bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitosis in the Mouse : A Study of Living and Fixed Cells in Tissue Cultures
Authors: Fell Honor B. , Hughes A. F. 
Published: April 2021

ABSTRACT
1. Mitosis has been investigated in cultures of infant mouse tissues, in both living and fixed material.
2. Phase microscopy combined with serial photography was used to study the living cell.
3. The formation of chromosomes has been traced in the living cell from the intermitotic chromonemata and heterochromatic chromocentres.
4. Dividing cells can be recognized early in prophase and the duration of each phase of mitosis has been measured.
5. Curves of anaphase movement have been plotted; they are sigmoid as in amphibian cells.
6. The reconstruction of the daughter nuclei has been studied in detail in both living and fixed cultures. The chromosomes swell, then begin to lose their nucleic acid charge and to unravel into a web of fine threads. The nucleolar material can be identified in the living cell early in telophase; it appears as a diffuse system of lumps and strands occupying most of the nucleus and its direct transformation into the interphase nucleoli was followed in the film records.
7. The origin of polyploid nuclei by the mitosis of binucleate cells has been demonstrated.
8. Analysis of the film records showed that the average length of the intermitotic period is 12 hours.
A Simple Method of Staining the Basement Membrane of Glomerular Capillaries
Authors: Linder J. E. 
Published: April 2021

ABSTRACT
In 1943 Thomas described a haematoxylin phosphomolybdic acid lake which stained collagen and reticulin. This observation has been confirmed and extended by the chance observation that on long stan’ding the lake acquires the power of colouring the basement membrane of the glomerular capillaries.
The Influence of a Gonadotrophin on the Seasonal Changes in the Testis and Deferent Duct of the Chaffinch (Fringilla coelebs)
Authors: Sluiter J. W. , Van Oordt G. J. 
Published: April 2021

ABSTRACT
1. Male chaffinches (Fringilla coelebs) were treated with gestyl, a gonadotrophin prepared from pregnant mare serum, in different seasons; using different techniques their testes and deferent ducts were histologically studied after autopsy on u August, 30 November, 28 January, and 5 May.
2. After Champy-fixation and Altmann-staining two types of interstitial cells can be distinguished in the intertubular tissue of sexually active chaffinches : lipoid cells, (= Leydig cells) and secretion cells.
3. Results of gestyl-administration : In summer- and winter-birds (Pl. I) whose testes are in the resting stage, the testis-tubule diameter shows a strong enlargement, which is partly due to the plasma of the cells being distinctly inflated ; spermatogenesis does not take place. In the intertubular tissue lipoid and secretion cells appear in abnormally large numbers. In 10 days the deferent ducts pass over from the quiescent into the fully-activated stage. In spring-birds (Pl. Ill), being in the reproductive stage, the administration of gestyl has practically no effect. In this stage the intertubular tissue also contains both lipoid and secretion cells.
4. From the results mentioned under 3, and the fact that in the control bird of 28 January, being in the beginning of the progressive stage (Pl. II), many lipoid cells were found, whereas its deferent ducts were still quiescent, it is concluded that only the secretion cells produce the male sex-hormone. The lipoid cells, which amongst others contain cholesterol, possess only a trophic function.
5. The difference in reaction of the seminiferous tubules of birds to chorionic and hypophyseal gonadotrophins as well as the function of the interstitial cells are discussed. Most opinions on the last-mentioned subject are not sufficiently well founded, as the investigators used routine techniques only for the cytological investigation of the interstitial tissue.
The Structure of Whale Blubber, and a Discussion of its Thermal Properties
Authors: Parry D. A. 
Published: April 2021

ABSTRACT
As a warm-blooded animal, a whale must be adapted not only to prevent an excessive loss of heat but also to control the rate of heat loss in relation to changes in its metabolic activity and in the temperature of its surroundings. This paper contains an account of whale blubber considered from this point of view. The first part is devoted to the morphology of blubber, particular attention being paid to the blood circulation which does not appear to have been previously described; and the second part contains a discussion of the efficacy of blubber as a thermal insulator of controllable conductance. The results are based on a study of the Common Porpoise (Phocaena phocaena), and the Blue and Fin Whales (Balaenoptera musculus and B. physalus).
Heliospora n.g. and Rotundula n.g., Gregarines of Gammarus pulex
Authors: Goodrich Helen Pixell 
Published: April 2021

ABSTRACT
From this study of the unknown stages in the life-histories of the two polycystid gregarines, which have been known for just 100 years in Gammanes pulex L., it is concluded that the long thread-like one should be Heliospora longissima (Siebold) and the short rounded one Rotundula gammari (Diesing), and that some other Amphipods have the same or similar gregarines.
A Critical Study of Techniques for the Cytochemical Demonstration of Aldehydes
Authors: F. Danielli J. 
Published: April 2021

ABSTRACT
A critical study has been made of Feulgen’s technique for demonstrating tissue aldehydes. Conditions are given within which the technique is reliable on the cytological scale. Five supplementary tests for aldehydes are described. It is shown how distinction may be made between free aldehyde, acetal aldehyde, and aldehyde formed by oxidation.
The Digestive Mechanism of the European Squids Loligo vulgaris, Loligo forbesii, Alloteuthis media, and Alloteuthis subulata
Authors: Bidder Anna M. 
Published: April 2021

ABSTRACT
1. The digestive mechanism has been investigated in Loligo forbesii, L. vulgaris, Alloteuthis media, and A. subulata. Histology and morphology were examined on living and fixed material and the feeding of L. vulgaris was observed in the living animal.
2. The food is bitten by the jaws and rapidly swallowed; the radula has no rasping action.
3. Preliminary digestion takes place in the stomach, which is cuticle-lined.
4. The caecum is a complex organ, containing the opening of the mid-gut gland. This opening is connected with the closing mechanism of the caeco-intestinal opening in such a way that the hepato-pancreatic secretion can be directed either to the caecum or to the stomach. The anterior part of the caecum contains a ciliary collecting mechanism whose main groove leads along the intestine towards the anus.
5. The posterior part of the caecum is a simple ciliated sac where digestion is completed, food absorbed, and pancreatic secretion stored between meals. Solid food other than particulate is never found in the caecum.
6. The intestine is a short, straight tube, lined with a ciliated and mucous epithelium. Absorption also takes place here, and continues after the caecum has ceased absorbing.
7. The junction of intestine and rectum is considered to be defined by the replacement of the ciliated epithelium by one with a hyaline border.
8. The rectum is short; in the region of the rectal sphincter it is lined with cells bearing curious retractile processes, whose possible function is discussed.
9. The mid-gut gland secretes all digestive enzymes; it is divided into two unequal and markedly different glands: the so-called ‘fiver’ and ‘pancreas’. These are connected in series, so that hepatic secretion flows through the main lumen of the pancreas to reach the caecum.
10. Hepatic secretion is passed into the caecum only during digestion. The liver has a single type of cell in which food reserves also accumulate. The hepatic duct can be closed by a sphincter.
11. Pancreatic secretion accumulates in the caecum between meals and apparently passes to the stomach during digestion. The structure and rhythm of the cells of the pancreas and the nature of its blood-supply suggest some second activity, possibly directed towards the blood-stream, alternating with that of enzyme-secretion.
12. Food is not absorbed in the mid-gut gland.
13. The structural and functional peculiarities of the digestive system of these squids may be related to an exceptionally speedy and efficient digestive mechanism, well fitted to the life of a perpetually swimming, active predator.
The Physiology of the Alimentary Canal of Tyroglyphus farinae
Authors: Hughes T. E. 
Published: April 2021

ABSTRACT
1. The pH of the stomach and its caeca lies between 5·0 and 6·0, that of the colon changes to the alkaline side of 7·0 but remains below 8 0. The pH of the post-colon is between 7·0 and 8·0. All these measurements are subject to protein error.
2. The stomach and its caeca are regions of:
(a) absorption;
(b) secretion of a mucus containing a digestive enzyme;
(c) digestion of carbohydrate and protein
3. The optimum pH of carbohydrate digestion is 5-4 and of protein digestion 5·6±2.
4. The thin-walled colon regulates the pH of the food bolus and is the site of formation of a peritrophic membrane and some absorption.
5. The post-colon is the site of further absorption of water and solidification of the faecal pellet.
6. Excretory substances are first recognizable in the colon; they do not appear to be produced by the Malpighian tubules or post-colon.
7. The chief nitrogen katabolite is guanine.
8. There is an accumulation of nitrogenous katabolites in the parenchyma of the body in animals on a high-protein diet.
9. The powers of excretion of nitrogenous waste appear to be poor.
10. The main food reserves are of glycogen in the parenchyma; fat is not stored to any extent.
11. The salivary glands produce a mucus which serves as a lubricant for the food in its passage through the pharynx and oesophagus.
The Outer Layers of the Cuticle in the Cockroach Periplaneta americana and the Function of the Oenocytes
Authors: Kramer S. , Wigglesworth V. B. 
Published: April 2021

ABSTRACT
In the epicuticle of the cockroach there is a cement layer formed, as in other insects, by secretion from certain of the dermal glands at the time of moulting. These dermal glands are widely distributed over the abdominal tergites and sternites in both sexes. Their cell-bodies are atrophied in the mature insect. They differ in this respect from the very numerous dermal glands on the abdominal tergites of the male, which remain distended with vacuoles.
The cuticular wax, which is freely exposed on the surface of the cuticle, is thought to be produced by the sub-epidermal oenocytes and to be discharged during the life of the cockroach, perhaps through the pore canals, by the epidermal cells.
The oenocytes of the honey-bee are much larger during the height of wax secretion than they are in the foraging bee.
The view that the oenocytes are concerned in wax metabolism is compatible with the view that they synthesize the lipoprotein (or wax protein) components of the cuticle and egg-shell.
A Study of the Male Germ-cells of the Rat and the Mouse by Phase-contrast Microscopy
Authors: Gresson R. A. R. 
Published: April 2021

ABSTRACT
1. The cytoplasmic components of the male germ-cells of the rat and the mouse were examined by phase-contrast microscopy. Most of the structures seen in fixed and stained preparations were identified.
2. The localized Golgi material of spermatocytes and spermatids consists of rods and filaments. The mitochondria are granular.
3. The archoplasmic vacuole, proacrosome, developing acrosome, proximal and distal centrioles, and the axial filament were visible. A structure which may be an accessory body was observed in spermatocytes and spermatids. The manchette was visible in late spermatids of the rat but not in those of the mouse.
4. Examination of spermatozoa revealed the acrosome, the post-nuclear cap, the mitochondrial sheath, the ring centriole, and the protoplasmic bead. A granule was sometimes visible in the neck region.
Cytochemical Studies on the Embryonic Development of Drosophila melanogaster: II. Alkaline and Acid Phosphatases
Authors: Yao T. 
Published: April 2021

ABSTRACT
1. Drosophila ovary and testis are very rich in acid phosphatase, but contain no histochemical trace of alkaline phosphatase. Thus the mature oocyte shows a strong acid phosphatase reaction both in the nucleus and cytoplasm. Sperm heads are equally reactive.
2. Acid phosphatase is demonstrable in Drosophila embryos from early cleavage up to the hatched larva. No striking change in enzyme activity has been observed during this period.
3. Alkaline phosphatase is not detectable in the first half of embryonic life. It suddenly appears in the ventral ectoderm near the future thorax during or shortly after the contraction of the germ band. The enzyme activity then spreads to the other parts of the embryo following definite patterns, until finally the whole embryo becomes active. The possible mechanism of the spreading of enzyme activity is discussed.
4. Alkaline phosphatase disappears in most tissues before hatching, but is retained in the gut epithelia, salivary glands, and Malpighian tubes. The relationship of this enzyme to histo-differentiaton is suggested.
5. The centte of origin of alkaline phosphatase activity is considered as the ‘differentiation centre’ of the Drosophila embryo.
6. The high cytoplasmic acid phosphatase activity of the oocyte and nurse cells and a similar activity of the yolk in the developing embryos indicate that the enzyme plays some role both in the synthesis and in the degradation of yolk.
Studies of the Egg of Bacillus libanicus (Orthoptera, Phasmidae) : I. The Egg Envelopes
Authors: Moscona A. 
Published: April 2021

ABSTRACT
1. The structure of the eggs of Bacillus libanicus (Uvarov) is described and measurements given. Both structure and size were found to vary considerably
2. The axial orientation of the eggs is not in accord with ‘Hallez’s law’, as the dorsal and ventral sides of the egg and of the early embryo are diametrically opposite to those of the mother.
3. The microscopic structure of the egg envelopes is described. The egg is covered by three main envelopes: a hard, brittle exochorion built of seven distinct layers, two of which consist almost solely of calcium salts; a double-layered, membranous endochorion·, a thin vitelline membrane. Layers of the chorion may be summarized as follows:
(i) exochorion—tubercular layer, dark layer, lamellar membrane, calcium oxalate layer, intermediate lamella, calcium carbonate layer, shell membrane.
(ii) endochorion—outer and inner membrane.
4. In developing eggs the calcium carbonate layer of the exochorion becomes reduced owing to loss of material from its inner surface. Consequently the shell membrane, initially attached to this layer, becomes almost completely detached. The calcium carbonate layer in shells of eggs which do not develop remains unchanged.
Metachromasy of Nucleic Acids
Authors: Lison L. , Mutsaars W. 
Published: April 2021

ABSTRACT
If nucleic acids and a metachromatic dye are mixed in amounts giving a low nucleic acid : dye ratio a ‘positive’ metachromatic effect occurs similar to that observed with truly chromotropic substances: for instance, thionine or toluidine blue become red or reddish-violet. This may be observed in test-tubes with pure solutions of the substances. In microscopical preparations this occurs when the staining, is strong.
If the amount of N.A. is such that the ratio N.A. : dye is high, a ‘negative’ metachromasy occurs, that is, shades of colour are produced that are greener than those obtained in pure water solutions. In microscopical preparations this occurs when the staining of nuclei is very light.
Both ‘positive’ and ‘negative’ metachromasy have the characteristics of truly metachromatic phenomena—specific absorption curves and suppression by heat.
An Investigation of the Histochemical Technique for the Localization of Acid Phosphomonoesterase
Authors: Macdonald Frances 
Published: April 2021

ABSTRACT
A method is described for assessing the depth of ‘staining’ obtained with the acid phosphatase technique and a detailed scheme is given of the standard technique used. It is concluded that the technique specifically demonstrates the activity of acid phosphatase, since ‘staining’ is abolished in the absence of substrate, in heated sections, and in the presence of fluoride. An investigation has been carried out to determine the extent to which the reaction is affected by altering various stages in the technique. The effect of formalin fixation on the reaction has been investigated. It has been shown that sites in the rabbit medulla having an affinity for the reagents used in the technique differ from the sites at which a precipitate is deposited as a result of enzyme activity. Evidence is presented suggesting that the technique may not demonstrate the true physiological localization of the enzyme. It is suggested that the technique may be of value as a neurohistological method.
On the Use of Wide Illuminating Cones in the Microscope
Authors: Oettlé A. G. 
Published: April 2021

ABSTRACT
In bright-ground illumination, glare is noticeable when the condenser aperture is equivalent to that of the objective. It can still be detected, though to a greatly reduced extent, after most causes of glare have been avoided. It is suggested that this residual glare is inevitable, and represents the loss of contrast resulting from a relative excess of direct rays, which occurs when the direct light falls in the marginal zone of the objective, since half of the diffracted rays then falls outside the lens.
The Mesoglea and Muscle-fibres of Chlorohydra viridissima
Authors: Holmes William 
Published: April 2021

ABSTRACT
The structure and relations of the mesoglea, muscle-fibres, arid cell layers were examined by several histological techniques.
Evidence is given that the muscle-fibres represent specializations of the mesogleal substance, and they are therefore referred to as mesogleal fibres.
The longitudinal fibrous system is regularly demonstrable in the body of the animal and the circular system in its tentacles. The circular system in the body cannot regularly be shown and is variable in its appearance.
The evidence from the study of the fibres, and of the mesoglea of the pedal disk, leads to the suggestion that some at least of the fibres are labile structures, ‘crystallizing’ from the mesoglea according to the shape and movements of the animal.
The Water Relations and Cuticle of Paradesmus gracilis (Diplopoda, Strongylosomidae)
Authors: Cloudsley-Thompson J. L. 
Published: April 2021

ABSTRACT
Water-loss in Paradesmus gracilis depends upon temperature and humidity, and is directly related to saturation deficiency. There is no evidence of any ‘critical point’ to indicate an epicuticular wax layer. Water is readily lost and taken up through the cuticle, the effect of the spiracles and of excretion being negligible. Despite great sensitivity to desiccation, there is nevertheless some degree of impermeability.
The cuticle is in many ways similar to that of an insect: it is composed of a ‘cuticulin’ epicuticle, a ‘tanned’ chitinous exocuticle, and a laminated endocuticle of two optically distinguishable layers. The outer endocuticle is strongly calcified. The cuticle is penetrated by pore canals and the ducts of dermal glands. The latter are concerned with the production of exo- and endocuticle, and the secretion of the polyphenols which tan the protein of the exocuticle. The double hardening is probably a specialized condition of millipedes.
Transpiration is almost quadrupled by extraction with hot, but not cold chloroform, as the exocuticle is impregnated with lipoids which reduce permeability. These are secreted by epidermal and dermal gland cells, and pass up the pore canals and gland ducts.
Sporozoa of Sipunculus
Authors: Goodrich Helen Pixell 
Published: April 2021

ABSTRACT
The gregarines of Sipunculus, so often recorded during the last hundred years, prove to belong to two or more species of the genera Urospora and Lithocystis, and further information especially about the gametes and zygotes is much needed.
The structure of the spores, the most diagnostic feature of gregarines, forces one to recognize three species, viz. Urospora légeri, U. hardyi, and Lithocystis lankesteri, as distinct from the original U. sipunculi Köll.
The Ecology and Digestive System of the Struthiolariidae (Gastropoda)
Authors: Morton J. E. 
Published: April 2021

ABSTRACT
The two neozelanic species Struthiolaria papulosa and Pelicaria vermis have been studied as regards ecology, feeding mechanism, and structure and function of the digestive system. They are dwellers on sand or sand-mud-flat, with a feeding position just below the surface, where they construct paired siphonal tubes with the rostrum. A ciliary mode of feeding has been acquired by the modification of the gill filaments and the pallial rejection system. The alimentary canal is adapted for deposit feeding and has developed a crystalline style. Food particles are conducted to the stomach by a functionally reduced mucus-secreting oesophagus, where they are subjected to the action of the rotating style, and a complex system of ciliary currents. Digestible particles are passed into paired diverticula, where absorption and intracellular digestion. takes place, while faecal material is surrounded with mucus and formed into firm pellets by the ciliary and muscular action of the intestine. The relationships of the Struthiolariidae are discussed, and their origin from the Aporrhaidae is postulated.
Sensory Cells and Pigment Distribution in the Tail of the Ammocoete
Authors: Steven D. M. 
Published: April 2021

ABSTRACT
The ammocoete of Lampetra planeri (Bloch) contains a single carotenoid, lutein, partly esterified and partly in the free state. The pigment is distributed in lipophores in the sub-dermal tissues, and plays no part in the colour changes of the animal.
The epidermis of the tail contains numerous sensory cells of a type previously undescribed, which satisfy the requirements predicted for the photoreceptors responsible for the light reaction of the animal.
Evidence is presented that these sensory cells are innervated by branches of the lateral line nerves.
Similarities are indicated between the sensory cells of the ammocoete and simple photoreceptor systems of certain invertebrates.
The Stolonic Vessels of the Didemnidae
Authors: Millar R. H. 
Published: April 2021

ABSTRACT
Stolonic test vessels are described in four members of the ascidian family Didemnidae. The epidermal cells of the terminal swellings of the vessels appear to produce test substance. The stolonic vessels, area of budding and muscular appendix are probably all derived from the posterior end of the ancestral zooid.