bluuebunny/crossref_metadata_2025 huggingface dataset:
Body Size in Relation to Oxygen Consumption and Pleopod Beat in Ligia Oceanica L.
Authors: Ellenby C.
Published: April 2021

Male Ligia oceánica were used in an investigation of the relationship of body size to rate of oxygen consumption and pleopod beat. Animals varied in weight from 0·04 to 1·03 g. and from 0·95 to 3·1 cm. in length. Body shape does not change significantly over the size range, for length and breadth both increase at the same rate, and pleopod dimensions bear a constant relation to body length. Specific gravity also is constant, for the relation of body weight to the cube of body length shows no trend with increasing size. Oxygen consumption per gram decreases with increasing size and is proporitional to the –0·274 power of body weight. Total oxygen consumption is therefore proportional to the 0·726 power of body weight; but this value does not differ significantly from two-thirds. As shape is constant, surface area is proportional to the square of a linear dimension. It is shown that oxygen consumption per unit of length2 is constant over the size range. Although body length was measured far less accurately than body weight it is shown that it assesses ‘body size’ more accurately. Rate of pleopod beat was measured at 15 and 25° C. ; it decreases with the size of the animal. At 15° C. time per beat varies as the 0°66 power of body length, and at 25° C. as the 0·59 power; neither of these values differs significantly from 0·5. Despite the fact that pleopod movement is heavily damped, the rate therefore varies like that of a pendulum. Theworkof Fox (1936–9) and Fox et al. (1937a) on the rate of oxygen consumption of animals from cold and warmer seas and from different habitats is considered. It is suggested that many of their comparisons are invalidated by differences in body size of the animals concerned, and that, in relation to environment, no basis, theoretical or experimental, has been established for a distinction between ‘non-locomotory’ and ‘activity’ metabolism.
The Experimental Investigation of Navigation in Homing Pigeons
Authors: Matthews G. V. T.
Published: April 2021

A series of field experiments were carried out in 1948, 1949 and 1950 to establish the facts of navigation in homing pigeons and to begin an investigation of the factors involved. A total of 158 pigeons aged 3–4 months were used in twenty-three tests involving a total of 902 sorties, all but 153 being by birds released singly. Three indices of performance were used, giving the degree of uncertainty on release, the accuracy of the initial course and the success in regaining home. It was shown that pigeons are able to fly in one particular direction when released at a series of unknown points at increasing distances north-north-west of the loft. The following of experienced birds or the use of distant landmarks were excluded. Overcast skies had a disorientating effect on these training-line releases. It was shown that if the sun was being used to determine the training direction, it was not by any simple fixed-angle relationship to home. The birds could take large Changes of azimuth into account, and at least ignore changes in altitude, without having witnessed the sun’s movement. Releases were also carried out in unknown areas at right angles to or in the opposite direction from the training line. Some of the birds flew in the training direction and homed badly. But a good proportion showed a definite orientation in the home direction and returned with fair success. This true navigational ability was shown to vary widely amongst individual pigeons. The proportion of able navigators also varied in different stocks. There is little evidence of a continuous maturation of the faculty with experience and none with age. There are suggestions that it is not connected with a learning process. The established facts require more than a random or systematic search for landmarks, or the use of atmospheric clues as an explanation. It is shown by experiment that pigeons do not depend on the interpretation of the earth’s magnetic field to be able to orientate in the training or in the home direction. Other experiments show that a displacement recording mechanism based on time/acceleration measurements is extremely unlikely. The only positive lead obtained is a definite suggestion that overcast had a disorientating effect on pigeons released off the training line. This requires detailed confirmation. The simplest way in which a pigeon could obtain a rough estimate of its position relative to home by measuring the sun’s co-ordinates is considered. Attempts to follow individual pigeons or groups of three by aircraft have so far been unsuccessful. An automatic flight recorder has been used successfully to some extent.
Fragmentation of Red Cell Ghosts in Relation to the Problem of Red Cell Structure
Authors: Ponder Eric
Published: April 2021

An indication as to whether a body is a solid or a hollow shell can be obtained by dividing it into a number of fragments and seeing whether the total volume of the fragments is substantially the same as, or smaller than, the initial volume of the body. If the former is the case, the indication is that the body is a solid, and if the latter is the case, the indication is that the body is a hollow shell. This test can be applied to the human red cell and to the human red cell ghost by heating them to temperatures between 49 and 54° C., a treatment which produces fragmentation into large enough fragments to be counted and to be thrown down by centrifuging, always provided that the cells and ghosts are discoidal (Ponder 1950a).
The Phases of the Oestrous Cycle in the Adult White Rat
Authors: Mandl Anita M.
Published: April 2021

Since the classical description of Long & Evans (1922) of the cyclical changes which take place in the vaginal smear of the rat, vaginal smea histology has always been used as an index of ovarian activity. It is also used as a test of the potency of various steroid hormones (e.g. Emmens, 1939), and as a means of correlating cyclical ovarian changes with those in the accessory reproductive organs and other endocrine organs (e.g. Astwood, 1939; Bourne & Zuckerman, 1940). Numerous studies have been made of the cytology of shed vaginal cells by means of trichrome stains (e.g. Hartman, 1944), and various modifications have been suggested for the original technique proposed for taking vaginal smears.

Under normal laboratory conditions it is inconvenient to take smears more than once a day. At the same time it is known that frequent smearing may itself induce cornification (Astwood, 1939). In view of the need to time various operative procedures accurately in relation to the phases of the oestrous cycle, the following study was undertaken (a) to determine the individual variability of cycle length in our own colony of rats and (b) to compare our data with those reported for other laboratories.
Cyclical Changes in the Vaginal Smear of Adult Ovariectomized Rats
Authors: Mandl Anita M.
Published: April 2021

According to Kostitch & Telébakovitch (1929), cyclical changes continue to occur in the vaginal smear of rats after removal of both ovaries. The following study was undertaken because of the important bearing this observation has on an understanding of the rhythmical changes which occur in the accessory reproductive organs, and because no reports of its confirmation have appeared in the literature.
Fermentation in the Rumen of the Sheep
Authors: Gray F. V. , Pilgrim A. F. , Rodda H. J. , Weller R. A.
Published: April 2021

Early workers in the field of ruminant physiology were aware of the presence of formic, acetic, propionic and butyric acids (Tappeiner, 1884), and of smaller amounts of higher members of the saturated fatty acid series (Mangold, 1934), in the rumen fluid. Accurate data were not reported, however, until recently, when partition chromatography became available as an analytical procedure for the analysis of complex mixtures of these acids (Elsden, 1946). By this means acetic, propionic and butyric acids were established as the main components of the mixture of fatty acids in the rumen fluid of sheep and of other ruminants. The butyric acid fraction, however, was thought to contain some higher acid or acids, and it was claimed that formic acid was not a component of the mixture (Elsden, 1945). Using modifications of the older partition and distillation methods Gray (1946) found similar proportions of the three main acids, but also stated that small amounts of formic acid were normally present.
The Physiology of Sea-Urchin Spermatozoa
Authors: Rothschild Lord , Cleland K. W.
Published: April 2021

Sea-urchin spermatozoa (Echinus esculentus) contain 4·14 mg. phospholipid per 1010 spermatozoa (arithmetic mean of five replicated experiments, standard error 0·06). This amount of phospholipid is about 5·5 % of the dry weight of a seaurchin spermatozoon. The seminal plasma contains very small quantities of phospholipid, about 20 mg./100 ml., less than one-thirtieth the content of fresh semen. When sea-urchin semen was diluted 1:20 with sea water and the spermatozoa incubated aerobically for some 7 hr. at 20° C., phospholipid disappeared. The average disappearance per 1010 spermatozoa was 19·0% (S.E. 2·4), while the corresponding oxygen uptake of the same sperm suspensions during the same time was 1·450 ml. (S.E. o·118). The oxidation of glycogen or glycogen-like material was found to be entirely insufficient to account for the observed oxygen consumption. Assuming that the combustion of 1 mg. phospholipid requires 1·6 ml. oxygen, the ratio of the theoretical oxygen uptake (associated with the observed disappearance of phospholipid) to the observed oxygen uptake was 0·86 (S.E. 0·04). It is concluded that the oxidative breakdown of phospholipid, located in the middle-piece, is the principal source of the energy required for movement.
The Effect of Pituitrin on Fluid Distribution in Bufo Regularis Reuss
Authors: Ewer R. F.
Published: April 2021

A new response to injection of posterior pituitary extract in Bufo regularis Reuss is described. If the animals are kept out of water after injection there is a significant increase in the fluid held in the lymph spaces, and fluid is resorbed from the bladder.

The accumulation of lymph is not accompanied by any significant decrease in the water content of the tissues.

The possible biological significance of the response is indicated.
Retinomotor and Diurnal Rhythm in Crustaceans
Authors: Henkes H. E.
Published: April 2021

The demonstration of the existence of a diurnal rhythm in the migration of the pigment in Leander, Portunus, Pachygrapsus and Carcinus justifies the supposition that in many species of Crustaceans such a rhythm exists in the retinomotor changes of one of the pigment systems.

These periodic changes in the position of the pigment, despite the exclusion of all light, correspond with sunrise and sunset. Even if the animal is kept in complete darkness during the hours of daytime, the pigment systems concerned exhibit a partial migration towards the position of light-adaptation; when the night returns the pigment system resumes its maximum state of dark-adaptation and is found in the same position as in the previous night.

The measurement of the size of the pseudo-pupil is of value in proving, in vivo, the existence of a diurnal rhythm in the iris pigment. The existence of a periodic change in the luminosity of the living eye when examined with the ophthalmoscope is of no value in ascertaining the occurrence of a diurnal rhythm in the retinal pigment or in the tapetum.

In C. maenas it was possible to demonstrate a periodic variation in metabolism, in terms of a diurnal rhythm in the production of carbon dioxide. This production was about 30 % smaller during the day than during the night.

The diurnal retinomotor rhythm may depend on a periodic hypoxaemia of the cell systems concerned.
The Response Of A Sense Organ To A Harmonic Stimulus
Authors: Pringle J. W. S. , Wilson V. J.
Published: April 2021

The response is described of the tactile ending in a femoral spine of the leg of Periplaneta to a harmonic (sinusoidal) mechanical stimulus of low frequency. The peak frequency of impulses in the sensory nerve precedes the maximum tension of the stimulus. This result is shown to be a corollary of the adaptation shown by the sensory response to a transient stimulus. The concept of the ‘transfer function’ is discussed in relation to neurophysiology. Its value is explained as a means of describing the dynamic properties of component parts of the nervous system when the objective is an understanding of the functioning of the complete rçflex arc.
The Co-Ordination of Insect Movements
Authors: Hughes G. M.
Published: April 2021

Though walking forms part of many insect behaviour patterns, the mechanism of insect walking has received relatively little attention in recent years. As a preliminary to a later investigation of neuromuscular co-ordination in insects, the normal pattern of walking movements in the cockroach and other insects has been studied. The results obtained and an account of the functional anatomy of the insect leg are given in this paper. The forces involved have not been measured, but a preliminary analysis of the mechanics of walking has been made with the help of ‘stills’ from cinematographic films. The use of cinematography greatly facilitates such an investigation.
The Metabolism of the Sea-Urchin Egg
Authors: Cleland K. W. , Rothschild Lord
Published: April 2021

The eggs of Echinus esculentus contain about 1·5% glycogen and 20% lipid (dry weight). Whole eggs produce lactic acid under anaerobic conditions, the maximum rate of production being 0·15 μl. lactate/hr./mg. eggs (dry weight) at 20° C. Lactic acid production is inhibited by fluoride, iodoacetate and phenylmercuric nitrate. The supernatant from centrifuged egg homogenates prepared in M/50-phos-phate buffer, pH 7° 5, (‘extract’), was found to be a satisfactory glycolytic enzyme preparation. The production of lactic and pyruvic acid by such extracts is greatly stimulated by the addition of glycogen, cozymase and adenosine triphosphate, (‘complemented extracts’). Complemented extracts glycolyse glucose and fructose with greater facility than glycogen or starch. With glucose or fructose as substrate, the rate of formation of lactate and pyruvate may reach 1° 7μd./hr./mg. eggs (dry weight) at 20° C. Complemented extract glycolysis is inhibited by fluoride, iodoacetate, phenylmercuric nitrate and phloridzin. Active extract glycolysis occurs with the following glycolytic intermediates as substrates: glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, hexose diphosphate and phosphoglyceric acid. It is concluded that the sea-urchin egg (E. esculentus) possesses a typical glycolytic system, whose activity is comparable with that found in other invertebrate tissues.
The Responses of the Honey-Bee to Repellent Chemicals
Authors: Jones G. D. Glynne
Published: April 2021

This paper is concerned, first, with the development of a technique for maintaining a population of honey-bees (Apis mellifera) under conditions where it does not have access to naturally secreted nectar, but is allowed free flying conditions, and secondly with the application of this technique to the study of the chemotropic responses of bees to repellent chemicals. Two types of stimuli are considered: (a) The effect of the addition of the repellent to an attractant (sucrose solution). (b) The effect of the repellent in the vapour phase in the vicinity of the attractant. In (a) techniques are described for measuring the response with the standard attractant alternating in time and space. Data collected on the rejection thresholds of acetic acid and phenol showed that whilst little variation in response occurred at the higher concentrations of the repellent, the offering of the standard attractant alternating in time as opposed to space greatly modified the response. Tests were carried out to determine the reproducibility of the results. It would appear that for a repellent chemical to be capable of effectively reducing the number of visits to a source of food, it must be capable of irritating the common chemical senses of the bee.
Differential Effects of Direct Current on Insect Ganglia
Authors: Hughes G. M.
Published: April 2021

The passage of small direct currents transversely through the intact thoracic ganglia of the cockroach affects the flexor-extensor balance of the legs in such a way that the leg on the negative side flexes while that on the positive side extends. With longitudinal stimulation, ascending currents bring about flexion of both legs and descending currents encourage extension. Preparations in which only a single nerve is attached to the ganglion do not show these differential effects when the polarizing current is applied between ganglion and nerve. The negative electrode excites when it is on the ganglion, and the positive inhibits irrespective of whether the nerve supplies flexor or extensor muscles. Intermittent discharge of impulses may occur before the spontaneous discharge is completely inhibited when the positive electrode is on the ganglion. At least three different responses have been recorded from some of the leg muscles under these conditions and they are excited in a ‘functional order’. That is, the ‘slow’ response accompanied by a tonic contraction occurs at a lower threshold than the ‘faster ‘twitch systems. A hypothesis is put forward to interpret these apparently contradictory results. It is suggested that the polarizing current influences the gradient of potential along oriented intemuncials which are stimulated at low threshold in the intact preparation. These intemuncials connect regions of the neuropile containing flexor and extensor synaptic endings.
The Morphology of Bull Spermatozoa
Authors: Hancock J. L.
Published: April 2021

The microscopical features of living and dead bull spermatozoa are described. The findings are discussed in. relation to previous observations on the structure of the head of the bull spermatozoon. The cytoplasmic cap of the living cell possesses a characteristic structure which is identical with that which has been ascribed to the acrosome. The altered structure of the cap of the dead spermatozoon is identical with that previously described as characteristic of a second cap-like structure, the galea capitis. It is concluded that the terms galea capitis and acrosome have been used to describe the same structure. It is suggested that the cytoplasmic cap of the bull spermatozoon should be called the acrosome.
On The Existence of Regionally Specific Evocators
Authors: Waddington C. H.
Published: April 2021

Spemann (1931) pointed out that different parts of the organization centre in the amphibian gastrula have different properties, in that the more anterior regions tend, other things being equal, to induce the formation of more anterior parts of the neural system, such as the brain and associated sense organs, while the posterior parts tend to induce the neural tube of the trunk or tail. Living organizer grafts frequently become more or less fused with the induced tissues, so that if a definite organ is finally produced, the individuation of it involves both inducing and induced materials, the former playing the leading part. When dead pieces of the organizer are used as grafts, they cannot be similarly incorporated, and any individuation which may occur must have arisen entirely within the reacting material. It might still be possible, however, that the dead organizer was able to specify which region of the embryonic axis was represented by the induction, and thus guide the individuating processes. It has been known, however, since the work of Holtfreter (1934a) that organizer material after being killed loses its power to induce mesodermal tissues. It evocates only the appearance of neural tissue. If this becomes individuated into any recognizable organ, it is usually found to represent some region of the brain or eye, while the organs resulting from secondary inductive effects of the brain (e.g. nose or ear) are also frequently found. It is certainly not impossible to find a dead material which can induce more posterior regions of the axis, since Holtfreter (1934b), Chuang (1938) and Toivonen (1949, 1950) have demonstrated such activity on the part of dead adult tissues or extracts from them. No phenomena of the kind have, however, been described as resulting from the action of dead parts of the gastrula organizer, and it has been usual to consider that this material loses its trunk-inducing powers, and becomes solely a specific head-organizer, when killed.
The Thoracic Gland in Rhodnius Prolixus (Hemiptera) and Its Role in Moulting
Authors: Wigglesworth V. B.
Published: April 2021

It is now generally accepted that the periodic phases of growth in insects, which terminate in the deposition of a new cuticle and the casting of the old skin, are initiated by chemical changes in the circulating blood. For these growth-stimulating factors the general term ‘moulting hormone’ has been used (Wigglesworth, 1934), although it has been realized for some time that this hormone ‘might ultimately prove to be made up of more than one constituent’ (Wigglesworth, 1940) and that a succession of secretions might in fact be concerned (Williams, 1947; Wigglesworth, 1949).
Anal and Oral Intake of Water by Crustacea
Authors: Fox H. Munro
Published: April 2021

In small and transparent Crustacea water can be seen with a microscope to be pumped through the anus into the intestine. The pumping is done by antiperistaltic contractions of rectal muscles, the movements being repeated rhythmically at intervals of one to a few seconds. They may continue almost without interruption or may occur for short periods with intervals of rest. In some genera the entrance of water by successive gulps is quite clear; this is the case, for example, in Triops, Sida, Diaphanosoma, Leptodora, Mysis, Sphaeroma, Ligia, Corophium. In other genera, such as Artemia, Chirocephalus, Limnadia and Bythotrephes, it is not obvious that water enters, although waves of contraction are seen to pass inwards over the rectal musculature. In Daphnia the gulps cannot be seen when the antiperistalsis is slow, but they are clearly visible when it is rapid.
The Toxicity of Potassium Cyanide to Trout
Authors: Herbert D. W. M. , Merkens J. C.
Published: April 2021

An apparatus is described in which fifty yearling rainbow trout can be tested in a stream of water at a constant temperature and containing a constant concentration of poison. Exposure to cyanide causes the fish to lose equilibrium control and to turn over. Resistance is measured as survival time, by which is meant the time taken to overturn the fish. When the experimental temperature is higher than that of the water in the stock aquaria the resistance of yearling rainbow trout to cyanide increases with increasing time of acclimatization to the temperature of the experiment. Small yearling rainbow trout tend to be more resistant to cyanide than larger fish of the same age. The distribution of the logarithms of the survival times of the test fish in cyanide solutions, though not precisely normal, is sufficiently close to a normal distribution to justify the application of standard statistical techniques. Neither the distribution of the survival times nor that of the reciprocals of the times provide a suitable basis. At 17·5°C. in the range 2·5 parts to 0·07 part CN per million it has been found that (i) mean log survival time decreases linearly with log concentration, (ii) the variance of log survival time is approximately constant, and (iii) the distribution of log survival time is approximately normal. At higher concentrations these conclusions are not true. The resistance of an individual rainbow trout to cyanide is mainly determined by inherent properties which persist for at least three weeks.
Studies in the Development of the Rainbow Trout (Salmo Irideus)
Authors: Smith Sydney
Published: April 2021

The total carbohydrate content of the trout egg and embryo has been measured. The carbohydrate content falls during three periods: (i) the establishment of the blood circulation; (ii) hatching; and (iii) the onset of starvation. The fats extracted by a non-polar solvent (carbon tetrachloride) from egg, embryo and yolk samples show no significant catabolism before hatching. These fats are considered to be glyceride-fats. In the yolk-sac stage such fats are only consumed between the 63rd and 80th days of incubation at 10° C. The combustion of phosphatide fat deduced from the heat-production figures is conspicuous during the early stages of yolk-sac absorption, and may be correlated with the consumption of protein as an energy source. These findings may be correlated with histological changes in the yolk-sac wall, and in the relation between yolk-sac and liver. The concept of a sequence of energy sources in ontogenesis is discussed.
The Relation Between the Development of the Secondary Sex Characters and the Structure of the Testis in the Teleost Xiphophorus Helleri Heckel
Authors: van Oordt G. J.
Published: April 2021

The aim of this study was to trace the relation between the development of the secondary sex characters and the structure of the testis in the Cyprinodont fish Xiphophorus Helleri Heckel.

The secondary sex characters of both male and female are described. Only the development of the most conspicuous sex characters, viz., the gonopod, i.e., the anal fin transformed into an intromittent organ, and the sword, i.e., the enormously elongated ventral part of the caudal fin is considered in relation to spermatogenesis. These secondary sex characters are formed in the young male and are present throughout further life.

The testis of the young immature male in which the secondary sex characters have not yet developed, contains only a small number of primary spermatogonia besides many tubules derived from the peritoneal epithelium. Simultaneously with the beginning of the transformation of the anal fin into an intromittent organ spermatogenesis starts, and at the same time the epithelium of these tubules transforms into germ cells, being situated in small cysts. When the spermatogenesis has reached the formation of spermatocytes the elongation of the caudal fin has generally started.

The testis of the male in which the gonopod is fully developed, but of which the sword has not reached its maximum length, contains all stages of spermatogenesis up to spermatophores, but the latter are still found in the cysts. In the fully mature male the spermatophores are lying in great numbers in the sperm ducts. The question as to the seat of the secretion of the sex hormones in the sex gland is discussed briefly. It appears that it is improbable that there is in the gonad a group of cells, being the specific source of the sex hormones.
Studies in the Parthenogenesis and Sexuality of Saw-Flies (Tenthredinidæ)
Authors: Peacock A. D.
Published: April 2021

After four years’ experimental work on parthenogenesis in saw-flies, the writer proposes to recount certain of the results in a series of papers under the above general title, and in doing so is desirous of designating as the first study of the series a former contribution to this Journal (Peacock, 1924). Hence, although this is the first time the general title has been used, the following paper is really the second study.
The Energy-Sources in Ontogenesis
Authors: Needham Joseph
Published: April 2021

The class of compounds used by the developing embryo for the extraction of energy from its environment raises one of the most important questions which arises in the biochemical analysis of embryological phenomena. Does it behave exactly like the adult animal from the very beginning, or does it pass through phases each of which are, in this respect, different? To be able to compile a chart showing the compounds which the developing embryo utilises as energy-sources throughout its ontogenesis, to know the times and periods in which one supersedes another, would be to possess clues of enormous importance for the unravelling of every event in embryonic metabolism.
A Retardation in the Rate of Metamorphosis of the Colorado Axolotl by Injection of Anterior Hypophyseal Fluid
Authors: Smith Philip E.
Published: April 2021

In 1922, the author with I. P. Smith, reported in a brief abstract that the intraperitoneal injection of fresh anterior hypophyseal fluid slowed decisively the environmentally-produced metamorphosis of the Colorado axolotl (A. tigrinum). In a second abstract (Smith and Smith, 1923), it was shown that the injection of fresh anterior lobe fluid also diminished the metamorphic stimulus afforded by thyroid administration.

Since the appearance of these abstracts, Hogben (1923) has reported opposite effects, namely, that the intraperitoneal injection of a commercial anterior lobe extract caused a rapid metamorphosis of the normal unoperated Mexican axolotl (A. tigrinum) and even of thyroidectomized individuals of this species. Spaul (1924 a), using the same commercial preparation as Hogben, confirmed the results of this investigator in the unoperated axolotl and found in addition that the metamorphic rate of the tadpole was greatly accelerated. More recently, Spaul (1924 b) tested some twelve commercial anterior pituitary preparations for the presence or absence of a principle which would metamorphose the axolotl. He found that only two of these produced what he terms “the appropriate response,” namely, metamorphosis ; the other ten gave negative results. He assumed that these ten preparations contained some inhibitory substance which prevented the principle inducing metamorphosis from expressing itself. The opposite assumption might seem as reasonable, namely, that the ten preparations, because of their great numerical majority, gave “the appropriate response,” and that the two preparations inducing metamorphosis contained some unusual substance giving an atypical response.
The Influence of Temperature and Moisture on the Uptake and Loss of Water in the Eggs of Gryllulus Commodus Walker (Orthoptera—Gryllidae)
Authors: Browning T. O.
Published: April 2021

Eggs placed on moist plaster took up water slowly at first and then more rapidly until they had reached their maximum water content. The duration of the initial period of slow water uptake was dependent upon temperature, becoming shorter as the temperature was raised. Similarly the duration of the period of rapid water uptake decreased with temperature. No special water-absorbing structure was identified in the eggs of Gryllulus. The rate of water loss from newly laid eggs was more rapid at higher than at lower temperatures under conditions of constant atmospheric saturation deficiency. Newly laid eggs died if they lost more than about 20 % of their original weight. At 90 % relative humidity, eggs which had completed water uptake lost water at a higher rate at high than at lower temperatures. The rate of water loss was also dependent on the stage of development of the embryo. Eggs that had completed diapause development at 13° C. and had completed water uptake were able to lose about 30 % of their weight through desiccation without being killed, but many of those that lost more than about 20 % of their weight failed to develop when replaced on moist plaster; it seemed as if they had entered a state resembling diapause.
Some Aspects of the Mechanics of Mammalian Locomotion
Authors: Barclay Oliver R.
Published: April 2021

Gray (1944) analysed the pattern of muscular activity in mammals, but there is practically no published experimental data which could be used to check this analysis. Elftman (1938, 1939a, b, c) working with man, and Manter (1938), working with the cat, developed various types of apparatus for recording the forces exerted on the ground, but Manter’s published results give adequate data for the calculation of patterns of muscular activity for a single stride only. Following similar work on the Amphibia (Barclay, 1946), an attempt was therefore made to record the forces exerted on the ground by various mammals and to obtain synchronous photographs of the limb positions with a view to calculating the activity in the main groups of limb muscles.
Potassium Ions and Insect Nerve Muscle
Authors: Hoyle G.
Published: April 2021

The ionic composition of the blood of insects, unlike that of vertebrates and most other invertebrates, shows a wide range of values, especially in regard to the physiologically important ions of sodium and potassium. Preparations are described in which the effect of potassium on the active nerve and muscle properties of Locusta migratoria have been investigated. The nerve axons are depolarized by high concentrations of potassium ions in the same way as vertebrate and crustacean axons. The whole nervous system is surrounded by a sheath which is an effective barrier to the diffusion of potassium ions. The muscle-fibre membrane is also depolarized by high concentrations of potassium ions in a similar way to muscle-fibre membranes of other animals which have been previously investigated. The tracheolated membranes surrounding the muscles, and the close arrangement of the constituent fibres, delay the passage of potassium ions through the muscles. It is predicted that the mechanical properties of the muscles of a herbivorous insect will be found to be subject to fairly marked changes if the blood potassium rises or falls to an appreciable extent.
Physiological and Pharmacological Observations on Muscle Receptor Organs of the Crayfish, Cambarus Clarkii Girard
Authors: Wiersma C. A. G. , Furshpan E. , Florey E.
Published: April 2021

The muscle organs recently described by Alexandrowicz in the tails of Homarus vulgaris and Palinurus vulgaris, have also been found to be present in the crayfish (Cambarus clarkii) and the rock lobster (Panulirus interruptus), and a study of them in the latter animals has been undertaken. The position of these units within the abdomen of the crayfish differs from their position in the lobsters. In almost all other respects, however, there is substantial correspondence in their morphological features. The organs are easily isolated and it is found that stretching them is accompanied by a discharge in one of the axons supplying each unit. There are two receptors in each half-segment of the abdomen and their responses show considerable differences. One has a very low threshold and can be sustained in continuous discharge for several hours. The threshold of the other is high and this receptor usually adapts completely to the most extreme stretch in less than 1 min. A phenomenon which is designated ‘over-stretch’ has been observed. All-but-maximal stretch causes a reversible cessation of the previous high-frequency discharge. The discharge can be restored by slight release of tension, but even if the tension producing ‘over-stretch’ is maintained for a sufficient length of time, discharge will resume spontaneously. The possibility that this spontaneous return is due to a slow rupture of the receptor tissues is not excluded. The muscular regions of the organs are not necessary for their sensory function. It has been possible to show that stimulation of the nerve trunk can induce contraction in these muscular regions and that such contraction results in discharge in the sensory axons. The unit with the low stretch-threshold responds to low concentrations of ACh and this effect is potentiated by eserine. In concentrations above 10−6 before eserinization and above 10−8 after eserinization, ACh consistently initiates rhythmic responses in relaxed units and augments the discharge from those under tension. ACh affects the sensory mechanism directly; the muscular regions of the organs are not necessary for its action. Atropine inhibits the ACh excitation, but only increases the response of the receptors to stretch. Eserine, except in high concentrations, has no consistent effect on the normal stretch discharge. The possibility that ACh has a role in the normal receptor mechanism is discussed, but the question is left open.
The Release of Phosphate From the Electric Organ of Torpedo
Authors: Fatt P. , Woodin A. M.
Published: April 2021

A technique is described for perfusing the isolated electric organ of Torpedo. With a constant perfusion pressure the admission of acetylcholine is found to cause an appreciable reduction in the rate of flow. Orthophosphate, sulphate, glutamate and aspartate have been identified as anions which pass from the electric organ into the fluid perfusing through it. With a perfusion rate of 4-8 ml./min., repetitive stimulation of the nerve caused an increase in the rate of phosphate released from the organ. The phosphate concentration in the venous effluent rose to a maximum of about 180% of the resting level, and stimulation to exhaustion resulted in the release of an additional 10 μmol. of phosphate. Perfusion of an electric organ by acetylcholine elicited a slowly developing response amounting at the most to about 1 mA. when passed into a low resistance and lasting for about 7 min. The possible role of intra-electroplate anions in generating the discharge of the Torpedo electric organ is discussed. The additional phosphate released from the organ on stimulation accounts for only 1 % of the charge which crosses the active electroplate membrane.
Polarized Light Studies Of The Cornea
Authors: Stanworth A. , Naylor E. J.
Published: April 2021

The importance of the cornea and the peculiar circumstances of its transparency have stimulated research for many years, but despite its apparent suitability there have not been any adequate quantitative investigations by means of polarized light. We shall show in this and the following paper that this technique, besides yielding results which throw light on the ultrastructure and fibre arrangement of the tissue (Naylor, 1952), also affords a means of assessing changes in the intra-ocular pressure of the intact eye by quantitative measurements of the photo-elastic properties of the cornea.
Polarized Light Studies of the Cornea
Authors: Stanworth A.
Published: April 2021

A method is described of measuring the birefringence of the intact cornea using light reflected obliquely from its posterior surface. The value obtained (0-0037) is in reasonable agreement with the results obtained by using transmitted light and from corneal sections. The change in birefringence with an increase in intraocular pressure from 10 to 40 mm. Hg is about 7 % of this. The change in birefringence was also assessed by changes in the density of the photographic image of the reflected light from the surface, and this affords a possible way in which the intraocular pressure could be measured in the human subject without touching the eye.
On Certain Properties of the Flight Muscles of the Orthoptera
Authors: Ewer D. W. , Ripley S. H.
Published: April 2021

The physiological characteristics of the wing musculature of insects have been but little investigated. Solf (1931) has given a brief account of the responses of the dorsal longitudinal muscles of Gryllotalpa vulgaris (L.) to direct electrical stimulation. A more extensive study has been made by Heidermanns (1931) of the responses to direct electrical stimulation of the wing muscles of Aeschna coerulea (Strom). The latter author found that at a stimulation frequency comparable with that of the normal wing beat of the dragonfly, the muscles were in a partial tetanus. He concluded that this was their normal condition in flight. More recently, Pringle (1949) has found that potentials recorded from the wing muscles of Calliphora occur at a lower frequency than the wing movements. He concluded that these flight muscles were highly specialized, and that impulses from the nervous system activated rather than excited the muscles. Similar observations have been made by Roeder (1950, 1951) on Vespa, Lucilia and Tabanus. In Periplaneta and the moth Agrotis, however, Roeder recorded a single muscle potential for each cycle of the wing beat. He concludes that in the latter two species the wing-beat frequency was such as to permit a conventional neuromuscular system to move the wings.
The Effect of Washing on the Motility and Metabolism of Ram, Bull and Rabbit Spermatozoa
Authors: White I. G.
Published: April 2021

The technique of washing tissues and cells has been widely practised in the field of enzyme chemistry, for removing natural substrates and for demonstrating important components of enzyme systems.
Relation of the Rate of Antennal Movement in Daphnia to the Number of Eggs Carried: In the Brood Pouch
Authors: Fox H. Munro , Mitchell Yvonne
Published: April 2021

The number of parthenogenetic eggs and embryos carried in the brood pouch of Daphnia varies greatly. In some natural populations of the pond-dwelling species females carry many eggs,* in other populations they have few. We have found in nature a female of D. magna Straus carrying 95 eggs, and de Kerhervé (1926) had one in culture with 105 eggs, whilst, on the other hand, in some natural populations of the same species no more than one, two or three eggs are borne. Two potent causal factors influencing egg number are the quantity of food and the aeration of the water : up to a certain maximum level of feeding, the number of eggs produced is proportional to the quantity of food eaten (Ingle, Wood & Banta, 1937; Fox, Hardcastle & Dresel, 1949), and below a certain degree of aeration of the water the egg number falls off proportionately to the amount of dissolved oxygen (Fox, Gilchrist & Phear, 1951). In addition, fewer eggs are produced at a high temperature (MacArthur & Baillie, 1929; Fox & Phear, 1953). Other factors influencing the egg number are the nature of the food (Lefèvre, 1942) and the age of the mother (Anderson, Lumer & Zupancic, 1937).
Further Studies on Ionic Regulation in Marine Invertebrates
Authors: Robertson James D.
Published: April 2021

The blood or coelomic fluid has been analysed in sixteen marine invertebrates to determine the amount of ionic regulation. Little regulation is shown by Holothuria and the bivalves Ostrea and Mytilus except in potassium. The bivalves accumulate potassium (up to 135% of the concentration in sea water), and Mytilus galloprovincialis accumulates sulphate (to 120%), an unusual feature. The nudibranch Archidoris accumulates potassium (128%), calcium (132%) and magnesium (107%), while the sipunculid Phascolosoma has lower magnesium (69%) and sulphate (91 %) but higher sodium (104%). The cephalopod Sepia regulates all its ions except magnesium, range of values (expressed as percentage of concentration in dialysed plasma) being Na 92-94%, K 193-223%, Ca 84-97%, Mg 97-100%, Cl 105-106%, SO4 17-29%. Protein averages 109 g./l. in the three specimens analysed. Fluid from the renal sacs contains high concentrations of NH4+ ions, in two specimens 146 and 59 m.equiv./kg. water, and differs from a plasma ultrafiltrate in the concentration of all other ions. The vitreous humour in the cephalopod eye is a clear protein-free fluid, isosmotic with the plasma within 1% but having ionic concentrations markedly different from those of a plasma ultrafiltrate or dialysate. In Sepia, Loligo and Eledone magnesium may be only 10-20% and sodium over 115% of the concentrations in a dialysate of the plasma. In one specimen of Sepia the aqueous fluid in front of the lens largely resembled sea water except for lower concentrations of magnesium and sulphate. Among the decapod and stomatopod Crustacea regulation of all ions exists, ranges in eight species being Na 97-111%, K 120-156%, Ca 84-137%, Mg 32-99%, Cl 96-103%, SO4 53-135%. Species of Portunus and Eupagurus show more regulation than Dromia and the spider-crabs Maia and Hyas. Regulation in the stomatopod Squilla resembles that in the portunid family. In the grapsoid crab Pachygrapsus each ion in the plasma is maintained below its equilibrium value: Na 94%, K 95%, Ca 92%, Mg 24%, Cl 87%, SO4 46%; total ions 1·163 g. ions/kg. water compared with 1·353 in sea water. In sixteen crustaceans an inverse relationship exists between the degree of activity and the magnesium content of the blood: the more active ones have low values of magnesium.
Osmotic Relations in Molluscan Contractile Tissues
Authors: Pilgrim R. L. C.
Published: April 2021

The bivalve molluscs include marine, estuarine and fresh-water forms, and they yield good heart and cilia preparations. Although the ecological distribution and powers of osmoregulation of several species have been studied in detail, little is known about the effects of osmotic pressure on the functioning of their tissues. At the suggestion of Dr G. P. Wells, the writer undertook a comparative investigation of the effects of osmotic pressure variations on the hearts and cilia of lamelli-branchs. The three species used were chosen because they are readily obtained and kept in London, where the work was done, and they represent a wide ecological range. The experiments on hearts are described in the following pages. Those on cilia will form the subject of a second paper.
A Polarized Light Analysis of the Human Red Cell Ghost
Authors: Mitchison J. M.
Published: April 2021

A new method is described for measuring the thickness of thin spherical birefringent membranes. It consists of measuring a curve of retardation against radial distance at the edge of the membrane, and comparing this curve with other curves calculated from theory for membranes of known thickness. Diffraction is taken into account. This method shows that the wet thickness of the human red cell ghost in glycerol is about A good agreement with the experimental results would be given by a model membrane consisting of a weakly birefringent layer 0·5μ thick surrounded by a strongly birefringent layer 40 A. thick. It is suggested that the thick layer is a 2 % protein gel, and that the thin layer is a bimolecular layer of lipids. The birefringence indicates that there is radial molecular and tangential micellar orientation in the protein gel. This can be explained by an arrangement of the protein chains in looped bundles. On the basis of these results a new model is put forward for the structure of the red cell membrane, and some of its implications are discussed.
The Lipids of Sea-Urchin Semen
Authors: Cardin A. , Meara M. L.
Published: April 2021

The constitution of the lipid material present in semen has received very scant attention. No reference appears in the literature relating to the component fatty acids of semen lipids, although the presence of neutral fat, free fatty acid, free and combined sterols, phosphatides, and sphingomyelin has been reported by Woodhouse (1928) in the sex organs of domestic animals and of humans ; likewise, Sakaki (1913) reported the presence of phosphatides and sphingomyelin in the human placenta; Sano (1922) reported the presence of these phosphatides in the fresh ‘sperm freed from membranes and connective tissue ‘of the cod, porgy and salmon. More recently, Lardy & Phillips (1941), in an investigation of the sources of energy for bull spermatozoa, showed that the phospholipid content of both semen and spermatozoa decreased when incubation was carried out in the absence of extracellular substrates but in the presence of oxygen.