Curiosities of Medical Experience Part 37

La pet.i.te vieille, { _B. monoceros_.--LINN.

{ _Alutus monoceros_.--CUVIER.

Le coffre triangulaire, _Ostracion trigonus_.--BLOCH.

La grande orphie, _Esox Brasiliensis_.--LINN.

La pet.i.te orphie, _E. marginatus_.--LACEPEDE.

Le congre, _Muraena conger_.--MINN.

Le perroquet, _Sparus psittacus_.--LACEPEDE.

Le capitaine, _S. erythrinus_.--BLOCH.

La becune, _Sphyraena becuna_.

Le thon, _s...o...b..r thynnus_.--LINN.

La carangue, _Caranx carangus_.

A work, in which a _synonymous_ catalogue of all the fishes supposed to be poisonous might be found, would be highly desirable, as they generally bear different popular and scientific names, thus producing a dangerous confusion even amongst naturalists; how much more dangerous amongst seafaring people and voyagers!

I cannot conclude this article without noticing the singular properties of those electric fishes denominated the _torpedo-ray_ and the _gymnote_.

They had been long known to naturalists, and the ancients attributed their destructive faculties to a magic power that Oppian had recorded in his _Alieuticon_, where he describes a fisherman palsied through the hook, the line, and the rod. This influence being voluntary on the part of the animal, seemed to warrant the belief in its mischievous nature, since it allows itself sometimes to be touched with impunity, while at others it burrows itself under the sand of the beach, when the tide has receded, and maliciously benumbs the astonished pa.s.senger who walks over it. This singular fish, which is common in the Mediterranean Sea, has been described both by the Greek and Roman writers; amongst others, by Aristotle and Athenaeus: and Socrates, in his Dialogues, compares a powerful objection, to the influence of the torpedo.

This voluntary faculty has been observed by Lacepede and Cloquet in the Mediterranean, and at La Roch.e.l.le. In torpedos kept in water for experimental purposes, Reaumur found that he handled them without experiencing any shock for some time, until they at last appeared to become impatient: he then experienced a stunning sensation along the arm, not easily to be described, but resembling that which is felt when a limb has been struck with a sudden blow. One of the experiments of this naturalist proved the extensive power of this faculty. He placed a torpedo and a duck in a vessel containing sea-water, covered with linen to prevent the duck from escaping, without impeding the bird's respiration. At the expiration of a few minutes the animal was found dead, having been killed by the electric shocks of its enemy.

Redi was the first who demonstrated this faculty. Having laid hold of a torpedo recently caught, he had scarcely touched it, when he felt a creeping sensation shooting up to the shoulder, followed by an unpleasant tremor, with a lancinating pain in the elbow. These sensations he experienced as often as he touched the animal; but this faculty gradually decreased in strength as the animal became exhausted and dying. These experiments he related in a work ent.i.tled "_Esperienze intorno a diverse cose naturali_." Florence, 1671.

In 1774, Walsh made some very interesting experiments at the Isle of Re and La Roch.e.l.le, and clearly demonstrated this electric faculty in a paper _On the electric property of the torpedo_. In one of them he found that this fish could produce from forty to fifty shocks in the course of ninety minutes. The electrified individuals were isolated; and at each shock the animal gave, it appeared to labour under a sense of contraction, when its eyes sunk deep in their sockets.

The _trichiurus electricus_ of Linnaeus, the _rhin.o.batus electricus_ of Schneider, and the _gymnonotus electricus_ of _Surinam_, are the species of this singular fish with which experiments have chiefly been made. The _gymnonotus_ is a kind of eel, five or six feet in length, and its electric properties are so powerful that it can throw down men and horses.

This animal is rendered more terrific from the velocity of his powers of natation, thus being able to discharge its thunder far and near. When touched with one hand the shock is slight; but when grasped with both, it is so violent that, according to the accounts of Collins Flag, the electric fluid can paralyze the arms of the imprudent experimentalist for several years. This electric action is a.n.a.logous to that which is obtained by means of the fulminating plate, which is made of gla.s.s with metallic plates. Twenty-seven persons holding each other by the hands, and forming a chain, the extremities of which corresponded with the points of the fish's body, experienced a smart shock. These shocks are produced in quick succession, but become gradually weaker as the fluid appears to be exhausted. Humboldt informs us, that, to catch this fish, wild horses are driven into the water, and after having expended the fury and the vigour of the gymnonotus, fishermen step in and catch them either with nets or harpoons. Here we find that the irritable or sensorial power is exhausted through the medium of electricity. These phenomena may be attributed to an electric or Voltaic aura; and the organ of the animal that secretes the fluid resembles in its wonderful structure the Voltaic apparatus. Both the gymnote and the torpedo obey the laws of electricity, and their action is limited to the same conducting and non-conducting mediums. The electric sparks proceeding from the gymnote have been plainly seen in a dark chamber by Walsh, Pringle, Williamson, and others. The fish has four electric organs, two large and two small ones, extending on each side of the body from the abdomen to the end of the tail. These organs are of such a size that they const.i.tute one third of the fish's bulk. Each of them is composed of a series of aponeurotic membranes, longitudinal, parallel, horizontal, and at about one line's distance from each other.

Hunter counted thirty-four of these fasciculi in one of the largest. Other membranes or plates traverse these vertically, and nearly at a right angle; thus forming a plexus or net-work of numerous rhomboidal cells.

Hunter found no less than two hundred and forty of these vertical plates in the s.p.a.ce of eleven inches.

This apparatus, a.n.a.logous to the Voltaic pile, is brought into action by a system of nerves rising from the spinal marrow, each vertebra giving out a branch; other branches, rising from a large nerve, running from the basis of the cranium to the extremity of the tail. All these ramifications are spread and developed in the cells of the electric organs, to transmit its powerful fluid, and strike with stupor or with death every animal that comes within its reach. Lacepede has justly compared this wonderful mechanism to a battery formed of a mult.i.tude of folio-electric pieces.

The electric organ of the _malapterus electricus_ is of a different formation. This fish, found in the Nile and in other rivers of Africa, is called by the Arabs _raash_ or thunder. In this animal the electric fluid extends all round the body, immediately under the integuments, and consists of a tissue of cellular fibres so dense, that it might be compared to a layer of bacon; but, when carefully examined, it consists of a series of fibres forming a complex net-work. These cells, like those in the gymnote, are lubricated with a mucous secretion. The nervous system of this intricate machinery is formed by the two long branches of the pneumo-gastric nerves, which in fishes usually run under each lateral line. Here, however, they approach each other on leaving the cranium, traversing the first vertebra.

Linnaeus had cla.s.sed the torpedo in the genus _ray_, and hence called it _raia torpedo_. Later naturalists have restored to it its ancient name, as given by Pliny, and termed it _torpedo_, of which four species are described: the _T. narke_, or with five spots; the _T. unimaculata_, marked, as the name indicates, with one spot; the _T. marmorata_, and the _T. Galvanni_.

The ancients placed much faith in the medicinal properties of these fishes. Hippocrates recommends its roasted flesh in dropsies that follow liver affections. Dioscorides prescribed its application in cases of obstinate headaches and rheumatisms. Galen and other physicians recommend the application of the living animal; and Scribonius Largus states that the freedman Anteroes was cured of the gout by this practice. To this day, in Abyssinia, fever patients are tied down on a table, and a torpedo is applied to various parts of the body. This operation, it is affirmed, causes great pain, but is an infallible remedy.

MEMORY AND THE MENTAL FACULTIES.

This n.o.ble faculty, the proudest attribute of mankind, justly called the mother of the Muses, is subject to be impaired by various physical and moral causes, while a similar agency can sometimes restore it to its pristine energy, or develope its powers when sluggish and defective.

Memory may be considered as the history of the past chronicled in our minds, to be consulted and called upon whenever circ.u.mstances stances or the strange complication of human interests demand its powerful aid. Its powers and nature widely differ, and these varieties depend upon education, natural capacities, mode of living, and pursuits. Thus memory has been divided into that faculty that applies to facts, and to that more superficial quality that embraces a recollection of things, to which must be added the memory of localities and words: "Lucullus habuit divinam quamdam memoriam rerum, verborum majorem Hortensius," said Cicero.

It is on this division that Aristotle founded his belief that the brute creation had not the faculty of reminiscence, although he allowed them to possess memory. According to his doctrine, reminiscence is the power of recollecting an object by means of a syllogistic chain of thought; an intellectual link with which animals do not seem to be gifted. Their memory appears solely to consist of the impressions received by the return of circ.u.mstances of a similar kind. Thus, a horse that has started on a certain part of a road will be apt to evince the same apprehension when pa.s.sing the same spot. This is an instinctive fear, but not the result of calculation or the combination of former ideas. Reminiscence is the revival of memory by reflection; in short, the recovery or recollection of lost impressions.

The recollection of things or facts can alone bring forth a sound judgment. It implies a regular co-ordination of ideas, a catenation of reflections, in which circ.u.mstances are linked with each other. The chain broken, no conclusion can be drawn. Newton was wont to lose the thread of an important conversation when his mind was in search of an idea. This is the reason why the society of the learned is seldom entertaining to the generality of men. They are considered absent, while their brain is busily employed in pursuits perhaps of great importance; they must therefore be anything but agreeable to those who generally think through the medium of other persons' brains.

The brain is considered to be the seat of memory. When it is injured, remembrance is impaired; and, on the other hand, an accident has been known to improve the recollective faculties. A man remarkable for his bad memory fell from a considerable height upon his head; ever after he could recollect the most trifling circ.u.mstance. The effects of different maladies will also produce various results on this faculty. In some instances names of persons and things are completely forgotten or misapplied; at other times, words beginning with a vowel cannot be found.

Sudden fright and cold have produced the same effects. An elderly man fell off his horse in crossing a ford in a winter's night; ever afterward he could not bring to his recollection the names of his wife and children, although he did not cease to recognise and love them as fondly as before the accident. Cold has been at all times considered injurious to memory; hence Paulus aeginus called Oblivion the child of Cold.

In fevers, and a state of great debility, in a disordered condition of the digestive functions, and various affections of the head, we generally find that the attention cannot long be applied to any one subject or a continued train of thoughts; all past circ.u.mstances are readily forgotten, while pa.s.sing occurrences are most acutely observed and felt, excepting in cases of delirium, when we have the perception of surrounding objects or receive an erroneous impression of their nature and agency. In many cases of this nature, we find that conversation produces great excitement and increases the evil, for the subject of such intercourse is generally misconceived and distorted through the medium of a morbid conception, while the past, the present, and the future are grouped in a confused and most heterogeneous and incoherent jumble.

Philosophers have endeavoured to fix the seat of memory in various portions of the brain. The ancients fancied that it was lodged in the posterior part of the cranium; having observed that when persons endeavoured to recollect any thing, they usually scratched the back part of the head. The Arabian physicians entertained a similar belief.

Gratarola maintained that a great protuberance of the occiput indicated a good memory. Gall places it above the orbitary cavity of the eye, and even behind it. It has long been thought that persons with protuberant eyes had quick recollections. The physical condition of the brain has also been considered as materially affecting memory. What physiologists have called a moist brain was looked upon as unfavourable to its development; and it was therefore owing to the soft and pulpy condition of the cerebral organs in young children that the difficulty of impressing anything upon their minds arose; the same stupidity being observed in cases where water was supposed to be lodged in the brain. While this humid state was considered as injurious to memory, dryness of the organ was also esteemed an obstacle of a similar nature; and in old age it is by this state of siccity that failure in memory was attempted to be explained. This failure of memory as age advances may, however, be explained in a much more rational manner.

Old people will bear in lively recollection the events that attended their childhood, their youth, and manhood; it is only recent occurrences that shed a transient impression on their minds. The cause of this may be considered to arise from the extreme _impressionability_ that prevails in early life, when every organ is prompt in responding to each call upon its powers; when the charms of novelty tinge with a brighter, yet a more lasting l.u.s.tre, all our pleasurable sensations; when grief had not yet wrung the young heart till its fibres became callous to future pangs, when perfidy and ingrat.i.tude have shown us that all is vanity, and calm philosophy has tutored our pa.s.sions in the school of Adversity. Reason now sits upon the judgment-seat, and all that we then can wonder at that is, at any time we could have wondered at any thing. Why, then, are we to seek for a material theory of the mind, when our daily experience shows us that it is under the influence of so many moral agents?

We have, moreover, convincing proof that the brain may be materially affected, without any deterioration of the mental faculties. Dr. Ferriar mentions a man in whom the whole of the right hemisphere, that is, one half of the brain, was found destroyed, but who retained all his faculties till the very moment of his death. Diemerbrook states another case where half a pound of matter was found in the substance of the brain. O'Hallaran relates the history of a man who had suffered such an injury of the head, that a large portion of his brain was removed on the right side; and extensive suppuration having taken place, an immense quant.i.ty of pus, mixed with large ma.s.ses of the substance of the brain, was discharged at each dressing, through the opening. This went on for seventeen days, and it appears that nearly one half of the brain was thrown out, mixed with the matter, yet the man retained all his intellectual faculties to the very last moment of his dissolution, and through the whole course of the disease, his mind maintained uniform tranquillity. I attended a soldier at Braburne Lees, who had received a wound in the head during ball practice.

The ball remained in the brain, and during three weeks large ma.s.ses of brainular substance were brought away with pus. To the last day of his life he would relate, with every circ.u.mstantial particular, the neglect of the comrade by whom he had been wounded, and who fired while he was running to the target to mark the shots. It is somewhat singular, but suppuration of the brain is more offensive than the foulest ulcer, and it is with great difficulty that the pestilential effluvia can be tolerated.

These cases plainly show that cerebral diseases have but little influence on the manifestations of the mind.

Amongst the many curious doctrines that have been started, to account for the operations of memory, some philosophers have compared it to the art of engraving; pretending that on those subjects where it requires much time and trouble to work an impression it was more durable, while it was only traced in a superficial manner on those brains that were ever ready and soft to receive this plastic influence. These several faculties they therefore compared to bronze or marble, to b.u.t.ter and to wax. Descartes, following up the phantasy, compared recollection to etching, and said that the animal spirits, being pa.s.sed over the lines previously traced, brought them more powerfully to the mind; thus comparing the brain to the varnished copper-plate over which the engraver pa.s.ses his mordants.

Malebranche endeavoured to establish another doctrine, and compared our cerebral organ to an instrument formed of a series of fibres, so arranged, that when any recent emotion agitated one of these chords the others would immediately be thrown into vibration, renewing a past chain of ideas. As these chords became less flexible in old age, of course these vibrations were more difficult to obtain. Recollection was also considered an attribute of each molecule of the brain; and Bonnet endeavoured to count how many hundred ideas each molecule was capable of holding during a long life.

The controversies of learned psychologists on the relation of memory and judgment, indeed on the a.n.a.logies that exist between our several mental faculties, have been as various as they are likely to prove interminable.

Without offending these ill.u.s.trious controversionalists, we may endeavour to enumerate these faculties, which, despite the ingenuity of theorists, appear in a practical point of view to exercise a wonderful influence upon each other. The first may be considered the faculty of _perception_, a.s.sisted by that of _attention_, to which we are indebted for our _ideas_.

These are preserved and called into action from the rich stores of the mind by _memory_, justly called by Cicero the guardian of the other faculties. _Imagination_ is the faculty of the mind that represents the images of remembered objects as if they were actually present.

_Abstraction_ forms general deductions from the foregoing faculties; while _judgment_ compares and examines the a.n.a.logies and relations of the ideas of sense and of abstract notions. Finally, _reason_ draws inferences from the comparisons of judgment.

It is from the combination and the workings of these wonderful powers that _appetency_, _desires_, _aversions_, and _volition_ arise. _Appetency_ occasions _desires_, and these, when disappointed or satiated, inevitably usher in aversions and antipathies; although, as we shall see in another article, our antipathies are frequently instinctive, and not arising from any combination of the faculties I have enumerated.

Dr. Gall has considered these mental faculties as fundamental; and in this view he was certainly correct, since they may be considered the source whence all other distinct capacities are probably formed by particular habits of study and the nature of our pursuits, independently of those specific capacities which appear to be innate, and, according to the system of the phrenologists, organic. Every man possesses these fundamental faculties in a greater or less degree, according to the obtuseness or the energies of his mind; but it is absurd to conceive that specific capacities can be brought into action without the agency of those which are fundamental. Let us take the instinct to destroy life, the sentiment of property, metaphysical sagacity, or poetic talent,--in short, any one of Gall's various faculties; can we for one instant conceive that they are not under the influence of _perception_, _memory_, _imagination_, and _abstraction_, although they may not be properly ruled by _judgment_ and by _reason_? Instincts are equally under a similar influence, and are, according to circ.u.mstances, regulated by judgment in the various modes of life of animals. Phrenologists deny that instinct is a general faculty, and a.s.sert that it is an inherent disposition to activity possessed by every faculty, and that there are as many instincts as fundamental faculties. This is a postulation by no means clear. Instinct is an inherent disposition possessed by every animal, but not by every faculty.

It is a disposition dependent upon the combination of all the mental faculties, according to the degree in which the animal may possess them: the reminiscences of animals prove it. We have instanced the horse, who endowed with the memory of locality, starts when pa.s.sing by the same spot where he had started before. But here the memory of facts, _memoria realis_, and probably of words, _memoria verbalis_, are superadded to the _memoria localis_. The horse recollects the tree, the carrion, the object that startled him, whatever it might have been; but to this reminiscence are a.s.sociated the chiding, the punishment he received from his rider. If this horse had possessed the faculties of _abstraction_, _judgment_, and _reason_, he would not have started, to avoid a reiteration of punishment; but he started under the impression of _perception_, _attention_, and _memory_. Wherever there does not exist a combination of the faculties, the intellectual ones may be considered imperfect. We certainly may have a greater perception and memory of one subject than of others. Thus, a man with a musical organisation will recollect any tune he may have heard, though it may not have attracted the _attention_ of one who "hath no music in his soul." We daily perceive different talents in children educated together. This is, no doubt, a strong corroboration of the doctrine of organic dispositions, which in reality no philosophic observer can deny; but to a.s.sert that these several dispositions are not regulated by what have been called the fundamental faculties, is, I apprehend, a position that cannot well be maintained; and we may be warranted in the conclusion that a particular faculty may be the result of the combined action of several faculties, if not of all; for, whether a man be a poet or a painter, a miser or a spendthrift, an affectionate father or an a.s.sa.s.sin, every one of the mental faculties that I have enumerated will to a certain extent be brought into action, however morbid that action may be.

All these disquisitions, however attractive they may be, when decked out with the fascination of the fancy, are the mere wanderings of metaphysical speculation, that never can be proved or refuted until we attain a knowledge of the nature and quality of the perceptions which material objects produce in the mind through the medium of the external senses. But while some of these speculations are idle and harmless, others may be fraught with danger, and occasion much misery to society. Let us for one moment conceive the possibility of our resolves and actions being dictated by a supposed phrenological knowledge,--a knowledge earnestly recommended to statesmen, and indeed to mankind in general;--what would be the result?

A diplomatic bungler would be sent on an emba.s.sy, because a minister, or a sovereign, with a phrenological map before him, may fancy that he displays the faculty of circ.u.mspection, or the sense of things; and a chancellor of the exchequer be found in some needy adventurer who possessed the organ of relation of numbers!

I do not at all presume to invalidate the statements of Dr. Gall. The profession is highly indebted to him for his accurate description of the brain; and physiology must ever consider him as one of the brightest ornaments of science: but I do maintain, that to recommend his conclusions as a guide to society would be the most rash of visionary speculations; and, to my personal knowledge, no man was ever more mistaken in his estimate of the persons whom he met in society than the learned doctor himself. Of this I had frequent opportunities of convincing myself, when I met him in Paris in the circle of a Russian family which he daily visited.

If I could admit, with a late ingenious writer, "that phrenology teaches the true nature of man, and that its importance in medicine, education, jurisprudence, and everything relating to society and conduct must be at once apparent," I should certainly agree with him in recommending its study to parents, judges, and juries; but for the present, I am inclined to believe that, although it may prove a most interesting and valuable pursuit to the physiologist, it is by no means calculated to be the _vade mec.u.m_ of any liberal man.

The memory of various persons is amazing, and has been remarked in ancient times with much surprise. Cyrus knew the name of every soldier in his army. Mithridates, who had troops of twenty-two nations serving under his banners, became a proficient in the language of each country. Cyneas, sent on a mission to Rome by Pyrrhus, made himself acquainted in two days with the names of all the senators and the princ.i.p.al citizens. Appius Claudius and the Emperor Hadrian, according to Seneca, could recite two thousand words in the order they had heard them, and afterwards repeat them from the end to the beginning. Portius Latro could deliver all the speeches he had hastily written without any study.

Esdras is stated by historians to have restored the sacred Hebrew volumes by memory when they had been destroyed by the Chaldeans; and, according to Eusebius, it is to his sole recollection that we are indebted for that part of Holy Writ. St. Anthony, the Egyptian hermit, although he could not read, knew the whole Scripture by heart: and St. Jerome mentions one Neopolien, an illiterate soldier, who, anxious to enter into monastic orders, learned to recite the works of all the fathers, and obtained the name of the Living Dictionary of Christianity; while St. Antonius, the Florentine, at the age of sixteen, could repeat all the Papal Bulls, the Decrees of Councils, and the Canons of the Church, without missing a word.

Pope Clement V. owed his prodigious memory to a fall on his head. This accident at first had impaired this faculty; but by dint of application he endeavoured to recover its powers, and he succeeded so completely, that Petrarch informs us he never forgot anything that he had read. John Pico de la Mirandola, justly considered a prodigy, could maintain a thesis on any subject,--_de omni re scibili_,--when a mere child; and when verses were read to him, he could repeat them backward. Joseph Scaliger learned his Homer in twenty-one days, and all the Latin poets in four months.

Haller mentions a German scholar, of the name of Muller, who could speak twenty languages correctly. Our own literary annals record many instances of this wonderful faculty.

To fortify this function when naturally weak, or to restore it to its pristine energy when enfeebled by any peculiar circ.u.mstances, has been long considered an essential study both by the philosopher and the physician. Reduced to an art, this pursuit has received the name of _Mnemonia_; and at various periods professors of it, more or less distinguished by their success, have appeared in the several capitals of Europe.

It has been justly observed, that remembrance is to the past what our sensations are to the present, and our busy conjectures to futurity.

Memory gives a lesson to mankind, by stripping past events of their _prestige_; thus enabling us to view what pa.s.ses around us with a more calm and philosophic resignation, while at the same time it tends to protect us, in the career lying before us, against the many contingencies that are likely to impede our path. Although it might appear desirable that we could obliterate from the mind the painful scenes of our past life, yet the wisdom of the Creator has deemed this faculty as necessary to our happiness as our utter ignorance of our future destiny. For let us mistake not by a hasty glance on this most important subject; the remembrance of past sufferings is not always painful. On the contrary, there is that which is holy in our past sorrows, that tends to produce a calm, nay a pleasurable sensation of grat.i.tude. St. Theresa beautifully expressed this hallowed feeling when she exclaimed, "Where are those blissful days when I felt so unhappy!" _Et olim meminisse juvabit._

Memory depends in a great measure on the vivacity with which these past scenes are retraced--I may say re-transmitted to the mind, in ideal forms "as palpable" as those that may be present. Therefore reminiscence may be said to result from a connexion between ideas and images recalled into being by a regular succession of expressive signs that the brute creation do not possess. Those characteristic signs and images that are generally circ.u.mstantial are co-ordained and cla.s.sified in the mind, and tend materially in weak memories to produce an artificial mode of recollecting the past. This faculty is therefore matured by habit. A literary man, whose library is properly cla.s.sed, will find the book he wants in the dark. The cla.s.sification of his books is ever present to his mind. These circ.u.mstantial signs are always remembered by a sort of a.s.sociation in our ideas. Thus Descartes, who fondly loved a girl who squinted, was always affected with strabismus when speaking of her. When we first see a person in any particular costume, the individual is clad in the same apparel whenever brought to our minds, even after a lapse of many years, when fas.h.i.+on has banished even from general recollection the costume that memory thus retraces individually. From these observations it has been concluded that the most probable method of improving memory would be to regulate these a.s.sociations by a proper cla.s.sification. One link of this ideal chain will naturally lead to another. Many military men, to recollect any number, will a.s.sociate it with that of a regiment, so far at least as the number of regiments extend; and the recollection of this particular regiment will not only bring to his mind the number of the house he seeks, but various other circ.u.mstances connected both with the regiment and the number. For instance, I wish to recollect No. 87 in a certain street. I had, when the number was mentioned to me, attached it to the 87th regiment; and instantly I not only recollect that the 87th regiment are the Irish Fusiliers, but that they took an eagle at Barossa, where they distinguished themselves, and that the figure of that eagle is borne upon all the appointments of the corps. At the same moment, with the rapidity of lightning I recollect all the circ.u.mstances of the battle of Barossa; the different conversations I may have had at various times with the officers of the 87th; the town, the camp, the bivouac where I last had met them. Thus are innumerable circ.u.mstances instantaneously converging in a mental focus while simply seeking for the lodgings of an individual.

This may be called the memory of locality, since it is locality that revives the recollection of it.

This train of thought has also been called the memory of a.s.sociation, and a.s.sociations have been referred to three cla.s.ses:--

I. Natural or philosophical a.s.sociations.

II. Local or incidental a.s.sociations.