Reasons have been given for supposing that images are formed by the cornea and crystalline cones together.
The refractive and elongatecrystalline cones, with their pointed apices and densely pigmented sides, must destroy any images formed by the lenses of the cornea.
The crystalline cones, still attached to the cornea, are turned towards the observer, and one is selected whose axis coincides with that of the microscope.
The crystalline cones are transparent, refractive, and coated with dark pigment; in the Cockroach they are comparatively short and blunt.
Beneath the cornea we find a layer of crystalline cones, each of which rests by its base upon the inner surface of a facet, while its apex is directed inwards towards the brain.
The refractive lens collects the rays, and the pigmented as well as refractive crystallinecone further concentrates the pencil, while it stops out all rays which diverge appreciably from the axis.
In the simple eye the non-faceted cornea and the retinula are readily made out, but the crystalline cones are not developed as such.
Grenacher has since ascertained that the crystalline cones of Flies are so fluid that they can hardly be removed, and he believes that Gottsche’s images were formed by the corneal facets alone.
This led him to reject the mosaic theory of vision, and to conclude that a partial image was formed behind every crystalline cone, and projected upon a multitude of fine nerve-endings.
The drift of his work had been to identify all colloids as liquid solutions of variable degrees of viscosity, and to treat crystalline bodies as the only solids.
In the greater number of Asteroidæ this common portion secretes carbonate of lime, which is deposited in the meshes of its tissues either in granules or in crystalline spiculæ, which imparts a solid consistency to the whole.
The tentacula are short, obtuse, ciliate on the margins, and strengthened at their roots by numerous crystalline spiculæ.
The polyps, which are fleshy and white, are provided with eight long retractile tentacula, beautifully ciliated on their inner edge with two series of short processes strengthened with crystalline spicula.
It has sometimes been argued that four or five red points at the summit of the dorsal face are eyes; but this opinion has not been maintained, nor has any crystalline lens been found in these spots to justify it.
The eyes are said to consist of certain small, hemispherical, cellulose, coloured masses, in which are sunk small crystalline globules, the free parts of which are perfectly naked.
When the fish is cooked, the crystalline lens constitutes that opaque and hard white substance which often comes under the teeth in eating fish of a certain size.
The crystallinelens is voluminous, spherical, and diaphanous.
The eyes must, besides, be very imperfect, for they possess no crystalline lens.
Each pedunculated eye presents upon its lower face a small yellow sac, in which are found, in greater or smaller numbers, small crystalline bodies clear as water.
It is a crystalline solid, very soluble in water, and is strongly basic and very poisonous.
It is a colourless, crystalline solid, readily soluble in alcohol and ether, melting at 137 deg.
The operation is varied according to the size of the anterior chamber, the presence or absence of the crystalline lens, the extent of sound cornea, and the condition of the iris.
The opaque body approaches the pupil and fills it, and may in this state be mistaken for disease of the crystalline lens; but the tumour soon pushes forward the iris, and fills the anterior chamber.
Of Cataract, or opacity of the crystalline lens and its capsule, attended with partial loss of vision.
The cone has its apex in the centre of the organ, seems thick and crystalline when viewed laterally, and when looked on from the front has a sparkling appearance.
The aqueous humour immediately escapes, and in most cases the crystallinelens and vitreous humour are also discharged.
The iris swells perceptibly, and the pupil loses its dark colour, or is almost entirely closed, either from effusion of lymph, or from inflammation and consequent opacity of the crystalline lens and its capsule.
As to the cause of the differences, other than regularcrystalline structure, there may be several.
This compound, which was probably the peroxide, being infusible and insoluble in the protoxide, formed a crystalline crust around the positive electrode; and thus insulating it, prevented the transmission of the electricity.
The granites of Queensland vary very much in their crystalline texture, passing from true granites into porphyry and quartz porphyry.
At Gympie, the auriferous area is confined to veins traversing a crystalline diorite, or within a certain limit of its boundary, marked by the presence of fossiliferous diabase tufas.
We have been told that this has been arranged by Mr. Aikin, according to the different modifications of its crystalline form, as they are described by Mr. William Phillips in his elaborate paper published in the 2nd Vol.
Miss Euphrasia thought of her roses, already in leaf, and refused to be enthusiastic over the supernal beauty of the crystallinestage settings.
Probably the study of crystalline form will be connected with these chemico-structural expressions, and from the union some greater generalizations will be born.
That different crystalline bodies differ in their behavior toward polarized light has long been known, and the polariscope is recognized as an instrument of great value in chemical research.
Pertaining to, or designating, an isomeric modification of ricinoleic acid obtained as a white crystalline solid.
The glycerin salt of ricinelaidic acid, obtained as a white crystallinewaxy substance by treating castor oil with nitrous acid.
A colorless crystalline substance of the phenol series, obtained by melting certain resins, as galbanum, asafetida, etc.
A phenol derivative of anthracene obtained as a white crystalline substance, which on oxidation produces a red dyestuff related to anthraquinone.
It is a sour white crystalline substance, consisting of a combination of dextrorotatory and levorotatory tartaric acids.
Pertaining to, or designating, an acid which is obtained from gallic acid as a brown or red crystalline substance, and is related to rufiopin and anthracene.
It is difficult enough to draw a curved surface, even when it is rough and has texture; but to indicate the varied and sweeping forms of a crystalline and polished substance, requires far more skill and patience than most artists possess.
At twilight it recovers its reflective power to the fullest extent, and the mountains of Carrara are seen reflected in it as clearly as if it were a crystalline lake.
Then, with regard to more compact crystalline or semi-crystalline rocks, no reliable opinion can be formed on mere inspection.
Near the points of contact, the metamorphism which they have undergone is revealed by the change of colour and aspect, which is exhibited all around the vein, often also by the development of a crystalline structure.
In other words, when the metamorphism has been so great that all traces of the semi-crystalline laminated structure have disappeared, a more perfect crystallisation has taken place.
In all the primary rocks in every quarter of the globe where they have been examined, its action is recognised in giving to the crystalline masses--granites and their laminated elongations--a polar grain and vertical cleavage.
In all cases, as we approach the masses of granite, in these regions, the crystalline structure becomes more and more marked.
Oolitic series, and the underlying crystalline rocks to be metamorphosed Secondary sandstones and shales.
The anhydrous chloride, MnCl2, is obtained as a rose-red crystalline solid by passing hydrochloric acid gas over manganese carbonate, first in the cold and afterwards at a moderate red heat.
It may be obtained crystalline by heating manganese sulphate and potassium sulphate to a bright red heat (H.
That which flows from the lower incisions is often collected on tiles or on a concave piece of the prickly pear (Opunlia), but is less crystalline and more glutinous, and is less esteemed.
The Maltese Islands consist largely of Tertiary Limestone, with somewhat variable beds of Crystalline Sandstone, Greensand and Marl or Blue Clay.
Marl, in juxtaposition with (g), the semi-crystalline Limestone.
This winding way conducts one to River Hall, beyond which lie the crystalline gardens that have been described.
For the preparation of the crystalline variety identical with the mineral pyrochroite (see A.
It combines with gaseous ammonia and forms crystalline compounds with certain alcohols.
In the north-west of the county the members of the Thurso group appear to overlap the Achanarras beds and to rest directly on the platform of crystalline schists.
Each stalactite usually consists of an aggregate of radially arranged crystalline individuals, though sometimes it may consist of a single individual with crystal faces developed at the free end.
The chief geological formations of Buru are crystalline slate near the north coast, and more to the south Mesozoic sandstone and chalk, deposits of rare occurrence in the archipelago.
The music of Patti’s crystalline voice has left no distinct echo in your remembrance, and the blossoming of the century-plant is dimmer than the shadow of a dream.
The rock is columnar basalt, sometimes called greenstone, and is solid, not stratified like water-formed rocks, but cracked in cooling and of a crystalline structure.
An experiment, showing how objects transmit their images or pictures, intersecting within the eye in the crystalline humour, is seen when by some small round hole penetrate the images of illuminated objects into a very dark chamber.
One of these intersections is in the pupil, the other in the crystalline lens; and if this were not the case the eye could not see so great a number of objects as it does.
Describe in your anatomy what proportion there is between the diameters of all the images in the eye and the distance from them of the crystalline lens.
The skeleton was still perfectly articulated, and gleamed through the crystalline amber as though its bony surfaces were encrusted with diamond dust.
A fraction of a second more and the projection had lengthened into a long slender arm of crystalline silver that streaked across the intervening space with the swiftness of a spear.
In the meantime the body of the second rodent had been drawn in and devoured by another of the carnivorous crystalline monsters.
The tip of one of thecrystalline arms struck his chest with a crashing tinkle of musical glass.
The same sort of crystalline amber egg that accompanied the work of the mysterious Tinkling Death, wasn't it?
For a moment Powell stared intently into the heart of the crystalline egg without answering.
The tinkling, crashing sound promptly swelled to a steady pulsing song like that of a brittle river of crystalline glass surging and breaking over granite boulders.
With the crystalline doom at last staring them squarely in the face, Powell went berserk in a final desperate effort to gain even a moment's respite.
They struck the bottom and staggered half-dazed to their feet, to confront the two crystalline monsters rocking on their rounded bases scarcely ten feet away.
The crystalline song swelled to a crescendo climax.
The crystal growths over the imprisoned body rounded their contours and merged together until they were in the form of a great crystalline egg.
It was shaped like a huge egg, a little over a yard long, and was apparently composed of a solid lump of some unknowncrystalline substance that closely resembled very clear, pale amber.
Her Silver Belt had been enclosed in one of those amber, crystalline eggs.
A second later the rat-man was pinned against the faceted crystalline side just under the opalescent nucleus.
Light may be polarized by several methods other than by reflection, as by refraction through most crystalline media, or by being transmitted obliquely through several plates of glass with parallel faces.
Pertaining to, or designating, a complex nitrogenous acid related to the ureids, and obtained from parabanic acid as a white silky crystalline substance.
CO2H)3 occurring naturally in unripe beet roots, and produced artificially from glycerin as a white crystalline substance.
A yellow crystalline substance allied to pyrrol, obtained by the distillation of gelatin.
It always occurs combined in nature, and is artificially obtained in the free state, usually as a dark brown amorphous powder, or as a dark crystalline substance with a meetallic luster.
Had even a shadow of longing to be united to the man she loved rested on the soul of this girl, she could not have had thus crystalline transparency and absolute freedom from embarrassment.
In common use the name is limited, as it was formerly applied only to the darkcrystalline minerals which are met with in long, slender prisms, either scattered in quartz, granite, etc.
When the small crystalline has been freed from all the adhering vitreous humour, the capsule which contains it will have a surface as fine as a pellicle of fluid.
A portion of the ice was melted, but the surrounding parts shone out as brilliant stars, produced by the reflection of the faces of the crystalline structure.
The light still continued after the iris was displaced; but on taking away the crystalline lens it greatly diminished both in intensity and colour.
Among crystalline bodies, rock-crystal, or silica, is the best conductor of heat.
Very good microscopes may be made with the crystallinelenses of fish, birds, and quadrupeds.
Professor Tyndall, in a lecture delivered by him at the Royal Institution, London, on the properties of Ice, gave the following interesting illustration of crystalline force.
This philosopher regarded the heaven of the fixed stars as a solid mass, formed from the ether which had been rendered crystalline by the action of fire.
Stearin is a white crystalline substance, sparingly soluble in alcohol and ether, but insoluble in water.
It is more certain that the crystalline substances found in flesh, such as, for example, kreatine, are incapable of ministering to the nutrition of animals.
Not only are such funnels filled with the crystalline mass of granite that flowed through them in a liquid state, but it has often poured over their sides, mingling with the stratified beds around.
