bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Function of Haemoglobin in Chironomus After Oxygen Lack
Authors: Walshe Barbara M. 
Published: April 2021

ABSTRACT
When Chironomus plumosus larvae receive aerated water after a period of anaerobiosis their oxygen consumption increases at once to a value well above the normal. This initial increase lasts for about 10 min. at 17° C., after which the oxygen consumption falls but continues to be slightly above normal for 1 hr. The initial sudden considerable rise in oxygen consumption is due to increased activity of the larvae ; it is absent in larvae made inactive by a low temperature of 1° C. Such larvae, however, maintain an oxygen consumption above the normal value for about 2 hr. The increased oxygen consumption lasting for 1-2 hr. after anaerobiosis represents the repayment of an oxygen debt, but this debt is only 0·5 % of the oxygen which would have been consumed had the anaerobic period been an aerobic one. The small size of the oxygen debt suggests that most of the products of anaerobic metabolism are excreted. The haemoglobin of the larvae does not function during the repayment in fully aerated water of the small oxygen debt. This is shown by experiments with and without carbon monoxide. During the initial short considerable rise in oxygen consumption at 17° C. due to larval activity after anaerobiosis the haemoglobin is functional. This activity occurs while the water is not yet fully aerated, and so the haemoglobin enables the larvae to maintain their activity aerobically in water containing little dissolved oxygen. In nature the undulatory activity of the larvae immediately after anaerobiosis must serve to ventilate the U-shaped tubes in which they live in the mud, and so to fill the tubes with aerated water.
Age-related reductions in the number of serial sarcomeres contribute to shorter fascicle lengths but not elevated passive tension
Authors: Power Geoffrey A. , Crooks Sean , Fletcher Jared R. , Macintosh Brian R. , Herzog Walter 
Published: April 2021

ABSTRACT
We investigated age-related changes to fascicle length, sarcomere length and serial sarcomere number (SSN), and how this affects passive force. Following mechanical testing to determine passive force, the medial gastrocnemius muscle of young (n=9) and old (n=8) Fisher 344BN hybrid rats was chemically fixed at the optimal muscle length for force production; individual fascicles were dissected for length measurement, and laser diffraction was used to assess sarcomere length. Old rats had ∼14% shorter fascicle lengths than young rats, which was driven by a ∼10% reduction in SSN, with no difference in sarcomere length (∼4%). Passive force was greater in the old than in the young rats at long muscle lengths. Shorter fascicle lengths and reduced SSN in the old rats could not entirely explain increased passive forces for absolute length changes, owing to a slight reduction in sarcomere length in old rats, resulting in similar sarcomere length at long muscle lengths.
The Regeneration of Legs in Rhodnius Prolixus (Hemiptera)
Authors: Lüscher Martin 
Published: April 2021

ABSTRACT
It is well known that many insects, and especially many Orthoptera, are capable of regenerating autotomized and amputated legs (Godelmann, 1901 ; Bordage, 1905 ; Megusar, 1910; Friedrich, 1930). Very little is known, however, about those factors governing regeneration, those initiating the excessive growth in regeneration, and those suppressing growth when the regenerated leg has reached a normal size. In order to investigate these factors and their mode of action, it is very convenient to have an insect in which the hormonal control of moulting and metamorphosis is well known. Such an insect is Rhodnius (Wigglesworth, 1936, 1940 a, b), and this insect is also able to regenerate the distal parts of its legs. As regeneration in Rhodnius has not previously been described, it has been necessary to study the normal process of repair in relation to time, temperature and amputation level in order to provide a basis for further work on the factors mentioned above. Normal regeneration will be described in this paper. Strangely enough the temperature and time relations have never been investigated in insect regeneration, although much physiological work has been carried out on the subject.
The Poisoning of Marinogammarus Marinus by Cupric Sulphate and Mercuric Chloride
Authors: Hunter W. Russell 
Published: April 2021

ABSTRACT
The toxicity, under various conditions, of cupric sulphate and mercuric chloride to the marine amphipod, Marinogammarus marinus, has been studied. With optimum conditions copper is virtually non-toxic over the range of concentrations studied (e.g. becoming effective as a poison on decrease in salinity or oxygen tension). The toxic action of mercury is not greatly affected by changed conditions. At very low concentrations, copper has a pronounced effect on animals undergoing mercury poisoning. Subtoxic traces of mercury have no effect on the course of copper poisoning. It is suggested that in M. marinus, mercury acts directly by poisoning of the protoplasm while the effect of copper is indirect, involving the upset of some metabolic process.
The relation of this work to other studies of the action of heavy metals is briefly discussed.
The Action of Colchicine in Arresting Epidermal Mitosis
Authors: Bullough W. S. 
Published: April 2021

ABSTRACT
In the foregoing paper (Bullough, 1949b) a doubt is expressed concerning the value of colchicine for collecting in the metaphase all those mitoses which normally occur during a 12 hr. period. It is probably true to say that most studies of animal mitosis made with the help of colchicine have been planned on two assumptions, namely that, within reasonable limits, the drug arrests every mitosis reaching the metaphase, and, equally important, that it neither increases nor decreases the number of resting cells entering mitosis. Following the pioneer work of Dustin (1934), Lits (1934) and others, these reasonable limits have been defined (see Allen, 1937) as a dose of 0·1 mg. given subcutaneously in water or normal saline and allowed to act for a period of hr. With smaller doses only a partial stoppage of mitosis is achieved; with larger doses the resting cells are prevented from entering the prophase; and with longer periods the number of arrested mitoses does not increase because there is a complete stoppage of all cell division.
The Effect of Calcium On the Axoplasm of Giant Nerve Fibres
Authors: Hodgkin A. L. , Katz B. 
Published: April 2021

ABSTRACT
As was first described by Bear, Schmitt & Young (1937), a jelly-like and apparently solid cylinder of axoplasm is obtained when the contents of a fresh giant nerve fibre of the squid are extruded. There are several observations which indicate that the axoplasm is also normally in a gelatinized state and behaves like a solid.
The Influence of Age and Sex on ‘Reasoning’
Authors: Hanson D. A. 
Published: April 2021

ABSTRACT
Genetically determined, or instinctive, behaviour arises from the selective effects of environment on the life history of a species, and at its first appearance in the life of an individual owes little or nothing to the previous experience of that individual. Most, if not all, organisms are also able to modify their behaviour through ‘personal’ experience. By their ability to learn, animals adapt themselves more intimately to their own particular environment. The new behaviour patterns set up are biologically advantageous to the individual. They arise out of, and are continuous with, the past history of the individual.
On the Reactions to Humidity of Peripatopsis Moseleyi (Wood-Mason)
Authors: Bursell E. , Ewer D. W. 
Published: April 2021

ABSTRACT
Quantitative studies have been made by previous workers on the reactions to humidity of three classes of terrestrial arthropod. The isopods have been studied by Gunn (1937) and Waloff (1941), the sheep tick by Lees (1948), while a number of insects have been examined in this connexion. The Onycophora have so far escaped attention. From a consideration of the usual habitat of these creatures it appeared likely that a marked humidity reaction might exist. The experiments described below give an account of this reaction, its character and mechanism.
Counting Spermatozoa
Authors: Rothschild Lord 
Published: April 2021

ABSTRACT
The number of spermatozoa in a sample of sea-urchin semen (Echinus esculentus) can be accurately estimated by measuring the amount of light scattered and absorbed by a subsample composed of semen diluted with sea water. A ‘Spekker’ photoelectric absorptiometer was used for the measurements, with a cell 1 cm. long. The number N of spermatozoa in a sample of sea-urchin semen was found to be given by the equation where Y′= 0·3010 – log10y′ and y′ = absorptiometer reading, when the original sample was diluted 200 times and the absorptiometer set to 2·000 for the blank. The light-scattering and light-absorbing properties of washed and unwashed suspensions were found to be virtually identical. The number of spermatozoa in a sample of bull semen was found to be given by the equation
The Effect of Posterior Lobe Pituitary Extracts On the Blood Pressure of Ornithorhynchus (Duck-Billed Platypus)
Authors: Feakes M. J. , Hodgkin E. P. , Strahan R. , Waring H. 
Published: April 2021

ABSTRACT
The carotid blood-pressure response to intravenous injection of histamine-free extracts of mammalian posterior pituitary extracts in the platypus (Ornithorhynchus) is described. Pitressin evokes a simple pressor response. Pitocin evokes a simple depressor response. Mixtures of pitressin and pitocin evoke a fall and a subsequent rise. Histamine evokes a depressor response. A preliminary note is made of the simple pressor response to pitressin and depression to pitocin in the deeply-anaesthetized bird and in a lizard. Comparison is made between the responses to posterior pituitary extracts in reptiles, birds, the platypus and eutheria. The possible phylogenetic significance of these observations is discussed.
The Retention of Salt and the Regulation of the Non-Protein Nitrogen Fraction in the Blood of the Aquatic Larva, Sialis Lutaria
Authors: Beadle L. C. , Shaw J. 
Published: April 2021

ABSTRACT
As in the blood of other insects, chloride forms only a small proportion of the total dissolved substances in the blood of Sialis lutaria larvae. (Chloride 0·15-0·35% NaCl, osmotic pressure 0·80-1·10% NaCl.) Only after more than 5 weeks of starvation in distilled or tap water was the blood chloride reduced to below 0·10% NaCl. With a few days’ treatment in 1.0% NaCl it could be increased to 0·5% or higher. The movements of chloride induced in this way were shown to occur through the external cuticle whose permeability to ions is thus very low. There is no mechanism for the active uptake of ions from the external water, and the resistance to several weeks of starvation in glass-distilled water must be attributed solely to the very low permeability of the cuticle. A large proportion of the non-chloride fraction of the total osmotic pressure is non-protein nitrogen, which is presumably amino-acid. Large and rapid changes in blood chloride were induced by repeated blood extractions which were followed by restoration of most or all of the blood volume by the uptake of water. There was no corresponding alteration in the total osmotic pressure. The concentration of non-protein nitrogen in the blood changes in such a way that the total osmotic pressure is not seriously affected by considerable dilution or concentration of the salts as indicated by chloride, which can be halved or doubled. Estimations of protein nitrogen have suggested the possibility that changes in the non-protein nitrogen are made at the expense of the blood protein. The mean normal protein nitrogen of the blood is approximately the same as that of mammals. But after 6 weeks of starvation it was reduced to about one-twentieth of the original, and in some cases to practically nil without apparent effect on the health of the larva. The initial level of non-protein nitrogen was, however, maintained throughout. These results suggest that a compensatory regulation of the blood aminoacids is an important component of the osmo-regulatory mechanism.
Osmotic Regulation in Mosquito Larvae
Authors: Ramsay J. A. 
Published: April 2021

ABSTRACT
The processes of osmotic regulation in the larvae of Aedes aegypti and of A. detritus have been studied by determination of the freezing-point of samples of fluid collected from different parts of the gut. In A. aegypti, kept in fresh water (its normal environment), the fluid passing down the intestine to the rectum is isotonic with the haemolymph. In the rectum it becomes strongly hypotonic before being eliminated. In A. detritus, kept in sea water (its normal environment), the opposite process is observed, the fluid in the rectum becoming hypertonic to the haemolymph and approximately isotonic with the external medium before being eliminated. In A. detritus, which is able to live in dilute media as well as in sea water, the only two specimens from fresh water available for examination were found to have the rectal fluid hypotonic to the haemolymph. The ability of A. detritus, not possessed by A. aegypti, to produce an hyper-tonic fluid in the rectum is tentatively associated with a region in the anterior part of the rectum and lined with an epithelium distinctly different from that in the remainder of the rectum. This anterior region has not been found in A. aegypti.
A Quantitative Study of the Fragmentation and Haemolysis of Mammalian Red Cells by Heat
Authors: Ponder Eric 
Published: April 2021

ABSTRACT
This paper is concerned with quantitative aspects of the fragmentation of red cells by heat and of the haemolysis which accompanies it. The former process involves a splitting of the cell into fragments which retain, at least in part, some of the properties of the intact cell (ability to swell in hypotonic media, ability to undergo certain shape transformations, etc.; see Ponder, 1949). The latter process results in the formation of ghosts with properties which vary with the haemolytic system ; in some systems, the cell becomes a ghost by an all-or-none process (as in hypotonic systems containing cells in low volume centration, see Parpart, 1931), while in other systems the ghosts are partially haemoglobinized and partially rigid. To describe the phenomena adequately, it is accordingly necessary to consider the transition of the red cell to the ghost as a process which can occur in several ways in addition to the all-or-none escape of Hb and the replacement of the cell by an unsubstantial ghost ; it is all the more important to do this because evidence is accumulating that red cell ghosts in several kinds of haemolytic system possess both shape and rigidity (Ponder, 1942, 1950, Lindemann, 19490a,b).
Inherent Activity in the Sea-Anemone,Metridium Senile(L.)
Authors: Batham E. J. , Pantin C. F. A. 
Published: April 2021

ABSTRACTA study of the anemone Calliactis parasitica (Pantin, 1935) showed that its most obvious activities are of a peculiarly simple kind. The unstimulated animal seems to be inactive. Activity originates directly as a response to external stimuli. Thus an adverse mechanical stimulus to the passive animal sets up impulses, transmitted by a special ‘through-conduction system’ which in this species activates the marginal sphincter muscle of the oral disk. The closure of this muscle protects the disk. Again, when food touches the tentacles, it is conveyed to the mouth by a series of local responses. In both these instances the activity consists of responses directly related to external stimuli, and the animal behaves as a passive vehicle for the conduction of excitation.
Radiological Observations On the Cardiovascular System in Anguilla Anguilla
Authors: Mott J. C. 
Published: April 2021

ABSTRACT
A description is given of an angiographic method for studying the circulation of blood in the anaesthetized common eel. The valves of the heart are concluded to be competent. The extreme elasticity of the bulbus arteriosus is noted, especially of its anterior end. The circulation time through the gills was 5·6 ±1·9 sec. The circulation in the head is relatively inconspicuous; all the emphasis is on the backward flow of blood from the gills. The circulation times to the viscera are very variable. It appears that the two alternative routes of venous return from the pneumatic duct artery, which are the pneumatic duct vein and the gas gland vein, may both be operating together or either may operate alone.
The Influence of Photoperiod and Temperature on the Induction of Diapause in Diataraxia Oleracea L. (Lepidoptera)
Authors: Way M. J. , Hopkins B. A. 
Published: April 2021

ABSTRACT
The induction of diapause in the pupa of Diataraxia oleracea is influenced by temperature and photoperiod during the larval stage. Low temperatures and short photoperiods tend to induce diapause while high temperatures and long photoperiods tend to prevent diapause.
Diapause is not influenced by light intensity during the larval stage providing the intensity is above a certain minimum.
Diapause is prevented at high temperatures (30-34° C.) if the larvae are reared in darkness.
The photoperiod is operative as a factor influencing diapause only between the beginning of the moulting sleep prior to ecdysis to the last instar and the 3rd-5th day of the last instar. A single diapause-preventing photo-period during the moulting sleep is probably sufficient to prevent diapause.
Diapause in D. oleracea is not influenced by photoperiodically controlled substances in the larval food plant.
Photoperiodicity in the Female Ferret
Authors: Hart D. S. 
Published: April 2021

ABSTRACT
Evidence accumulated during two years’ work and experience in photoperiodicity in ferrets suggests the following conclusions:
Oestrus or anoestrus may be induced by influencing the activity of the pituitary gland; this is effected through a contrast-sensitive mechanism which is stimulated by light:dark sequences. The total daily quantity of light is not the controlling factor. In order to obtain the long-light : short-dark ratio necessary for an oestrusactivating sequence, the ratio should be in the proportion of two parts or more of light to one part darkness and reversed if it is desired to induce a state of anoestrus. Slowly increasing or decreasing planes of light are not an essential part of an oestrus-activating sequence. Because ferrets can be brought into anoestrus quicker than they can be brought into oestrus it is considered that the sexual season curve is more acute when entering anoestrus than when entering oestrus. Doubling the number of light–dark contrast stimuli from one every 24-hour period to two every 24-hour period produced no acceleration of the onset of oestrus nor any indication of a ‘tetanus effect’.
A Bifunctional Single Motor Axon System of a Crustacean Muscle
Authors: Wiersma C. A. G. 
Published: April 2021

ABSTRACT
It is shown that the opener muscle of the hermit crab, Eupagurus bernhardus L., receives a single motor axon. Stimulation of this axon results, when appropriate stimuli are used, in two types of contractions comparable with the fast and slow contractions of doubly motor-innervated crustacean muscles. The theoretical implications of this finding are discussed and a hypothesis offered to explain the mechanism which makes the two contraction types possible. The physiological and anatomical features of the innervation of the four most distal muscles in the legs of Eupagurus are described.
The Function of Haemoglobin in Relation to Filter Feeding in Leaf-Mining Chironomid Larvae
Authors: Walshe Barbara M. 
Published: April 2021

ABSTRACT
Tendipes (= Chironomus) plumosus larvae are unique among species of Tendipes in employing a filter-feeding mechanism for obtaining their food (Walshe, 1947 a). The larva spins a sheet of salivary secretion across the lumen of its tube, after which, by rapid anteroposterior undulations of the body, it irrigates the tube. Plankton or other organic particles in the incoming water current are thereby caught in the salivary net and subsequently eaten. This filter feeding is an energetic process involving glandular activity in spinning the salivary sheet and muscular activity in maintaining a rapid current of water during the filtration of food particles. A study (Walshe, 1950) of the amount of filter feeding at different oxygen concentrations has shown that this is essentially an aerobic process, declining at low oxygen concentrations and absent under anaerobic conditions. Normal larvae are incapable of feeding below about 10% air saturation of the water, while larvae without functional haemoglobin (i.e. after carbon monoxide treatment) cease to feed at 26 % air saturation. Even above this value larvae with carboxyhaemoglobin feed less than normal animals. Thus the haemoglobin, in addition to its established significance as an oxygen carrier at low oxygen pressures (Harnisch, 1936; Ewer, 1942) and during recovery from oxygen lack (Harnisch, 1936; Walshe, 1947b), also plays a part in enabling the larvae to continue an active aerobic feeding process even when little oxygen is available.
Fermentation in the Rumen of the Sheep
Authors: Gray F. V. , Pilgrim A. F. 
Published: April 2021

ABSTRACT
Analyses of the rumen fluid of sheep fed on wheaten hay and on lucerne hay showed that characteristic changes take place in the composition of the mixture of volatile fatty acids in the rumen throughout the day. The changes conform closely to those predicted from the composition of the mixture of fatty acids produced from the same two fodders in vitro. They support the view that propionic acid is relatively more rapidly absorbed than either acetic or butyric acid, and that the fermentation of these fodders in the rumen produces a mixture of the acids in which propionic acid forms a larger proportion than it does in the rumen fluid.
Carbonic Anhydrase Activity During Embryonic Development
Authors: Clark A. M. 
Published: April 2021

ABSTRACT
Tissue carbonic anhydrase is usually formed at an early stage in the embryonic development of the chick and mouse. The enzyme does not appear in the blood until a relatively late stage has been reached. In the erythrocytes, it is probable that the enzyme is confined to those cells produced in bone marrow. Evidence is presented to support the theory that towards the end of development, there is a replacement of red cells which contain an embryonic type of haemoglobin but no carbonic anhydrase, by corpuscles in which the enzyme is present together with the adult type of haemoglobin.
The Effect of Pitressin and Pitocin on Water Balance in Bufo Regularis Reuss
Authors: Ewer R. F. 
Published: April 2021

ABSTRACT
In Bufo regularis the injection of either pitressin or pitocin is followed by an increase in the rate of water absorption through the skin, together with a marked decrease in urine flow. The response to pitressin is greater than that to pitocin. The effect of pitocin in increasing water uptake can be attributed to the activity of the 5-10% of the pressor fraction which it contains. A mixture of pitressin and pitocin has the same effect on water balance as a corresponding dose of pituitrin. Pitressin alone has a greater anti-diuretic effect than it has when pitocin is added. Taking into account the antagonistic action of pitocin to pitressin it is possible to account for the anti-diuretic action of pitocin in terms of its pressor fraction content. It is concluded that the pressor fraction is the main factor responsible for both the dermal and the renal components of the water-balance effect produced in B. regularis by injection of mammalian posterior pituitary extracts. This conclusion is discussed in relation to the findings of other workers.