bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Site of Damage in Amoebae Exposed to Lethal Concentrations of Methyl di-(β-Chloroethyl)-Amine (a ‘Nitrogen Mustard’)
Authors: Ord M. J. , Danielli J. F. 
Published: April 2021

ABSTRACT
The technique of nuclear transfer in Amoeba proteus was used to study the extent to which methyl di-(β-chloroethyl)-amine damages nucleus and cytoplasm. Results obtained showed that cytoplasm was damaged directly by the drug; exposure of normal cytoplasm to nuclei damaged by β-chloroethylamine for up to 3 days caused no lethal damage. Nuclei were probably directly damaged, but could also be damaged by injured cytoplasm, normal nuclei being lethally damaged when exposed to injured cytoplasm for only 2 hours. Death from lethal cytoplasmic damage generally occurred within a few days; animals with lethally damaged cytoplasm seldom divided. Death from lethal nuclear damage was delayed in some cases for as long as 6 weeks, such nuclei being able to divide once or twice before death.
The Fate of ‘Thorotrast’ (Thorium Dioxide) injected into the Dorsal Lymph Sac of the Frog, Rana temporaria
Authors: Foxon G. E. H. , Rowson K. E. K. 
Published: April 2021

ABSTRACT
Thorotrast (a colloidal suspension of thorium dioxide) injected into the dorsal lymph sac of the common frog, Rana temporaria, can be shown by radiological methods to pass through the anterior lymph hearts and so into the blood system. From the blood the thorotrast is removed, as in mammals, by cells of the reticulo-endothelial system and by macrophages, the sites of greatest activity being the liver, spleen, and bone-marrow. Whereas in mammals almost all uptake of such colloidal substances takes place in these organs, in the frog there is considerable macrophage activity elsewhere, notably in the submucosa of the alimentary canal. Our results suggest that macrophages which ingest thorium particles in the wall of the alimentary canal migrate through the blood system to the liver where the thorium is ultimately deposited. This may be correlated with the possession by the frog of a macrophage and reticuloendothelial system less highly organized than that possessed by mammals.
The Histochemical Recognition of Phenols, especially Tyrosine
Authors: Baker John R. 
Published: April 2021

ABSTRACT
Sections of tissue embedded in collodion are heated in an acidified aqueous solution of mercuric sulphate and sodium nitrite. A red colour denotes the presence of phenols (generally the tyrosine of proteins). The reagent is more rational than Millon’s and most of the modifications of his method used up till now in histochemistry. It gives a particularly strong coloration.
The Morphology of the Golgi Bodies with reference to Secretion in the Liver-cells of the Slug, Anadenus altivagus, as seen under the phase-contrast Microscope
Authors: Rishi Rajinder 
Published: April 2021

ABSTRACT
Golgi bodies in the living liver-cells of the slug, Anadenus altivagus, exist in two forms: (a) homogeneous granules or spheres of dark contrast, and (b) spheres showing a duplex structure with a light greyish internum and a dark externum, which may be single or composite. The greyish internum of these duplex spheroids grows into the secretory granules, the dark externum disappearing in the process of growth. Mitochondria appear as fibres of light greyish contrast with a dark granule at each tip. This dark granule disassociates itself from the mitochondrion and forms the Golgi granule of dark contrast—the Golgi ‘pre-substance’. The Golgi pre-substance, stainable with neutral red, forms the Golgi spheroids.
Mitotic Activity during the Early Differentiation of the Scleral Bones in the Chick
Authors: Hale L. J. 
Published: April 2021

ABSTRACT
The dispositions of mitoses in the mesenchyme beneath the conjunctiva of parts of a 7-, 8-, 9-, and 10-day embryo have been ascertained. For the purpose of analysis, the number of mitoses, cell population density, and mitotic index have been found in small segments of annuli which include parts of the rings of bone primordia, and the mesenchyme between them. Twenty-three primordia were studied.
It is found that the cell population density increases from about 4−14 × 105 per cubic mm within the primordia, but only from about 4−9 × 105 in the mesenchyme between them.
Mitotic activity increases sharply within young primordia from about 12-27 mitoses per 1,000 cells, and thereafter decreases. It is found that this mitotic activity probably occurs in three waves of decreasing intensity. Between the primordia mitotic activity is at a markedly lower level and probably follows a simpler pattern.
The cells involved in this mitotic activity in the primordia are particularly those just beneath the conjunctival papilla, and the number of mitoses decreases the greater the distance from the conjunctiva. In the 8-and 9-day embryos, the number of mitoses is inversely proportional to the distance.
Calculation indicates that in each of the three waves of cell division, the cells that divide do so only once; and that this mitotic activity is adequate to account for the increase in cell population density which is found.
The cause of the increase in the number of cell divisions in the primordia is not clear, but the result is probably the production of blastemas, the cells of which become the osteoblasts of the scleral bones.
Mesodermal Cell Deaths during the Early Development of the Scleral Bones in the Chick
Authors: Hale L. J. 
Published: April 2021

ABSTRACT
The positions of degenerating cells in the mesenchyme of the scleral bone pri- mordia of the chick, and in the fibrous sclera beneath them, have been ascertained. It is shown that the number of cell deaths within the bone primordia, and also beneath them in the fibrous sclera, is markedly higher than, and follows a different pattern from the regions between. A centre of cell destruction is seen to occur at and near to the boundary of the mesenchyme and fibrous sclera. This begins in 7- to 8-day primordia, rises to a peak at 8 to 9 days, and subsides in 9- to 10-day primordia. A second centre of cell death occurs in the mesenchyme nearer to the conjunctival papilla. It starts in 8- to 9-day eyes about mid-way between the conjunctiva and sclera, and as it increases in intensity, the centre moves nearer to the conjunctival papilla (9 to 10 days), beneath which it appears to subside (some 10-day primordia). The function of these waves of cell destruction is discussed. It is concluded that their most likely function is morphogenetic; they may make a space into which the osteogenic cells migrate, or they may ensure a normal position and shape for the developing bone. Consideration has also been given to the possibility that the products of cell death might have a histiogenetic function.
Studies of Serpulid Tube Formation: I. The Secretion of the Calcareous and Organic Components of the Tube by Pomatoceros triqueter
Authors: Hedley R. H. 
Published: April 2021

ABSTRACT
Calcium carbonate, in a finely granular form, is secreted into the fold of the peristomial collar by a pair of tubulo-racemose glands in the peristomium.
Most of the organic material of the tube is secreted by the ventro-lateral epithelial cells which surround the main ducts of the calcium-secreting glands. These cells are always filled with a basiphil mucigen which contains some free a-glycol groups. This material retains its affinity for basic dyes and for ferric iron at a low pH. The affinity for iron is retained when the pH is low enough to exclude carboxyl and phosphoric acid groups from the reaction and it is probable that the sulphuric acid groups are responsible..
The reactions of this mucigen to histochemical tests together with the similarity in behaviour of a precipitated heparin preparation make it likely that the material is a sulphomucopolysaccharide.
The Growth and Development of a Viviparous Compound Ascidian, Hypsistozoa fasmeriana
Authors: Brewin Beryl I. 
Published: April 2021

ABSTRACT
The viviparity recorded for this ascidian parallels that of placental mammals in reduction of the number and size of the eggs, the development of extra-embryonic membranes, and the prolongation of larval development with increase in the gestation period.
The ovum is alecithal, 25 μ. in diameter; it develops within an oviducal brood pouch in which the lining cells become distinctly modified and which remains attached to the parent for 5! months.
Exposure of the embryo to the lumen of the pouch is brought about by rupture of the overlying follicle cells due to enzyme secretion by the dorsal-most cells of the blastula.
Endodermal development is precocious. At the gastrula stage the future oesophageal region, the future stomach, and a pair of endodermal tubes are distinguishable.
The paired endodermal tubes are unique in the ascidians. They are larval structures which disappear after metamorphosis and bear no relation to the functional stigmata of the oozooid. They resemble the branchial tubes of the Appendicularia, developing as blind outgrowths which later open through to the exterior ; but in this species they open dorsally, not ventrally. They act as passive channels through which material from the pouch passes into the gut (a bolus being present from the gastrula stage onwards) and as anchoring strands for the ectotrophe.
This extra-embryonic membrane formed by elevation of the dorsal ectoderm ultimately practically envelops the embryo and becomes apposed to the lining of the pouch. It is extremely simple, exhibits no vascularization, makes no actual liaison with the oviducal epithelium, and shows little cell differentiation.
Extra-embryonic material reaches the embryo indirectly by diffusion across the ectotrophe (which unlike the remaining embryonic ectoderm secretes no test), and directly through the endodermal tubes. The latter method is the more important during early stages of development, the former during later stages.
The production of an extremely large and complex tadpole with numerous buds at an advanced stage of organogenesis testifies to the success of this type of viviparity.
On the Origin of the Electric Organ in Malapterurus electricus
Authors: Johnels Alf G. 
Published: April 2021

ABSTRACT
The present study was made on two small specimens of Malapterurus electricus, of standard lengths n.4 and 12.7 mm. As is well known, the postembryonic growth of electric organs in Malapterurus and other electric fishes takes place by an enlargement of the electric units and not by an increase in the number of the electric plates. In the present material, however, there is a multiplication of electric tissue elements in the rostral portion of the electric organ. The structure of this multiplication zone is described. In the anterior region the connective tissue membranes which surround the two halves of the electric organ form structures similar to tendons which are fixed to the ventral surface of the shoulder girdle on each side of the median line. A small deficiency on each side in the muscular wall in the same region was observed in adult specimens by Maurer. This deficiency is more evident in the young specimens studied in the present paper and it is covered from the outside by the multiplication zone of the electric organ. In this place the electric nerve joins the electric organ. The giant electric cell, the surface of which is penetrated by intracellular capillaries, is situated in the anterior part of the spinal cord and its axon emerges with the third ventral spinal root. In the multiplication zone the connective tissue membranes are completely independent of the dermal connective tissue and the space between the electric organ and the skin is of a conventional subdermal type. These circumstances strongly indicate that the electric organ is of myoblastic origin in Malapterurus as in all other electric fishes known in this respect. Nothing has been observed which supports the idea of an adenoid origin of the electric organ in Malapterurus.
Formation and involution of striated muscle fibres during the growth and moulting cycles of rhodnius prolixus : (hemiptera)
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
The ventral intersegmental muscles of the abdomen in Rhodnius undergo a cycle of development and involution during each larval stage. They are fully developed only at the time of moulting or hatching from the egg. Within 3 or 4 days after moulting the fibrils have disappeared ; but the nuclei, with a little cytoplasm containing mitochondria, survive within the highly folded muscle-sheath.
The formation of fibrils begins between 2 and 3 days after feeding. At first they are uniformly birefringent. The striations appear later, and the muscles will then contract after transection. The fibrils are 0·1–0·2μ thick when first formed; they grow by intussusception and splitting to a thickness of about 0·8 μ.
Succinoxidase first appears in quantity in the mitochondria at the time when striation and contractility develop. It disappears within 3 days after moulting, during the involution of the fibrils. The distribution of ribonucleic acid in the developing muscle is described.
Involution results from autolysis which begins around the nuclei in the centre of the muscle. The phagocytic blood-cells play no part in the break-down.
The rich nerve-supply to the muscles persists apparently unchanged throughout the cycle of involution; and the cycle of growth occurs normally after section of the nerves.
A Note on Insect Wing Veins and their Tracheae
Authors: Smart John 
Published: April 2021

ABSTRACT
Experiments involving interference with the tracheae of the nymphal fore-wing pad of the American cockroach (Periplaneta americana (Linn.)) are described and the results discussed. It is concluded that the pattern of the tracheae is not immutable and so cannot be regarded as fundamental in determining the pattern of the imaginai wing-venation ; the pattern may, however, continue to be used, in the first instance, as a guide to the more fundamental pattern of the lacunae that precede the veins.
The Growth of the Trout Retina
Authors: Lyall A. H. 
Published: April 2021

ABSTRACT
I. The growth of the trout eye is negatively allometric in relation to body-length.
The relative thicknesses of the retinal layers, and their cell densities, change as the eye grows. The addition of new cells takes place from a peripheral growth zone. Measurements from a wide size-range of trout retinae show that the dimensions of the cone pattern increase as the retina grows. The relative importance of these two processes changes as the eye grows; in early growth the addition of new cells is the principal factor, but the enlargement of the cone pattern, which occurs at an almost constant rate throughout growth, becomes more significant later.
A Histochemical Study of the Connective Tissue-Fibres in the Leech, Glossiphonia complanata
Authors: Bradbury S. 
Published: April 2021

ABSTRACT
The fibres and the connective tissue ground-substance of Glossiphonia complanata have been studied morphologically and histochemically. The fibres, which run in the connective tissue-substance between the organs of the body, are cytoplasmic extensions of bipolar or multipolar cells. The average diameter of the fibres is between 1 and 2 μ, and a single fibre may exceed 100 μ in length. Each fibre is differentiated into a cortex and a medulla. The cortex contains arginine, and some acid and neutral mucopolysaccharides ; this suggests that it is collagenous. The medulla is an extension of the protoplasm of the cell-body.
The cell-body of the fibre has a basiphil cytoplasm which contains arginine, acid and neutral mucopolysaccharides, and much ribonucleic acid. Spherical lipochondria up to 4 μ in diameter are present in the cytoplasm, especially near the nucleus ; they contain chiefly phospholipid. Threadlike mitochondria are present in the cytoplasm of this cell.
The connective tissue ground-substance is present as a matrix between the cells and organs of the body. Histochemical tests showed that it contains small amounts of arginine, tyrosine, neutral and acid mucopolysaccharides. The refractive index of the ground-substance is about 1·35.
The Chemical Composition of Lipid Globules in the Neurones of Helix aspersa
Authors: Chou J. T. Y. 
Published: April 2021

ABSTRACT
1. The three kinds of globules that can be recognized in the living neurone of Helix aspersa are sharply distinguishable from one another by histochemical tests.
2. One kind of globule contains phospholipid; another appears to consist of triglyceride ; the third is complex chemically, containing mixed lipids with some protein and carbohydrate.
3. When osmium techniques for the ‘Golgi apparatus’ are applied to this particular cell, phospholipid is blackened.
Cytoplasmic Inclusions of the Neurones of Gastropods
Authors: Malhotra S. K. 
Published: April 2021

ABSTRACT
The neurones of the sub-oesophageal ganglionic mass of the Simla slug, Anadenus altivagus, and the Bharwain snail, Euaustenia cassida, have been investigated by phasecontrast microscopy of the living cells and in fixed preparations. The mitochondria are seen as granules and filaments in both living and fixed material. Alignment of granules into filamentous mitochondria has also been observed in the fixed preparations. The lipid spheroids (corresponding to the ‘binary spheroids’ of Thomas and the ‘lipo-chondria’ of Roque) are sudanophil, osmiophil, and argentophil. The bigger spheroids show a duplex structure, consisting of a cortical, chromophil, lipid component, which may be in the form of a complete ring (Anadenus) or in the form of one or two granules or a crescent (Anadenus and Euaustenia), and a chromophobe medulla (neutral red vacuome of Parat), in which lipochrome develops to form the ‘mulberry spheroids’ of Thomas. The small homogeneous lipid spheroids also contribute to the formation of ‘mulberry spheroids’.
A Note on the Opacity to X-Rays of Tissues fixed with Mercuric Chloride
Authors: Foxon G. E. H. 
Published: April 2021

ABSTRACT
The radiography of ‘soft’ tissues normally requires special X-ray apparatus which generates soft X-rays. Fixation with mercuric chloride, either alone or in mixture, has been found to render such ‘soft’ tissues opaque to those harder X-rays generated by normal clinical X-ray apparatus. Radiographs made by the use of such standard apparatus may be useful in several fields of biological research such as anatomical investigation and illustration, or in the study of the penetration and behaviour of the fixatives themselves.
The Growth of Mixed Populations of Chilomonas paramecium and Tetrahymena patula
Authors: Mučibabić Smilja 
Published: April 2021

ABSTRACT
In mixed cultures, where Tetrahymena patula preys on Chilomonas paramecium, the growth of the Chilomonas population does not initially differ significantly from that in single cultures. Later, however, the decrease in numbers of Chilomonas is more rapid in mixed cultures, where it dies out after two months.
The composition of the polymorphic Tetrahymena patula population depends on age and on the presence or absence of Chilomonas. Slitmouthed forms are absent at the beginning of growth in both mixed and single cultures, and only appear subsequently in mixed cultures. The percentage of these forms increases in older cultures. The percentage of microstomatous forms is larger, however, at the beginning of population growth, both in mixed and single cultures. The percentage of macrosto-matous forms increases from the beginning, reaches a maximum, and then decreases. Cannibalism has been observed in old mixed cultures.
Significant differences in the size of individual organisms of Chilomonas between single and mixed cultures appeared from the beginning of the logarithmic phase of growth, and were pronounced up to the end of observations. Significant differences in the size of Tetrahymena patula between single and mixed cultures appeared somewhat later, from the sixth day onwards.
The differences in size and shape between organisms in cultures of the same kind but of different ages were also significant. Variation in size and shape of both species was greater in mixed than in single cultures.
A Bleaching Method for Melanin and two Staining Methods
Authors: Chesterman W. , Leach E. H. 
Published: April 2021

ABSTRACT
An acidified permanganate method can be used for bleaching melanin in mammalian skin and eyes. It allows good staining to be performed later.
Microfilariae in nitrocellulose sections can be stained by a modified phloxine tartrazine method.
Elastic fibres can be selectively stained by using a diluted solution of synthetic orcein.
The Vascular System of Crustacean Compound Eyes, especially those of the Euphausid, Meganyctiphanes norvegica
Authors: Mauchline J. 
Published: April 2021

ABSTRACT
When the compound eyes of Meganyctiphanes and a number of decapods were examined a constant general pattern of blood-vessels was found.
The optic artery produced a branch to each of the following: the medulla terminalis, medulla interna, medulla externa, lamina ganglionaris, and the subretinal region. It then terminated in the dorsal region of the eye, passing the remaining blood into the ommatidial sinus.
The blood from the ommatidial sinus and from the systems of fine vessels in the nerve ganglia and subretinal region flows into the eye-stalk sinuses, whence it reaches the cephalothoracic sinuses.
The Utilization of I131 by Certain Lamellibranchs, with Particular Reference to Shell Secretion
Authors: Beedham G. E. , Trueman E. R. 
Published: April 2021

ABSTRACT
A study of the utilization of I131 by the lamellibranchs Anodonta cygnea, Sphaerium comeum, and Mytilus edulis has been made with particular reference to the secretion of the valves and ligament.
While autoradiographs show that I131 is localized in the alimentary canal and digestive gland, the main distribution of the isotope is on the surfaces of the shell and body exposed to the radioactive medium. The iodine associated with the shell occurs principally on the periostracum. There is, however, no positive evidence to show that I131 is actively incorporated into the shell by the secretory activity of the mantle. The results are discussed in relation to the ability of other invertebrates to accumulate protein-bound iodine.
The Action of Colchicine on the Intestinal Epithelium of the Cat and Dog
Authors: Mcminn R. M. H. 
Published: April 2021

ABSTRACT
Varying doses of colchicine have been administered intraperitoneally to cats and dogs in order to study histologically the reactions in the epithelium of the small intestine. In normal animals of both species, approximately 1 % of the total number of epithelial cells in the ileum are in mitosis at a given time. After exposure to colchicine for 5 h, the maximum number of arrested mitoses in the cat was found to be 3—77%; in the dog the maximum number rose to 17—12%. The results indicate that in the epithelial cells of the dog’s small intestine, colchicine not only arrests mitosis in meta-phase, but also stimulates the cells to enter mitosis.