De Roget says, that in animals that graze and keep their heads for a long time in a dependent position, the danger from an excessive impetus in the blood flowing towards the head is much greater than in other animals; and we find that an extraordinary provision is made to obviate this danger. The arteries which supply the brain on their entrance into the basis of the skull suddenly divide into a great number of minute branches, forming a complicated network of vessels, an arrangement which, on the well known principle of hydraulics, must greatly check the velocity of the blood conducted through them. That such is the real purpose of this structure, which has been called the rete mirabile, is evident from the branches afterwards uniting into larger trunks when they have entered the brain, through the substance of which they are then distributed exactly as in other animals, where no such previous subdivision takes place. The rete mirabile is much developed in the sheep, but scarcely perceptible in the Cat.
Being an animal which hunts both by day and night, the structure of its visual organs is adjusted for both. The retina, or expansion of the optic nerve, is most sensitive to the stimulus of light; hence, a well-marked ciliary muscle contracts the pupil to a mere vertical fissure during the day, while in the dark, the pupil dilates enormously, and lets in as much light as possible. But even this would be insufficient, for Cats have to look for their prey in holes, cellars, and other places where little or no light can penetrate. Hence, the Cat is furnished with a bright metal-like, lustrous, membrane, called the Tapetum, which lines part of the hollow globe of the eye, and sheds considerable light on the image of an object thrown on the retina. This membrane is, we are told, common to all vertebrated animals, but is especially beautiful and lustrous in nocturnal animals. The herbivora, such as the ox and sheep, have the tapetum of the finest enamelled green colour, provided probably to suit the nature of their food, which is green. The subject, however, of the various colours of the tapetum in different animals is not yet understood. The sensibility of the retina in Cats is so great that neither the contractions of the pupil nor the closing of the eye-lids would alone afford them sufficient protection from the action of the light. Hence, in common with most animals, the Cat is furnished with a nictitating membrane, which is, in fact, a third eyelid, sliding over the transparent cornea beneath the common eyelids. This membrane is not altogether opaque, but translucent, allowing light to fall on the retina, and acting, as it were, like a shade. The nictitating membrane is often seen in the Cat when she slowly opens her eyes from a calm and prolonged sleep: it is well developed in the eagle, and enables him to gaze steadfastly on the sun’s unclouded disk.
The illumination of a Cat’s eye in the dark arises from the external light collected on the eye and reflected from it. Although apparently dark, a room is penetrated by imperceptible rays of external light from lamps or other luminiferous bodies. When these rays reach the observer direct, he sees the lamps or luminiferous bodies themselves, but when he is out of their direct sight, the brightness of their illumination only becomes apparent, through the rays being collected and reflected by some appropriate substance.
The cornea of the eye of the Cat, and of many other animals, has a great power of concentrating the rays and reflecting them through the pupil. Professor Bohn, at Leipsic, made experiments proving that when the external light is wholly excluded, none can be seen in the Cat’s eye. For the same reason, the animal, by a change of posture or other means, intercepting the rays, immediately deprives the observer of all light otherwise existing in, or permeating, the room. In this action, when the iris of the eye is completely open, the degree of brilliancy is the greatest; but when the iris is partly contracted, which it always is when the external light, or the light in the room, is increased, then the illumination is more obscure. The internal motions of the animals have also great influence over this luminous appearance, by the contraction and relaxation of the iris dependent upon them. When the animal is alarmed, or first disturbed, it naturally dilates the pupil, and the eye glares; when it is appeased or composed, the pupil contracts, and the light in the eye is no longer seen.
A German savant says, that at the end of each hair of a Cat’s whiskers is a sort of bulb of nervous substance, which converts it into a most sensitive feeler. The whiskers are of the greatest use to her when hunting in the dark. The nervous bulbs at the ends of a lion’s whiskers are as large as a small pea.
But an English writer differs from him; thus:—
“Every one must have observed what are usually called the “whiskers” on a Cat’s upper lip. The use of these, in a state of nature, is very important. They are organs of touch; they are attached to a bed of close glands under the skin; and each of these long and stiff hairs is connected with the nerves of the lip. The slightest contact of these whiskers with any surrounding object is thus felt most distinctly by the animal, although the hairs are of themselves insensible. They stand out on each side in the lion, as well as in the common Cat; so that, from point to point, they are equal in width to the animal’s body. If we imagine, therefore, a lion stealing through a covert of wood in an imperfect light, we shall at once see the use of these long hairs. They indicate to him, through the nicest feeling, any obstacle which may present itself to the passage of the body: they prevent the rustle of boughs and leaves, which would give warning to his prey if he were to attempt to pass through too dense a bush, and this, in conjunction with the soft cushions of his feet, and the fur upon which he treads (the retractable claws never coming in contact with the ground), enable him to move towards his victim with a stillness even greater than that of the snake, who creeps along the grass, and is not perceived till he is coiled round his prey.”
Black Cats especially are said to be highly charged with electricity, which, when the animal is irritated, is easily visible in the dark. Here are directions I have for producing the effect:—Lay one hand upon the Cat’s throat, and slightly press its shoulder bones. If the other hand be drawn gently along its back, electric shocks will be felt in the hand upon the Cat’s throat. If the tips of the ears be touched after the back has been rubbed, shocks of electricity may also be felt, or they may be obtained from the foot. Lay the animal upon your knees, and apply the right hand to the back, the left fore paw resting on the palm of your left hand, apply the thumb to the upper side of the paw, so as to extend the claws, and by this means bring your fore finger in contact with one of the bones of the leg, where it joins the paw; when from the knob or end of this bone, the finger slightly pressing on it, you may feel distinctly successive shocks similar to those obtained from the ears. The Reverend Mr. Wood expresses an opinion, that on account of the superabundance of electricity which is developed in the Cat, the animal is found very useful to paralysed persons, who instinctively encourage its approach, and from the touch derive some benefit. Those who suffer from rheumatism often find the presence of a Cat alleviate their sufferings. The same gentleman, writing of a favourite Cat, says, that if a hair of her mistress’s head were laid upon the animal’s back it would writhe as though in agony, and rolling on the floor, would strive to free herself from the object of her fears. The pointing of a finger at her side, at a distance of half a foot, would cause her fur to bristle up and throw her into a violent tremour.
It is difficult to account for the fondness of Cats for fish, as nature seems to have given them an appetite, which, with their great antipathy to water, they can rarely gratify unassisted. Many instances have, however, been recorded of Cats catching fish. A Mr. Moody, of Sesmond, near Newcastle-upon-Tyne, had a Cat in 1829 which had been in his possession for some years, and caught fish with great assiduity, and frequently brought them home alive. Besides minnows and eels, she occasionally carried home pilchards, one of which, about six inches long, was once found in her possession; she also contrived to teach a neighbour’s Cat to fish, and the two were sometimes seen together watching by a river side for their prey. At other times they were seen at opposite sides of the river, not far from each other, on the look out for game.
A writer in the Plymouth Journal, June 1828, says:—“There is now at the battery, on the Devil’s Point, a Cat which is an expert catcher of the finny tribe, being in the constant habit of diving into the sea and bringing up the fish alive in her mouth, and depositing them in the guard room for the use of the sailors. She is now seven years old, and has long been a useful caterer. It is supposed that her pursuit of the water-rats first taught her to venture into the water, to which it is well known Puss has a natural aversion. She is now as fond of the water as a Newfoundland dog, and takes her regular peregrinations along the rocks at its edge, looking out for her game ready to dive for it at a moment’s notice.”