for there exists among the North American Indians a tribe whose mode of punishment consists in subjecting their prisoners to the influence of the odours of certain plants. This produces the most exquisite mental distress and bodily pain; and occasionally, if the prisoner be exposed long to its influence, death has been known to

ensue.

expos

It is said that in some portions of China, and in the South Sea Islands, the natives are in the habit of ing their victims as a punishment to what Falstaff terms, the "rankest compound of villanous smells."

We occasionally observe unnatural manifestations and exquisite conditions of the sense of seeing, hearing, touch, and taste, quite apart from disease of the brain. In some persons the sense of hearing is in an exalted state of manifestation, the slightest sound coming from remote distances being at once perceptible. Celebrated musicians, owing in the first place to the natural vigour and acuteness of the sense of hearing, and secondly, to the careful education and long-continued exercise of this faculty, have had this special sense in a high state of activity. It is said of Mozart that, during the performance of a most complicated piece of concerted music, he was able, among several hundred musicians, to detect with wonderful precision and quickness the slightest deviation from the correct score. He was

able also to name the instrument that was at fault. Any aberration of harmony produced the most painful sensations in the nervous system of this wonderful musical genius.

Among blind persons we often notice an extraordinary capacity of recognising objects by the sense of touch. A person who became blind at an early period of life, was able to distinguish individually, by means of the touch, a number of botanical plants, and to single them out

with wonderful accuracy. We occasionally witness, as the effects of certain diseases, particularly of the nervous system, a great acuteness in the capacity of the special senses, as well as positive perversion in their modes of action.

I have known instances in which the sense of hearing and smell have become painfully sensitive after recovery from attacks of fever, conditions of nervous debility and exhaustion. In other cases the various special senses have been perverted, or their functions either diminished in power, or entirely lost.

Dr. Heberden records the particulars of the following case :-"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 sun-rising, 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 indi

vidual 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 influences.

A lady of advanced age, lodged 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 dif fused 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 with sound sight prevailed the whole of the 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.

Some remarkable instances are recorded of want of power in distinguishing colours. These facts are important to bear in mind when testing the healthy condition of the organs of vision. In some cases a morbid condition of this sense (symptomatic of centric disease of the brain) consists in the patient not being able to distinguish one colour from another, as well as in their observing certain objects surrounded by a halo, variously coloured and tinted.

Dr. Priestly has published 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, was 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 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.

CHAPTER XXII.

Morbid Phenomena of Vision.

In diseases of the brain the visual power may be,

IMPAIRMENT AND LOSS OF VISION.-These are common and important symptoms of organic disease of the brain. The impairment of vision may come on gradually or occur suddenly. The sight is occasionally lost in one eye before the defect is observed, but, as a general rule, the disordered function of the eye is of slow and progressive growth, proceeding, pari passu, with the development of subtle structural changes in the delicate tissue of the brain, its membranes and vessels, more immediately connected with the origin, course, and distribution of the optic nerves.

Impairment of vision is often symptomatic of gastric, hepatic, and intestinal derangement. It is of importance not to overlook this fact, when diagnosing a suspected condition of brain disease, associated with what may be considered, symptoms of cerebral amaurosis.

This affection of sight arises, occasionally, from general debility, hemorrhage, morbid states of the blood, and exhausting and debilitating discharges. Sudden loss of vision has been known to succeed a severe mental shock.