bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Blood-system in the Serpulimorpha (Annelida, Polychaeta): III. Histology
Authors: Hanson Jean 
Published: April 2021

ABSTRACT
The histology of the blood-system of Pomatoceros triqueter has been studied in detail. Comparative observations have been made on the following serpulids and sabellids: Serpula vermicularis, Hydroides norvegica, Vermiliopsis infundibulum, Sal- macina incrustans, Protula intestinum, Apomatus ampulliferus, Spirorbis militaris, S. cor- rugatus, Sabella spaUanzanii, Potamilla sp., and Dasychone lucullana. Living coelomic capillaries of Sabella have been investigated. All vessels possess a three-layered wall consisting of an endothelium, a skeletal coat, and a peritoneum containing muscle-fibres which lie transversely to the long axis of the vessel. The outer wall of the gut sinus had the same three layers. On its inner side the sinus is bounded by an endothelium lying on a skeletal coat which in most species is the basement membrane of the gut epithelium. In Sabella and Branchiomma a muscle coat, with fibres lying transversely to the long axis of the gut, is situated inside the inner skeletal coat and rests on the basement membrane of the gut epithelium. The function of these muscles is not known. Longitudinal muscles are found in the same position in Myxicola. The endothelium of the coelomic capillaries of Sabella, and probably of all serpulids and sabellids, is a syncytial reticulum of cell bodies connected by cytoplasmic strands. The endothelium of Sabella and Branchiomma, but not of the other species investigated, contains chloragosome-like globules. In Sabella it also contains iron in some organic compound. Blood-cells are absent from all serpulids and sabellids investigated. The skeletal coat is linked by fibres with the rest of the internal skeleton of the body. It is a homogeneous sheet of a substance giving the staining reactions of collagen. Reticular and elastic fibres are absent from it. When the vessel contracts the skeletal coat does not change in thickness but is thrown into longitudinal folds. The coelomic capillaries of Sabella have a peritoneum which is apparently syncytial, and in which are muscle-fibres arranged in a wide-meshed reticulum. The reticulum and the nuclei of the peritoneum can be vitally stained with methylene blue. The nuclei are sparsely scattered over the surface of the vessel without any special relation to the fibres of the reticulum. On the larger vessels and on the gut sinus separate muscle-fibres, each with one nucleus, are present. The peritoneum constitutes a muscle-epithelium. The nucleus lies in a small membrane of cytoplasm extending along the outer surface of the fibre. The muscle-fibres of the gut sinus are composed of unstriped fibrils. The fibres of the smaller vessels sometimes show alternating stained and unstained bands of equal length. On the larger vessels each muscle-fibre apparently contains both striped and unstriped fibrils. The fibre seems to be covered by a thin sheath of striped fibrils covering a central core of unstriped fibrils which are arranged so that the core shows a double-oblique striation. The muscles of the rest of the body are unstriped.
The Tegumental Glands in the Land Isopoda: B. The Lobed Glands: Structure and Distribution
Authors: Gorvett H. 
Published: April 2021

ABSTRACT
The structure and distribution of the lobed glands in Porcellio scaber Latr. are described. The glands have a remarkable structure, each being deeply divided into many lobes, and provided with four nuclei which do not appear to be separated by cell membranes. They open externally at intervals along the margins of the body, on the lateral plates and uropods, always by separate pores, and always in exposed positions. The lateral plate and uropod glands resemble each other in many respects, but differ in size, staining reactions, and type of secretion. The glands do not differ in the two sexes, and are present in young animals newly liberated from the brood pouch. The glands of Porcellio scaber Latr. are compared with those of one species of each of the following genera: Asellus, Limnoria, Idotea, Ligia, Ligidium, Trichoniscus, Haplophthalmus, Oniscus, Platyarthrus, Hemilepistus, and Armadillidium. Lobed glands are peculiar to the terrestrial Isopoda (Oniscoidea), and appear to be present in all genera of this group, but no related structures are known in other Crustacea. They vary little in essential structure or distribution in the various genera. They vary considerably in size and number, but this variation is independent of sex, moulting condition, evolutionary position, respiratory mechanism, or humidity requirement. The lobed glands appear to have been evolved in adaptation to terrestrial life, but their function does not seem to be connected in any way with the problems of reproduction, moulting, respiration in air, or adaptation to dry surroundings.
A Twin-knife Microtome Attachment
Authors: Sloane J. F. , Harris J. E. 
Published: April 2021

ABSTRACT
A microtome knife carrier, holding two knives, has been designed to produce alternate sections as two separate ribbons. The position of the knives can be altered to give sections of the same or of different thickness in the two ribbons. The application of this device in various histochemical and counting techniques is-briefly indicated.
The Effect of Cortisone on Uterine Growth in Ovariectomized Rats receiving Estradiol
Authors: Fawcett Don W. , Deane Helen Wendler 
Published: April 2021

ABSTRACT
The growth of the uterus in ovariectomized rats treated with estradiol was compared with that of similar animals given both cortisone and estradiol.
Examination of histological sections of the uteri of rats treated in these two ways revealed no significant differences in general histological topography or cytology.
The results of one of the two experiments performed suggested that cortisone may antagonize the increase in interstitial fluid of the uterine wall but does not interfere with the growth of the uterus which results from administration of an estrogen.
These results are compared with those on skin and other organs in which cortisone has been found to inhibit the growth and repair of mesenchymal tissues.
The Role of Iron in Histological Staining
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
Rapid methods for staining sections with iron sulphide are described which give results comparable with iron haematoxylin.
Nucleic acids and proteins are mainly responsible for the uptake of iron. The staining capacity of different proteins runs parallel with the number of free carboxyl groups they contain. It is concluded that the iron forms non-ionizing complexes with carboxyl and phosphoric acid groups.
The intensity of staining is a measure of the relative abundance of such groups in the proteins and nucleic acids present, and of the concentration density of these substances.
In the staining of nuclei and chromosomes with iron the proteins are at least as important as the nucleic acids.
The iron taken up is mostly in the ferric state but it is partially converted to ferrous iron by reducing substances (chiefly sulphydryl groups) present in many fixed tissues. Iron in the form of iron sulphide or undifferentiated iron haematoxylin therefore acts as a metachromatic stain : a blue colour indicates ferrous iron, a brown colour ferric iron.
Studies of the Histology of the Mid-gut of the Chelonethi or Pseudoscorpiones
Authors: Gilbert Owen 
Published: April 2021

ABSTRACT
The histology of the mid-gut of Dactylochelifer latreilli (Leach) is described. The mid-gut is divided into two regions : an anterior diverticular region consisting of digestive cells, excretory cells, and small basal cells of unknown function, and a narrow, posterior post-diverticular region possessing a syncytial epithelium. The whole mid-gut is invested in a layer of peritoneal cells. The changes in the staining reaction of protein globules undergoing intracellular digestion are followed. The development of excretory cells is described. The function of the post-diverticular mid-gut in the excretory process is outlined. Storage of fatty material and glycogen occurs in the digestive cells and in the peritoneal epithelium. The structure and functions of the false scorpion mid-gut are compared with those of other Arachnids.
Studies upon the Gram Reaction of the Basiphil Cells of the Anterior Pituitary: Part I. Some Preliminary Observations upon the Basiphil Cell of the Human Pituitary
Authors: Foster C. L. , Wilson R. R. 
Published: April 2021

ABSTRACT
The basiphil cell granules of the human anterior pituitary react positively with Gram’s stain, but no specific differentiation of these granules occurs when the iodine treatment is omitted. The granules of the acidophil cells are Gram-negative.
Various workers have suggested a connexion between the Gram reaction of various micro-organisms and the presence of ribonucleoprotein, and the pituitary cells were investigated from this point of view.
Pyronin methyl green staining demonstrates what is probably ribonucleoprotein material in the cytoplasm of both chromophobes and chromophils, but not in the granules of either kind of chromophil. As with micro-organisms, the Gram reaction is destroyed by treating the sections with hot oxygenated bile salt, which has a detergent action upon the ribonucleic acids, but, unlike micro-organisms, the reaction remains unaffected by digestion with a buffered solution of crystalline ribonuclease, although this treatment destroys the nucleic acid, as demonstrated by the loss of pyronin basiphilia in the cytoplasm.
Bile salt also diminishes the strong positive reaction of the basiphil cell granules to the periodic acid Schiff (P.A.S.) test—a reaction which probably indicates the presence of intragranular mucoprotein.
It seems unlikely that the Gram-positive reaction of the basiphil cell granules of the human anterior pituitary is due simply to the presence of ribonucleoprotein.
We have employed the term ribonucleic acid, bearing in mind that this is a generic term and not the name of a single molecular species (cf. Davidson, 1950).
The Cell-theory: A Restatement, History, and Critique: Part III. The Cell as a Morphological Unit
Authors: Baker John R. 
Published: April 2021

ABSTRACT
A long time elapsed after the discovery of cells before they came to be generally regarded as morphological units. As a first step it was necessary to show that the cell-walls of plants were double and that cells could therefore be separated. The earliest advances in this direction were made by Treviranus (1805) and Link (1807).
The idea of a cell was very imperfect, however, so long as attention was concentrated on its wall. The first person who stated clearly that the cell-wall is not a necessary constituent was Leydig (1857). Subsequently the cell came to be regarded as a naked mass of protoplasm with a nucleus, and to this unit the name of protoplast was given. The true nature of the limiting membrane of the protoplast was discovered by Overton (1895).
The plasmodesmata or connective strands that sometimes connect cells were probably first seen by Hartig, in sieve-plates (1837). They are best regarded from the point of view of their functions in particular cases. They do not provide evidence for the view that the whole of a multicellular organism is basically a protoplasmic unit.
Two or more nuclei in a continuous mass of protoplasm appear to have been seen for the first time in 1802, by Bauer. That an organism may consist wholly of a syncytium was discovered in i860, in the Mycetozoa. The syncytial nature of the Siphonales was not revealed until 1879. The existence of syncytia constitutes an exception to the cell-theory. No wholly syncytial plant or animal reaches a high degree of organization.
Natural polyploidy was discovered by Boveri (1887), who was also the first to produce it experimentally (1903). Although many organisms contain some polyploid constituents and others are polyploid throughout their somatic tissues, yet diploid and haploid protoplasts (haplocytes and diplocytes) are the primary components of plants and animals and are still retained as such by most organisms. The haplocyte is more evidently unitary than the diplocyte.
Haplocytes and diplocytes are not composed of lesser homologous units, and with the necessary reservations required by the existence of syncytial and polyploid masses of protoplasm, they may therefore be said to be the fundamental morphological units of organisms.
Some Effects of Abnormal Tonicity on Dividing Cells in Chick Tissue Cultures
Authors: Hughes Arthur 
Published: April 2021

ABSTRACT
Chick tissue cultures were treated with hypo-and hypertonic saline for periods up to i hour. Dividing cells are more sensitive than resting cells to abnormal tonicity. The effects of this treatment on dividing cells closely resembles that of various mitotic inhibitors. Cells are arrested either in pre-prophase or in metaphase, in which the chromatid pairs are scattered throughout the cell. With hypotony, anaphase may be disturbed, and cleavage may be prevented. There is partial recovery when cultures are returned to normal saline after this treatment. Cells re-enter mitosis. After hypotonic saline, inhibited metaphases may either regenerate a spindle, or their scattered chromosomes may reconstruct as irregular nuclei or as separate chromosomal vesicles. These results may have some bearing both on the course of normal mitosis and on the action of mitotic inhibitors.
Further Observations upon the Oxyntic Cells with Special Reference to Acid Phosphatase
Authors: Menzies Gordon 
Published: April 2021

ABSTRACT
In continuation of work already reported (Menzies, 1949) further data are presented on the structure and cyto-chemistry of the granules in the oxyntic cells of the rat’s stomach. After multiple doses of pilocarpine or histamine, and after feeding, the phos-pholipine (as shown by acid haematein) is shed from some or all of the granules. The lipine first leaves the granules in cells situated in the basal part of the tubules, and finally those in the neck of the tubules, but a non-lipine lipoid remains in all the granules (as shown by sudan black). The granules enlarge after prolonged starvation as they do after a single injection of pilocarpine ; but after extraction of lipoids by hot pyridine and subsequent straining with iron haematoxylin, enlargement (i.e. of the non-lipoid moiety) is shown only after prolonged starvation. A light, uncoloured central area is found in some of the largest granules after feeding and colouring with acid haematein. An acid phosphatase appears in the oxyntic cells whose granules are about to lose their lipine component, and it disappears when they have done so. It is suggested that the acid phosphatase may cause hydrolysis of the phospholipine. Only after prolonged starvation is there any apparent change in granule numbers, when they are decreased.
Interstitial Cells in the Regeneration of Cordylophora lacustris
Authors: Moore Janet 
Published: April 2021

ABSTRACT
An experimental investigation of the induction of regeneration in the 21. hydroid Cordylophora lacustris has been described in an earlier paper (Moore, 1952). The results of the experimental work may be summarized as follows. First, Cordylophora reconstitution masses, made by chopping up unspecialized tissue and piling the fragments into heaps, may regenerate hydranths ‘spontaneously’. An oral cone grafted into a mass induces the development from the tissue of the mass of hydranth regions basal to the oral cone. Regeneration of the mass at points other than the graft site is inhibited.
The Innervation of the Skin of Teleost Fishes
Authors: Whitear Mary 
Published: April 2021

ABSTRACT
A detailed study of the innervation of the skin of teleosts by fibres of the general cutaneous system has demonstrated anatomical differences which may be correlated with the various senses known to be mediated by these nerves. The anatomy of the plexus which these nerves form in the skin is very similar to that of other vertebrates which have been studied. There exist in the epidermis certain elongated cells, which may be isolated sensory cells taking part in the perception of ‘common chemical’ stimuli. It is possible to trace single fibres throughout a considerable part of their course in the skin; a study has been made of the distribution at the surface of the branches of certain fibres of a type which is almost certainly tactile.
Receptor Elements in the Thoracic Muscles of Homarus vulgaris and Palinurus vulgaris
Authors: Alexandrowicz J. S. 
Published: April 2021

ABSTRACT
In the thoracic muscles of Homarus vulgaris and Palinurus vulgaris the presence of receptor elements of various kinds has been recorded. Muscle receptor organs belonging to the same category as described previously in the abdomen have been found in the two posterior (7th and 8th) thoracic segments. According to their situation one lateral and one median receptor may be distinguished on each side of each segment. Like those in the six abdominal segments they are linked with the system of the extensor muscles. The topography of these organs in relation to that of the thoracico-abdominal muscles is described. There are certain differences in their location between the two species. Receptor organs of this category, with one exception, are composed of a special thin muscle and a nerve-cell ending in connective tissue intercalated in this muscle. The lateral receptor of the 7th thoracic segment in Homarus has no muscle of its own and terminates on connective tissue fibres accompanying an ordinary muscle. In the nerve supply of these receptors in the thorax the same elements as in the abdomen, i.e. the motor nerves and the two accessory nerves, can be distinguished, but their distribution in the thorax has certain special features. It is assumed, in view of certain differences in the appearance of the nerve-cells and their processes, that the muscle receptor organs of this category are of two types in each of the segments. Nerve-cells regarded as receptors of a different category have been found in some of the muscles inserting in the median surface of the epimeral plate. These cells, termed ‘N-cells’, are smaller elements than those of the first category and have not a special muscle of their own, but end with long processes between the fibres of the ordinary muscles. In each of the species investigated five such elements have been found. No evidence is as yet available as to whether they are present exclusively in the thoracic region or are more generally distributed. It is suggested that the N-cells may represent more primitive forms of muscle receptors, and that the receptor organs of the extensor muscles in the thorax and abdomen are more highly evolved forms.
A Comparison of some Aspects of the Retinae of the Manx Shearwater, Fulmar Petrel, and House Sparrow
Authors: Lockie James D. 
Published: April 2021

ABSTRACT
Most birds are either diurnal or nocturnal. The Manx shearwater is one of the very few that regularly perform such normal activities as feeding, hunting, and flying by day, and other activities, such as homing to the nest, by night. The retinal structure of the Manx shearwater is compared with that of a diurnal passerine (house sparrow) and a diurnal sea-bird (fulmar petrel), in order to determine what features are common to sea-birds and what, if any, may be specific adaptations to vision over a wide range of light intensity. Both sea-birds have a linear area centralis but lack a fovea. The rods of the dark-adapted fulmar and shearwater show great difference of shape from those of the light-adapted. The shearwater has more rods at the area centralis, a larger rodparaboloid in the dark adapted retina, and a greater ratio of total number of visual cells to ganglion nuclei than has the fulmar.
A New Type of Light Source for Phase-Microscopy
Authors: A.Kempson D. 
Published: April 2021

ABSTRACT
The method described here is a modification of the system of phasemicroscopy described by Kempson, Thomas, and Baker (1948) and Baker, Kempson, and Brunet (1949). In this system the phase-plate is placed behind (above) the rear focal plane of the objective. A large illuminating annulus is placed immediately in front of the microscope lamp, and an image of it is made to coincide with the phase-plate annulus by lowering the substage condenser and adjusting the mirror.
Phase Contrast and Electron Microscope Studies of the Appearance and Behaviour of the White Cells of Normal Human Blood
Authors: Marchant June 
Published: April 2021

ABSTRACT
The phase-contrast microscope has been used to study form and movement of human leucocytes and blood platelets in three types of preparation ; (a) warm sealed blood drops, (b) warm sealed films of leucocytes adhering to coverslips after incubation of blood drops at 37° C. for 30 minutes or more, and (c) warm sealed films of blood platelets obtained by similarly incubating drops of saline suspensions of these cells. Similar preparations to (b) and (c) were obtained on formvar films and studied in the electron microscope. Phagocytosis was studied in all the above preparations after adding suspensions of collodion particles or of Staphylococcus albus. The neutrophils were the most versatile cells seen in the above preparations. The amoeboid forms were the most mobile and phagocytic. Another form showed rapidly waving processes which gradually spread into a flat membrane on the glass. Flattened immobile neutrophils were still capable of phagocytosis. Bacteria which adhered to the cell surface moved over it towards the thicker central region of the cell where ingestion occurred. Eosinophils showed a mobile amoeboid form and flattened forms which were often very bizarre in shape. They did not phagocytose readily. Monocytes showed slowly moving amoeboid forms or forms with ruffle-like membranes around the cell. They were phagocytic. Lymphocytes were capable of amoeboid movement but did not flatten on glass and were not phagocytic.
Amoeba hugonis n.sp.: Life-history
Authors: Taylor Monica 
Published: April 2021

ABSTRACT
Material collected in Loch Tannoch was allowed to macerate in a chemical nutrient. A rich crop of Euglena gracilis as well as other infusoria resulted. Eight months later, when the Euglena had encysted, many amoebae were found at the bottom of the receptacle. They constitute a new species, here named Amoeba hugonis. An average adult specimen, when extended, measures about 104 × 5· 2μ. The nucleus consists of a central karyosome lying in the nuclear sap, separated from the cytoplasm by a well-marked nuclear membrane. Between the latter and the karyosome is situated an achromatic ‘collar’ with chromatin particles embedded in it.
Fission is described, but a study of mitosis has been deferred. The life-history of this small amoeba is very similar to that of the large A. proteus, &c The cycle occupies two months. Chromidia begin to appear in the cytoplasm of the early adult. They give rise to spores, out of which amoebulae hatch.