bluuebunny/crossref_metadata_2025 huggingface dataset:
Fibrillogenesis in the wax-moth, Galleria mellonella
Authors: Ashhurst Doreen E.
Published: April 2021

The fibroblasts of the pupa are characterized by the great development of the endoplasmic reticulum, which becomes dilated to form vesicles containing a rather electron-dense material which is thought to be a precursor of the collagen fibrils. Fibrils are seen within the cytoplasm of the fibroblasts ; these are about 12’5 to 20 mp in diameter and some of them show indications of banding with a periodicity between 15 and 20 mp. It is thought that these fibrils and their surrounding cytoplasm become incorporated into the fibrous connective tissue. The plasma membranes of the fibroblasts are discontinuous where they are adjacent to the fibrous tissue. The fibrils in the connective tissue are obscured by masses of mucopolysaccharide, but there are indications that these fibrils are essentially similar to the intracellular fibrils.

The processes of fibrillogenesis in the moth and in various vertebrate tissues are shown to have many features in common.
Flagellar movement of the sessile flagellates Actinomonas, Codonosiga, Monas, and Poteriodendron
Authors: Sleigh M. A.
Published: April 2021

Water currents set up by flagellar activity are used to bring food particles to the body in each of the sessile flagellates Actinomonas, Codonosiga, Monas, and Poteriodendron. The water currents produced by the 4 organisms are all somewhat different, and, while that set up by Codonosiga is in the expected direction with water flow from the flagellar base towards the tip, the currents set up by the other 3 forms flow from the tip towards the base. In all 4 types the flagellar movements take the form of plane sinusoidal undulations propagated from the base of the flagellum towards its tip, but the different types show adaptive modifications according to the pattern of water currents required. The rates of beat of the flagellum (range 30 to 50 cycles/ sec) and the speeds of propagation of the contraction wave (range too to 600 μ/sec) did not differ sufficiently to explain different current patterns. It is suggested that the ‘unexpected’ direction of current flow in 3 of the types may be the result of the presence of flagellar mastigonemes ; these are known to be present in the chrysomonad phytoflagellates, to which group Monas and probably also Actinomonas and Poteriodendron belong. Attention is also drawn to the peculiar mode of coiling and unrolling of the flagellum of the bicoecid Poteriodendron.
Studies of differential staining with acid dyes in the human adenohypophysis
Authors: Fisher A. W. F. , Bulmer D.
Published: April 2021

With Mallory techniques the differential staining characteristics in the human adenohypophysis are mainly dependent upon the treatment with phosphotungstic acid. Though this does not remove dye which is already bound to the acidophils it prevents the subsequent access there of anilin blue or acid fuschin, but not of orange G. The molybdenum blue reaction, used after treatment of sections with phosphomolybdic acid, shows that hexavalent molybdenum is strongly bound to the basiphils but more weakly to the acidophils; it can be inferred that phosphotungstic acid reacts with the tissues in a similar manner. Deamination, acetylation, and benzoylation produce a marked reduction in dye-binding, though the granules of the basiphils are resistant to the benzoylation. Methylation results in a marked increase in the staining of all elements. The differential effect of the phosphotungstic acid is abolished, so that the dyes are able to gain admission to the acidophils after the polyacid treatment.

The differential staining is most probably dependent upon the differing permeabilities of the tissue proteins to molecules of differing sizes, the acid fuchsin, anilin blue, and phosphotungstic acid competing with each other for basic groups. On the other hand, it is possible that phosphotungstic acid has a different type of reaction with the acidophils, involving chelate linkages to carboxyl and other groups of the tissue proteins.
The histochemistry and fine structure of the accessory nuclei in the oocyte of Bombus terrestris
Authors: Hopkins C. R.
Published: April 2021

The accessory nuclei are present throughout vitellogenesis in the peripheral ooplasm ; they probably originate from the oocyte nucleus. Structurally they resemble nuclei and in addition their electron-dense inclusions contain RNA, possibly of nucleolar origin. They do not, however, contain chromosomal material.

During development they increase in size and multiply by equal division or by a form of terminal budding.

They do not become transformed into albuminous yolk spheres but are probably concerned with the control of albuminous yolk synthesis at the periphery of the oocyte. They remain after the termination of yolk synthesis and are associated with the formation of the vitelline membrane.
Histochemical changes correlated with reproductive activity and nutrition in the chiton, Katharina tunicata
Authors: Nimitz M. Aquinas , Giese A. C.
Published: April 2021

The chief sites of nutrient reserves observable histochemically are the germinal epithelial cells of the gonads and storage cells of the foot and mantle ridge. The germinal epithelial cells store neutral lipid and a glycogen-like material, both of which diminish in quantity during gametogenesis. In the female the disappearance of lipid from the germinal epithelium coincides with the accumulation of lipid in the oocytes.

Special storage cells of the foot and mantle contain neutral lipid globules and minute granules (1 to 2 μ) which stain with phospholipid and protein procedures and the PAS reaction. The globules and granules are embedded in a matrix of glycogen-like material. The granules disappear from the cells two months before spawning and reappear after spawning. There is no histochemical evidence for marked utilization of lipid from the storage cells of the foot and mantle during normal gametogenesis, but these lipid depots are depleted when a period of starvation is coextensive with the 5 months of active gametogenesis. A starving animal produces fewer gametes than a normal one, but the gametes are normal in so far as can be determined histochemically.

Muscles are surrounded by a sheath of glycogen-like material which is still present after 5 months of starvation.

The connective tissue ground substance throughout the animal, the secretory cells of the glandular oviduct, the mucous cells of the intestinal valve, and the mucous cells of most of the epithelium of the foot and palliai groove have similar staining affinities. They appear to contain either neutral and unsulphated acid mucopolysaccharide or a hyaluronate-like polymer with some simple sugar residues. Certain epithelial cells of the mantle ridge and of the lateral surface of the foot secrete a sulphated acid mucopolysaccharide.

The anterior gut secretes a neutral mucopolysaccharide. Lipid droplets are found in the epithelium of the stomach and intestines, and in the ‘enzyme cells’ of the digestive gland.
A study of the histochemical demonstration of cytochrome oxidase
Authors: Butcher R. G. , Diengdoh J. V. , Chayen J.
Published: April 2021

Burstone’s procedure for the histochemical demonstration of cytochrome oxidase has been studied and applied to sections prepared by freezing in hexane and cutting by the controlled-temperature freezing-sectioning technique. The method has been modified by the inclusion of a treatment with Lugol’s iodine to yield a stronger colour, which is stable for at least several weeks and which localizes the enzyme activity more precisely. The variants of the reaction have been compared in their effect on cardiac muscle, liver, and kidney of the rat.
The staining of degeneration in the nervous system of the octopus by modified silver methods
Authors: Lund R. D.
Published: April 2021

The Nauta-Gygax and Glees methods used on mammalian material for demonstrating degenerating nerve fibres have been modified for similar use on Octopus vulgaris. The results compare well with the Cajal method which has been employed up to the present. Degenerating fibres stain more intensely than with the Cajal method and many of the normal fibres are differentially suppressed.
The ultrastructure of the tegument of Moniliformis dubius (Acanthocephala)
Authors: Nicholas W. L. , Mercer E. H.
Published: April 2021

The ultrastructure of the body wall of Moniliformis dubius has been studied in the light and electron microscope. It consists of an apparently syncytial tegument, overlaid by a tenuous cuticle in the form of a finely fibrous extracellular fringe and is backed by a basement membrane and fibrous connective tissue. The tegument contains a framework of fibres, which, distally, is connected to a dense fibrous meshwork separated from the cuticle by two membranes. Within the syncytial tegument are found the usual cytoplasmic organelles : mitochondria (often degenerate in structure), Golgi clusters, small amounts of other smooth membranes, and numerous dense particles (glycogen and perhaps ribosomes). Many mitochondria contain dense particles. Evidence of vacuole formation at the surface of the tegument suggests that pinocytosis plays a part in assimilation.
The histochemical demonstration of alkaline phosphatase in unfixed frozen sections
Authors: Bitensky Lucille , Cohen S.
Published: April 2021

Although, ideally, enzyme histochemistry should be performed on unfixed sections, so as to avoid potential artifacts inherent in chemical fixation, it is usually considered necessary to fix sections so as to stop the ‘soluble’ enzymes from becoming lost into the incubation medium. However, provided that suitable frozen sections are used, alkaline phosphatase can be demonstrated fully in unfixed sections, even though this is typically a ‘soluble’ enzyme.
The synthesis and migration of nuclear proteins during mitosis and differentiation of cells in rats
Authors: SIMS R. T.
Published: April 2021

Hooded rats were given an intraperitoneal injection of 3H-tyrosine, and killed in pairs io min, 30 min, 12 h, 36 h, 7 days, and 30 days later. A piece of skin with white growing hair, and the tongue, were taken from each animal and radioautographs were prepared. Silver grains were counted over whole nuclei and whole mitotic figures of the germinal cells and whole nuclei of differentiating cells of both tissues. It was found that the interphase nuclei have significantly more silver grains over them than the chromosomes at all stages of mitosis and there are virtually no grains over metaphase, anaphase, and early telophase chromosomes in both tissues of all the animals killed up to 36 h after the injection. The difference between the grain counts over the interphase nuclei and the chromosomes of dividing cells is at least 20-fold at 30 min in the hair matrix, at least 5-fold at 30 min in the tongue and at 36 h in both tissues. It was established that the differences observed between the radioactivities of the nuclei and chromosomes of mitotic figures are real from estimates of : the radioactivity of the cell cytoplasm, volumes of the metaphase chromosomes and interphase nuclei within 1 μ. of the photographic emulsion, and the volumes of cytoplasm separating the photographic emulsion and these structures. No protein synthesis was demonstrable in the chromosomes during metaphase, anaphase, and early telophase. Nuclear proteins leave the chromosomes during prophase and prometaphase and return to the nucleus during late telophase. The cells in the matrix and upper bulb of the growing hair follicle and those in the germinal, prickle, and granular cell layers of the tongue are in different functional states ; 30 min after injection of 3H-tyrosine they have different amounts of it in their nuclear proteins. It is suggested that the amount incorporated into each nucleus is related to the rate at which proteins are being synthesized by the cell.
Observations on the histochemical distribution of alcohol dehydrogenase
Authors: Ferguson M. M.
Published: April 2021

Alcohol dehydrogenase capable of utilizing primary alcohols (straight and branched chain, unsaturated and cellosolves), secondary alcohols, polyhydric alcohols but not tertiary alcohols is described in the rat brain, lung, heart, liver, kidney, gut, spleen, pancreas, uterus, and seminal vesicle. With the straight chain primary alcohols the extent to which the alcohols were used increased relative to increasing chain length until the optimum length of six to seven carbon atoms had been reached, whereafter activity decreased, probably due to the insolubility of the higher members of the series in water. Side groups on the chain, double bonds and ethereal oxygen atoms, all had the effect of hindering the ease of dehydrogenation of the alcohol. Secondary alcohols were suitable as substrates; however, tertiary alcohols did not seem to be satisfactory for the demonstration of alcohol dehydrogenase. Polyhydric alcohols were suitable substrates although they were not as well used as were the monohydric alcohols. Furfuryl alcohol dehydrogenase was found in all tissues and is apparently a separate enzyme.
An electrical counter for cell population studies
Authors: Galbraith W.
Published: April 2021

A cheap and simple electrical counter is described which is convenient for the simultaneous assessment of the frequencies of several different characteristics in a cell population.
The Use of Nile Blue in the Examination of Lipoids
Authors: Cain A. J.
Published: April 2021

Nile blue, introduced by Lorrain Smith for distinguishing between neutral fats (triglycerides) and fatty acids, was considered by Lison to be of no histochemical value except that the red coloration was specific for lipoids in general. This conclusion was based principally on Lison’s own researches, and in part on those of Kaufmann and Lehmann.

Reinvestigation has shown that some of Kaufmann and Lehmann’s results are of doubtful value and all require careful interpretation, but in general these and other results lead to the conclusion that nile blue can be used to distinguish neutral lipoids (esters and hydrocarbons) from acidic lipoids (phospholipines and acids). Cholesterol is not detected.

A method for using both the oxazine and oxazone of nile blue is described, which has greater sensitivity to acidic lipoids.
A Study of the Spheroid System of Sympathetic Neurones with Special Reference to the Problem of Neurosecretion
Authors: Thomas Owen Lewis
Published: April 2021

1. Evidence is put forward in support of the view that the Golgi complement of the vertebrate sympathetic neurone consists of a dispersed system of spherical bodies. These bodies can be studied in living cells and with vital dyes and each consists of a neutral red staining core (the vacuome of Parat) enveloped in a lipoidal sheath.

2. The classical Golgi body is shown to be an artifact produced within the cell. With the osmium techniques the spheroid bodies together with the mitochondria form a framework which serves as a centre for a non-specific deposition of metallic particles.

3. The Golgi spheroids exhibit a secretion cycle with the formation of a granular product. The granules are identified with the ‘neurosecretion’ granules of Scharrer.

4. These granules appear to be transported to the nucleus of the cell and there to be absorbed. This observed interrelationship between nucleus and Golgi product is discussed.
Observations on Hypotrichous Ciliates: The Genera Stichotricha and Chaetospira
Authors: Froud Joan
Published: April 2021

The structure, behaviour, and asexual reproduction of a plant-cell-inhabiting hypotrichous ciliate are described. The systematic position of the ciliate is discussed and it is placed in the genus Stichotricha Petty as S. intermedia n.sp. New information concerning behaviour, nuclear apparatus, and asexual reproduction is given for the loricate Chaetospira miilleri Lachmann. Cysts are described for the first time.
Oogenesis in the Desert Snail Eremina desertorum with Special Reference to Vitellogenesis
Authors: Fahmy Onsy G.
Published: April 2021

The histological structure of the ovotestis is briefly described.

The germinal epithelium gives rise to both categories of germ cells (male and female) as well as to the nurse cells.

During the differentiation of the germinal epithelial cell towards the germ line, it passes through a certain stage, ‘the progerminative indifferent stage’, before it is polarized either towards the male or female line.

A detailed description of the mode of differentiation of the progerminative indifferent cell into the earliest female element is given.

Mitotic multiplication of the early female elements never occurs. Nevertheless the diploid chromosome complement is represented by prochromosomes.

During the oocytic meiotic prophases, parasynaptic conjugation of the chromosomes is quickly followed by relational coiling of the synaptic mates and the formation of the strepsitene double spirals.

The strepsitene double spirals give rise to the diplotene bivalents of the haploid count 28.

The steps of chromatin diffusion that lead to the construction of the typical oocytic germinal vesicle are described.

Changes in size, number, and stainability of nucleoli during oocytic growth are recorded. Extrusion of basiphil material from the nucleolus into the ooplasm is highly probable.

The mitochondrial granules at the beginning of the period of active oocytic growth form a huge zone to one side of the nucleus. Later they increase in number and widely scatter in the ooplasm. It is held (in favour of Harvey’s view, 1929 and 1931) that mitochondria are probably concerned in the chemical synthesis of yolk from raw material provided in the ooplasm.

The Golgi bodies in oocytes are in the form of rods and not vesicular. In the early oocyte they form a group to one side of the nucleus. Eventually they disperse in the ooplasm either singly or in small typical complexes. Each of the latter is constituted of a few rods arranged end to end as if on the perimeter of an irregular circle.

The earliest yolk spheres (largely proteid) appear in the interior of the Golgi complexes or on the concave sides of the separate Golgi rods.

The Golgi rods become severed from the yolk spheres and migrate mainly towards the periphery of the oocyte where they collect in clumps.

The elements of the Golgi clumps become loaded with an unsaturated free fat. The original Golgi rod always preserves its identity and never transforms itself into fat.
Location of Absorbed Carcinogens within the Amphibian Cell
Authors: Waddington C. H. , Goodhart C. B.
Published: April 2021

Cells from explants of newt gastrulae which had been-cultuted in Holtfreter’s standard solution containing the ‘carcinogen 3:4-benzpyrene rendered soluble by caffeine were examined for fluorescence by ultra-violet light. The lipoid constituents of the cells, lipochondria and liposomes, .showed the bright blue fluorescence of benzpyrene in molecular solution and there was also occasionally a structureless blue fluorescence round the nucleus corresponding, perhaps to the so-called ‘Golgi Apparatus’. The yolk platelets were slightly fluorescent but this was probably due to the associated lipides and it largely disappeared in jnoribund preparations, where the lipochondria became detached from the platelets. The nucleus showed ho fluorescence, nor was a fluorescept nucleolus observed. It could be shown that the pyronine-stapling cytoplasmic granules of ribonucleoprotein (microsomes) were not fluorescent and so probably do not have any affinity for the carcinogen. The very smalt fluorescent granules in Brownian movement that had previously been looked upon as ribonucleoprotein microsomes are in fact small liposomes and do not stain with pyronine.

It is suggested that the evocating power of the carcinogenic hydrocarbons is probably not due to cytolytic activation of the evocator, by the killing of some cells in the exposed ectoderm. It may be by physiological activation, operating through a specific action on the lipochondria, leading to their breakdown into liposomes and the release of active evocator substance. Some evidence is produced which suggests that the lipochondria contain ribonucleo-protein, and this fraction of them may constitute the active evocator; this would be congruent with the theories of Brachet (1947). It cannot yet be excluded, however, that the hydrocarbons act as direct evocators, simulating the effects of the naturally occurring substance.

The observation that benzpyrene is not accumulated by nucleoprotein makes it likely that the mutagenic activity of the carcinogens is indirect.
On the Cuticle of the Scorpion Palamneus swammerdami
Authors: Krishnan G.
Published: April 2021

1. The cuticle of the scorpion Palamneus swammerdami shows the same fundamental layers as that of insects. It consists of a thin outer epicuticle and a thick inner endo-cuticle; the outer layers of the latter are transformed by hardening into an amber-coloured exocuticle.

2. The chemical characteristics of the constituent layers of the cuticle in different regions are described and it is shown that the proteins impregnating the endocuticle during hardening appear to be different from those described in insects and possess resistant properties.

3. The exocuticle in addition to giving evidence of tanning indicates the presence of disulphide bonding. A similar indication is obtained in the epicuticle.

4. The mode of hardening of the cuticle of scorpion is discussed and compared with similar processes in other arthropods.
The Preservation and Investigation of Plant Mitochondria
Authors: Chayen J. , Miles Ursula J.
Published: April 2021

A method for making squash preparations of plant root tip cells is described. This entails the use of an inert preserving substance, polyvinyl alcohol. The advantages of the method are the preservation of the cytoplasmic bodies, including the mitochondria ; the retention of fat droplets inside the cells; the fact that the nucleus remains optically homogeneous; and the fixing of free aldehyde groups and of diffusible substances in the cytoplasm. It is a relatively rapid and simple technique, and the cells produced by it resemble closely those produced by the method for making living squash preparations of such cells.
The Origin of Sensory Neurones in an Insect, Rhodnius prolixus (Hemiptera)
Authors: Wigglesworth B. V. B.
Published: April 2021

Beneath each sensillum in the integument of the insect is a bipolar cell (or group of cells) connected to the sense organ by a distal filament and to the central nervous system by a proximal filament or axon. It is generally believed that this cell is a primary sense cell (vom Rath, 1888; Hanström, 1928), but whether it arises by differentiation from the ordinary ectodermal cells or whether it has migrated outwards from the central nervous system has not been proved.
Cytological Studies of the Acinar Cell of the Pancreas of the Mouse Part II. The Argentophil, Osmiophil, and Sudanophil Substance
Authors: Morgan Winfield S.
Published: April 2021

It is shown by the Aoyama, Mann-Kopsch, and Sudan black techniques that there is a definite series of changes in the pancreas acinar cell of the mouse after the subcutaneous injection of a pre-determined optimum dose of neutral red. These changes are similar to those observed in the fresh tissue. In the fixed preparations they are characterized by the appearance of argentophil, osmiophil, and sudanophil bodies having the position, number, general configuration, and relative size of the neutral red granules and aggregates. It is further observed that there is a shift of this substance from an apical position in the cell to a more basal one, apparently in response to the presence of neutral red.
A Comparative Study of the Spermatophores of three Scyllarid Lobsters (Parribacus antarcticus, Scyllarides squammosus, and Scyllarus martensii)
Authors: Matthews Donald C.
Published: April 2021

In Parribacus antarcticus and Scyllarus martensii mitotic division of germinal epithelial cells produces primary spermatocytes, whereas in Scyllarides squammosus this function of the germinal epithelium is limited to comparatively few large, oocyte-like cells. Metamorphosing spermatids in all three species are expelled from the sacculi of the testis by the rhythmical activity of their germinal epithelium. This probably accounts also for the clumping of the spermatozoa in the collecting tubule; each clump represents the extended contents of a single sacculus. In Scyllarus martensii and Scyllarides squammosus a continuous, cord-like, encapsulated spermatogenic mass traverses the vasa deferentia, whereas in Parribacus antarcticus the spermatogenic mass separates into distinct ampullae which become encapsulated and are further provided with an enveloping sheath. This sheath between adjacent ampullae becomes ribbon-like, twists, and ultimately forms short, doubly twisted peduncles. A secretion of the typhlosole in all three species surrounds the completed spermatophores and forms the homogeneous matrix. Although these three species are anatomically similar, the spermatophores of Scyllarus martensii and Scyllarides squammosus resemble non-pedunculate spermatophores of the palinurids, the astacids, the homarids, and the nephropsids, whereas those of Parribacus antarcticus more nearly resemble the pedunculate spermatophores of certain pagurids. Spermatophoric evidence above does not justify the inference that Parribacus antarcticus occupies a systematic position intermediate between the Macrura and the Anomura.
The Lateralis Organs and their Innervation in Xenopus laevis
Authors: Murray R. W.
Published: April 2021

The innervation and general morphology of the lateralis organs of Xenopus laevis are described. Each group of organs is innervated by two large and two or fewer small fibres. Each of the large fibres gives off a branch to each of the lateralis organs in the group, but the branching of the small fibres is less regular. Each lateralis organ is therefore innervated by two large and up to two small fibres. The large fibres branch extensively at the base of the organ, the small fibres less so, and the nerve endings lie basal to or between the sensory cells. No terminal swellings could be seen. The endings of a particular fibre are not restricted to any one region of the organ.

No special function could be assigned to the dual arrangement of the innervation.

The original accounts of the structure of the lateralis organs were adequate. The recently suggested division of the supporting cells into three types is not justified.

It is probable that a cupula exists on the lateralis organs but it could not be observed. It is suggested that the supporting cells secrete the cupula.
Egg-capsule Proteins of Selachians and Trout
Authors: Brown C. H.
Published: April 2021

The material of the egg-capsules of selachians and the chorion of trout eggs has been examined by physical, chemical, and histochemical methods.

The material of the egg-capsule of selachians has been found to be a quinone-tanned protein.

The chorion of trout eggs is not quinone-tanned but its formation and chemical behaviour allies it with the invertebrate cuticular proteins rather than with the vertebrate keratins.
A Study of the Round Pigment Cells in the Uterus of the Ewe
Authors: Hadek R.
Published: April 2021

The round pigment cells in the uterus of the ewe have been found to contain, in addition to melanin granules, Abnützungspigmente 2 (pigments of ‘wear and tear’). On account of their ability to absorb and store material from the neighbouring tissue, the cells are regarded as phagocytes.
Notes on the Mechanism of Food Movement in the Gut of the Larval Oyster, Ostrea edulis
Authors: Millar R. H.
Published: April 2021

The histology and mechanism of food movement in the stomach of the larval oyster are described. Cilia line the stomach, except the left wall, roof, and upper part of the right wall, which bear the smooth gastric shield. The diverticula contain non-ciliated absorptive cells and ciliated non-absorptive cells. A slender muscle passes round each diverticulum. Food is rotated in the stomach by the style, and also turned over in the sagittal plane. Particles are drawn into the diverticula and returned to the stomach by the rhythmic expansion and contraction of the diverticula.
The Site of Damage in Amoebae Exposed to X-Rays
Authors: Ord M. J. , Danielli J. F.
Published: April 2021

The technique of nuclear transfer was used to study the extent to which X-rays damage nuclei and cytoplasms of Amoeba proteus. Results showed that cytoplasm was directly damaged by the radiations. Cytoplasmic damage with doses below 280,000 r was reversible, though damaged cytoplasm could lethally damage normal nuclei. Damage with doses above 300,000 r caused lethal damage and death occurred without division in 0–3 days. Damage to nuclei was probably a combination of a direct action of the radiations and exposure to reversibly damaged cytoplasm. Nuclei were 2·4 times as sensitive as cytoplasms, the LD50 doses being approximately 120,000 r for nuclei and 290,000 r for cytoplasm. Death due to nuclear damage generally occurred without division within 3 to 6 weeks. Nuclear damage cannot be interpreted in terms of the ‘target’ theory.
A Microscopical Finder-slide
Authors: Bradbury S. , Galbraith W. , Lyster M. E.
Published: April 2021

The finder-slide is produced by photographic reduction of a typescript chart. By its use, recorded objects can be re-located on different microscopes.
The Distribution of Mast-Cells in the Digestive Tract of Laboratory Animals: Its Bearings on the Problem of the Location of Histamine in Tissues
Authors: Mota I. , Ferri A. G. , Yoneda S.
Published: April 2021

The mast-cell distribution in the digestive tract of the rat, dog, cat, and guinea-pig was studied. In the rat mast-cells were present in the tongue, oesophagus, and forestomach, but practically absent from the glandular stomach, duodenum, ileum, and rectum. In the other species, mast-cells were numerous throughout the whole of the digestive tract, presenting a large individual variation. In the tongue and oesophagus mast-cells were found mainly in the submucosa and lamina propria, where they were located near the epithelium. In the stomach, mast-cells were more numerous in the mucosa and concentrated in the muscularis mucosae and between the necks of the glands. In the duodenum, mast-cells were also more numerous in the mucosa, being concentrated in the muscularis mucosae and frequently also in the summit of the villi. In the ileum and rectum mast-cells were less numerous than in the stomach and duodenum, keeping the same disposition as in these. The contribution of the mastcells to the histamine content of the digestive tract is discussed.
Human Saliva as a Convenient Source of Ribonuclease
Authors: Bradbury S.
Published: April 2021

Saliva, heated to 80° C for io minutes and centrifuged to remove mucus, is used as a source of ribonuclease. Slides of mouse pancreas incubated in this for 3 hours at 60° C show complete removal of cytoplasmic basiphilia. Incubation of control slides in distilled water before staining is essential in order to avoid errors due to possible solution of basiphil material in aqueous media. Errors due to incomplete elimination of the salivary amylase are prevented by using the PAS reaction to check the absence of all diastatic activity.

Formaldehyde and phenyl isocyanate are used as specific enzyme inhibitors. If these are added to the saliva before use, the ribonuclease is inactivated, and there is then scarcely any action on the cytoplasmic basiphilia.

With these controls, incubation of slides in prepared saliva, followed by staining with basic dyes, may be used in histochemistry as a means of localizing ribonucleic acid.
Experimental alteration of the peri-renal tissue of protopterus
Authors: Moorhouse D. E.
Published: April 2021

The experiments were carried out on Protopterus aethiopicus in East Africa. They were: the injection of commercial adrenocorticotrophic hormone, hypophysectomy, administration of ACTH after hypophysectomy, artificially induced aestivation, and artificially induced ‘stress’.

The two elements of the lipid tissue show differing reactions to the experiments carried out. The large lipid cells appear to be under direct pituitary control: active secretion follows ACTH administration, hypophysectomy leads to a blocking of secretion. After ‘stress’ and hypophysectomy the small lipid cells develop sudanophil inclusions which are positive to the histochemical tests for steroids. This does not occur after ACTH administration.

The phagocytes of the endothelial system take part in the transfer of material within the peri-renal tissue; this is shown by their cytology after ACTH administration and ‘stress’. Evidence from these experiments indicates that the round pigment cells characteristic of the normal animal are syncytial structures formed by the fusion of phagocytic cells containing pigment and remains of large lipid cells.

The steroid tissue shows little change in these experiments other than a decrease in the amount of steroid material after ACTH, and a more intense staining of the mitochondria after hypophysectomy.

The number of eosinophil leucocytes increases as the result of ACTH administration.

The round cell nodules showed no detectable changes in these experiments.
The development of the malpighian tubules of schistocerca gregaria (orthoptera)
Authors: Savage A. A.
Published: April 2021

1. Schistocerca gregaria Forsk. possesses about 250 Malpighian tubules arranged in twelve groups, situated dorso-laterally, laterally, ventro-laterally, and in the six intervening positions around the posterior end of the mid-gut. The gut forms an expanded ampulla at the point of entry of each group.

2. Each tubule is composed of five rows of cells, spirally arranged. Upper and lower segments are present, as in Rhodnius (Wigglesworth, 1931), the former very short. There is also a spiral trachea.

3. Tubules arise in seven generations, two in the embryo and one in each of the five nymphal instars. The first embryonal generation is composed of six primary tubules, the second of twelve embryonal secondaries. In the other five a variable number of nymphal secondaries is added, with means of 25, 51, 88, 63, and 6 respectively. The six primary tubules are attached distally to the rectum, the embryonal and first and second instar secondaries pass forwards, the fourth and fifth instar secondaries pass backwards, and the third in both directions.

4. The development of any one tubule comprises a period of initiation, a period of mitosis and elongation, and a period of differentiation. The first is restricted to the first few days of the particular stadium, the second takes place throughout the stadium, and the last throughout the life of the tubule.

5. The secondary tubules are arranged in an arc round the periphery of the ampulla. These arcs are perfectly symmetrical, the tubules arising alternately left and right of the mid-line during all the nymphal stages.

6. Tubule buds formed late in the period of initiation may cease to develop until the corresponding phase of the succeeding instar is reached.

7. The origin of tubules from a posterior interstitial ring and its relation to the interpretation of insect gastrulation and the nature of nymphal developmental cycles is discussed.
Tissues for Assessing Histochemical Methods for Calcium
Authors: McGee-Russell S. M.
Published: April 2021

An account is given of three tissues which are suitable for use as standard objects when attempting methods that are said to reveal calcium salts in tissues. The tissues are the digestive gland of the snail Helix, the gut diverticulum of the crab Carcinus, and the left colleterial gland of the cockroach Periplaneta. They contain respectively calcium carbonate, calcium phosphate, and calcium oxalate deposits. The deposits are little, if at all, contaminated with other calcium salts.
Cyclical Changes in the Distribution of the Testis Lipids of a Teleost Fish, Esox lucius
Authors: Lofts B. , Marshall A. J.
Published: April 2021

A study of the cyclical changes in the distribution of testis lipids in the pike reveals a sequence of events comparable with that occurring in seasonal birds. These events include the post-nuptial appearance of cholesterol-positive lipid material which accumulates within the seminiferous lobules, and its subsequent gradual disappearance. A lipid cycle occurs also in the lobule walls, where apparently fibroblasts, in the absence of a true secretory interstitium, become glandular and probably take on an endocrine function. These ‘lobule boundary cells’ seasonally accumulate cholesterolpositive cytoplasmic lipids which suddenly become depleted at the time of the annual pre-spawning assembly.

The pike differs from wild birds in the ‘timing’ of such rhythmical activity. In birds, despite a rapid post-nuptial interstitial regeneration, the tubule cholesterol lingers until spermatogenesis begins during the following late winter or spring. In the poikilothermous pike, on the other hand, the next spermatogenesis begins almost immediately (in June, when the temperature of the water is still rising). It continues without interruption while the length of day and later the temperature decrease, until tbe testis reaches its maximum size in December. ‘Lobule boundary cells’ start to become lipoidal in September, at a time of high temperature but decreasing day-length. The cells are fully charged by December. Both tubules and gland-cells now become inactive. Then in April at the spring period of increasing day-length, and immediately a iter water temperature starts to rise, the boundary cells begin to secrete and the prespawning assembly occurs. This is followed by the shedding of spermatozoa later in ti e month or early in May. The only period of true inactivity is at the height of spermatogenesis during mid-winter and early spring.
The Shrinkage of Air-dried Bacteria prepared for the Electron-microscope
Authors: Ross K. F. A. , Deutsch K.
Published: April 2021

Values for the mean thickness of living bacilli in a number of different cultures of Lactobacillus bulgaricus were obtained from phase-change measurements. These were made with an interference microscope. The bacilli were mounted in media of several different refractive indices. The accuracy of these measurements is not limited by the wavelength of the light used, so that the mean thickness of bacteria can be measured more critically in this way than by an eyepiece micrometer scale.

The values obtained for the mean thickness of the living bacilli were compared with the mean width of similar bacilli measured in electron-micrographs, after they had been prepared for electron-microscopy by drying them in air on formvar. The method used for preparing the bacteria for the electron-microscope is described in detail.

It was found that osmium-fixed air-dried L. bulgaricus so prepared shrink linearly in the plane of the formvar film by 59% ±5%, and similar unfixed bacilli by 51% ±5%. Phase-change measurements through these air-dried bacilli indicated a similar degree of shrinkage, or a slightly greater shrinkage, in the direction at right angles to the formvar film.
Observations on the Structure of Hydra as seen with the Electron and Light Microscopes
Authors: Hess Arthur , Cohen A. I. , Robson Elaine A.
Published: April 2021

Sections of hydra studied with the electron microscope show various structures which have been identified by referring to control histological sections and to previous descriptions. Certain features have also been examined in frozen-dried sections under the light microscope.

In the ectoderm, epithelio-muscular cells contain various organelles, and also smooth longitudinal muscle-fibres with which mitochondria may be associated. The so-called ‘supporting fibres’ appear to be thin bundles of muscle-fibres. Although points of contact exist between muscle-fibres, there appears to be no cytoplasmic continuity. The muscle-fibres insert on the mesogloea, and appear to be separated from it by two membranes, one belonging to the cytoplasm surrounding the musclefibre and the other to the mesogloea.

The mesogloea is extracellular and quite distinct from the intracellular muscle-fibres. It appears granular and sometimes presents an indistinct fibrous background. In frozen-dried material the mesogloea stains blue with Mallory’s method, while the muscle-fibres stain red.

Two main types of cells are found in the endoderm. Among these, some of the digestive cells contain transverse muscle-fibres, but they are less distinct than the longitudinal ectodermal fibres. Otherwise the digestive cells vary much in structure, but generally they contain vacuoles and their free surface is thrown into villi covered with small granules. The ‘foamy gland cells’ are filled with much larger vacuoles containing granular material. The vacuoles are discharged together with portions of cytoplasm, and at this stage lamellated double membranes and mitochrondria appear between the vacuoles. Both types of cell possess two flagella, which show a typical ultrastructure and are surrounded by a thick membrane.

Various other cells of the ectoderm are distinguished by their characteristic appearance. Cnidoblasts, for instance, have been found to contain an extensive system of intercommunicating vacuoles bounded by membranes, and do not resemble the interstitial cells. In unexploded penetrant nematocysts the tube is preformed and the butt and stylets can also be seen. The special gland-cells of the pedal disk show large, electron-dense granules which are extruded from the cell without any cytoplasm. A relatively thick homogeneous layer on the surface of the pedal disk is distinguished by the electron microscope.
The Formation and Properties of the Organic Matrix of Reptilian Tooth Enamel
Authors: Poole D. F. G.
Published: April 2021

A number of features of enamel formation in the lizard Agama atricollis are described. The behaviour and properties of the ameloblasts indicate that the process of enamel formation is similar to the corresponding process in mammals; the fibrous enamel matrix appears to be formed from outgrowths of the cytoplasm of these cells. Inter-prismatic material, as it is known in mammals, is not produced, so that reptilian matrix tends to be uniformly fibrous. Nevertheless, the fibres are initially arranged in groups corresponding to the ameloblasts. There is no distinct pre-enamel stage because matrix production is immediately followed by a limited influx of mineral in an elementary state, converting the matrix into an basiphil form. Striae of Retzius may be due to periodic pauses in the normal process of matrix production enabling the ameloblasts to assimilate and secrete mineral. Before the onset of final calcification, the matrix seems to undergo a modification rendering it capable of influencing the size and orientation of mineral crystallites.

The organic matrix has a refractive index of 1-57 and has no intrinsic birefringence. However, in suitable liquids the parallel fibres produce a positive form birefringence. If paraffin wax is allowed to crystallize on the matrix, optically negative streaks are formed parallel with the fibres, perhaps as the result of crystal overgrowth.

Evidence obtained indicates that this reptilian type of ectodermal enamel is a likely precursor of the mammalian prismatic type. The evolution from one to the other could have been achieved in a comparatively simple step.
Variability of Behaviour of Aggregating Cellular Slime Moulds
Authors: Shaffer B. M.
Published: April 2021

A description is given of the development of certain structures—centre, stream, and ring—formed by the amoebae of four species of Dictyostelium and Polysphondylium during aggregation, and of the outcome of experimentally cutting a stream, recombining lengths of stream in simple geometrical relationships, and excising a centre. In all cases there is a high degree of intraspecific variation in behaviour, and it is not possible to predict, except in terms of rough probability, what the future course of development will be. An amoeba at this stage of the life cycle can exist in one of four main states. In the first, it is unaggregated and cannot react chemotactically; in the second, it is unaggregated but can react; in the third, it is in a stream moving towards a centre or has properties similar to those of a stream cell; and in the fourth, it is in a centre and nearly stationary. Though an enormous variety of patterns may be produced by large numbers of interacting amoebae, their behavioural repertory may be considered, without too much simplification, to be restricted to approaching these four states in various sequences and at various rates. Most of these sequences can be observed over a wide range of environmental conditions. Changes in humidity produce the greatest effect: the drier the culture, the stronger the drift from the first state to the fourth. It is suggested that variability is occasioned by the simplicity of the mechanisms controlling development.
The Effect of Acetic Acid on Cytoplasmic Inclusions
Authors: Baker John R.
Published: April 2021

Acetic acid at 5 % is not necessarily destructive of cytoplasmic inclusions. Hermann’s fluid gives excellent mitochondrial preparations if tissues are postosmicated for several days at 34° C. The mitochondria are blackened by this treatment. Mann’s fluid with the addition of 5 % of acetic acid gives, on postosmication, very good preparations of the ‘Golgi apparatus’ of certain cells.
Spermateleosis in Fasciola hepatica
Authors: Gresson R. A. R.
Published: April 2021

The stages of spermateleosis and the structure of the spermatozoon of Fasciola hepatica were studied in smears of fixed material and in preparations of living tissue examined under phase-contrast microscopy.

Smears were fixed in Bouin’s picro-formol and in Flemming without acetic. Smears were also prepared according to the Feulgen technique.

The nucleus of the late spermatid undergoes elongation and grows out from the distal end of the cell. An extension of cytoplasm gives rise to the sperm-tail or flagellum. The spermatozoon becomes free of the greater part of the cytoplasm of the spermatid; the latter remains as a residual mass.

The spermatozoon consists of a nucleus and a flagellum. The latter is probably composed of an axial filament surrounded by a thin sheath of cytoplasm.
The Functional Anatomy of the Mid-gut of Larvae of the Ant, Myrmica
Authors: Weir J. S.
Published: April 2021

The functional anatomy of the mid-gut of larvae of Myrmica rubra microgyna Brian and Brian is described.

Observations have been made on the modes of formation of the two distinct types of peritrophic membrane, which may correspond to the primary and secondary peritrophic membrane of Wigglesworth.

These membranes are highly developed independently and the hypothesis is advanced that they have different functions. Further, it is suggested that the corresponding structures in adult Apis do not represent, as advanced by earlier workers, an intermediate stage in the evolution of the peritrophic membrane, and in its mode of formation.