bluuebunny/crossref_metadata_2025_split huggingface dataset:
II.—MICROSCOPY IN THE REGION OF WAVE‐LENGTH Λ= 2,000Å. to 1,000Å
Authors: Johnson B. K. 
Published: November 2011

SynopsisThe paper describes the technique for using the microscope in the region 2,000Å. to 1,000Å. and the instrument for doing this. The experimental work shows that if the instrument is mounted in a chamber containing nitrogen instead of in vacuo the technique is greatly facilitated. Reflecting objectives of the Schwarzschild type and a refracting type monochromat (made in fluorite) have been used in this work. Photomicrographs taken with the instrument are included in the paper.
VII.—THE PERFORMANCE OF SPHERICAL‐MIRROR REFLECTING OBJECTIVES WHEN USED FOR ULTRA‐VIOLET PHOTOMICROGRAPHY
Authors: Wilkins M. H. F. 
Published: November 2011

SynopsisSome of the factors influencing design and performance of spherical‐mirror reflecting objectives are briefly discussed. The Beck reflecting objective of 0.60 N.A. was designed primarily for micro‐spectrography, but gives fair all‐round performance when used for photomicrography with visible or ultra‐violet light. Photomicrographs are shown taken with the Beck 0.60 N.A. objective and a solid quartz 0.90 N.A. objective.
FLAGELLA AND CELL WALL OF SPIRILLA
Authors: Pijper Adrianus 
Published: November 2011

SYNOPSISWith sunlight dark‐ground microscopy two new spirilla, one motile and the other not, at first showed typical single polar flagella and later polar flagella dissimilar in number, shape, size, and place of attachment. After that many frankly lateral flagella of various kinds arose, bringing about a peritrichous appearance. Finally the spirilla became covered with a mass of fibrils mixed with odd flagella. Cell walls of spirilla apparently contain a network of submicroscopic fibrils. These may become twisted into typical and atypical flagella and may also come off as masses of fibrils. None of these structures can be regarded as motor organs.
OVULATION, FERTILIZATION, AND EARLY CLEAVAGE IN THE HAMSTER (Mesocricetus auratus)
Authors: Austin C. R. 
Published: November 2011

SYNOPSISThe mean number of eggs ovulated was found to be 10.0 eggs per hamster, range 3 to 17. The fertilization rate was 85.7 p.c. In eggs recovered shortly after ovulation the mean overall diameter was 117.8μ, the thickness of the zona pellucida was 11.6μ, and the diameter of the vitellus was 73.2μ in unpenetrated eggs and 70.9μ in penetrated eggs. The first polar body always persisted until after ovulation. When the second maturation spindle could be identified it was always in metaphase in unpenetrated eggs examined soon after ovulation. The hamster egg has an unusually large perivitelline space.The zona pellucida dissolved in acid solutions at pH 2.8 and lower; it was readily digested by trypsin solutions, the zona from penetrated eggs being a little less resistant than that from unpenetrated eggs. The zona may undergo expansion during cleavage and was often lacking from eggs in the 4‐cell and later stages.When hamsters were kept from birth or weaning under controlled illumination (light from 4.0 p.m. to 7.0 a.m., dark from 7.0 a.m. to 4.0 p.m.), ovulation occurred chiefly between 2.0 p.m. and 4.0 p.m. There was a delay of approximately 2 hr. between ovulation and spermatozoon penetration.With natural lighting (July to September), nearly half the eggs recovered at 7.0 p.m. were in stages immediately preceding the first cleavage. On the next day (day 2) all fertilized eggs were 2‐cell, on day 3 they were 3‐ to 8‐cell, and on day 4 they were morulæ or early blastocysts.The process of fertilization is briefly described and compared with that seen in rat and mouse eggs. The male and female pronuclei resemble each other in size and form and are often indistinguishable. When one pronucleus is larger than the other it is probably the male. In nuclear and nucleolar dimensions the hamster egg resembles the mouse egg rather than the rat egg.In 519 penetrated eggs the incidence of polyspermy was 1.08 p.c. Not one of the penetrated eggs, however, had a supplementary spermatozoon. The zona reaction in the hamster egg is therefore very‐rapid and may constitute the only protection against polyspermy.Six eggs presenting anomalous features are described.Results are discussed in relation to previous observations on the hamster and other species.
AN ELECTRON MICROSCOPE STUDY*
Authors: Gatenby J. Brontë , Tahmisian T. N. 
Published: November 2011

SYNOPSISIn the fresh water and marine sponges, the Golgi apparatus in the collar cells in each type is differently arranged. In the former there are contractile vacuoles which have no direct connection with the Golgi apparatus; in the latter there are apparently non‐contractile bound vacuoles surrounded by a lamel‐lated osmiophile material; the vacuoles presumably form a water reserve. In the amœbocytes of both types of sponges, the Golgi apparatus is in the form of dictyosomes flattened against the nuclear membrane, and in fresh water sponges these dictyosomes have no direct connection with contractile vacuoles.
I.—PROSPECTS FOR SUBSTANCE DIFFERENTIATION BY ELECTRON AND X‐RAY MICRO‐METHODS*
Authors: Cosslett V. E. 
Published: November 2011

SYNOPSISVarious methods have been considered for identifying specific elements or compounds in the electron microscope or by related techniques. X‐ray emission spectrometry has high detection sensitivity (to 10−14 gm.) combined with an accuracy of location similar to that of the optical microscope (to 0.5 μ). Electron transmission measurements give a much higher spatial resolving power, but the prospects for quantitative analysis on unstained biological material are very limited. Recent theoretical work on electron scattering, in the conditions of electron microscopy, suggests that not only heavy element stains but the normally used organic reagents as well may prove useful in devising analytical procedures similar to the stoichiometric staining methods of optical microscopy, though with distinctly less latitude in sensitivity. The use of a much lower voltage than is usual for electron microscopy, of the order of 10 kV, would give greater image contrast and therefore better accuracy of analysis. Three other physical effects are briefly discussed which may be possible of development for quantitative analysis with electron beams: energy loss, phase shift, and secondary electron emission.
B.—QUANTITATIVE ELECTRON STAINING OF VIRUS PARTICLES
Authors: Valentine R. C. 
Published: November 2011

SYNOPSISAs test objects for measuring the uptake of electron stains, virus particles have the advantage that their thickness is constant and known with fair accuracy. The fraction of the incident beam scattered by them out of the image can easily be deduced from the optical densities of electron micrographs and the degree of staining thus measured quantitatively. Some results are given and discussed in terms of electron scattering theory.
III.—THE USE OF STEREOSCOPIC TECHNIQUE IN ELECTRON MICROSCOPY
Authors: Little K. 
Published: November 2011

SYNOPSISAn account is given of some of the means by which, using three‐dimensional viewing, effective use can be made of the great depth of focus of the electron microscope. Some modifications in methods of preparation of specimens are mentioned. The main drawback to the method which has been encountered —lack of adequate stereoscopic vision in many people—is briefly discussed.
THE GOLGI APPARATUS OF THE CLUB CELLS OF THE CATFISH SYNODONTIS SCHALL BL. SCH.
Authors: Lutfy R. G. 
Published: November 2011

SYNOPSISThe Golgi apparatus of the epidermal club cells of the catfish Synodontis Schall can be revealed by the classical methods and is formed of chromophobe vacuoles surrounded by chromophil walls. At certain phases the vacuoles are either missing, or they may be submicroscopic and thus beyond the limits of resolution of the light microscope.The Golgi apparatus undergoes marked morphological changes and hypertrophy according to the age and the physiological condition of the club cell.In the early stages of the growth of the club cell, hypertrophy of its Golgi apparatus takes place by the production of a large number of spherical bodies which are mostly dictyosome‐like. Further additions to the Golgi material are mainly in the form of long filaments which spread out into the cell cytoplasm and enclose at intervals spherical inner chromophobe vacuoles. There is evidence that some of the filaments may develop from the early‐formed dictyosomes by the lateral extension of the osmiophil material.With the further growth of the club cell, the Golgi vacuoles change from spherical to oval and later to more elongated forms, giving the Golgi material the conventional canalicular picture. Later the Golgi apparatus undergoes fragmentation, the fragments being found close to the cell periphery.In some of the club cells the Golgi fragments are seen in close contact with vacuoles which are interpreted as of secretory nature. These vacuoles are of common occurrence in the peripheral cytoplasm of most of the larger club cells.The secretion referred to arises in the cell cytoplasm in the immediate vicinity of the osmiophil material and not inside the Golgi chromophobe vacuoles.
THE SPERMIOGENESIS OF PETROBIUS MARITIMUS
Authors: Mathur R. S. 
Published: November 2011

SYNOPSISThe sperm of Petrobius maritimus is a normal flagellate type and is formed in the normal manner. The acrosome is a clearly marked and easily followed structure. In the final stages the acrosome can be seen to be deposited on the proximal end of the nucleus as a composite structure with a small granule at the tip. It is a secretory product of the Golgi body and not the Golgi body itself. The spent acroblast (dictyosome, Golgi body) drifts down the lengthening spermatid as the acroblast reject, as normally occurs in flagellate spermiogenesis. The centriole region probably consists of the centriole plus the centriole adjunct, but is too small to be resolved by the light microscope. The mitochondrial nebenkern is formed by the aggregation, but apparently not the agglutination, of the mitochondria, and is not typical of the mitochondrial nebenkern of holometabolous insects.
LIGHT AND ELECTRON MICROSCOPY AND ITS USE IN THE STUDY OF FACTORS INFLUENCING SPERMATOGENESIS IN THE RAT
Authors: Lacy Dennis 
Published: November 2011

SYNOPSISThe value of employing both light and electron microscopy in cytological research is discussed. It is pointed out, however, that depending upon the kind of problem being studied it may be necessary to employ a wide variety of experimental techniques. This is particularly true when attempting to relate structure to function. To emphasize this, and to present a synthesis of some recent work, observations made by the writer and collaborators on the testes of normal, irradiated and oestrogen‐treated rats are described. The following main results are reported: 1. The residual bodies, cast off by the newly‐formed spermatozoa, consist of basic cytoplasmic constituents; they are especially rich in R.N.A. 2. The residual bodies are phagocytosed by the Sertoli cells and degenerate. During the latter process their R.N.A. component is absorbed or dispersed. Their lipid, however, remains and probably constitutes the bulk of the lipid seen with the Sertoli cells during later stages of the seminiferous cycle. 3. A lipid cycle is shown both by the germ cells and the Sertoli cells. The germ cells contain most lipid during about stages 1–8. The Sertoli cells contain most lipid during about stages 9–14. The two cycles are essentially out of phase with each other. 4. The lipid of the germ cells, residual bodies and Sertoli cells, gives a negative reaction to Schultz's test for cholesterol. 5. High doses of radiation (10,000 rads; 50,000 rads) cause the germ cells to degenerate; they are then phagocytosed by the Sertoli cells. The degenerating germ cells form large amounts of lipid which comes to lie freely embedded within the Sertoli cytoplasm. This lipid gradually becomes markedly cholesterol‐positive. 6. Preliminary tests suggest that the cholesterol‐positive lipid of irradiated animals possesses progestin‐like activity. 7. During prolonged treatment with oestrogenic hormone, large amounts of lipid slowly accumulate within the Sertoli cells. This lipid gradually gives a strong positive cholesterol‐reaction.As a working hypothesis it is suggested that in normal animals the lipid within the Sertoli cells represents a steroid hormone or its precursor which it utilized by the germ cells at some particular stage, or stages, of their development. On this basis the residual bodies initiate the production of this hormone. Thus the well‐marked co‐ordination of spermatogenetic stages about a radial axis in seminiferous tubules of the rat may depend upon the phagocytosis of the residual bodies and the secretion of a steroid hormone by the Sertoli cells.
AN ELECTRON MICROSCOPE STUDY OF SOME CYTOPLASMIC INCLUSIONS OF THE NEURONES OF THE PRAWN, LEANDER SERRATUS
Authors: Malhotra S. K. , Meek G. A. 
Published: November 2011

SYNOPSISNeurones from the thoracic and abdominal ganglia of the prawn, Leander serratus, were studied by optical and electron microscopy. The following cytoplasmic inclusions have been studied:1. The endoplasmic reticulum, which is more or less uniformly distributed throughout the cytoplasm in a vesicular form. Parallel lamellæ associated with granules have rarely been encountered. Sufficiently large aggregates of organized endoplasmic reticulum, corresponding to the Nissl bodies of vertebrates, have not been seen.2. The “dictyosomes”, which are composed of stacks of paired non‐granular membranes. The stacks are generally seen as rods, crescents, and horse‐shoes in electron micrographs, and resemble the complex known generally as the “Golgi apparatus”. The evidence indicates that these lamellar structures correspond to the spherical or nearly spherical bodies that are seen in living cells and colour with neutral red.3. The “trophospongium”, which is shown to consist of branching invaginations of the cell membrane, containing processes from the glial cells. It ramifies in the form of long, thin, branching filaments throughout the cytoplasm. Some workers with the light microscope have mistaken these branching invaginations for mitochondria.4. The mitochondria, which are mostly short. Long, filamentous mitochondria which might be expected to give the appearance of the “trophospongium” have not been encountered.
IMPROVEMENTS IN DETERMINING TOTAL COUNTS OF BACTERIA
Authors: Norris K. P. , Powell E. O. 
Published: November 2011

SYNOPSISAn interferometric method of measuring the thickness of counting chambers is described. It is simple enough to be used every time a chamber is assembled. Accurate measurement of chamber depth removes a large systematic error from total counts as ordinarily calculated. Experiments on various other details of counting technique lead to recommendations conducive to still further improvement. The standard error of a count under the best conditions need be no more than 50 p.c. greater than the error due to random sampling.
SOME OBSERVATIONS ON MICROSCOPE COVER‐GLASSES
Authors: Norris K. P. 
Published: November 2011

SYNOPSISMeasurements made on over 3400 cover‐glasses of 16 different grades show that only 43 satisfied the Royal Microscopical Society's specification of thickness and only 18 of these were of the specified refractive index. Many cover‐glasses are highly wedge‐shaped and in some samples there is a significant high positive correlation between the mean thickness and the slope of the wedge.
THE FALGIC ACID DYES AND THEIR APPLICATIONS IN HISTOLOGICAL STAINING
Authors: Gurr E. , MacConaill M. A. 
Published: November 2011

SYNOPSISSections stained with acid fuchsin and counterstained with light green SF (yellowish) show a striking polychrome effect in shades of red, violet, and blue. This is noteworthy for at least two reasons:

Blue is, of course, a primary colour and cannot, therefore, be produced by the mere admixture of red and green, which are the colours of the two dyes used. Chemical union must therefore take place between these two acid dyes to produce a series of new dyes, one of which is blue.
It has long been known to histologists that a basic dye will unite chemically with an acid dye to form a two‐colour stain, but similar union between two acid dyes was not hitherto thought possible or even considered.
LYMPH NODE STRUCTURE IN THE SUMATRAN RHINOCEROS
Authors: Cave A. J. E. , Aumonier F. J. 
Published: November 2011

SYNOPSISThe histology is described, for the first time, of certain of the lymph nodes of the rare Sumatran Rhinoceros (Didermocerus sumatrensis). These have a marked structural resemblance to the spleen, but reveal no uniform evidence of being hæmolymph organs, though their metaplasia thereinto is indicated.
EMBEDDING COALS AND COKES IN PLASTIC FOR MICROSCOPIC EXAMINATION
Authors: Zeidler W. , Taylor G. H. 
Published: November 2011

SYNOPSISCoal, coke and some other carbonaceous materials present special difficulties in both thin sectioning and polishing, whether the sample is granular or in lump form. Improved techniques using polyester resin have been worked out, and have been found more reliable and convenient than other methods of thin sectioning and polishing. Large parallel‐sided thin sections, wholly enclosed in plastic, are useful for studying and demonstrating comparatively gross structures, but may also be used at high magnification to study fine detail. Methods of preparing sections and surfaces of very small amounts of material (i.e. down to 0·1 mg or even less) are described, also the use of vacuum embedding and impregnation.
A RAPID AND ACCURATE METHOD OF MOUNTING SECTIONS FOR ELECTRON MICROSCOPY
Authors: Noble Henry W. 
Published: November 2011

SYNOPSISAn improvement in the speed and accuracy with which ultra‐thin sections can be mounted upon formvar coated grids is possible by means of a simple device. The greater degree of precision with which sections can be placed upon the formvar film enables the steel slot type grid to be used with a greater degree of success in histological investigations.
OBSERVATIONS ON LAMELLATED STRUCTURES AND THEIR FORMATION IN DENERVATED SKELETAL MUSCLE
Authors: Lee Joseph Ching‐Yuen 
Published: November 2011

SYNOPSISIn muscle fibres of the gastrocnemius of adult rabbits and rats, denervated for at least one month, electron microscopy revealed peculiar lamellated structures. Some of these appeared as arrays of parallel double lamellæ; others folded themselves into ovoids or asterisk‐like patterns, while still others were of irregular shape.One to three months after denervation, the outer membrane of many muscle nuclei protruded to a varying extent, and later the protrusion folded into an array of parallel double lamellæ. When the array reached a certain size, it became detached from the nuclear membrane and assumed various forms. Such structures were more numerous in muscles denervated for longer than 3 months. They seemed to move gradually toward the sarcolemma and to become finally attached to it or to fuse with it. These findings support the current view that all membrane‐bounded cytoplasmic organelles belong to a common “membrane system” extending from the plasma membrane to the nuclear membrane. It is concluded that the lamellated structures in denervated muscle are derived from the outer nuclear membrane and that they are an outcome of the degeneration of muscle nuclei.
CYTOCHEMICAL LOCALIZATION OF ANTIGENS OF PARAMECIUM BY FERRITIN‐CONJUGATED ANTIBODY AND BY COUNTERSTAINING THE RESULTANT ABSORBED GLOBULIN
Authors: Mott Margaret R. 
Published: November 2011

SYNOPSISThe localization and transformation of the immobilization antigens of Paramecium aurelia were studied with the use of ferritin‐conjugated antibody. The reaction was extremely specific, ferritin granules being found only on the pellicle and cilia of homologous animals. In the transformation from one antigenic type to another, ferritin granules, conjugated with antibody specific for the “new” antigen, appeared initially on the pellicle and subsequently on the cilia.An electron‐dense counterstain, of potassium permanganate and uranyl acetate, not only increased the detail of the structure of the organism, but also stained the absorbed globulin of the specific antibody as a thick fuzz on pellicle and cilia. This fuzz, unlike the ferritin granules, was clearly visible at very low magnifications of the electron microscope. This gave a quick scanning method, especially useful in transformation experiments, when various stages could be quickly scanned for the first appearance of globulin fuzz.
SOME OBSERVATIONS ON THE FIXATION AND STAINING OF LIPIDS
Authors: Casley‐Smith J. R. 
Published: November 2011

SYNOPSISFormalin, acrolein, or controlled chromation do not retain maize oil or butter during embedding.Post‐chromation after calcium formol fixation retains some butter and much maize oil, but the fixation is not uniform.Sudan Black B and Sudan IV stain these lipids for electron microscopy. These stains do not contain atoms of high atomic weight.The double bonds of unsaturated lipids are stained by floating the sections on osmium tetroxide solutions, or by exposing the sections to ultra‐voilet light and then staining them with Schiff's reagent in the presence of a source of copper.
HISTOCHEMICAL DEMONSTRATION OF THE ACTIVATION OF RAT ACETYLCHOLINESTERASE BY SODIUM CACODYLATE AND CACODYLIC ACID USING THE THIOACETIC ACID METHOD
Authors: McAlpine John C. 
Published: November 2011

SYNOPSISIn this histochemical study, sections of rat tongue muscle were incubated in thioacetic acid substrates containing different molarities of various organic arsenicals; the effects were compared with control substrates, and with other substrates containing magnesium, manganese, and calcium chlorides.Evidence is presented to show that sodium cacodylate and cacodylic acid act as strong activators for the acetylcholinesterase of the muscle motor end‐plates.The cacodylate‐activated substrate gives a clean, precipitate‐free solution and short incubation times; the enzyme activity is localized as a fine non‐granular reaction product.
NEW DEVELOPMENTS IN THE GOLGI CONTROVERSY
Authors: Baker John R. 
Published: November 2011

SYNOPSISThe author accepts, after long hesitation, the view that the “Golgi apparatus” in the neurones of vertebrates corresponds with the organelle of the same name in other cells. He has been much influenced by the results of the application of A. B. Novikoff's histochemical test for thiamine diphosphatase to various cells. This test gives a positive reaction in the Golgi apparatus in many cells of vertebrates, and in the neurones of this group of animals the lamellæ of the apparatus are the only site of positive reaction.When Novikoff's test is applied to the neurones of certain invertebrates, however, the lipochondria react positively, the Golgi apparatus feebly or not at all. The author stresses that the remarkable morphological similarity of the Golgi apparatus, as represented in electron micrographs of diverse cells, may disguise very considerable chemical and enzymic differences.