bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Structure of the Lachrymal Glands
Authors: Boll Franz 
Published: April 2021

ABSTRACT
Recently, in histological researches, peculiar star-shaped cells have been noticed in the aciniferous glands. Krause was the first man who isolated these, in the case of the parotid of a cat, by means of maceration in vinegar. He is inclined to treat them as nervous organs. Henle also describes stellate cells in the walls of the rennet glands, as well as the parotid and mammæ. He also thinks that they are most likely of a nervous character, although he has. never seen any connection with the nerve-fibres. Pflueger describes multipolar cells in the salivary glands of the rabbit. He holds them to be multipolar ganglion-cells, and observed on one side their connection with the fibres, and on the other-side with the secretory epithelial cells. Finally, Kölliker has made closer researches concerning the cells in question in the salivary glands. He considers them to be simply forms of the covering structure of the alveolus, which seem to him to represent a kind of reticulum.
Observation, on the Breeding and Development of the viviparous fish, Heterandria formosa
Authors: Fraser Elizabeth A. , Renton Rachel M. 
Published: April 2021

ABSTRACT
A short account is given of the breeding habits of Heterandria formosa in an aquarium. The ovary and the mature ovum are briefly described, the noteworthy feature of the ripe ovum being the small quantity of yolk. 8. Degeneration of ova is found to be a common occurrence in unfertilized females, and to a less extent in those full of developing embryos. The method for ensuring the fertilization of the egg within the follicle is portrayed. Over the area where the spermatozoa have entered the cells of the ovarian epithelium and those of the follicle form a solid plug which eventually disrupts to enable the fully developed embryo to escape into the cavity of the ovary. It is characteristic of early development that the egg is encircled by a unilaminar ectoderm before there is any visible differentiation into endoderm and mesoderm. Owing to the scarcity of yolk only a few periblast cells arise and no syncytial layer is formed. The primitive-germ cells are visible at an early stage within the apparently undifferentiated mesendoderm cells. A striking feature is the large size of the pericardium and its growth upwards as a pericardium hood which completely surrounds the head region of the embryo. Over the walls runs a network of blood-vessels from which the maternal capillaries become eventually separated by only an attenuated layer of protoplasm. Both respiration and nutrition are effected through the follicle. A remarkable specialization is the development of a urinary bladder which expands into a thin-walled vesicle of enormous dimensions, finally occupying almost the entire area formerly filled by the pericardium and the yolk-granules. The development of Heterandria is compared with that of other viviparous fishes. The significance of the unusual features in early and late development is discussed and some comparisons are made with the conditions in higher vertebrates.
Facts bearing on the Structure and Arrangement of a Nervous Mechanism demonstrated in the Auricle of the Frog’s Heart
Authors: Beale Lionel S. 
Published: April 2021

ABSTRACT
The rhythmic contractions of a portion of the muscular tissue of the heart continue for some time after it has been severed from the rest of the organ and removed from the body. A closely allied fact is observed in the case of the muscular coat of the intestinal canal; and in some muscles of insect larvæ, which have been removed from the body with due care, the muscular tissue continues to contract for some time after its removal. The muscles of the common maggot will retain their contractility for an hour or more after they have been placed upon a glass slide (“Croonian Lecture,”‘Proceedings of Royal Society,’ May 11, 1865, p. 229).
Monograph of Monera
Authors: Häckel Ernst 
Published: April 2021

ABSTRACT
While on the one hand the kingdom of the Protista is increased by the Labyrinthulea with a separate class, on the other hand it may now be satisfactorily proved that another group of Protista should be removed from this kingdom, and referred to the animal kingdom as decided animals. These are the Sponges, of whose animal nature very decided morphological indications have been very reeently discovered. As long ago as 1854, Leuckart, the illustrious founder of the sub-kingdom Coelenterata, in his yearly report upon the progress of zoology (in the ‘Archiv für Naturgeschichte’), united the sponges or Poriphera with the Coelenterata, by a comparison of the canal system of the sponges with the cœlenteric gastrovascular apparatus of the true Coelenterata.
A Phase Contrast Study of the Blood-cells in Prodenia Larvae (Order Lepidoptera)
Authors: Colvard Jones Jack 
Published: April 2021

ABSTRACT
The various classes of blood-cells in air-dried, Wright-stained blood-smears described by Yeager (1945) from heat-fixed Prodenia can be recognized in unfixed and unstained preparations with the phase microscope. With only one exception, the blood- cells do not undergo extensive transformations in vitro for at least one hour. Hence, the blood-cells may be accurately identified and differentially counted by phase microscopy. Two kinds of blood-cells undergo marked alterations in appearance on heatfixation, whereas the other types remain mostly unmodified. One type of blood-cell, the oenocytoid, typically undergoes a marked change in character in vitro in unfixed blood. Several changes in Yeager’s classification of insect blood-cells are proposed, and it is suggested that this new system will be found sufficient for identifying and comparing blood-cells in the different orders of insects.
The Innervation of the Gut of the Brown Trout (Salmo trutta)
Authors: Burnstock G. 
Published: April 2021

ABSTRACT
The extrinsic and intrinsic innervation of the trout gut has been examined by using methylene blue, osmium tetroxide, and silver staining techniques. Left and right vagus nerves penetrate the oesophageal wall and run between the longitudinal and circular muscle-coats of the stomach, but do not reach the intestine. Branches of these nerves anastomose with each other and become incorporated into Auerbach’s plexus. Pericellular endings of vagal fibres are found about enteric neurones in the stomach, while some fibres end directly on the striated muscle-cells of the oesophagus. A single, fine, anterior splanchnic nerve anastomoses along the major branches of the coeliaco-mesenteric artery to supply both the stomach and intestine. Most of the splanchnic fibres pass directly into the smooth muscle-coats, but some fibres run into the subserous plexus. Two posterior autonomic nerves provide separate innervation of the rectum. Three main types of nerve-cells have been distinguished in the gut by their distribution as well as structure. (a) Small uni-, bi-, and multi-polar cells (10-15 μ in diameter) form the main body of Auerbach’s plexus, lying between the muscle-coats. Throughout most of the gut they are not arranged in true ganglia, since only from 1 to 3 neurones occur at the nodes and many cells lie singly along the internodal connectives. (v) A smaller number of large multipolar neurones (30-60μ in diameter) lie halfembedded in the longitudinal muscle along the whole length of the gut, their principal axons passing down to lie between the muscle-coats in Auerbach’s plexus. (c) A third cell type consisting mainly of large mono-or bi-polar cells (30-70 µ in diameter) contributes to Auerbach’s plexus in the stomach only and is associated with the endings of vagus nerve-fibres. Bundles of nerve-fibres pass down through the circular muscle-coat from Auerbach’s plexus to join a loosely arranged plexus of nerve-fibres, the submucous plexus; but unlike Meissner’s plexus of mammals, which occupies a similar region, no nerve-cells are present. Nerve-endings, some of which may be sensory, are located at the bases of the mucous epithelial cells and are continuous with fibres forming a prominent subepithelial plexus from which fibres pass to both submucous and Auerbach’s plexuses. A subserous plexus and ‘interstitial cell network’ are also present in the fish gut. A quantitative study of nerve-cell densities in different regions of the trout gut revealed density peaks of 93 cells per square mm and 170 cells per square mm in the posterior cardiac stomach and anterior duodenum respectively. The ratio of small to large neurone types in Auerbach’s plexus is about 20 to 1 in all regions. The total number of nerve-cells in the whole gut was calculated to be about half a million.
The Feulgen Reaction in the Different Stages of the Life-cycles of Certain Sporozoa
Authors: Dasgupta B. 
Published: April 2021

ABSTRACT
The nuclei of the male and female gametocytes of the malarial parasites (Plasmodium and Hepatocystis) are Feulgen-negative, while the nuclei of the gametocytes of Hepatozoon, which are not sexually differentiated, are Feulgen-positive. The nuclei of the male gametocytes of Eimeria are strongly Feulgen-positive, while the nuclei of the female gametocytes are Feulgen-negative. The nuclei of the male gametes of Plasmodium are Feulgen-negative, while the nuclei of the male gametes of Eimeria are strongly Feulgen-positive. DNA appeared to be present in the gametocytes of Plasmodium when the fluorescence method of Armstrong (1956) was employed.
Feulgen-positive inclusions have been found to occur in the cytoplasm of some of the oocysts of Plasmodium. The oocysts containing such inclusions may degenerate totally or partially. There is no evidence to relate this type of degeneration with the formation of Ross’s black spores. These inclusions have been found in abundance in the oöcysts of P. cynomolgi, while in those of P. gallinaceum they were found only once.
Certain Feulgen-positive granules have been found in the cytoplasm of some of the oocysts and the female gametocytes of Eimeria. These granules did not appear to be related to any degenerating changes. A probable loss of some of the nuclei during sporogony of Eimeria is discussed.
The nuclei in the early pre-erythrocytic schizonts of Plasmodium cynomolgi are Feulgen-positive, notwithstanding an earlier report to the contrary.
The Masked Lipids of Nuclei
Authors: Chayen J. , Gahan P. B. , La Cour L. F. 
Published: April 2021

ABSTRACT
The histochemistry of masked lipids of chromosomes has been investigated with the aid of paper chromatographic procedures. At least three tightly bound associations of phospholipid with protein have been identified in calf thymus nucleohistone. Hence it seems likely that the ‘spurious’ reactions of nuclei and of nucleohistone, especially after extraction with lipid solvents, is a true indication of the increased availability of these closely linked phospholipids. Moreover, not more than about 10% of the material extracted by hot pyridine from calf thymus was fatty, the rest being watersoluble. After treatment of plant cells with hot trichloroacetic acid had produced increased staining with methods for demonstrating lipids, fatty matter could be extracted from the tissues. This demonstrates that the cells which gave the ‘spurious’ reaction did contain lipid. Hence it seems probable that extraction with solvents does not remove all lipids but may make those that remain more availabel for staining, so giving rise to what has been considered to be a spurious reaction.
The nature of the binding of lipid to protein and the relevance of such complexes to histochemistry and the composition of nuclei are discussed.
Neurosecretory Cells in the Abdominal Ganglia of Larvae of Lucilia caesar (Diptera)
Authors: Fraser Alastair 
Published: April 2021

ABSTRACT
Ten neurosecretory cells can be found in each of the first 5 abdominal ganglia of the larva of L. caesar L. These are arranged as two lateral pairs and a single ventral cell in each half of a ganglion. Half the lateral cells go through a cycle of secretory activity before pupation in developing larvae. In diapause larvae while half the lateral cells are in a resting phase the remainder are in various stages of secretory activity. The destination of the product is not known. Chemically this product is, unlike that of brain neurosecretory cells, PAS-positive. It may contain a glyco-or phospholipid or lipoprotein component.
The Connective Tissue Sheath of the Locust Nervous System: A Histochemical Study
Authors: Ashhurst Doreen E. 
Published: April 2021

ABSTRACT
The connective tissue sheath surrounding the nervous system of Locusta migratoria has been studied histochemically. It consists of an outer non-cellular layer, the neural lamella, and an inner layer of cells, the sheath-cells.
The neural lamella has been identified as being composed of a collagen-type protein and neutral mucopolysaccharide on the evidence of its histochemical reactions and the identification of hydroxyproline by paper chromatography in a hydrolysate of the neural lamella.
The sheath-cells possess large numbers of lipochondria composed of phospholipids and cerebrosides, and small spherical mitochondria. The cytoplasm also contains lipids (some of which may be cerebrosides), glycogen, and RNA.
Histochemical Studies of Herpetomonas muscarum
Authors: Dutta G. P. 
Published: April 2021

ABSTRACT
The cytoplasm of the ‘leptomonas form’ of Herpetomonas muscarum contains a parabasal body, mitochondria, and so-called ‘volutin’ granules. The parabasal body consists of neutral lipid (probably triglyceride), lipoprotein, and DNA. The mitochondria are in the form of granules. The volutin granules are more numerous and smaller than the mitochondria. The volutin granules appear to be composed of ribonucleoprotein. Glycogen is dispersed homogeneously in the cytoplasm. The cytoplasm is rich in RNA and protein. The nucleus is DNA-positive. Near the parabasal body lies a basal granule; a long flagellum arises from it. A flagellar vacuole lies near the base of the flagellum.
A New Method for Staining Connective Tissue Fibres, with a Note on Liang’s Method for Nerve-fibres
Authors: Owen G. 
Published: April 2021

ABSTRACT
A new method of staining connective tissue fibres is described. The stain used is alcohol-soluble aniline blue (spirit blue), after oxidation with potassium permanganate. The method is rapid and easy in application. Liang’s method for staining nerve-fibres is discussed briefly and its use in demonstrating the excretory system of Fasciola described.
The Central Nervous System in Larval Acraniates
Authors: Bone Quentin 
Published: April 2021

ABSTRACT
This paper describes a part of the organization of the spinal cord of the larva of the Acrania, dealing chiefly with those tracts and cell groups that are probably concerned. with the control of the swimming pattern.
These observations serve as a basis for the comparison of the organization of the cord of the larva with that of the adult, and with that known for the larvae of the Agnatha and higher vertebrates. Other observations are concerned with the arrangement of the peripheral nervous system, which differs in some respects from that of the adult. The first section deals with the arrangement of the fibre tracts in the cord, and of the cell-bodies which give rise to these fibres.
The form and connexions of the giant cells are then described; it is shown that these cells are equivalent to the Rohon-Beard sensory cells of vertebrate embryos. They send peripheral processes out through dorsal root nerves, but they differ from the vertebrate sensory neurones in their greatly enlarged dendrite field and the longitudinal axon in the cord.
Thirdly, the innervation of the gill musculature is described. A ventro-lateral asymmetrical nerve is found, formed by the junction of fibres from the right anterior dorsal root nerves.
Lastly, the arrangement of the whole system is discussed in relation to the systems found in the larval stages of other primitive chordates.
The Use of Fixed and Stained Sections in Quantitative Studies of Peripheral Nerve
Authors: Williams P. L. , Wendell-Smith C. P. 
Published: April 2021

ABSTRACT
A technique which has been widely used in quantitative studies of peripheral nerve involves fixation in Flemming’s fluid, embedding in paraffin wax, and staining with haematoxylin. An appraisal of the size changes induced by a standardized form of this technique has been made. Observations have been confined to changes in the thickness and external diameter of the internodal compact myelin sheath of the non-fasciculated nervus gastrocnemius medialis of the adult rabbit.
For a comparison of external diameters, sections from adjacent parts of the chosen nerve were prepared (a) by the standardized Flemming-Wolter technique; (b) by the rapid freezing technique, previously shown to reproduce accurately the dimensions present in fresh teased unfixed nerve-fibres. There was no significant difference in distribution of external diameters between sections prepared in the two ways.
For a comparison of sheath thicknesses, a regression line of 2 × myelin sheath thickness on external diameter was derived from each type of preparation. As external diameter was not appreciably affected by processing, a direct comparison of these regression lines could be made. It was found that regardless of external diameter or original sheath thickness, processing caused a reduction of sheath thickness of some 20% as a result of increase in internal diameter. This latter increase ranged from about 50% to under 20% with increasing fibre size.
Single frozen sections were passed through the series of reagents used in the Flemming-Wolter technique and photographed after each of seven stages. The principal changes in sheath thickness occurred in the first and last stages of processing. External diameter was not appreciably affected whereas the internal margin of the sheath was extremely labile. Observations suggest that slight inconsistencies in technique may be accompanied by relatively gross errors when measurements are undertaken. All stages need careful standardization, the most important in this respect being fixation, differentiation, final dehydration, and photographic exposure.
The Cytoplasmic Inclusions of the Neurones of Crustacea
Authors: Malhotra S. K. 
Published: April 2021

ABSTRACT
Those who have studied the neurones of Crustacea have given very- divergent accounts of the ‘Golgi apparatus’ of these cells. Poluszynski (1911) described only short, straight or slightly sickle-shaped threads; he considered them as the Golgi apparatus. Monti (1915) believed that the Golgi apparatus of this cell was constituted by the mitochondria. She thought that they were long, wavy threads, which were blackened by the Golgi methods and formed a reticulum of the type seen in the neurone of vertebrates. Ross (1922) described a framework of ‘trophospongium’ connected with the surface of the cell. He thought this was additional to a reticular ‘Golgi apparatus’.
The Histology and Activities of the Tube-feet of Antedon bifida
Authors: Nichols David 
Published: April 2021

ABSTRACT
The histology of the tube-feet and adjacent parts of the water-vascular canal of the crinoid Antedon bifida is described. The tube-feet possess the same basic structure as other, better-known tube-feet; here, however, they are adapted to collect food particles. They shoot out mucus by means of special muscle-operated glands and bend rapidly inwards to waft the mucus with entrapped particles into the food-grooves. The protraction of the tube-feet is probably brought about by a mechanism very similar to the ampulla system of other extensile tube-feet, but here the contraction of restricted portions of the water-vascular canal provides the necessary hydrostatic pressure.
A Study of Potassium Permanganate ‘Fixation’ for Electron Microscopy
Authors: Bradbury S. , Meek G. A. 
Published: April 2021

ABSTRACT
The action of buffered potassium permanganate as a fixative for electron microscopy has been investigated. Electron contrast has been shown to be produced by the deposition of granular material in the tissue. The particles are about 50 A in diameter. Actual fixation of the tissue is performed by the dehydrating alcohol.
Histochemical studies have shown that RNA and histones are removed, whereas phospholipid-protein complexes are ‘unmasked’. The reaction of the permanganate with unmasked protein gives rise to high membrane contrast in electron micrographs.
The Demonstration of Glycogen in Liver Cells fixed in Osmium Tetroxide
Authors: Foster C. L. 
Published: April 2021

ABSTRACT
Glycogen can be demonstrated histochemically in mammalian liver cells fixed in osmium tetroxide and embedded either in gelatine or in media used in electron microscopy. The form and distribution of the glycogen correspond very closely with those of structures seen in electron micrographs and which have been presumed to be glycogen.
Evidence was obtained which suggests that the glycogen occurring in some cells as small particles is probably not associated with mitochondria.
The Chorionic Plastron and its Role in the Eggs of the Muscinae (Díptera)
Authors: Hinton H. E. 
Published: April 2021

ABSTRACT
In flies of the subfamily Muscinae the egg-shell has both an outer and an inner meshwork layer, each of which holds a continuous film of air. Between these two meshwork layers there is a more or less thick middle layer to which the shell chiefly owes its mechanical strength. Holes or aeropyles through the middle layer effect the continuity of the outer and inner films of air. Both meshwork layers consist of struts that arise perpendicularly from the middle layer. In both layers the struts are branched at their apices in a plane normal to their long axes. These horizontal branches form a fine and open hydrofuge network that provides a large water-air interface when the egg is immersed.
When it rains or when the egg is otherwise immersed in water, the film of air held in the outer meshwork layer of the shell functions as a plastron. To be an efficient respiratory structure a plastron must resist wetting by both the hydrostatic pressures and the surface active materials to which it is normally exposed. The plastrons of all the Muscinae tested resist wetting in clean water by pressures far in excess of any they are likely to encounter in nature. The resistance of a plastron to hydrostatic pressures varies directly as the surface tension of the water, and the surface tension of water in contact with the decomposing materials in which the Muscinae lay their eggs is much lowered by surface active materials. These considerations seem to provide an explanation for the great resistance of the plastron of the Muscinae to wetting by excess pressures and for the paradox that the plastrons of these terrestrial eggs are more resistant to high pressures than are the plastrons of some aquatic insects that live in clean water.
Axon Structure and the Dictyosomes (Golgi Bodies) in the Neurones of the Cockroach, Periplaneta americana
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
The large axons in Periplaneta are composed of bundles of osmiophobe strands about 0·5 µ thick which fan out into the body of the nerve-cell. These strands are here termed ‘neurofibrils’; it is suggested that the dictyosomes (Golgi bodies) are concerned in their secretion.
The dictyosomes are well stained by the osmium and ethyl gallate method. Each dictyosome surrounds or is applied to an unstained canal which runs into the cytoplasm and is believed to be continuous with the ‘neurofibrils’ as defined. There are all intermediate stages between thin fusiform sheaths of osmiophil material around the ‘neurofibrils’ and the thick rings or cuffs which form the dictyosomes. The clear canals through the dictyosomes are arranged in the main concentrically around the nucleus in the body of the cell; they commonly converge upon the nerve-fibre in the axon cone.