferent fibres leaving the ‘FD-organ’. Elimination of the receptor organ ‘CP1’ abolishes all reflex response to stretching, and ‘CP2’ elimination abolishes the reflex responses to bending.

These proprioceptive motor and inhibitor ‘resistance reflexes’ are discussed in relation to control and co-ordination of the propo-dactylopodite (PD) and carpopropodite (CP) joints, and to the types of afferent fibres involved.
The Composition of the Seminal Plasma of Balanus Balanus
Authors: Barnes H.
Published: April 2021

Studies of a small number of mammalian species, a few common fishes, and to a lesser extent some echinoderms, have provided much of the available data on the biochemistry of semen: the Crustacea have hardly been investigated. The present work is part of a study of the physiology and biochemistry of reproduction in the Cirripedia, particularly in relation to the ecology of this group.
Visco-Elastic Properties of the Body-Wall of Sea Anemones
Authors: Alexander R. McN.
Published: April 2021

Creep of narcotized Metridium and Calliactis body-wall at constant tensile stress has been studied quantitatively. It was found to be reversible, and seemed to be controlled by the mesogloea. Its course could be represented by equations of the form where the retardation time τ was about 1 hr. for Metridium and many hours for Calliactis. The results can most simply be explained in terms of a cross-linked and a noncross-linked polymeric system, acting in parallel. An explanation in terms of a lattice of inextensible fibres is not satisfactory. The results are discussed in relation to the behaviour of the animals.
The Imaginal Ecdysis of Blowflies. Observations On the Hydrostatic Mechanisms Involved in Digging and Expansion
Authors: Cottrell C. B.
Published: April 2021

The digging movements and the expansion process of newly emerged blowflies involve the production of positive internal pressures. During digging newly emerged blowflies produce a characteristic cycle of internal hydrostatic pressure changes which in Sarcophaga reach, at their maximum, 6 – 12 cm. of mercury. During expansion, two different pressure phenomena are detectable. First, there is a gradual rise and fall in the basic haemolymph pressure which reaches a maximum (of 6 cm. of mercury in Calliphora and 9-5 cm. in Sarcophaga) a few minutes after full wing extension and then falls to atmospheric pressure in the next 20 min. Secondly, superimposed on the basic rise there is a series of brief rhythmic pressure pulses which gradually decline and then cease about the time of full wing extension. Evidence obtained by blocking the proboscis or denervating the abdominal muscles of newly emerged flies indicates that the gradual rise in haemolymph pressure is attributable to air-swallowing and the pressure pulses to the performance of ‘muscular efforts’ (i.e. simultaneous contractions of both the ptilinal and abdominal muscles). The wing expansion of flies which have had their abdominal muscles denervated is abnormal, suggesting that at least some of these muscles play a part in bringing about normal expansion. After full wing extension has occurred (or after an operated fly has reached a point in the air-pumping cycle at which expansion would have occurred) ‘muscular efforts’ cease and digging movements can no longer be stimulated. This cessation is not due to the hardening of the cuticle and it is suggested that it is due to loss of the ability to excite the muscles concerned. Within a few days of emergence many (perhaps all) of the muscles concerned in the production of digging movements and ‘muscular efforts’ degenerate. Immediately after expansion flies eliminate large quantities of fluid via the anus. This appears to be correlated with the change from a combined hydrostatic and external skeleton to a hard exoskeleton.
Training, Speed and Stamina in Trout
Authors: Bainbridge Richard
Published: April 2021

A number of trout (Salmo irideus) were kept continuously swimming for a period of 12 months in experimental tanks in which the water was made to rotate at a mean speed of 25 cm./sec. These fish become available for study in the ‘Fish Wheel’ and measurements were made of the maximum speed they sustained for periods of swimming of different duration. For bursts of swimming of up to 20 sec. duration the mean accomplishments of these fish were identical with those of the unexercised trout studied previously. Considerable variability was found amongst the specimens tested and the best of the present exercised fish were appreciably better than the best of the previous unexercised ones. The biggest improvement was 36% at the 10 sec. period of swimming; the mean percentage improvement for all periods was 11%. Some specimens were found better at swimming for short periods and others at swimming for longer. In the absence of comparable figures for the earlier fish, the measurements of cruising speeds sustained for periods up to hr. were compared with other figures in the literature and found to be about half some of these for wild fish. The implications of the results are considered and two interpretations stressed. First, it is assumed that there is a real identity of accomplishment for short periods of swimming, values being determined perhaps solely by gross mass of muscle; while for longer periods of swimming differences dependent upon respiratory rate etc. may well occur. Secondly, for such longer periods the discrepancies reported here may well be accounted for by differing degrees of stimulus and behavioural response under varied experimental conditions.
Olfactory and Visual Learning in the Red-Eared Terrapin, Pseudemys Scripta Elegans (Wied.)
Authors: Boycott B. B. , Guillery R. W.
Published: April 2021

Terrapins have been trained to olfactory and visual stimuli. The animals are able to discriminate meat alone from meat with amyl acetate, vanillin, eucalyptus or a black figure. The olfactory discrimination is learned less readily than the visual discrimination under comparable conditions. Destruction of the olfactory nerves shows that amyl acetate and vanillin are olfactory stimuli. The discrimination to amyl acetate is lost for about 6 weeks after destruction of more than half of the olfactory nerves, and the postoperative feeding behaviour is temporarily altered. Olfactory lesions do not disturb the discrimination or feeding behaviour of animals trained to a visual situation. Animals with large olfactory lesions show recovery of the amyl acetate discrimination after 6 and more weeks of postoperative training. It remains to be determined whether the recovery is due to a taste or general chemical discrimination or to surviving olfactory fibres. The method should prove suitable for studying the olfactory and perhaps other functions of the chelonian forebrain.
Temperature Acclimation and the Nervous System in Fish
Authors: Roots Betty I. , Prosser C. Ladd
Published: April 2021

The cold-blocking temperature of a simple reflex in goldfish (Carassius auratus) and bluegills (Lepomis macrochirus) was 10,° 5° and 1° C. respectively for fish acclimated to 35°, 25°, and 15° C. The response of 5° C. fish was not blocked at 1° C. Similar results were obtained with goldfish in which the spinal cord had been cut immediately posterior to the medulla. Conditioned inhibition of respiration in goldfish acclimatized to 30°, 25°, 15° and 5° C. was blocked at 20°, 15°, 10° and 1° C. respectively. A conditioned avoidance response of goldfish acclimated to 25° C. was blocked at 15° C. The cruising speed of green sunfish (Lepomis cyanellus) is related to the ambient temperature, and the upper and lower temperatures at which they do not swim are related to their thermal history. Peripheral nerves of bluegills and green sunfish acclimated to 25° C. continued to conduct impulses at temperatures below 5° C. It is concluded that the site of cold-block is in the central nervous system.
Structural Changes in the Suprarenal Gland of the Mouse During Pregnancy
Authors: Tamura Y.
Published: April 2021

In the mouse there is no correlation between body weight, body length, and the size of the suprarenal gland. The size of this gland is not always indicative of its functional activity. Unilateral ovariotomy has no effect on the functional activity of the suprarenal gland. During pregnancy the gland becomes reduced in area. The hypertrophy of the zona glomerulosa occurs during pregnancy and at the 17 mm. stage it reaches the maximal secretory activity. Observations on the hypertrophy of the zona fasciculata are in agreement with those of other workers. This hypertrophy may be caused by either an enlargement of cells or an increase of their number. In the latter case it is due to the appearance of a new zone, zona gestationis. This zone reaches its maximal activity at about 17 mm., and at this stage so-called siderophile bodies (secretory granules) are visible in great numbers. Zona reticularis degenerates rapidly at an early period (before formation of placenta) of pregnancy, and at the middle of pregnancy the site of this zone is occupied by vacuoles. The hypertrophy of the medulla occurs at the closing period of pregnancy. Mitotic figures were observed in every zone except zona reticularis at an early period of pregnancy. The secretory activity of this gland increases slowly and reaches its maximum at about the third quarter of pregnancy, followed by a partial decrease during the last quarter.
Studies on the Sex-Ratio and Related Phenomena
Authors: Parkes A. S.
Published: April 2021

1872 normal mice bred during November 1922-October 1925 had an average litter-size of 6·18, and a male percentage of 51·7 ± ·77, both of which figures are lower than the corresponding ones found for 1921–2. The annual variation in the sex-ratio is, however, not very appreciable, the figures for the four years running 54·2 ± 1·04, 50·4 ± 3·22,52·2 ± I-18, 51·4 ± 1·09. The average size of litter during these four periods ranged from 6·65 to 5·93. Considerable seasonal variation in both fertility and sex-ratio occurred, the highest figures being fertility 6·46 and male percentage 55·9 ± 1·83 in the October-December quarter, and the lowest being fertility 5·82 and male percentage 48·2 ± 1·46 in the April-June period. Litter-size appeared to be uncorrelated with any sort of definite variation in the sex-ratio. Recent work on the mouse is discussed.
The Relation of Combined Nitrogen to the Physiological Activity of Azotobacter
Authors: Zoond Alexander
Published: April 2021

Increasing concentrations of nitrate, amino acid and peptone decreased proportionally the amount of atmospheric nitrogen fixed in culture solutions oi Azotobacter. Increasing concentrations of sterile, unheated, plant extracts increased the amount of atmospheric nitrogen fixed up to a maximum limit, after which the fixation gradually decreased with further additions. The addition of sterile, unheated plant extracts to pure solution cultures greatly stimulated the multiplication of Azotobacter. Very heavy applications of plant material to soil effectively checked the assimilation of nitrogen, and at the same time greatly increased the concentration of nitrogen in the soil solution. It is suggested that Azotobacter always prefers to derive its nitrogen from a combined source but that plant tissues contain certain unknown “essential food substances” which stimulate the growth of the organism to such an extent that the supply of available nitrogen derived from moderate applications of vegetable material is soon exhausted, and the organism then assimilates nitrogen from the air.
A Chemical Study of the Manoilov Test for the Differentiation of the Sexes
Authors: Falk K. George , Lorberblatt I.
Published: April 2021

The chemical differentiation between the sexes of substances derived from various animal and plant products, which is shown by the Manoilov reaction, has aroused considerable interest. An attempt to throw light on the chemical changes involved in this reaction, together with a simplification of the test, will be described in this paper. The test as described by Manoilov (1) consists essentially of successive additions to an aqueous or 60 per cent, alcoholic extract of the substance in question of a definite number of drops of solutions of the following substances : papain, dahlia (or methyl green), potassium permanganate, hydrochloric acid, and thiosinamine. If the test is successfully carried out, the preparation from the female gives a pink to red or violet solution, while that from the male remains colourless. The directions for carrying out the tests include definite pauses after the addition of some of the reagents, and precautions against agitating the mixtures until after the addition of the first four.
Lactic Acid in Fish and Crustacean Muscle
Authors: Ritchie A. D.
Published: April 2021

Lactic acid is produced in the muscles of several species of fish examined and of lobsters under conditions in which it is known to be produced in other animals already studied. The quantity present is less than in the skeletal muscles of the land-living vertebrates. The highest concentration found (in haddock) is comparable to that found in mammalian heart muscle ; the lowest (in hake) is comparable to that found in reptilian smooth muscle. There is a remarkable difference between these two fish of the same family; greater than any difference observed between the skeletal muscles of land-living vertebrates.
Experiments on Artificial Cryptorchidism and Ligature of the Vas Deferens in Mammals
Authors: Cunningham J. T.
Published: April 2021

It has long been known that as a rule the abdominal or undescended testis in man and other Mammals is sterile, and that normal and complete spermatogenesis does not occur in it. Dr F. A. E. Crew (2) suggested in 1922 that the cause of this infertility was the higher temperature of the abdominal cavity compared with that of the scrotal cavity. Mr Carl R. Moore ((5) 1922) of the Hull Zoological Laboratories, University of Chicago, made the same suggestion in the same year and has since published evidence in support of it (Moore, C. R.(6) 1924). He has shown that experimental cryptorchidism produces a condition of the testis essentially similar to natural cryptorchidism. The testis may be made to remain in the body cavity in Rodents, which have a wide and open inguinal canal, by separating the testis from the scrotal wall, pushing it into the abdomen, and closing the inguinal canal with a purse-string suture; by fastening the caput epididymis to the abdominal wall with a suture; or by everting the scrotal sac into the abdomen and securing its walls to the body-wall. In the adult guinea-pig 7 days’ retention was sufficient to produce degeneration of the various cells in the different stages of spermatogenesis.
Chemotaxis of Rabbit Spermatozoa
Authors: Dickmann Z.
Published: April 2021

The aim of the study was to determine whether rabbit eggs’attract’ homologous spermatozoa in vivo.

Preliminary experiments showed that, in vitro, rabbit spermatozoa readily and irreversibly attach to the zonae of rat eggs.

When rat and rabbit eggs were transferred into oviducts of previously mated rabbits, a significantly larger number of spermatozoa collected within the rabbit eggs than on the zonae of the rat eggs. Since the experiments were designed so that rat and rabbit eggs had equal chances of sustaining collisions with rabbit spermatozoa, the great preponderance of spermatozoa in the rabbit eggs suggests that the latter exert a chemotactic influence on rabbit spermatozoa.