bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Structure, Development, and Operation of the Hinge Ligament of Ostrea edulis
Authors: Trueman E. R. 
Published: April 2021

ABSTRACT
The ligamental structure of Ostrea edulis is briefly described. The ligament is situated between the valves of the shell immediately below the urtibo and may be divided into two main layers, the outer and the inner, the principal features of which appear to correspond with those of other bivalves. The outer layer is divided into anterior and posterior halves by the inner layer, which occupies a central position. The axis (hinge or pivotal axis) about which the valves open is situated in the adult oyster along a line drawn through the outer layer and the upper part of the inner layer. When the valves are closed the ligament above this axis is subjected to a tensile strain and that portion below to compression, the forces so produced causing the opening of the valves. An attempt has been made to measure this force in relation to the surface area of the valves and it is found to be approximately 4·5 gm. mm./mm.2 This figure is comparable to those obtained when certain other species of bivalves are used. The ligament is shown to develop from the simple outer layer of the early larval stages, first by the addition of an inner layer and then by growth of this structure chiefly in a ventral direction. The initial dorsal region of the ligament soon degenerates and at the same time the pivotal axis moves ventrally between the valves, thus increasing in length. This method of growth is compared with that of an elongate external ligament and the mechanical implications are suggested.
A Comparative Study of the Chilopod and Diplopod Cuticle
Authors: Blower Gordon 
Published: April 2021

ABSTRACT
The histology of the cuticle and epidermis of certain chilopods and diplopods is described. Two principal layers of the cuticle are recognized, an outer homogeneous and refractile exocuticle which is usually but not invariably pigmented and an inner endocuticle. The endocuticle and the exocuticle both contain chitin. The exocuticle is considered as a modification of the outer part of the chitinous matrix by an impregnating substance. Certain properties of the impregnating substance are described. It appears to be a substance rich in phenolic groups, perhaps a protein, which has a stability and resistance to acids in its own right irrespective of the presence of pigment or aromatic cross-links. Pro-sclerotin is suggested as a name for this substance. Chemical tests show that it is present in regions not optically definable as exocuticle. The epidermis is virtually an epithelium of gland cells which appear to secrete lipoid material. The lipoid passes on to the surface of the cuticle by means of ducts passing through the cuticle. Here it appears to form a superficial layer and to impregnate the sclerotin and pro-sclerotin. There appears to be an intimate association of lipoid with the aromatic groups of the pro-sclerotin and sclerotin. Destruction of the aromatic groups by means of an oxidizing agent appears to intensify the colouring of the lipoid by Sudan. The myriapod cuticle is shown to have many features in common with that of other arthropods. The main difficulty in the way of extensive homology with other arthropod types is the absence in myriapods of an outer non-chitinous and resistant layer.
The Specific Granules of the Pancreatic Islet Tissue of the Frog (Rana temporaria)
Authors: Barrington E. J. W. 
Published: April 2021

ABSTRACT
An account is given of some characteristics of the pancreatic islet tissue of the frog, based largely on material fixed in Helly’s fluid and subsequently postchromed. It is shown that the cells, which superficially differ greatly amongst themselves in appearance, can be interpreted as representing stages in a single secretory cycle, and cannot be readily differentiated into the entirely distinct cell types which have commonly been thought to characterize the islet tissue of other vertebrates. Secretory activity centres round an organelle which is believed to be the true ‘specific granule’, and which is formed by the condensation of chromophil material within a chromophobe body. The latter develops a sudanophil rim which is also a characteristic feature of the specific granule itself, the secretory activity of the latter involving an intense lipoid metabolism and being accompanied by a reduction of chromophilia. These observations cannot at present be readily related to the traditional descriptions of the ‘A’ and ‘B’ (and more recently ‘D’) cells, although the specific granule in the earlier stages of its activity appears to resemble the ‘A’ granule of other vertebrates in its staining reactions. Certain reactions characteristic of ‘B’ and ‘D’ granules can also be recognized, but it is too early to evaluate these with confidence. The observations are discussed in the light of current views on the cell-inclusions, particular attention being drawn to the similarity which the chromophobe bodies bear to Golgi spheroids (lipochondria), both in their appearance and in their apparent ability to segregate material from the surrounding cytoplasm.
Studies on the Effect of Infection with Nosema apis on the Physiology of the Queen Honey-bee
Authors: Hassanein M. H. 
Published: April 2021

ABSTRACT
When a queen honey-bee becomes infected with Nosema apis, the result can be very serious indeed for her colony. The metabolic processes are disturbed by the damage done by the parasite to the epithelial cells of the mid-gut, and this apparently leads to severe damage to the ovaries, at first by the production of a high proportion of eggs that fail to hatch, and ultimately by complete cessation of ov1-pqsition and supersession or death of the queen. In the case of Nosema bombycis, which attacks the silk moth, infection is carried from the female to her offspring via the egg; but there is no evidence that this ever occurs in the case of Nosema apis. Although large numbers of eggs, larvae, and pupae produced by infected queen honeybees were examined, none was found to be infected with any stage of Nosema apis.
The Activity of Amoebocytes and of Alkaline Phosphatases during the Regeneration of the Shell in the Snail, Helix aspersa
Authors: Wagge L. E. 
Published: April 2021

ABSTRACT
Experiments show that in Helix aspera amoebocytes repair a damaged shell after transporting calcium carbonate and proteins from other parts of the shell, or from the digestive gland. The mantle is firmly applied to the damaged area and over it exudes fluid rich in amoebocytes. These secrete, and rapidly calcify, a protein membrane. Similar additional calcified membranes give firm protection after 24 hours.
The shell serves as a reservoir of calcium and protein, invaluable to a terrestrial gastropod. Amoebocytes can carry calcium back to the body. Extensive shell damage is repairable provided enough reserves remain: a snail cannot rebuild an entirely new shell. Thickening occurs whenever calcium and protein are available. Shell growth, however, initiated by the secretion of the periostracum, exclusively formed by the mantle skirt, happens only in conjunction with body growth.
Provided feeding activities are normal, alkaline phosphatases are abundant during shell repair, especially around digestive gland lime cells. Shell repair and digestion are closely associated. Amoebocytes, ineffective in an active, starved snail, can repeatedly repair damaged shell when a snail feeds, if only on filter paper: for once stimulated ample calcium and proteins are available for them in the shell.
Phenolic Tanning and Pigmentation of the Cuticle in Carcinus maenas
Authors: Krishnan G. 
Published: April 2021

ABSTRACT
The histochemistry of the cuticle in different stages of the moult cycle of Carcinus maenas is described. The newly formed cuticle of a crab exposed at moulting shows evidence of phenolic tanning in the epicuticle. The subsequent tanning of the pigment layer of the endocuticle is confined to a brief period immediately after moulting. The polyphenol oxidase of the epicuticle involved in tanning disappears soon after moulting, but some time later an oxidase is again indicated, this time in the pigment layer. It appears to be secreted by the tegumental glands. From the concurrent appearance of a polyphenol oxidase and tyrosine and the subsequent formation of dihydroxyphenols and melanin-like substances in the cuticle, it is suggested that the oxidation products of tyrosine are responsible for the pigmentation of the cuticle. Pigmentation of the cuticle is discussed in relation to phenolic tanning in Crustacea and Insecta.
Intranuclear Birefringent Inclusions, an Artifact Occurring in Paraffin Sections
Authors: Nedzel G. A. 
Published: April 2021

ABSTRACT
Intranuclear birefringent inclusions, apparently paraffin, are often observed in paraffin sections which are dehydrated in acetone instead of alcohol after staining. These inclusions are not removed by prolonged immersion of the sections in xylene or other fat solvents at room temperature. They may be removed from unmounted sections by clearing these sections in xylene after the usual hydration and alcohol dehydration, either before or after staining. They may be removed from resin-mounted sections, but not completely so, by warming the sections in an oven at 58° C. for 15 minutes.
On the Abdominal Appendages of Larvae of Trichoptera, Neuroptera, and Lepidoptera, and the Origins of Jointed Limbs
Authors: Pryor M. G. M. 
Published: April 2021

ABSTRACT
The musculature of the abdominal appendages of the larvae of Sialis and Corydalus (Neuroptera) is described, and their homologies discussed. The terminal appendages of a primitive Trichopteran, Rhyacophila sp., correspond muscle’ by muscle with those of Corydalus. The terminal appendages of the larvae of typical members of other families of Trichoptera are compared with those of Rhyacophila-, although there is great variety of form, the same muscles can be traced in all. Similarities between the larvae of Neuroptera and Lepidoptera are not so close ; the resemblances are in general features which are shared with other soft blood-filled appendages such as those of Tardigrada or Onychophora. Finally the general mechanical principles governing the bending of limbs are discussed. Soft turgid appendages such as the abdominal legs of caterpillars depend on a mechanism quite unlike that of the hard, jointed limbs of other arthropods, and it is difficult to see how the one can have evolved from the other. It is suggested that a parallel evolution has taken place in the terminal appendages of Trichopteran larvae, and intermediate stages are described which suggest a way in which the change may have come about in true appendages.
The Blood-system in the Serpulimorpha (Annelida, Polychaeta) IV. Intravasal Tissues
Authors: Hanson Jean 
Published: April 2021

ABSTRACT
Intravasal tissues of unknown function have been found in Pomatoceros triqueter, Vermiliopsis infundibulum, Protula intestinum, and Apomatus ampulliferus. They consist of connective tissue fibres clothed with small cells with densely staining cytoplasm. In Pomatoceros the tissue is situated intersegmentally in the gut sinus of the thorax and anterior part of the abdomen; it lies on each side of the sinus, and the ring vessels open into spaces within it. In Vermiliopsis the intravasal tissue fills the sinus in the posterior part of the abdomen. In Protula and Apomatus it is situated in swellings of specialized structure on the abdominal ring vessels close to the sinus. They closely resemble the ‘blood-glands’ of Pheretima (Stephenson, 1924). These intravasal tissues may correspond to the heart body which other annelids possess but serpulids and sabellids lack.
The Histochemical Demonstration of Keratin by Methods involving Selective Oxidation
Authors: Pearse A. G. Everson 
Published: April 2021

ABSTRACT
Oxidation of tissues with performic acid gives rise to histochemically detectable reaction products particularly in two classes of material. These are keratin and lipoids of the phosphatide class. Three methods have been evolved for visualizing the effect of performic acid on cystine-containing structures; two of these (performic acid/Schiff and perfoimic acid/cobalt nitrate) also record the effect on lipoids. An attempt has been made to elucidate the chemistry of the reactions and it is suggested that oxidation of cystine in the tissues gives rise not only to cysteic acid (alanine-beta-sulphonic) but to another acid (alanine-beta-sulphinic). The latter is responsible for the positive reaction with Schiff’s solution. The Schiff reaction with performic acid oxidized lipoids is due to the formation of substances giving the reactions of aldehydes. It is possible that similar groups may be produced from lipoid molecules by periodic acid oxidation and that these and not polysaccharides (ri glycols) are responsible for the periodic acid-Schiff reaction in such cases.
The Cytosome of differentiating Cells in the Ovotestes of Slugs
Authors: Pelluet D. , Watts Anne H. G. 
Published: April 2021

ABSTRACT
The distribution of ascorbic acid, alkaline phosphatase, and mitochondria has been followed during the differentiation of germinal epithelium cells into spermatogonia, oocytes, and nurse-cells in the ovotestes of slugs. All three substances appear in the cytoplasm of the oocyte and increase during its growth. Occasionally the oocyte nucleolus gives a positive test for ascorbic acid. The heads of the mature spermatozoa contain alkaline phosphatase. The cytoplasm of the germinal epithelium, spermatogonia, and spermatocytes occasionally gives’ a positive reaction for ascorbic acid. The development of the nurse-cells is accompanied by an increase in the size of the mitochondria. Attachment of the spermatids results in a decrease in size and number of the mitochondria in the nurse-cells. Alkaline phosphatase, ascorbic acid, and mitochondria show no significant change, either in form or quantity, in the indifferent cells of the ovotestis by which one could predict their destiny.
The Structure and Function of the Basement Membrane Muscle System in Amphiporus lactifloreus (Nemertea)
Authors: Cowey J. B. 
Published: April 2021

ABSTRACT
The body wall of A. lactifloreus has the following structure from the outside inwards.
A basement membrane of five to six layers immediately underlying the epithelium. Each layer consists of right-hand and left-hand geodesic fibres making a lattice, whose constituent parallelograms have a side length of from 5 to 6μ. The fibres are attached to one another where they cross ; so there can be no slipping relative to one another. A layer of circular muscle-fibres running round the animal containing two systems of argyrophil fibres—one of fibres at intervals of 10μ. running parallel to the muscle-fibres and the other of fibres running radially through the layer from the basement membrane to the myoseptum. A myoseptum which is identical in structure with a single layer of the basement membrane. A layer of longitudinal muscle, whose fibres are arranged in layers on each side of a series of longitudinal radial membranes.
Membranes identical in structure with the basement membrane invest the nerve cords, the gut, the gonads, and the proboscis.
The interrelations of argyrophil and muscle-fibres in the muscle layers is described and their functioning discussed.
The system of inextensible geodesic fibres is analysed from a functional standpoint. The maximum volume enclosed by a cylindrical element (cross-section circular), of such a length that the geodesic makes one complete turn round it, varies with the value of the angle θ between the fibres and the longitudinal axis. When θ is o° the volume is zero; it increases to a maximum when θ is 54° 44’ and decreases again to zero when θ is 90°. The length of the element under these conditions varies from zero when θ is 90° to a maximum (the length of one turn of the geodesic) when θ is o°.
The body-volume of the worm is constant. Thus it has a maximum and minimum length when its cross-section is circular, and at any length between these values its cross-section becomes more or less elliptical. It is maximally elliptical when θis 54° 44’, i.e. when the volume the system could contain, at circular cross-section, is maximal. From measurements of the ratio of major to minor axes of this maximally elliptical cross-section, the maximum and minimum lengths of the worm relative to the relaxed length and values of θ at maximum and minimum length are calculated. The worm is actually unable to contract till its cross-section is circular; but measurements of its cross-sectional shape at the minimum length it can attain, permit calculation of the theoretical length and value of θ for this cross-sectional shape.
Calculated values of length and the angle θ agree well with the directly observed values.
On the Nutrition of Ochromonas
Authors: Pringsheim E. G. 
Published: April 2021

ABSTRACT
A species of the chrysophycean genus Ochromonas from England was grown in pure culture and compared with similar strains isolated in the United States. Although these organisms possess chromatophores with chlorophyll, they need organic substances not only as a source of nitrogen compounds, but as independent carbon and energy sources; they also require certain growth factors. Peptones are better as nitrogen sources than single amino-acids, few of which give satisfactory results. The utilization of inorganic nitrogen could not be demonstrated. As carbon sources sugars, alcohols, and fats, and, to a lesser degree, acetate, are suitable. Growth factors contained in liver extract, milk and yeast autolysate, and in smaller amounts in most peptones, are indispensable. Enzymes hydrolyzing starch, sucrose, fat, and protein are excreted.
Ochromonas ingests and digests starch grains, casein, oil droplets, and small organisms. Neither bacteria nor yeast nor small algae were found able to support growth of any of the strains, even in the light. An additional carbon compound and possibly special vitamins are required. The hypothesis is put forward that phagotrophy chiefly serves for obtaining chemical compounds which the cell cannot synthesize itself and which have the character of vitamins. Phagotrophy therefore supplements the other means of nutrition, in the main qualitatively, while sugar, &c., supplement it quantitatively and are indeed indispensable.
The same media which support ample growth in the light do so also in the dark. This shows that photosynthesis is of little importance for the growth of the organisms, although it keeps them alive for long periods, while in the dark they soon die.
Correlated with the manifold ways of acquiring food, there is also a remarkable variability in the size and shape of the cells, and still more in the dimensions and pigmentation of the chromatophores, and in the reserves stored as leucosin, volutin, and oil. These features which now prove to depend so much on conditions have previously been widely used in the diagnosis of species. The basis of classification should therefore be revised. Apart from the stigma, which is specific, use ought to be made only of those characters whose variation with conditions is reasonably well known.
The extraordinary nutritional versatility of Ochromonas is considered to be a primitive character. From ancestors with a mixed nutritional habit, phototrophic, phagotrophic, and saprotrophic flagellates seem to have evolved, each with only one of the three modes of nutrition that are combined in Ochromonas.
The Effects of Single Doses of Pilocarpine and of Histamine upon the Granules of Oxyntic Cells of Rats, with Special Reference to their Phospholipine Content
Authors: Menzies Gordon 
Published: April 2021

ABSTRACT
New data are presented on the morphology and cytochemistry of the granules of the oxyntic cells of the rat’s stomach in continuation of work previously reported (Menzies, 1949). The effects of single injections of pilocarpine and of histamine on the granules were investigated, with particular reference to their phospholipine content as shown by Baker’s acid haematein method. Pilocarpine causes a marked enlargement of the granules with loss of phospholipine from the central part of many of the larger granules, and complete loss of phospholipine from others. The granules that have lost their phospholipine probably still contain lipoid as shown by sudan black. Pilocarpine also causes marked aggregation of the granules. Histamine causes a less marked increase in granule size and no observable loss of phospholipine, but some of the granules became elongated, an effect that can be seen with the phase-contrast microscope, and there is a tendency for them to recede to the peripheral parts of the cells associated with an enlargement of the intracellular canals. Both pilocarpine and histamine result in some enlargement of the oxyntic cells, the effect being more marked with pilocarpine. Neither pilocarpine nor histamine alters the size or shape of the non-lipoid moiety of the granules. Supravital colouring with neutral red shows a few droplets in oxyntic cells in the bases of the gastric glands. These enlarge slightly after histamine and greatly after pilocarpine, and they are always spherical. It has not yet been possible to decide as to their exact nature.
Experiments with P32 and I131 on Species of Helix, Arion, and Agriolimax
Authors: Fretter Vera 
Published: April 2021

ABSTRACT
If Helix aspersa, H. pomatia, Arion hortensis, and Agriolimax agrestis be fed on a diet which contains P32, autoradiographs show that the isotope is taken up by the digestive and lime cells of the digestive gland. From the formermost of it passes to the haemocoel, though some is retained for immediate metabolic activities ; in the lime cells it is stored in calcium spherules. A very small amount of the tracer enters the body through the wall of the oesophagus, and more through the intestine, this site of diffusion being most pronounced directly after hibernation.
The P32 in the haemocoel is dispersed to all tissues : all of them take up a little ; in some it becomes concentrated. Concentrations appear in the nerve ring, the mucous and salivary glands, the odontophore and certain cells of the mantle.
In the nervous system deposits are heavy around the fibres and slight in the cytoplasm of the cells ; they indicate a compound, soluble in alcohol, which may be phos-pholipine, associated with medullated nerves.
The phosphorus in mucous cells, most pronounced in the pedal and salivary glands, may be combined with the calcium which stabilizes mucus and prevents its rapid dispersal.
The incorporation of isotope into the developing tooth of the radula indicates the relative activity of the basoblasts and cuspidoblasts : in early development of a tooth the basoblast secretes more actively, but as it becomes effete secretion by the cuspidor-blast is accelerated. When the tooth is liberated from the latter there is no further addition to its substance.
Phosphorus deposits in the mantle are in the calcium cells which secrete the shell. Here, as in the lime cells, and around certain blood-vessels, excess may be stored as calcium phosphate ; reserves in the digestive gland are the largest.
Amoebocytes concerned with the regeneration of the shell of Helix pomatia and H. aspersa carry the tracer element, and some of it is deposited in the shell. Also in the slug the tracer is transported by amoebocytes.
Radioactive iodine in the lumen of the gut is taken up most readily by digestive cells ; some enters the lime cells. Only in sparing quantities does this isotope pass from the gland to the rest of the body, and this entry is presumably associated with ionic exchange. It is not accumulated in any cell, except in the kidney whence it is excreted ; it leaves the digestive cells to pass from the body with the faeces.