Adhesion

“ Partial adhesion of the lid to the globe in which a few bands pass from the lid to the globe are best treated by division followed by union of the ocular conjunctiva over the raw surface; no external dressing should be applied. Any tendency to fresh adhesion may be prevented by daily inspection. ”

“ Their adhesion, from which the cohesion of bodies results, is clearly an effect of their mutual attraction. Upon the spring being pressed this adhesion is not de [365] stroyed, because, although the particles are separated, they are not removed beyond the sphere of their mutual attraction; consequently the moment the pressure is taken away the force is renewed, the separated parts draw near, and their spring is restored. ”

“ Their action is attended with very little friction acting only when necessary to supply the deficiency of adhesion and their pressure against the flank of the teeth is only the balance of the leverage which is not sustained by the adhesion at the tread. ”

“ In the adult, as the calcareous substance gradually encrusts its most internal fibres, the adhesion becomes very strong; it is extreme in old age, in which this membrane is often reduced to a very delicate layer by the progress of ossification. The constant pressure exerted by the muscles in their contractions, can also have a little influence upon this adhesion. Various elongations pass from the periosteum to the bone. They are much more numerous at the extremities of the long bones and upon the short bones, than upon the middle of the long bones, or the broad ones ”

“ Aderno′, a town of Sicily, 18 miles N.W. of Catania and about 10 miles W.S.W. of Mount Etna. Pop. 25,000.
Adessena′rian, one of a sect of Christians which holds that there is a real presence of Christ in the Eucharist, but denying that it is effected by transubstantiation.
Adhesion, the tendency of two bodies to stick together when put in close contact, or the mutual attraction of their surfaces; distinguished from cohesion, which denotes the mutual attraction between the particles of a homogeneous body. Adhesion may exist between two solids, between a solid and a fluid, or between two fluids. ”

“ The adhesion is complete, it can be moulded with perfection, to suit every inequality of the gums and teeth, and supplies an artificial periosteum, as it were, to the teeth, when become painful by the wasting away of the gum, added to these is the elasticity of the material, which completely obviates the inconveniences that arise from any motion with artificial teeth, as made by other means. ”

“ But an adhesion which continued after the cessation of the magnetizing currents then contributed to diminish the mechanical effect; whilst in the preceding arrangement the adhesion not only ceased, but to a certain point changed to repulsion, with the same rapidity with which the current, scarcely interrupted an instant by the action of the bascule, precipitated itself (the communication being inverted) into the middle spiral, in a direction contrary to its original one, resuming its ordinary course in the two other spirals. ”

“ Firstly, that in such mending, the adhesive be applied with care, in as even and as thin a coat as possible; to which I would add, that the unskilful amateur is apt to daub it on irregularly and carelessly, with the impression that the more cement there is the better it will stick, which is just so far wrong that every superfluous grain is just so much of an impediment to good drying or adhesion. ”

“ When, therefore, the sinus extends upwards, the ichor readily flows out from the sore, and adhesion easily takes place; but when it extends downwards the ichor by remaining within corrodes the continuous parts, and unless you first make an incision for its discharge, you will be able to effect nothing; for the sores can neither be incarnated nor the parts made to unite. But if the sinus is in any of the limbs, as the arms or legs, one may produce adhesion without a counter-division by putting the limb in a declining position. ”

“ Adhesion of one or more of the fingers, even to their points, is met with occasionally as a congenital affection. Separation is readily accomplished; but the dressing requires to be carefully attended to. Adhesions may result from careless management of extensive abrasion or ulceration, or from a burn, and such are not so easily remediable. Superfluities may be abridged. Some children are born with two thumbs or two little fingers ”

“ However gentle the contact, adhesion is at once established. When I lift the straw, the threads come with it and stretch to twice or three times their length, like a thread of india-rubber. At last, when over-taut, they loosen without breaking and resume their original form. They lengthen by unrolling their twist, they shorten by rolling it again; lastly, they become adhesive by taking the glaze of the gummy moisture wherewith they are filled.
In short, the spiral thread is a capillary tube finer than any that our physics will ever know. ”

“ Adhesion is commonly spoken of as existing between the particles of dissimilar bodies, but it is more accurately defined by calling it that molecular force which holds two distinct bodies together, whether they are of the same substance or not. ”

“ Not unfrequently the exact spot where the jarring or chattering takes place is not easy to find by mere examination of the exterior, especially if the separation is fresh and at a part where very little adhesion has taken place at any time, or possibly the very slight portion of glue originally placed at the time of construction, has, with the progress of time, gradually dried away. ”

“ If the pull of gravity is stronger, would not all the water drop off, leaving your finger dry? If the pull of adhesion is the stronger, would not all the water stay on your finger, none dropping off?
The truth of the matter is that gravity is stronger than adhesion unless things are very close together; then adhesion is stronger. The part of the water that is very close to your finger clings to it in spite of gravity; the part that is farther away forms drops and falls down because of the pull of gravity. ”

“ Is the firm adhesion of the two plates merely owing to the attraction of cohesion?
Mrs. B. There is no force more powerful, since it is by this that the particles of the hardest bodies are held together. It would require a weight of several pounds to separate these plates. In the present example, however, much of the cohesive force is due to the attraction subsisting between the metal and the oil which is interposed; as without this, or some other fluid, the points of contact would still be comparatively few, although we may have employed our utmost art, in giving flat surfaces to the plates. ”

“ Molecular attraction manifests itself in three ways, by cohesion, by adhesion, and by chemical affinity. The degree of cohesion in the same solid depends much upon the arrangement of its particles, as may be observed in the different degrees of hardness between tempered and untempered steel, and the difference in tenacity of metals in ingots or in hammered or rolled plates. The distinction between cohesion and adhesion is not always easily to be established. ”

“ The normal stage of a resin used for impregnation.
Bonding strength.—The amount of adhesion between a binder and filler. More specifically, the measure of the extent to which the composite layers of a laminated product are bonded together. ”

“ Neutral Substances, or Binding Materials.—Almost any substance not easily soluble in water, and many which are, from common dust or earth, or clay, sand, chalk, powdered egg-shells, sawdust, 6 shell-powder, &c., when combined with certain adhesives, form cements. This is sometimes due to chemical combination, but more frequently to mechanical union. In the latter case the adhesive clinging to every separate grain has the more points of adhesion, just as a man by clinging with both hands to two posts is harder to remove than if he held by one. ”

“ A safe way of performing this operation, when admissible, is to destroy a portion of the mucous membrane with strong nitric acid. The blood in the vessels then becomes charred, and their cavities obstructed, till they are permanently closed by adhesive inflammation. Every means of treating a local injury which tends to produce healthy [Pg 63] union or adhesion, may be considered in some sort as a preventive mode of treatment. ”

“ Whether the rising sheath shall leave the surface of the sphere, or shall follow it, depends upon the efficiency of the adhesion to the sphere. If the sphere is smooth and clean, the molecular forces of cohesion will guide the nearest layers of the advancing edge of the sheath, and will thus cause the initial flow to be along the surface of the sphere. ”

“ An ear-lobe should not be tried to be elongated just after the adhesion of its two severed parts, inasmuch as the centre of the adhesion, still being raw, might cause them to fall off again. Thus an ear-lobe under the circumstance should be gradually elongated, only when it would be found to be marked by the growth of hair on its surface, and the hole or the perforation has assumed a circular look, and the adhesion has become firmly effected, well-dried, painless, even and level in its entire length. ”

“ For instance, not only do liquid molecules cling together to form drops and streams, but they cling to the molecules of solids as well, as is shown by the wet surface of an object that has been dipped in water. The attraction of like molecules for one another is called cohesion, while the attraction of unlike molecules is called adhesion, although the force is the same whether the molecules are alike or unlike. It is the former that causes drops of water to form and that holds iron, copper, and other solids so rigidly together. ”

“ When a fluid adheres to a solid we say the solid is wet. We turn this natural adhesion to our own purposes in many ways,—we whitewash our walls, and paint our houses; we paste our papers together, etc. ”

“ We may, however, distinguish between the normal incrustation of the fibre-cells, and such an incrustation of the filaments as would be described as a loose adhesion of non-fibrous matter. The latter is seen in such tissues as the bast of the adansonia, and the fibro-vascular bundles of the aloes. These are points with which observation alone can familiarise the student; as experience grows he will find it increasingly easy to follow general distinctions, and in proportion as he uses his own faculties, so he will be able to generalise for himself. ”

“ No sooner therefore is the circumference of the disc placed in close and air-tight contact with the surface of an object, than the muscular piston is strongly drawn inwards, and a vacuum being thus produced, the adhesion of the sucker is rendered as firm as mechanism could make it. ”

“ Early in this article adhesions were mentioned as one of the results of pericardial inflammation, and it was stated that the exudation may appear in spots or extend over the visceral or parietal layers of the pericardium or over both, and become organized tissue filled with blood-vessels, gluing the walls together, and completely obliterating the sac. Limited adhesions are much more common than those which are extensive or complete. The intensity of the inflammation offers no indication of the probability of the formation of adhesions. ”

“ In 24 to 48 hours this engorgement is followed by an exudation of sero-fibrinous fluid, the fibrinous portion of which may soon form a coating over the internal surface of the pericardial sac, and may ultimately form a union of the opposing surfaces. Generally this adhesion will only be found to occupy a portion of the surfaces. As the serous or watery portion of this effusion is absorbed, the distinctness of the friction sound recurs, and may remain perceptible in a varied degree for a long time. ”

“ In amount.—In certain cases no adhesions exist, while in others, omentum, intestines, tumour, uterus, and abdominal wall may be all matted together in one common mass.
b. In organisation.—Occasionally they are so soft and friable as to break down under the finger with ease, and so slightly organised as not to bleed at all in the process, while again they may be so firm and close as to require a careful and prolonged dissection, and so vascular as to require many points of ligature to be applied to large active vessels. ”

“ If these cannot escape freely, by reason of adhesion between the coagulum and the partitions, “pitting” occurs.
Thickened Ends or Edges, after Rolling.—As a rule these defects may be ascribed to the employment of too rich a latex, or faulty manipulation. Even if the standard of dilution should be correct it sometimes happens that, in the preliminary rolling of a long strip of rubber, coolies begin in the middle, rolling with a forward pressure and tension towards the ends of the strip. ”

“ That a single fiber of wool, when manipulated by itself in a lubricant of soap, has no fulling property, but rather a tendency to lengthen the fiber; 2. That a number of fibers placed side by side, just as they grew on the sheep, and with simply tension enough to take out the kinks, when manipulated with a lubricant of soap, have no felting property, 3. That fibers similarly treated, but with the roots and tips alternating, have no fulling or felting property, and no power of adhesion ”

“ When a large individual has been a good while adherent to one spot, and at length chooses to change its quarters, it does so by causing its base to glide slowly along the surface on which it rests;—the glass side of the tank, for instance. But it frequently happens that small irregular fragments of the edge of the base are left behind, as if their adhesion had been so strong, that [Pg 80] the animal found it easier to tear its own tissues apart than to overcome it. The fragments so left soon contract become smooth, and spherical or oval in outline ”