bluuebunny/crossref_metadata_2025_split huggingface dataset:
Basic limb kinematics of small therian mammals
Authors: Fischer Martin S. , Schilling Nadja , Schmidt Manuela , Haarhaus Dieter , Witte Hartmut 
Published: April 2021

SUMMARYA comparative study of quantitative kinematic data of fore- and hindlimb movements of eight different mammalian species leads to the recognition of basic principles in the locomotion of small therians. The description of kinematics comprises fore- and hindlimb movements as well as sagittal spine movements including displacement patterns of limb segments, their contribution to step length, and joint movements. The comparison of the contributions of different segments to step length clearly shows the proximal parts (scapula,femur) to produce more than half of the propulsive movement of the whole limb at symmetrical gaits. Basically, a three-segmented limb with zigzag configuration of segments is mainly displaced at the scapular pivot or hip joint, both of which have the same vertical distance to the ground. Two segments operate in matched motion during retraction of the limb. While kinematic parameters of forelimbs are independent of speed and gait (with the scapula as the dominant element), fundamental changes occur in hindlimb kinematics with the change from symmetrical to in-phase gaits. Forward motion of the hindlimbs is now mainly due to sagittal lumbar spine movements contributing to half of the step length. Kinematics of small therian mammals are independent of their systematic position, their natural habitat, and also of specific anatomical dispositions (e.g. reduction of fingers, toes, or clavicle). In contrast, the possession of a tail influences `pelvic movements'.
The Time of Action of the Gene Antennaless and its Effect on the Development of the Cephalic Complex of Drosophila Melanogaster
Authors: Begg Michael , Sang James H. 
Published: April 2021

ABSTRACT
A. The development of the antenna buds of the mutant antennaless of D. melanogaster has been examined and it is shown that: Prior to about 70 hr., no histological difference is detectable as between normal and abnormal anlagen. Normal antenna buds continue to grow exponentially after 70 hr. ; abnormal buds scarcely grow at all. The abnormal bud is also distinguished from wild type by its failure to segment. Both normal (ant. +) and antennaless (ant. −) frontal sacs are everted normally in the pupa. B. The period during which the course of development of antennaless buds of the same genotype could be modified by specific nutritional substances was also determined. It is shown that media containing a high concentration of dextrose will induce a lowered exhibition. By transferring larvae from normal media to media of high dextrose content, it is found that the course of development of the antenna bud cannot be modified after about the 80th hr. of larval life.
These experiments suggest that the effective period of the gene is relatively short and is probably not more than 12 hr. for each individual larva. This period corresponds to the T.E.P., butis not necessarily identical with ‘the time of action of the gene’.
Oxygen Consumption of Prepupae of Drosophila Melanogaster Meigen, in Relation to the Surface Area of the Puparium
Authors: Ellenby C. 
Published: April 2021

ABSTRACT
A method is described by means of which the surface area of puparia of Drosophila melanogaster may be measured. Measurement of almost 200 puparia showed that the relationship between surface area, per mg., and body weight could best be expressed in the form Of the equation S = 7·7049 – 2·1099X, where S = sur-face area, sq. mm. per mg. wet weight, for prepupae of mean wet weight X mg. As the standard error of estimate, ±0·117, is equal to only 2·2% of the mean surface area per mg., the surface area can be accurately estimated from the wet weight. The prepupal oxygen consumption, per mg. wet weight, is shown to decrease steadily with increasing body weight ; with an increase in mean wet weight from 0·847 to 1·700 mg., the oxygen consumption, per mg., decreases by about 50%. Utilizing the above regression equation, the surface area of prepupae of known oxygen consumption was estimated and thus the oxygen consumption per sq. mm. of body surface. These values show no significant variation with increasing body weight, so that it can be concluded that the oxygen consumption of prepupae of D. melanogaster is proportional to the surface area.
Some Observations on The Physiology and Pharmacology of the Nerve Endings in the Crop and Gizzard of the Earthworm, With Special Reference To The Effects of Cooling
Authors: Ambache N. , Dixon A. ST J. , Wright E. A. 
Published: April 2021

ABSTRACT
The use of the crop and gizzard of the earthworm as a convenient smooth-muscle preparation was first suggested by Mines (1907). The pharmacological properties of this preparation have recently been described by Wu (1939). His experiments and Millott’s (1943) have shown that the digestive tract of the earthworm, including the crop and gizzard, is reciprocally innervated. The nerve fibres concerned are cholinergic in the augmenter and adrenergic in the inhibitory nerves.
The Cuticular Lipoids of Insects
Authors: Beament J. W. L. 
Published: April 2021

ABSTRACT
The ability of insects to withstand desiccation was shown by Kühnelt (1928) to be due to the epicuticular layer of the cuticle. This outermost part was found to be highly resistant to strong acids and was shown, by chemical tests, to contain fatty acids and cholesterol type molecules. Wigglesworth (1933) described a complex fatty or waxy substance in the upper layers of the cuticle which he called ‘cuticulin’ ; Pryor (1940) found that this lipoid is entirely confined to the epicuticular layer, suggesting that it is used to impregnate a tanned protein. Lipoid material has also been extracted from the exuviae of the silkworm Bombyx mori (Bergmann, 1938). Bergmann found that hot alkali merely fused the epicuticle into oily droplets suggesting that saponification was taking place. The extract so obtained was a brown waxy substance, forming about 4% of the total weight of the cuticle, and it consisted of paraffins, saturated aliphatic acids and esters. A more detailed study of the waxes of certain insects specialising in wax formation has been given by Chibnail, Piper, Pollard, Williams & Sahai (1934b) ; Chibnall, Latner, Williams & Ayre (1934a), and Blount, Chibnall & el Mangouri (1937). All these substances were complicated mixtures of alcohols, acids, paraffins and esters with chain length of the order of C30.
Hurst (1941) has suggested that the asymmetry of the insect cuticle is regulated by the ‘outer free lipoid’. He postulates a cuticle surface in the form of a lipoprotein mosaic.
It is the object of this study to investigate the distribution and properties of these lipoid materials, to obtain evidence of the structure of the epicuticle by comparison of in vitro phenomena with those of living insect cuticle, and to indicate the function of lipoids in resisting the action of certain insecticides.
Studies on the Organizer Problem in Pelmatohydra Oligactis: I. The Induction Potency of the Implants and the Nature of the Induced Hydranth
Authors: Yao T. 
Published: April 2021

ABSTRACT
The existence of a physiological gradient in Hydra has been repeatedly demonstrated by a number of investigators, and the hypostome, which is supposed to be the region of highest metabolic activity, has generally been regarded as the organization centre of the animal. Earlier transplantation experiments (Browne, 1909; Rand, Bovard and Minnich, 1926; Mutz, 1930) indicated that when a piece of hypostome is grafted, it can act as an organizer and induce a new hydranth. Although these are all well-known facts, the underlying mechanism in the induction process remains obscure. The present work is the first step in an attempted physiological analysis of the problem, with special reference to the induction potency of implants derived from different body levels, and to the nature of the induced hydranth.
Studies on the Organizer Problem in Pelmatohydra Oligactis: II. The Effect of Some Respiratory Inhibitors and Stimulants and of Oxygen Deficiency on the Induction Potency of the Hypostome
Authors: Yao T. 
Published: April 2021

ABSTRACT
In a previous communication (Yao, 1945(a)) it has been shown that only the material of the hypostome, when used as implant, has the properties of an organizer; such a graft is able to induce a new hydranth, in which the hypostome is developed from the implant itself, while the rest, including tentacles and body proper, is derived from the host. Supposing the induction process to be evoked by some active substance present in the organizer, this active substance, as well as the initial act of induction, might be modified by those agents which inhibit or stimulate respiration. The present paper deals with the effect of certain respiratory inhibiting and stimulating agents on the induction ability of the hypostome. The effect of oxygen deficiency on induction will also be described.
The details of the method used will not be described, since these were essentially similar to those given in the former paper.
Studies On the Organizer Problem in Pelmatohydra Oligactis
Authors: Li H. P. , Yao T. 
Published: April 2021

ABSTRACT
Determination of the hypostome occurs very early in the development of a bud (our stage 1) in Pelmatohydra oligactis. The mode of induction by a developing hypostome (type II) is different from that by an adult hypostome (type I). In the former case, an implant always induces a long tube-like outgrowth before any tentacle rudiment becomes visible. In the latter case,.simultaneous induction of tentacles and body takes place. Frequently, tentacle rudiments appear before visible differentiation of the body. Type II induction is characteristic of developing hypostomes from some phase of stage 1 up to a stage at which the bud possesses short, but non-motile tentacles (our stage 4). As soon as the detachment of a young polyp from the parent occurs, there is a sudden change in the mode of induction, from type II to type I. Possible explanations of the course of differentiation in the hypostome and of the transition between the two types of induction are suggested.
The Sickling Phenomenon and its Bearing on the Problem of Red Cell Structure
Authors: Ponder Eric 
Published: April 2021

ABSTRACT
In considering the various forms of disk-sphere transformation which mammalian red cells undergo, reference has repeatedly been made to the ideas of Norris, Gough, Teitel-Bernard and others who have suggested that the discoidal form of the cell is the result of an equilibrium between two sets of forces, one expansive, and the other (which includes surface tension) conducing to contraction of the surface (Norris, 1882; Gough, 1924; Teitel-Bernard, 1932; Ponder, 1929, 1934, 1936, 1937, 1939, 1941, 1942 a, b, c;Furchgott, 1940a, 19406; Furchgott & Ponder, 1940, 1941). When the disk changes into the sphere, we are dealing with a diminution or disappearance of the ‘expansive force’ which is probably due to a modification or even a destruction of a surface ultrastructure, and in the absence of anything to oppose it, the tension at the cell-fluid interface determines that the cell takes up the spherical form in which the surface is a minimum for the volume. As will be seen below, other forces are probably operative in the same direction. A re-establishment of the ultrastructure, with the ‘expansive forces’ inherent in its molecular arrangement, leads to the transformation of the sphere into the original disk, and the various conditions under which this reversal can be brought about have already been described. We have now to consider a situation in which the ‘expansive forces’ are so great, or the forces resisting them so small, that the red cell assumes a series of shapes which are characterized by extension, just as the spherical form is characterized by contraction.
The Mechanism of Locomotion in Gastropod Molluscs
Authors: Lissmann H. W. 
Published: April 2021

ABSTRACT
As is the case in all terrestrial animals, the progression of a snail or other gastropod depends on the exercise by the animal of an adequate force directed posteriorly against the ground ; in an animal moving horizontally and at constant speed, this force overcomes the frictional resistance encountered by the parts which are gliding forwards. The movements of the pedal surface of some gastropods have been discussed in a previous paper (Lissmann, 1945). The experiments described below were designed to correlate these movements with the forces set up during locomotion. The salient point which appears to be established is that during progression the foot exhibits (i) areas of forward motion, coinciding with phases of longitudinal muscular contraction, followed by extension ; (ii) areas at rest, which remain essentially elongated. However, the state of the muscles is no indication of the tensions they may set up within the body, nor of the propulsive force they may exert; it is by no means obvious how the external forces are produced, or how they lead to progression.
The Fermentation of Carbohydrates in the Rumen of the Sheep
Authors: Elsden S. R. 
Published: April 2021

ABSTRACT
Acetic, propionic and butyric acids are the main volatile fatty acids in the rumen of the sheep. Acetic acid accounts for 55 –75 % of the total. Cellulose, glucose and lactic acid are rapidly fermented in vitro by rumen contents with the production of acetic, propionic and butyric acids. Propionic acid is the major component in all cases : very little if any butyric acid is formed from cellulose. The in vitro fermentation of glucose closely resembles the in vivo. The in vitro fermentation of dried grass yields the same three acids, but with acetic acid predominating. Members of the genus Propionibacterium have been isolated from the rumen, and evidence is presented to show that these organisms are responsible for the production of the propionic acid found in the rumen. The dietary history of the animal is shown to influence the rate at which glucose is fermented in the rumen, and the composition of the rumen microflora.
The Dietetics of the Clothes Moth, Tineola Bisselliella Hum.
Authors: Fraenkel G. , Blewett M. 
Published: April 2021

ABSTRACT
Much attention has been paid in the past to the peculiar mechanism of keratin digestion which enables the clothes moth to infest woollen materials (Schulz, 1925 ; Lipderstnøm-Lang & Duspiva, 1935 ; Duspiva, 1936), but little is known about its general food requirements. It is known that the larvae will not grow on clean wool (Titschak, 1922; Crowell & McCay, 1937) and that damage to clothing is generally restricted to parts soiled by dirt and sweat. On the other hand, Tineola has been bred in the laboratory on various foods in the absence of keratin, and there are no indications that keratin is a necessary constituent of the food (Titschak, 1922). A study of some aspects of the nutrition of Tineola has been made by Crowell & McCay (1937) and will be discussed below.
The Dietetics of the Caterpillars of Three Ephestia Species, E. Kuehniella, E. Elutella, and E. Cautella, and of a Closely Related Species, Plodia Interpunctella
Authors: Fraenkel G. , Blewett M. 
Published: April 2021

ABSTRACT
In the course of a previous analysis of the dietetics of several insects found on dried foods (Fraenkel & Blewett, 1943 a), it was discovered that the larva of Ephestia kuehniella, which normally feeds on flour, grew badly, unlike the larvae of several beetles, on artificial diets consisting of casein, glucose, cholesterol and salts and the moths failed to emerge. Later the investigation was extended to E. elutella, which is known to infest such divergent materials as grain, tobacco, cacao beans and dried fruit. E. elutella grew fairly well on artificial diets, but again the moths failed to emerge from the pupae. Here the work was held up until it was discovered that Ephestia required, for successful growth and metamorphosis, fat-soluble factors which can be supplied with wheat-germ oil (Fraenkel & Blewett, 1945). In the present paper, which mainly deals with the requirements for carbohydrates, sterols and vitamins of the B complex, most of the diets described contain wheat-germ oil. An analysis of the factors concerned in wheat-germ oil will be given in the following paper.
Linoleic Acid, Vitamin E and Other Fat-Soluble Substances in the Nutrition Of Certain Insects, Ephestia Kuehniella, E. Elutella, E. Cautella and Plodia Interpunctella (Lep.)
Authors: Fraenkel G. , Blewett M. 
Published: April 2021

ABSTRACT
In a previous publication (Fraenkel & Blewett, 1943) it has been shown that a number of insects which normally live on wholemeal flour or other cereal products grow badly or not at all on flour thoroughly extracted with chloroform unless a sterol, e.g. cholesterol, is added to the diet. For several beetle larvae the diet becomes optimal upon addition of a pure sterol, but for the caterpillars of a moth, Ephestia kuehmella, wheat-germ oil has a much better effect than a sterol. Using artificial diets, consisting of glucose, casein, yeast and cholesterol, it was found that E. kuehmella grew well in the presence of wheat-germ oil and badly without it. Subsequently it emerged (Fraenkel & Blewett, 1946b) that the closely related species E. elutella grew fairly well on similar diets in the absence of wheat-germ oil and pupated normally, but the adults invariably failed to emerge from the pupae. With wheat-germ oil, growth was fast and emergence normal. Analysis of the factors in wheat-germ oil which are required by the moths of the genus Ephestia is the subject of the present paper. Some of the results have already been shortly reported (Fraenkel & Blewett, 1945).
The Influence of Peripheral Connexion on the Diameter of Regenerating Nerve Fibres
Authors: Sanders F. K. , Young J. Z. 
Published: April 2021

ABSTRACT
Stretches of regenerating rabbit’s nerve in which no connexion with the periphery is allowed contain numerous and small nerve fibres. Both cutaneous sensory and motor nerve fibres become large when allowed to reach their endorgans, but the motor fibres attain greater diameters than the cutaneous sensory fibres. Motor fibres regenerating without opportunity of reaching muscle fibres become little if any larger than sensory fibres when both are unable to reach their end-organs. It is, therefore, probable that the peripheral connexion is of great importance in determining fibre diameter. The fibres of the central stump of a nerve regenerating unconnected with the periphery remain small and have relatively very thick myelin sheaths. The diameter of nerve fibres regenerated in the region below a crushed point on a nerve is not influenced by the length of nerve to be regenerated distally. Increase of diameter and medullation proceeds centrifugally from a lesion, more distant points showing a lesser degree of maturation at any given time. Fibres regenerated in a grafted piece of posterior tibial nerve were only slightly smaller than those in a grafted piece of peroneal nerve. Connexion with the periphery is, therefore, able to produce an increase in fibre diameter which overrides any constriction of fibre growth produced by the slightly smaller Schwann tubes.
Studies on Temperature Regulation
Authors: Kirk R. L. , Hogben Lancelot 
Published: April 2021

ABSTRACT
The upper thermal death-point of the slow worm (Anguis fragilis) is significantly above that of either the toad (Bufo bufo) or the frog (Rana temporaria). That of the toad differs only slightly from that of the frog. In response to external variation with respect to temperature and humidity, the body temperature of the toad behaves in a manner similar to that of the frog, being considerably below that of the air at low humidities, though appreciably above that of the wet-bulb thermometer. It is concluded that the toad loses water as freely as the frog. The body temperature of the slow worm and that of the alligator (A. mississippiensis) differs only slightly from that of the air under all conditions of sustained air temperature and humidity. The body temperature reaction of the alligator is more sluggish than that of the slow worm, pre-sumably owing to the higher thermal capacity of the animal. The significance of these results in relation to the evolution of the terrestrial vertebrates is discussed. It is suggested that homoeothermic stocks could arise only from reptiles of relatively small size, and that large body size would militate against survival during periods of low mean external temperature.
Fertilizing Capacity of Spermatozoa Following Cold Treatment of the Scrotal Testes of Rabbits
Authors: Chang Min Chueh 
Published: April 2021

ABSTRACT
The fertility or sterility of a male depends on several factors, among which are the chemical constituents of the semen, the number, morphological integrity, motility, metabolism and viability of the spermatozoa. These factors, of course, are interrelated in effecting fertility or probability of fertilization.
The Function of the Insect Ocellus
Authors: Parry D. A. 
Published: April 2021

ABSTRACT
Little light is thrown on the function of the insect ocellus by blinding experiments or by a study of its distribution within the class. The ocellus cannot, on optical grounds, receive an image, but can only be affected by changes in intensity of illumination. The ocellar nerves are characterized by a small number of constituent fibres, and by the large diameter of the latter. When the ocellus is darkened, the electrical response in the nerve consists of a decrease in potential near the ocellus, relative to the cut end of the nerve. No impulses were detected in the ocellar nerve. When the ocellus is darkened, or one of the lateral ocellar nerves cut, there is a continuous discharge of nerve impulses in the commissures. This ceased as soon as the ocellus was reilluminated. It is suggested that darkening the ocellus causes depolarization which spreads down the ocellar nerve and depolarizes a ganglion in the brain, thereby inducing the discharge of impulses down the commissures. It is pointed out that this might facilitate reflexes at lower centres, and so accelerate the animal’s response to shadows.
A Metal Micro-Respirometer of the Barcroft Type Suitable for Small Insects and Other Animals
Authors: Crisp D. J. , Thorpe W. H. 
Published: April 2021

ABSTRACT
A Barcroft-type micro-respirometer, made of metal, is described. It is particularly suitable for rapid determination of the respiratory rate of small insects or other animals which can be maintained in air during the course of the experiment. It is especially convenient for experiments in which it is necessary to employ different gas mixtures. Sensitivity is approximately 100 times that of the standard glass Barcroft apparatus. The possible sources of error are considered.
The Function of Haemoglobin in Tanytarsus (Chironomidae)
Authors: Walshe Barbara M. 
Published: April 2021

ABSTRACT
Eighty years ago Lankester(1867) identified spectroscopically the red blood pigment of the larvae of Chironomus plumosus as haemoglobin. Subsequently (1873) he correlated its presence with the fact that they inhabit stagnant ponds and putrescent mud where the amount of accessible oxygen must often be small. Since then it has been generally assumed that their haemoglobin enables the larvae to live in surroundings deficient in oxygen, and experimental evidence for this has lately been supplied by Harnisch (1936) and by Ewer (1942). These workers compared the metabolism of normal larvae with that of larvae whose haemoglobin had been made functionless by conversion to carboxyhaemoglobin. They found that the pigment was only used as an oxygen carrier at low pressures of oxygen; it is used to the greatest extent in water which is 22 % saturated with air at 17° C. Ewer also made a series of measurements of the oxygen content of the pond from which her larvae were obtained and found oxygen concentrations corresponding to 32 % air saturation or less for periods of at least 16 consecutive hours. Thus it may be assumed that in nature the haemo-globin of the species with which Ewer worked is of functional value.