Part 45

I. Night sight. II. Day sight. III. Long sight. IV. Short sight. V. Skew sight. VI. False sight.

_Night sight_, specifically called _Lucifuga_, was also termed _Nyctalopia_, from [Greek: nyx], _night_, and [Greek: ôps], _eye_; it was also known as the _Noctem amans_. This affection was thus named in consequence of the person labouring under it being only able to see at night, or in a deep shade; hence the first name: while nyctalopia has been used by most modern writers in the opposite sense of _night-sight ache_, agreeably, according to Mason Good's observations, to the technical or implied meaning of _opia_, in which case it always applies to a diseased vision; whence nyctalopia has been made to import day sight, instead of night sight.

This disease appears to be dependent upon a peculiar irritability of the retina, produced by two different causes,--a sudden exposure to a stronger light than the eye has been accustomed to bear, or a deficiency of the black pigment which lines the choroid tunic. If the iris be weak and torpid, it is enlarged; if strong and contracted, diminished. Thus, those who from peculiar circumstances reside in dark caverns and subterraneous abodes, or who have long been confined in obscure dungeons, labour under the first of these causes; instances of which were observed in two of the captives liberated from the Bastille in 1789.

Ramazzini informs us that this affection is commonly observed among the Italian peasants, amongst whom he was not able to trace any other peculiarity than an enlargement of the pupil. This state of the vision, however, has been attributed to the peculiar brightness of the Italian sky, its clear atmosphere, and the relaxing warmth of the temperature. The Italian peasants are therefore constantly exposed to all those causes that tend to debilitate the iris, while they irritate the retina. We thus find these causes acting with renewed power at the season when the disease usually makes its attack,--the vernal equinox, when an increased flood of solar rays breaks on them. Such is the dimness that this brightness produces, that the peasantry frequently lose their way in the fields in the glare of day; but on the approach of night they can see distinctly. Hence are they obliged to remain for some weeks in the shade to recover their sight.

A deficiency of the black pigment of the eye is occasionally found in persons of a very fair complexion and light hair. This affection is therefore common in the Albinoes. This circumstance arises from the whiteness of the eyelashes and hair, whereby the retina is deprived of the natural shade that softens the light in its descent. This debilitated race generally inhabit warm and damp regions; they are seldom long-lived, and frequently low-spirited and morose. The iris is of a pink colour, and this circumstance, added to the constant winking that the weakness of the organ occasions, gives them a distressing appearance. In horses, this want of the dark pigment constitutes what is called the _wall eye_.

Acuteness in night vision is natural to most, if not to all, animals that prowl in the dark. In the feline genus we observe that the iris can be contracted much closer than in mankind, when exposed to a vivid glare; but they also expand to a much greater degree when obscurity sets in. Owls, bats, and many insects, possess a similar faculty.

_Day sight_, the nyctalopia of some authors, is said to be endemic in some countries,--Poland, the West Indies, Brazil, and various intertropical regions. This affection arises from causes totally different from the former one. Here the eye is habitually exposed to too great a flood of light, whence the retina becomes torpid. It has been said to be endemic in some districts of France, particularly in the neighbourhood of Roche Guyon, on the banks of the Seine; but here the soil is of a dazzling white: and as it makes its attacks in the spring, and continues for three months, it is supposed to arise from the keenness of the reflected light, after the dreary winter months.

This disease has also been commonly observed in Russia, especially in the summer, when the eye is exposed, with scarcely any intermission, to the constant action of light, as the sun dips but little below the horizon, and there is scarcely any interval of darkness. Hens are subject to this affection, and cannot see to pick up their food in the dusk of the evening. The complaint is, from this circumstance, called _hen blindness_.

Dr. Heberden has communicated the following curious case of this species of affection: "A man about forty years old had in the spring a tertian fever, for which he took too small a quantity of bark, so that the returns of it were weakened without being removed. Three days after his last fit, being then employed on board a ship in the river, he observed at sun-setting that all objects began to look blue, which blueness gradually thickened into a cloud; and not long after he became so blind as hardly to perceive the light of a candle. The next morning about sunrising his sight was restored as perfectly as ever. When the next night came on, he lost his sight again in the same manner, and this continued for twelve days and nights. He then came ashore, where the disorder of his eyes gradually abated, and in three days was entirely gone. A month after he went on board another ship, and after three days' stay in it the night blindness returned as before, and lasted all the time of his remaining in the ship, which was nine nights. He then left the ship, and his blindness did not return while he was upon land. Some little time afterwards he went into another ship, in which he continued for ten days, during which time the blindness returned only two nights, and never afterwards." It appears, however, that this individual had previously laboured under an affection produced by the use of lead, which had left him in a state of much nervous debility. Notwithstanding this circumstance, this case clearly proves that the affection is liable to be increased and brought on by local influence.

_Long sight._ In this species of vision the iris is habitually dilated, and not easily stimulated into contraction. Several varieties of this affection have been observed. Dr. Wells, in the Philosophical Transactions, relates the case of a young person who, from a permanent dilatation of the pupil, saw near objects with much difficulty and confusion, but remote bodies with singular accuracy. The power of moving the upper lid was completely lost. This dilatation of the pupil, which may be artificially produced by the application of belladonna, can be remedied by the use of convex glasses.

_Short sight._ In this case the iris is contracted, and the cornea, which in long sight is too much flattened, is too convex or polarised; therefore spectacles of an opposite character, and with concave glasses, become necessary. Mice are said to be short-sighted; hence the affection has been termed myopia or myopiasis, literally "mouse-sight."

_Skew sight_, or _sight askew_, is a condition of our vision only accurate when the object is placed obliquely, in consequence of some partial obfuscation of the cornea, frequently from slight scars, scarcely, if at all, observable. In this lateral vision the axis of the eye affected usually coincides with that of the sound eye. In squinting, on the contrary, the two axes do not coincide.

In _false sight_, imaginary objects float before the sight; or, at other times, objects assume imaginary forms and qualities. The latter species has been divided in cases where the objects that are supposed to be seen have no real existence, and in cases where actual objects have assumed qualities that do not appertain to them. The first are termed ocular phantasms or spectres; the latter, ocular transmutations or illusions. These spectres sometimes form dark spots, called by physicians _muscæ volitantes_. In another species, a net-work seems to be spread before the eyes; hence called _visus reticularis_. In a third form sparks scintillate, and this appearance is experienced when the eye has been struck. The eye is also troubled with an imaginary sense of dazzling, constituting the _myrmaryge_ of the Greek writers; at other times, an iridescent appearance, exhibiting the colours of the rainbow, is experienced, although sometimes this impression is confined to a single colour. Dr. Heberden relates the case of a lady of advanced age, lodging on the eastern coast of Kent, in a house that looked immediately upon the sea, and exposed to the glare of the morning sun. The curtains of her room were white, a circumstance which added to the intensity of the light. When she had been there about ten days, she observed one evening, at the time of sunset, that first the fringes of the clouds appeared red, and soon after the same colour was diffused over all the objects around her, especially if they were white. This lasted the whole night, but in the morning her sight was again perfect. This alternation of morbid and sound sight prevailed the whole time the lady resided on the coast, which was three weeks; and for nearly as long after she left it, at which time it ceased suddenly of its own accord.

There exists another variety of false sight, that Plenk has denominated _metamorphopsia_, and in which objects appear changed in their natural qualities, producing error of form, error of motion, error of number, and error of colour. I had a patient in Lisbon who fancied that all the horses he saw carried horns or extensive antlers. A young lady whom I attended beheld every one of a gigantic height. Dr. Priestley has given a curious case of error of colour in five brothers and two sisters, all adults. One of the brothers could form no idea whatever of colours, though he judged very accurately of the form and other qualities of objects; hence he thought stockings were sufficiently distinguished by the name of stockings, and could not conceive the necessity of calling them white or black. He could perceive cherries on a tree; but only distinguished them, even when red-ripe, from the surrounding leaves by their size and shape. One of the brothers appeared to have a faint sense of a few colours, but still a very imperfect notion; and, upon the whole, they did not seem to possess any other distinguishing power than that of light and shade, into which they resolved all the colours presented to them,--so that dove or straw colour were regarded as white; and green, crimson, and purple, as black or dark. On looking at a rainbow, one of them could distinguish that it consisted of stripes, but nothing more. Dr. Nicholl relates the case of a boy who confounded green with red; and called light red and pink, blue. His maternal grandfather and one uncle had the same imperfection. The latter was in the navy, and having a blue coat and waistcoat, purchased a pair of red breeches to match. The same physician knew a gentleman who could not distinguish green from red; a cucumber and a boiled lobster did not offer the least difference in colour. His brother and his niece laboured under a similar affection.

Some philosophers are of opinion, that in the power of conceiving colours there is a striking difference in individuals, and are inclined to think that in many instances the supposed defects of sight ought to be ascribed to a defect in the power of conception, arising probably from some early habit of inattention. This theory is scarcely tenable. The utmost inattention and indifference regarding surrounding objects could never lead to a delusive view of any colour; also, it is more than probable that, in the case of a child in whom such a defective vision was observed, his attention would be incessantly called on by those around him, to correct, if possible, so strange a delusion. Moreover, this defect of vision, as we have seen, appears in some instances to be hereditary; and to prevail in families.

Phrenologists of course are of opinion that the judgment of colours resides in a particular organ, remarkably full and prominent in painters distinguished by the perfection of their colouring. According to Gall, a local deficiency of brain is observable where the power of distinguishing colours is wanting.

The sense of vision exhibits more variety in the different classes of animals than any of the others. In man, and the greater number of quadrupeds, this organ is guarded by an upper and a lower lid, both of which in man are fringed with lashes. This is not the case in most quadrupeds. In the elephant, opossum, seal, cats, other mammalia, birds, and all fishes, we find a third eyelid, or nictitating membrane, as it is called, arising from the internal angle of the eye, capable of covering and protecting the eye from danger, either wholly or in part. In the dog this membrane is narrow; in oxen and horses it extends half over the eyeball. It is by means of this veil that eagles are capable of fixing their eyes on the noon-day sun. The largest eyes in proportion to the size of the animal are found in birds,--nearly the smallest in whales; but the most diminutive are those of the shrew and mole, the latter's not exceeding the size of a pin's head.

The situation of the organs of vision differs materially. In man and monkeys they are placed directly under the forehead; in some fishes, such as the turbot and flounder tribes, both eyes are placed in the same side of the head. In the snail they are situated on the horns; and in the spider, distributed over various points of the body, and in different arrangements.

Eyes, however, are not indispensable to become sensible of the presence of light. Several zoophytes, that do not possess the organs of vision, are perfectly alive to its influence. A distinct organ is not always indispensable for a distinct sense. It is probable that in those animals that appear to be endowed with particular senses, without displaying particular organs relating to them, the senses are diffused like that of touch, over the whole surface. This subject has been admirably commented on by Cuvier.

HELLEBORE.

From time immemorial this substance has been considered an efficacious remedy in mania. The Greeks pretended that the daughters of Proetus, smitten with insanity by Bacchus, were restored to reason by the shepherd Melampus, who gave them some milk drawn from goats that had eaten hellebore. It is supposed that the use of purgatives arose from this fabulous tradition, whence this plant was called _melampodium_.

The ancients described two varieties, the white and the black. The first, according to Theophrastus, was found on a part of Mount Oeta called Pyra, on which the body of Hercules was burnt. It is not certain whether they confounded our hellebore with our veratrum. Pinel supposes that the veratrum album was their hellebore, as it is not probable that the veratrum nigrum should have been thus confounded. Tournefort, in his travels in the Levant, fancied that he had discovered the root of the ancients in one that the Turks called _zopteme_, which answered in its character to the description recorded in older writers.

Howbeit, it was considered a powerful purgative and emetic, especially indicated in the treatment of mental affections. Celsus forbade its exhibition in summer and during the winter, or whenever febrile symptoms were prevalent. This precaution, however, applied to all purgative medicines; and to this day, in several parts of the continent, similar injunctions are usual; and even in France practitioners of the old school prepare a patient several days before any opening medicine is given,--a learned precaution, that has but too frequently rendered every medicine useless.

The exhibition of this drug was a matter of so much importance amongst the ancients, that it was specifically termed _helleborism_; and it was considered of so powerful a nature in mania, that the treatment of the malady was called _navigare Anticyras_, since it was near the town of Anticyras that the plant was generally gathered. If this process of helleborism proved efficacious, it is more than probable that its beneficial results proceeded from the violent evacuations that preceded it. The following was the mode adopted with the helleborised: The patient was first well fed for several days until the decline of the moon, when a powerful emetic was given to him; five days after a similar dose was prescribed, and then good living ordered for a month: at the expiration of this invigorating respite, emetics began again to work him every three days. After the last attack on his digestive head-quarters, he was bathed, fed again, and hellebore was given after he had been submitted to several hours' friction with olive oil. The emetics were invariably administered on a full stomach, which was cleared either by medicine or the excitement of the beard of a quill poked down the unfortunate patient's throat. At other times, (by way, no doubt, of variety,) rejection was excited by making the patient eat a pound or more of horseradish; after which he was walked about for some time; and then, after a short repose, the fingers or the quill were brought into action. After this operation he was lulled to sleep by a regular shampooing. It appears that, despite of all these practices, the stomachs of the ancients were sometimes so pertinaciously retentive, that more powerful means to _relieve_ them were adopted; and when the longest feather that could be plucked from a goose proved unavailing, gloves dipped in the oil of cyprus were put on, and the fingers thus inuncted replaced the feathers. When this failed, the obstinate sufferer was made to swallow a quart or two of honey and hot water, in which rue had been infused; and when this proved ineffectual, he was slung in a hammock to produce the sensation of sea-sickness. In some cases it appears that, despite this practice, the patient thought proper to faint. On such occasions little wedges of wood were driven between his obstinate and rebellious teeth clenched against medicine, so as to allow the introduction of the goose-quill, while cephalic snuff of the precious hellebore and euphorbia was blown up his nostrils to produce sneezing. The last trial to relieve him was tossing the ill-fated wight in a blanket. After this experiment the patient was left to nature or to his friends, if he _would_ not recover. These friends immediately proceeded to give him punches in the stomach, roll him about the floor, and endeavour to restore him to his senses by driving him out of them by every possible noise that could frighten him, if his _frightful_ condition was at all susceptible of any thing left in the arsenal of medicinal ingenuity.[45]

Small doses of hellebore seem to have been taken not only with impunity, but were supposed to assist the mental faculties. According to Valerius Maximus and Aulus Gellius, orators were in the practice of using this stimulus before their disputations. Such, it is said, was the habit of Carneades, whose doctrines might well have been applied to this very day to many theories, since he denied that any thing in the world could be perceived or understood.

Hellebore is to this day an ingredient in many of the fashionable pills vended by successful quacks. This introduction, at any rate, shows that their compounders have candour enough to think (although they may not acknowledge it) that the intellectual faculties of the purchasers of their nostrums do stand in need of some medicinal aid.

SYMPATHIES AND ANTIPATHIES.

The constant effects produced by causes which do not appear connected with them, are phenomena both of organic and inorganic nature which have long fixed the attention of philosophers, and have not yet been satisfactorily explained. This operation between distant bodies cannot be traced to any medium of communication. It arises from an attractive and a repulsive power that cannot be defined. Almost every substance evinces inclinations or antipathies; is attracted with more or less strength by one body, indifferent towards a second, and constantly avoiding a third; nay, bodies appear to act where they are not present, and where no communication can exist. We are as ignorant of the nature of these phenomena as of those of gravitation, magnetism, and electricity. Still, although this medium of communication is not evident, it must be admitted by inference that there must exist a connecting channel, although its nature be unknown.

The ancients called sympathy _consensus_, and the moderns have also defined it a _consent of parts_; nor is this definition incorrect, since sympathy arises from the relative ties that mysteriously unite our several organs, however distant and unconnected they may appear; thus establishing a beauteous harmony between all the functions of the animal economy. Sympathies must therefore constitute the chief study of the physiologist: on this alone can the physician ground his investigation of the various disorders to which flesh is heir. Symptoms arise from sympathies: without a knowledge of the one we can never attain a clear insight in the other.

Sympathies are of a physical or a moral nature. The first consist, as I have already stated, of a consent between the different parts of the organism; the latter of certain impressions, unaccountable, unconquerable, that harmonize in a multiplicity of phenomena various individuals, or that induce them, without their being able to assign any reason or motive to warrant the repugnance, to avoid each other, and not unfrequently to entertain a feeling of disgust or horror. A secret voice has spoken,--organism instinctively obeys. Moral sympathies have been defined as faculties that enabled us to partake of the ideas, the affections, or the dislike of others; although this sentiment is by no means reciprocal, and we often dislike those who fondly love us. So far sympathy is instinctive; yet, like many instincts, it is more or less under the control of our reason. We often acquire an artificial partiality to substances that we naturally disliked. Our senses may be considered the instruments of our sympathies; yet senses are regulated by education and habit. Oil, olives, tobacco, and various other substances, are naturally, one might say instinctively, unpleasant to most individuals; yet by custom they are not only relished, but ardently wished for when they cannot be obtained. It is the same with our relative partiality or aversion towards individuals; and indifference is often turned into affection, while the most ardent love is not far remote from hate, when vanity more especially, removes its boundaries.

If we admit that our sympathies are lodged in certain specific organs, we must consider that we are the slaves of organism; whereas it is pretty positive that to a certain extent we are the slaves of habit. Even the most ardent and prevailing passions, the indulgence in which has become an absolute necessity, cease to be brought into action when they have long remained dormant. To associate our moral sympathies with physical consents of parts is to level man with the brute creation; although we hourly see the most decided instinctive dislikes in animals overcome by education. A mouse may be brought up with a cat, and a hawk with a sparrow; although a chicken has been known to dart at a fly the moment its head was out of the egg.