bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modes of determining, by the use of the microscope, the refractive index of fluids.
Authors: Robertson William 
Published: April 2021

ABSTRACT
A knowledge of the laws which the rays of light observe in their course through refracting media enables us, with the help of the microscope, to determine the index of refraction of certain substances, to which, on account either of their small quantity or of their insufficient transparency except when in layers of extreme thinness, the ordinary methods are inapplicable.
On Stephanosphæra Pluvialis
Authors: Currey Frederick 
Published: April 2021

ABSTRACT
Stephanosphæra pluvialis was first observed by Cohn, in 1850, near Hirschberg, and described in Siebold and Kölliker’s ‘Zeitschrift’* vol. iv, part 1. It consists of a hyaline globe, containing eight green primordial cells, arranged in a circle in its equator. The globe rotates upon an axis perpendicular to the plane in which the primordial cells are arranged, and moves actively in space by the aid of cilia, two of which proceed from each of the primordial cells, and pierce the hyaline envelope.
Further Observations on the Genera Triceratium and Chætoceros
Authors: Brightwell T. 
Published: April 2021

ABSTRACT
My former papers on these Genera have been chiefly confined to the description of species, and are necessarily imperfect, and to that extent unsatisfactory, in consequence of the difficulty of obtaining specimens in a living state. The species being all marine, very few opportunities occur of seeing them alive, and it is doubtful whether any one of them has been seen in a state of conjugation. If, as one of our highest authorities (the late lamented author of the ‘Synopsis of the British Diatomaceæ’) says, “neither size nor outline can be wholly relied on, and striation is the best guide for specifie character and, when this fails, the arrangement of the endochrome, or the habitat of the living frustule,” it is obvious how few of the described species can have been sufficiently known to warrant us in deeming them finally established, and how important is every step towards attaining a knowledge of the living diatom, and especially of its modes of increase.
On some peculiarities in the Microscopical Structure of Crystals, applicable to the determination of the Aqueous or Igneous Origin of Minerals and Rocks
Authors: Sorby H. C. 
Published: April 2021

ABSTRACT
In this paper the author showed that when artificial crystals are examined with the microscope, it is seen that they have often caught up and inclosed within their solid substance portions of the material surrounding them at the time when they were being formed. Thus, if they are produced by sublimation, small portions of air or vapour are caught up, so as to form apparently empty cavities; or, if they are deposited from solution in water, small quantities of water are inclosed, So as to form fluid-cavities. In a similar manner, if crystals are formed from a state of igneous fusion, crystallizing out from a fused-stone solvent, portions of this fused stone become entangled, which, on cooling, remain in a glassy condition, or become stony, so as to produce what may be called glass- or stone-cavities. All these kinds of cavities can readily be seen with suitable magnifying powers, and distinguished from each other by various definite peculiarities.
On Apparatus for Dredging at Moderate Depths in the Deep Sea, and for Capturing Floating Objects from Shipboard
Authors: Wallich G. C. 
Published: April 2021

ABSTRACT
During a recent voyage from India, the success attending the use of certain appliances contrived by me for capturing such marine objects as came in our way, induces me to offer the subjoined account of them to the public. I may mention that, although familiar with the ordinary form of towing net and sounding apparatus, it struck me that much more might be done by resorting to some simple form of casting net, than is possible where the chapter of accidents is relied on for bringing within the jaws of the towing net the objects required, and by constructing some more portable sounding apparatus, which would at the same time prove effective at moderate depths, and bring up a much larger quantity of material than is attainable under the ordinary sounding lead, or the more complicated and cumbrous contrivance of Lieutenant Maury and others. I would further premise that whoever desires to make a collection of marine floating molluscs, tunicaries, ascidians, and the like, and also the minuter organisms which exist in all latitudes in the open ocean, to a greater or lesser extent, will be grievously disappointed if he imagines that the trailing net used astern of a ship will suffice for the purpose. For, to be at all successful, constant and unremitting watchfulness is, in the first place, essential ; and what is equally important, a fitting place of observation at the stern of the vessel, with ten or twelve feet of the water bend. In my own case, the quarter gallery of a 1500-ton merchantman afforded the best of all look-out ports ; and from it I was enabled to use the casting net about to be described with ease and certainty. In the clear blue water of the open sea it is astonishing how rapidly the eye accustoms itself to detect creatures of the minutest size ; and how readily it learns to distinguish, even in the small patches of calm water between each wave when a considerable sea is running, any object that may chance to be swimming near the surface. Nor is this confined to the portion of sea immediately below the observer, but it can be done at a distance of several yards. In order to embrace this distance the following casting net was constructed, and in the course of a short practice it became easy to pitch this net, quoit fashion, over any object within such range.
On the Recent Foraminifera of Great Britain
Authors: Williamson William Crauford 
Published: April 2021

ABSTRACT
The publication of Professor Williamson’s work is a triumph for the microscope that we must not pass over without notice. This beautiful volume, which has been published by the Ray Society presents for the first time, to the British naturalist a full account of the living Foraminifera found on our coasts. It embraces a very accurate description of each species, with a delineation by Tuffen West. The only complaint we could possibly make about the book is that the Ray Society has chosen to publish it in a quarto form, when it would have been so much more convenient as an octavo, or even duodecimo. In these days of locomotion, when we pack our microscopes into the smallest possible space, we also want our books small, if they are to travel with us. It was all very well for our forefathers to publish quartos and folios, for they had leisure to admire the grandeur of their tomes; but we have the greatest difficulty in keeping up with our day, and everything that spares time must be accepted as a boon.
Descriptions of diatomaceæ Observed in californian guano
Authors: Greville R. K. 
Published: April 2021

ABSTRACT
It is well known that in studying Diatomaceæ as they occur in guano and in deposits, the observer labours under great disadvantages. The materials he has to work upon are often scanty, and forms which attract his attention are sometimes so scarce that he is obliged to review with the utmost care a multitude of preparations before he can arrive at a satisfactory conclusion regarding them. The conditions so well laid down by Professor Smith, as requisite for the determination of species, are in such cases, to a considerable extent, beyond his reach. It has consequently been a question whether any Diatom ought to be described except from recent, and, in some genera, actually living individuals. Undoubtedly it would be always desirable to conform to such a rule when practicable; but so many justifiable exceptions present themselves, that it can never be enforced as a positive law. The best writers on this most interesting order, even Professor Smith himself, occasionally deviate from it. Witness his description of Himantidium (?) William- sonii, made from specimens insufficient to determine even the genus; for he had only the front view of the frustules- before him. Professor Gregory supplied the deficiency by figuring the side view, and still the genus is not settled. Nevertheless, it was unquestionably desirable that we should possess good representations of so very curious a production. Were we rigidly to confine ourselves to those species only, whose history as living vegetables we have the means of tracing, many of the most curious and beautiful forms on record—even entire genera—would have to be expunged from our books; such, for example as Heliopelta, Asteromphalus, Asterolampra, &c. The truth is, that while many frustules occurring in deposits require to be described—if described at all—with extreme caution, numerous others, especially of disciform genera, exhibit at least sufficiently marked distinctive characters. All that can be said, I apprehend, against the description; of such diatoms is that from the very nature of the case we are unacquainted with their history. Something, nevertheless, it must be admitted, is gained by the publication of accurate figures; for even if they fail in some cases to establish species, they will at least assist to indicate the range of variation, a point in itself of no small importance.
On the Measurement of the Vertical Thickness of Microscopic Objects; and on the Determination of the Chemical properties from their Refractive Power
Authors: Welcker H. 
Published: April 2021

ABSTRACT
In the ‘Zeitschrift f. Rat. Medicin,’ N. F., vi, p. 172, and viii, p. 241, the author endeavoured to show, that when by a methodical raising or depression of the tube of the microscope the relief of microscopic objects has been ascertained,—the question, especially as respects the more difficult class of objects, may be decided, as to whether they are hollow or solid, depressed or convex. If a microscopic object be of such a size as to allow of its near and distant surfaces being each distinctly and separately brought into view by the proper adjustment of the tube of the instrument, the determination of this question is usually unattended with any difficulty; the proceeding, in fact, being one commonly practised. The author, however, has endeavoured to show, that in the smaller or even in the most minute microscopic formations—so small even that they appear only as simple dark points—a bright flash or gleam ensues upon the elevation of the tube, in those cases that is to say in which the bodies in question are convex; and a similar flash on the depression of the tube, when they are concave. “I have shown,” he says, “that in the former case the convex corpuscles act like minute convex lenses, and in the latter like concave lenses. Oil-drops contained in water or air, albuminous and many other sorts of particles,—in short, all such as in regard to their optical property are referable to the perfectly spheroidal form, show the brilliant appearance on the elevation of the tube; whilst minute air-bubbles, the cavities in bone, teeth, &c., containing air or fluid, &c., present the same phenomenon when the tube is lowered.
On the Markings of Diatomaceæ
Authors: Rylands Thos. G. 
Published: April 2021

ABSTRACT
It is not easy to over-estimate the importance of the department “Notes and Correspondence” in your Journal. Not only does it afford a means of recording facts which might otherwise remain unpublished; but the various hints and memoranda contained in it possess a value to the country student which those only who are similarly situated can appreciate. The note by Dr. Greville, “On a Structure observed in Surirella,’ vol. vii, p. 116, recalled my attention to the subject of the present article, and reminded me that on two occasions I had observed something similar in naviculoid frustules. The first was in Pleurosigma balticum, where the internal marking was hexagonal; and the second in a frustule of Amphipleura pellucida, where there were transverse lines, but much more distant than the 130 to 001” observed in that species by the Hull microscopists. Ill neither of these instances were the slides my own, and they were not seen under circumstances which enabled me to do more than record the fact of their occurrence. In neither case was the idea of a septum entertained; the internal markings had distinctly the curve of the side of the frustule, and the impression conveyed was simply that both surfaces of the silica were marked. I had the less hesitation in coming to this conclusion, from having frequently seen something similar, but apparently constant, in certain disciform species. The fact that certain species of Actinocyclus, &c., have two very evident sets of markings is generally known. It is hardly less probable that the same thing has been seen in Coscinodiscus centralis, and that the fine secondary markings of Triceratium favus (indicated by Dr. Wallich in what he calls T. fimbriatum) have been observed by those who have directed their attention to that species.*
Some Observations on the Structure of Nerve-fibres
Authors: Lister Joseph , Turner William 
Published: April 2021

ABSTRACT
Having recently had the opportunity, through the kindness of Mr. Lockhart Clarke, of inspecting some of his beautiful preparations of the spinal cord, we were struck -with an appearance which had not yet received a satisfactory interpretation ; and, having been induced to investigate the point, we have met with some facts which seem of sufficient interest for publication.
Supplementary Observations
Authors: Lister Mr. 
Published: April 2021

ABSTRACT
The fibroid arrangement of the white substance of Schwann in nerves hardened by chromic acid has been minutely described by Stilling, in his elaborate treatise on the ‘Nervefibre and Nerve-cell,’ * a work which we had not seen when the foregoing communication was written, but a copy of which was kindly lent me by Professor Goodsir, soon after Mr. Turner had left Edinburgh for the vacation. According to Stilling, the medullary sheath is, even in perfectly fresh nerves, composed of a network of fibres, which are continuous with others in the axial cylinder and in the proper investing membrane; so that, in his opinion, these three constituents of the nerve-fibre differ from each other only in the manner in which their elements are disposed * This view is not only quite novel anatomically, but is opposed to the generally received physiological opinion, that the axial cylinder is the essential part of the nerve-fibre, and the medullary sheath an insulating investment. Considering the high estimation in which the writings of Stilling on the anatomy of the nervous centres are deservedly held, and the influence which therefore attaches to his opinions, it seems fortunate that we have been able to present so clear a demonstration that the axial cylinder is chemically as well as morphologically totally distinct from the medullary sheath.
On American Diatomaceæ
Authors: Edwards Arthur M. 
Published: April 2021

ABSTRACT
A taper of mine, on American Diatomaceæ, was read before the London Microscopical Society, March 30th, 1859, and published iu their Transactions, in which an omission occurred which I herein wish to rectify. A mistake occurred in re-writing, so that the description of the species found at Charleston harbour, S. C., was left out. A paper on this subject, by the present writer, was read before the New York Lyceum of Natural History, February 21st, 1859, a copy of which is annexed:—
Memoir on the Spermogones and Pycnides of Filamentous, Fruticulose, and Foliaceous Lichens
Authors: Lindsay W. Lauder 
Published: April 2021

ABSTRACT
This very able and laborious memoir was published in the ‘Transactions’ of the Royal Society of Edinburgh, and we call the attention of our readers to it, as affording by far the most exhaustive account yet published of the minute structure of the lichens. Dr. Lindsay, in his papers in this Journal, on the genus Abrothallus, and on the structure of Lecidea lugubris (vol. v), commenced that line of investigation, which he has carried out in this memoir to a large section of the whole family of lichens. In his introduction, the author draws attention to some of the difficulties which impede the progress of the inquirer in the path he has chosen for investigation.
On Some Freshwater Rhizopoda, New or Little-Known
Authors: Archer William 
Published: April 2021

ABSTRACT
Having endeavoured in the foregoing to give some account of the remarkable form, Diaphoropodon mobile, I pass on to the three others, which in the present series seem next related thereto, figured on Pl. XX, figs. 1, 2, 3 (vol. ix), and which I would (provisionally at least) identify as above. I regret, however, that I have it in my power, at present at least, to do but very little more than refer to the figures and the accompanying explanation of the plate.
On the Embryonic Form of Nematobothrium Filarina, Van Ben
Authors: Van Beneden Edouard 
Published: April 2021

ABSTRACT
In his memoir on the Intestinal Worms, M. P. J. Van Beneden made known an extremely remarkable animal which he described under the name of Nematobothrium filarina.1 It lives parasitically in Sciæna aquila, a fish which is found sometimes on our coasts and which is met with from time to time in the Channel and on the coasts of the Atlantic. But as it is always a relatively rare fish, one has not at all times the opportunity of studying the singular parasites which this animal harbours.
On the Minute Anatomy of some of the Parts concerned in the Functions of Accommodation to Distance, with Physiological Notes
Authors: Macdonald John Denis 
Published: April 2021

ABSTRACT
No organ in the body exhibits more beauty of construction to unravel, or more interesting physiological problems to solve, than the eye; and it is no wonder, notwithstanding the great advances of modern science, that much room should still remain for the improvement of our knowledge of its minute anatomy, and the function subserved by every part in the economy of vision. It would be quite impossible within the limits of a few pages to deal with a twentieth part of the facts and views that have been advanced from time to time in relation to the subject of the present paper. Nor would that be the writer’s intention, though it were possible, being merely desirous of making known some few anatomical particulars which do not appear to have been hitherto noticed, and of associating these with the function of accommodation to distance.
On an Aplanatic Searcher, and its Effects in Improving High-Power Definition in the Microscope
Authors: Royston-Pigott G. W. 
Published: April 2021

ABSTRACT
The Aplanatic Searcher is intended to improve the penetration, amplify magnifying power, intensify* definition, and raise the objective somewhat further from its dangerous proximity to the delicate covering-glass indispensable to the observation of objects under very high powers.
Researches on the Composition and the Significance of the Egg, based on the Study of its Mode of Formation, and of the first Embryonic Phenomena—(Mammifers, Birds, Crustacea, Worms)
Authors: van Beneden Edouard 
Published: April 2021

ABSTRACT
The very valuable Memoir of Dr. Van Beneden is at length published, consisting of nearly 280 pages quarto, and twelve excellent plates. It is impossible for us here to give an adequate sketch of so extensive and valuable a work. The numerous details and observations which it contains are, however, all directed to establish certain conclusions concerning the signification of the egg, and the various parts which compose it, which we shall state, referring the reader with great confidence to the clear, logical, and interesting details of observation given in the Memoir. It was not,” remarks Dr. Van Beneden, “until after the appearance of the memorable works of Von Baer, Purkinje, R. Wagner, Coste, Prevost, Dumas, and Rusconi on the Vertebrata, of Rathke, Hérold, von Siebold, and P. J. Van Beneden on the lower animals, that the bases of comparative ovology and embryogeny were definitely established. The constitution of the egg of the superior animals, and of a certain number of inferior animals, was known, and it was perceived that throughout the egg consists of the same essential parts: of a membrane, of a vitellus, and of a germinal vesicle, holding in suspension one or several refringent corpuscles. On the other hand, the breaking up or cleavage which Prevost and Dumas had established in the Batrachia came to be discovered in Fishes by Rusconi and Von Baer; Von Siebold pointed it out in certain Nematods; Dumortier, Van Beneden, and Windischman in some Gasteropods.
On some New Species of the Genus Amphiprora
Authors: O’Meara Eugene 
Published: April 2021

ABSTRACT
Some of the Diatoms which are the subject of this paper have been brought under notice from time to time at our club meetings. And now I desire to present them in regular form, adding such species as have come under my observation in the interval. The material which furnished them was collected by our respected club member, Dr. E. Perceval Wright, during his sojourn in the Seychelles. This very active member of our circle has contributed largely to the interest of our meetings, and to the value of our ‘Proceedings,’ by various communications in his own speciality, arising out of his researches in that hitherto unexplored district, and has placed me under a debt of gratitude for the material with which he has supplied me, containing in abundance diatomaceous forms of the greatest beauty and rarity.
Microscopic Objects, Figured and Described
Authors: Martin John H. 
Published: April 2021

ABSTRACT
This work contains 194 tolerably executed figures of what are sometimes called “natural history objects,” among which we find, for instance, the “pollen of the evening primrose/’ “a skin parasite from the human nose,” and “marble from the Temple of Diana, at Ephesus;” represented under various degrees of magnifying power, and some without any enlargement at all. The figures are accompanied by short descriptions and a few hints as to preparation. When we say that the specimens selected are almost unclassified, and that the author does not claim to establish, by his delineations, any facts unknown before, or to contribute anything to the settlement of disputed points, the character of his book will, we think, be evident. It does not fall specially under the head of any one of the sciences which the microscope is used to illustrate, but rather appeals to those who are on the look-out for objects to use their microscope upon. It is obviously the work of a zealous and experienced field naturalist, who has brought together his materials from very various sources, and takes genuine delight in the beauty and strangeness of the forms which display themselves before him.
On The Production of Spores in the Radiolaria
Authors: Cienkowski L. 
Published: April 2021

ABSTRACT
Almost all that we know of the developmental history of the Radiolarians renders it extremely probable that the Capsule takes an important part in the reproduction of these organisms. Besides the oft observed multiplication of the Capsule by division, science possesses some other evidence which seems to be of great importance. Joh. Müller1 saw in the interior of an Acanthometra a swarming of small monad-like vesicles, which moved about for a time, and then changed themselves into Actinophrys-like structures. Since the subsequent history of these monad-like bodies was not made out, the suspicion of the intrusion of some parasitic organism could not in this case be set aside.