bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Chemical Control of Feeding Behaviour in Cyphastrea Ocellina and in Some Other Hawaiian Corals*
Authors: Mariscal Richard N. , Lenhoff Howard M. 
Published: April 2021

ABSTRACT
The feeding response of the Hawaiian coral Cyphastrea ocellina was elicited by alcoholic extracts of Artemia nauplii and of plankton. Chromatographic analysis of these extracts revealed that the imino acid proline was primarily responsible for the observed mouth opening and feeding behaviour. Somewhat less feeding activity was also caused by the reduced tripeptide glutathione. Analogues of these compounds, pipecolic acid and S-methyl glutathione, respectively, were as effective as the naturally occurring compounds. Some data are also presented for the feeding responses of two other Hawaiian corals, Pocillopora damicronis and Fungia scutaria.
The Morphology and Physiology of the Salamander Thyroid Gland
Authors: Uhlenhuth Eduard , Schwartzbach Saul 
Published: April 2021

ABSTRACT
In the study of the physiology of the thyroid gland it is becoming more and more evident that the function of this organ is composed of a number of component activities. Only some of them are controlled by intrinsic mechanisms, while the most important of them, the release of the active secretion product of the gland from the follicles into the blood circulation is effected by stimulation through an extrinsic “releasing mechanism.” In warm-blooded animals the study of this releasing mechanism has received considerable attention, and although the question cannot by any means be considered a closed chapter of thyroid physiology, the work of O. A. Andersson(1), Leo Asher(2), Cannon and Fitz(3), L. B. Wilson(o) and others, is generally credited with having demonstrated that the autonomous nervous system is the path over which the stimuli of the releasing mechanism reach the thyroid in warm-blooded animals.
The senior author of this paper has been interested, for some time, in the physiology of the thyroid of cold-blooded animals, and especially in that aspect of it which concerns the nature of the releasing mechanism. This work has now entered an advanced stage and certain definite conclusions are possible. Although the results, together with the records, will be published in a series of more extensive articles, it seems desirable that the chief results be made accessible at once.
A Note on the Effect of Temperature on the Cardiac Rhythm of Certain Schizopods
Authors: Henderson Jean T. 
Published: April 2021

ABSTRACT
It has been shown by Arrhenius that an expression analogous to the Van’t Hoff isochore can be applied to the velocity of chemical reactions, viz.: where K2, K1, are velocity constants corresponding to the absolute temperatures T2, T1 and μ is the energy of activation per gm. molecule. Arrhenius himself put forward the suggestion (1915) that this relation might be extended to the analysis of reactions which occur in animate systems. But as Heilbrunn has emphasised there is no a priori reason why an equation which defines a property of homogeneous systems, derived on the assumption that the system is homogeneous, should necessarily apply to systems of such heterogeneity as those which the biologist studies.
The Effect of Temperature Upon the Diffusion and Autolysis of the Metamorphic and Pigmentation Principles of the Pituitary Gland
Authors: Spaul E. A. 
Published: April 2021

ABSTRACT
Diffusion and autolysis of the pigmentation and metamorphic principles of the pituitary proceed together after death of the animal. Rise in temperature increases the rate of diffusion and autolytic action. The presence of other principles and of autolytic products does not affect the response of the pigmentation principle but the activity of the metamorphic principle is reduced by diffused and autolytic products. As these products increase a point is reached when the presence of the metamorphic principle cannot be detected. Diffusion and autolysis are responsible in a large measure for the variations in the metamorphic and pigmentation results obtained by the administration of anterior and posterior lobe products.
The Absorption of Oxygen by Plaice Eggs
Authors: Burfield S. T. 
Published: April 2021

ABSTRACT
The rate of oxygen absorption by plaice eggs, contained in a closed volume of sea water, falls when the eggs and water are allowed to remain relatively quiescent. This fall takes place even when a large volume of water is used. It has been shown that small changes in the partial pressure of dissolved oxygen do not appreciably affect the rate of absorption, so that this is not the factor concerned in the fall. The rate of oxygen absorption in a closed volume of sea water does not fall if the eggs be frequently moved. The removal of eggs to a closed volume of fresh sea water at the end of a period prevents the rate of absorption from falling during a second equal period. The removal of eggs to a closed volume of “used” sea water at the end of a period causes the rate of absorption to fall during a second equal period. The addition of urea in small quantities to the sea water has no effect on oxygen absorption. The addition of carbon dioxide to the sea water has a marked effect in lowering the rate of oxygen absorption, and the accumulation of excreted carbon dioxide is probably the factor causing the fall in absorption mentioned under paragraphs 1 and 5. This effect is possibly directly due to the alteration in the hydrogen ion concentration produced by the carbon dioxide. The Respiratory Quotient of young plaice eggs is about ·75.
The Influence of Age at Castration on the Size of Various Organs
Authors: Baker John R. 
Published: April 2021

ABSTRACT
Male pigs were castrated at the ages of 50, 100 and 200 days. Others were not castrated. All were killed at 300 days. The weights of various sexual and endocrine organs at 300 days were determined, and a comparison instituted between pigs castrated at each age. The following results were obtained: (1) The vesicuiae seminales, bulbo-urethrals, and adrenals are smaller when castration is performed at 100 days than when it is performed at 200 days. There is much less difference (possibly none) according to whether castration is performed at 50 or 100 days. In uncastrated pigs the vesicuiae seminales and bulbourethrals are enormously larger even than those of pigs castrated as late as 200 days.(2) It is probable that some change occurs in these organs at about the age of 100 days, rendering them progressively more and more sensitive to the gonad hormone.(3) The thyroid, pineal, and pituitary are not significantly affected by time of castration. Body-weight also is not significantly affected.
A general discussion is given on the causes governing the size of the accessory sexual characters in mammals.
On the Influence of Intermittent Starvation on the Longevity of the Imaginal Stage of Drosophila Melanogaster
Authors: Kopeć Stefan 
Published: April 2021

ABSTRACT
Under all the intensities of starvation investigated, the longevity of the imago stage of Drosophila was as a rule diminished. At the same time, flies which were starved for six hours out of every 24 and which were not deprived of water, lived at least as long as the controls. The longevity of flies increased in inverse proportion to the intensity of starvation. The longevity was greater in series in which the flies were never subjected to lack of water than in those in which intermittent starvation without water was practised. The injurious influence of longer, though less frequent fasting intervals was more pronounced than that of shorter though more frequent periods of inanition, both with or without administration of water. Starvation for six successive hours out of every 24 without water affected the flies most during the middle period of their life. The same effect was found during starvation for 12 successive hours out of every 24 when the flies were supplied with water. With lapse of time the flies became less resistant to the temporary absence of food.
Though the experiments performed did not give any clear results as to the supposed prolongation of life under the influence of intermittent starvation, some valuable hints for further study may be obtained from the observations recorded. The experiments on the influence of starvation for six hours out of every 24 with administration of drinking water must be repeated on a larger scale and it is intended to perform further experiments using a less intense degree of inanition. As with lapse of time the animals become less resistant to starvation, special experiments are also planned in which the flies will be intermittently starved until middle age and thereafter will be fed continuously.
This work was performed whilst holding a fellowship of the International Education Board (Rockefeller Foundation).
Comparative Studies of Accelerated Amphibian Metamorphosis
Authors: Spaul E. A. 
Published: April 2021

ABSTRACT
The administration of active anterior lobe extracts in solution is not effective in producing precocious transformation of tadpoles. The rate of metamorphosis induced by injection of either thyroid or anterior pituitary depends within limits on the concentration of the initial dose. The time for completion with thyroid depends upon the total quantity given—a cumulative effect. The repetition of the stimulus given by a dose, the quantity per dose having maximum and minimum values, at suitable intervals decides the time of completion with anterior pituitary. Susceptibility of tadpoles to metamorphosis inducing factors increases with age. The effects produced by iodine in metamorphosis (mortality, reduction in size and shrinkage) agree more closely with those obtained in thyroid than pituitary treatment. There is a differential response of certain tissues to concentrations of the thyroid but not to anterior pituitary. Exposure of tadpoles to X-rays alters the susceptibility to factors accelerating metamorphosis. The effect increases with age. Alcohol and potassium cyanide lower the response to thyroid and anterior pituitary stimulation according to the concentration and the age of tadpoles. Normal rates of change are produced by thyroid and anterior pituitary in tadpoles under narcosis. The mortality is slightly higher with thyroid and depends on the concentration of the anaesthetic. Prolonged narcosis reduces the rate of change. Precocious metamorphosis is not found in tadpoles after feeding lipón the endostyle of Ciona intestinalis. The relation to iodine, quantitative and qualitative responses of tadpoles to treatment, and the differential tissue response serve to differentiate between the metamorphic principles of the thyroid and anterior pituitary.
The Effect of Hydrogen Peroxide on the Permeability of the Cell
Authors: Thomson David Landsborough 
Published: April 2021

ABSTRACT
Szücs (1913) reported that hydrogen peroxide increased the permeability of the living cell. Following up a previous observation [Bokorny, 1886], he found that if threads of Spirogyra were treated first with hydrogen peroxide and then with ferrous sulphate solutions, a dark precipitate appeared within the cells. He concluded that the hydrogen peroxide had so increased the permeability of the cell that the ferrous ions were able to enter and form a dark iron-tannin compound. It was also found that hydrogen peroxide increased the permeability of the cell to various dyes. In view of the ever-increasing importance of the rôle assigned to hydrogen peroxide in cell metabolism it seemed worth while to re-open this question. As Szücs gives no details of his experiments, an exact repetition was impossible.
The Action of Potassium on Muscle-Preparations from Invertebrates
Authors: Wells George P. 
Published: April 2021

ABSTRACT
When the crop of Aplysia is bathed by a solution containing 0.011 M KC1, tonic contraction and inhibition of the rhythmic movements result if potassium is either withdrawn or added in excess. The action of potassium on tone in the Aplysia crop is independent of the calcium concentration. Rb, Cs and NH4 act like potassium on the Aplysia crop, but Li does not. Rb is about twice as active, Cs about one-half as active, and NH4 about one-fifth as active as potassium. The changes of tone seen in the Helix crop when the potassium concentration is varied are identical with those seen in vertebrate plain muscle under like conditions. Addition of a little potassium to the heart of Maia perfused with a potassium-free fluid causes a drop of tone. High concentrations of potassium have two opposed effects, a contracting action and a secondary depressing action. The action of potassium on the striped muscle of the Maia heart is essentially like its action on molluscan or vertebrate plain muscle.
New Developments in Ovarian Dynamics and the Law of Follicular Constancy
Authors: Lipschutz Alexander 
Published: April 2021

ABSTRACT
It has been shown in previous papers in this Journal (1, 2) that very characteristic phenomena take place in an ovarian fragment if the total ovarian mass is reduced by partial castration. There is an hypertrophy of the ovarian fragment and a greatly reduced number of young ova, while large follicles and often follicular cysts are found in the fragment. The diminution of the number of primary follicles was explained by assuming that they had been absorbed during follicular development. These conclusions, together with those of Arai, Hammond and Asdell in mammals, of Hartman in the opossum, of Pearl and Schoppe in the fowl, were summarised in “the law of follicular constancy,” which means that the number of ova entering into follicular development, the rhythm of follicular development and the degree which is attained by follicular development are constant and are controlled by somatic factors outside the ovary. The latter supposition was a further development of the theories of Heape, Sand (3), Hammond and Marshall (4). In further experiments on cats (2) it was shown that the diminution of the number of young ova in an ovarian fragment and the formation of follicular cysts do not depend upon the operative interference itself, as there is no diminution of young ova and there are no follicular cysts in ovarian fragments when the total ovarian mass is not diminished. Later, further experimental evidence (5) concerning the law of follicular constancy was obtained by grafting a third ovary into normal guinea-pigs. No corpus luteum was ever found in such ovarian grafts when examined several months later, though corpora lutea are always present in ovarian grafts in previously castrated females.
The Pigmentary Effector System V. the Nervous Control of Excitement Pallor in Reptiles
Authors: Hogben Lancelot T. , Mirvish Louis 
Published: April 2021

ABSTRACT
The chromatic responses of the chameleon have excited curiosity from the earliest times. They were known to Aristotle, who wrote concerning them: “the change in the colour of its skin takes place when it is filled with air. It can acquire either a black colour like that of a crocodile, or ochreous like that of a lizard, or spotted with black like the panther; for the eyes also change like the rest of the body, and so does the tail1” (Book II, History of Animals).
The Effect of Dilution on the Activity of Spermatozoa
Authors: Gray J. 
Published: April 2021

ABSTRACT
As long as the seminal fluid of a ripe sea-urchin remains undiluted, little or no movement occurs on the part of the spermatozoa. If, however, a small drop of this fluid comes into contact with sea-water, the cells at the surface of the drop at once become intensely active and eventually the whole of the spermatozoa exhibit lively movement. There appear to be at least four possible causes for this immediate activation in sea-water : (i) The failure to move in the testicular fluid may be due to the presence of an inhibitory substance in the medium, so that on dilution this substance is removed and the spermatozoa are activated, (ii) Sea-water may contain some element, absent from the testicular medium, which is necessary for movement. (iii) The viscous resistance of the testicular fluid may be too high for active movement, (iv) Each spermatozoon may exert some form of inhibition on the movements of its neighbours. The following experiments were designed to test these hypotheses.
The Iodine Content of the Thyroid of the Fowl with Reference to Age and Sex
Authors: Chaudhuri A. C. 
Published: April 2021

ABSTRACT
The iodine content of the thyroid of the sexually immature male fowl is lower than that of the thyroid of the sexually mature. The increase in iodine content is coincident with the attainment of sexual maturity as estimated by the histological picture of the testis. In the case of the material used there was no indication of a sex dimorphism in the matter of iodine content. The average percentage of iodine content of the thyroid of the bird is significantly higher than that of the mammal.
The Length of the Oestrous Cycle in the Unmated Normal Mouse: Records of One Thousand Cycles
Authors: Parkes A. S. 
Published: April 2021

ABSTRACT
Analysis of the records of 1000 oestrous cycles in the normal unmated mouse give the following results :
Mean length of whole cycle = 6 ·213 ± 0 ·0554 days.
Mean length of dioestrus (including meta-oestrus) = 3 ·719 ± 0 ·0502 days.
Mean length of oestrus (including pro-oestrus) = 2 ·494 ± 0 ·0223 days.
Neuromuscular Properties of Mesenteries from the Sea-Anemone Metridium
Authors: Robson E. A. , Josephson R. K. 
Published: April 2021

ABSTRACT
A method is described for a simultaneous electrical and mechanical recording from isolated mesenteries of the sea-anemone Metridium senile (L.). The retractor muscle gives quick and slow contractions. Shock intervals of 0·15–2 sec. produce facilitated twitches on all stimuli after the first, usually followed by a slow contraction. Trains of stimuli at lower frequencies are followed by slow contractions only. Slow contractions may also arise spontaneously. Two types of potential were found using external suction electrodes, provisionally interpreted as nerve-net impulses and muscle action potentials. The first is an all-or-none compound pulse, whose brief components summate (1–3 msec., height up to 0·4 mV.). Conduction speed in an expanded anemone would be 70–120 cm./sec. at 14–16 °C., corresponding to that of the through-conduction system. The second always precedes a twitch and is a smooth, graded potential lasting 50–100 msec. Its size, up to 1·2 mV., is inversely related to stimulus interval, but unlike the quick mechanical rseponse it shows but slight initial facilitation. A muscle potential follows a nerve-net impulse and is propagated at the same speed. The refractory period of the nerve-net probably exceeds that of the muscle. Potentials showing similar features have been recorded from the oral disk and tentacles. These results support the suggestion that the sites of facilitation and initiation of contractions are neuromuscular junctions throughout the retractor muscle. Quick contractions are co-ordinated by the nerve-net, whereas it is possible that slow contractions, however initiated, may at least in part be propagated in the muscle itself.
Excitation and Habituation of the Crayfish Escape Reflex: The Depolarizing Response in Lateral Giant Fibres of the Isolated Abdomen
Authors: Krasne Franklin B. 
Published: April 2021

ABSTRACT
Crayfish commonly evade capture by darting backwards when one tries to pick them up or otherwise disturbs them. They do this by sharply flexing the abdomen, the tail fan acting as a paddle; at the same time they streamline themselves by thrusting their appendages forward.
Polyneuronal Innervation of the Fast Muscles of the Marine Teleost Cottus Scorpius L
Authors: Hudson Richard C. L. 
Published: April 2021

ABSTRACT
Histological and electrophysiological studies of the spinal nerves, nerve roots and muscles of the abdominal wall of the marine teleost Cottus scorpius have been undertaken to determine the extent and nature of polyneuronal innervation of the fast muscles. Spinal nerves at proximal and distal levels, and the dorsal roots, contain axons in a single mixed population with a mean diameter of 2–4 μm., while the ventral roots contain axons in two diameter classes with means at 4–6 and 12–14 μm. Between 8 and 22 distributed nerve terminations were counted on fifty-two teased intact single muscle fibres stained for acetylcholinesterase activity. The average distance between the terminals is 0·64 mm. (range 0·094–2·050 mm.). The compound action potential of the nerve comprises two principal peaks with conduction velocities of 17·0–23·8 m./sec. and 1·5–12·2 m./sec. at 10–12°C. Fast muscle fibres gave two types of electrical response-all-or-none spike potentials that are propagated with a conduction velocity of c. 1·1 m./sec. at 10–12° C., and quantized distributed junction potentials. The electrical properties of the nerves and roots suggest that the fast muscles are innervated by a single class of fast axons and possibly by a few slow axons. Simultaneous recordings of nerve and muscle activities were made at different stimulus intensities. In all cases muscle responses were correlated with the first peak of the compound action potential, and appeared with the same or only slightly different latencies. Each muscle fibre is shown electrophysiologically to be polyneuronally innervated by 2–5 axons from a single spinal nerve, and to receive a similar axonic complement from each of four spinal nerves. Polyneuronal innervation of the muscle fibres by 8–22 different axons in the absence of multiterminal innervation is postulated.
Measurements of the Osmotic Pressure in the Habitat of Polymorphus Minutus (Acanthocephala) in the Intensine of Domestic Ducks
Authors: Crompton D. W. T. , Edmonds S. J. 
Published: April 2021

ABSTRACT
The osmotic pressure in the environment of Polymorphus minutus in the alimentary tract of ducks has been measured. Samples of intestinal contents were collected through cannulae inserted at known positions into the parasite’ s environment. Samples were recovered from two healthy living ducks, without inducing anaesthesia, from points at 60% and 80% of the distance along the intestine, and from ten freshly killed ducks at a point 70 % of the distance along the intestine. The mean osmotic pressures at 60%, 70% and 80% of the distance along the intestine were found to be 170·5, 171·6 and 178·2 mM-NaCl/1. respectively and the variance was found to be 154·84, 84·41 and 30·13 for the three positions respectively. It is postulated that the greater fluctuations in osmotic pressure at the anterior end of the environment may be responsible for the posterior migration of the parasite during the course of the infection. The method here described for investigating osmoregulation in P. minutus may be of general application for studying aspects of the biology of small intestinal helminths in vivo.
The Central Nervous Control of Complex Movements in the Uropods of Crayfish
Authors: Larimer J. L. , Kennedy D. 
Published: April 2021

ABSTRACT
The control of postural uropod muscles in the crayfish has been investigated by stimulating ‘command’ interneurones isolated from central connectives. Reciprocity is preserved between exciters and inhibitors innervating the same muscle, and between motor axons serving antagonists. The control of combined movements, involving groups of muscles that are neither synergists nor antagonists, was analysed by simultaneous recording. Most command fibres affected several different motor pathways, and different command fibres produced different combinations of output. It is concluded that quite complex movements may be encoded in the connexions of a single central element. In several instances it was shown unequivocally that single central neurones were responsible for releasing the motor output. One identified command neurone produces a stereotyped, rhythmic pattern of activity in several motor pathways. This effect did not depend upon afferent feedback for its form or frequency. Command interneurones often produce asymmetrical responses in the appendages of the two sides. Some of these make connexions only to the ipsilateral motor neurones, others only to contralateral ones, and most make differential connexions on the two sides.