suggest to him, that a little more equality in the allotment of his references would be a material improvement in a future edition; several diseases of considerable importance being dismissed with: very slight notice, while others, comparatively insignificant, are almost overwhelmed with a profusion of authorities. The author has arranged the different accounts which have been given of the yellow fever, under three different genera, cauma, synochus, and anetus; we are rather disposed to believe that the disease is always essentially the same, and dependent on paludal effluvia. He has followed Dr. Crichton in suppressing the order of the exanthemata; an innovation, which has produced some difficulty in the arrangement of scarlatina, measles, and small-pox, diseases which certainly do vary in the type of the fever attending them, in such a manner as to require some other generic character, than can be derived from the nature of that fever alone: we do not deny that some of these difficulties are almost unavoidable; but we trust that something more may hereafter be done for overcoming or diminishing them, than our author has hitherto effected.

The remaining division of the work, referring to the means to be used for the removal of disorders, differs but little in its arrangement from that which is usually admitted into all later systems of therapeutics. The sub-divisions are established upon the acknowledged agency of pharmaceutical means. Posology has been usefully annexed to this part of the subject; and there are added, as intimately connected with pharmacy, the very ingenious tables of chemical affinities, constructed by Dr. Young, and already published in the Philosophical Transactions.

The extensive range of the author's literary attainments has, enabled him to give us a translation of some of the Swedish works of Professor Berzelius, upon animal chemistry, and the laws of chemical combinations. This compendium contains the chief of what has been discovered upon the subject so interesting and important to a medical philosopher. The authorities upon which the facts and opinions rest are historically detailed, together with the corrections afforded by the arguments and experiments of the professor, and the discoveries which he has made in this department of chemistry. The name of Berzelius is a sufficient surety of the value of this treatise.

Two essays, by the author, close the volume, the first containing remarks on the measurement of minute particles, especially those of blood and pus, and the last on the medical effects of cli

mates.

The observations and discoveries in the former are not only relevant and subservient to physiology, but, in a more especial manner, to pathology, by the suggestion of an easy mode of distinguish

ing morbid from natural secretions. It has always been a desideratum with medical practitioners to obtain some test of the difference between pus and mucus; as being the products of different states of the secerning vessels. Most of the chemical methods, which have been pointed out, have been found in practice insufficient or inconvenient. Dr. Young, however, has invented an optical test of a decisive power, and of easy application. The optical discoveries which led to this invention, and to the present observations, were read before the Royal Society in July, 1802, from a paper by the author, entitled, An account of some Cases of the production of Colours, not hitherto discovered.' Having given a test, applicable to all cases of minute particles held in suspension in transparent fluids,' he proceeds to observe, that

'Where the greater number of the particles are nearly equal in dimensions, a luminous object, viewed through them, is surrounded by rings of colours, somewhat resembling those of the rainbow, but differently arranged, and often beautifully brilliant. The blood, a little diluted, always exhibits them in great perfection, and they afford a very accurate criterion for the distinction between pus and mucus. Mucus, containing no globules, affords no colours, while those which are exhibited by pus exactly resemble the appearance produced by the blood, the rings being usually of the same dimensions.' A minute quantity of the fluid, to be examined in this manner, may be put between two small pieces of plate-glass, and if we hold the glass close to the eye, and look through it at a distant candle, with a dark object behind it, the appearance, if the globules are present, will be so conspicuous, as to leave no doubt respecting their existence.'-P. 547.

This discovery he has further improved, by rendering it applicable to the measurement of the fibres of wool, hair, and other substances employed in manufactures; the construction of an instrument for this purpose is next described, and its uses explained. These principles and optical observations are employed also for the solution of some microscopical, optical, and meteorological phenomena.

The essay on the medical effects of climates will be read with equal eagerness and advantage by medical practitioners, and by those whose health requires them to consult the means of obviating the effects arising from the variableness of the weather. It contains all that can be said for their information in a medical point of view, and is replete with judicious remarks. These are grounded on philosophical observations, and are urged with much force.

The stile throughout is clear and polished; refined without affectation, and easy without the sacrifice of dignity and correctness. It may be regarded both as an example and incitement to the introduction of a more finished mode of writing in medical compositions. We are not pronouncing too favourably of this work,

when

when we express our confidence that, stored with such valuable learning and information, and enriched with such advantages of method and composition, it will not only be resorted to as a direction to students, but will find its way, as a book of reference, into the hand of the enlightened physician. It is no less a guide to youth, than a staff to age; and both descriptions of practitioners are under great obligations to the author for this productive effort of talent, labour, and erudition.

ART. VIII. The New Art of Memory,' founded upon the Principles taught by M. Gregor Von Feinaigle, illustrated by Engravings. 8vo. London, Sherwood. 1812.

6

6

Dr. R. Grey's Memoria Technica, or Method of artificial Memory. To which is subjoined Lowe's' Mnemonics, 9th Edit. 8vo. London. 1812.

ΤΟ

TWO years have elapsed since we first heard of Mr. Feinaigle's lectures upon Mnemonics and Methodics' in this country; but the treatise which professes to explain the principles of his art, has but just appeared. There is a general disposition in the public to suspect some latent quackery even in the best parts of such systems; and it would be difficult to avert the scepticism of those, who are impatient of means, as well as of effect. It has been frequently remarked that the characteristics of memory, are, susceptibility, readiness, and retention. The palpable inequality with which these properties are meted out to different individuals, would encourage the hope that the deficient qualities may be materially supplied by the intervention of mechanical aid, founded upon philosophical principles. Those who have susceptible and ready memories, but whose minds are indisposed to habits of method and classification (so favourable to the retention of acquired knowledge) should impose upon themselves the adoption of philosophical arrangement. Those, on the other hand, whose minds are only inclined towards abstraction and arrangement, should not hesitate to supply the want of a susceptible and ready memory, by those helps which ingenious men have invented for the purpose. No method of assisting the memory can be popular, unless its object be to direct and apply those faculties, whose exercise appears to be involved in every effort of memory; nor should we doubt that as the body may be trained to extraordinary feats of strength and agility by the pursuance of a system adapted to give free scope to the powers of muscular action, so the judicious direction of those mental faculties, by whose agency the mind is competent

to

to perform certain offices, cannot fail to give superior efficiency to its powers. The most approved philosophy asserts the dependence of memory upon two leading principles, attention, and the association of ideas; it follows, therefore, that whatever tends to concentrate attention, and to command and direct associations, may very essentially contribute to its improvement.

Objects perceived by the eye are remembered more easily than by any other of our senses, in proportion as the impressions of sight are more rapid and numerous. We comprehend the infinite variety of a prospect in a momentary glance, and the imagination can revive the picture; but a verbal description of it would be tedious, and the impression faint: on this principle geography is taught by maps, geometry by diagrams, and architecture by drawings. The most casual observation was sufficient to prove the constant association of ideas with sensible objects, and the effect of these objects in recalling to the mind former ideas. This naturally suggested the hint of a topical memory, which should encourage an association of ideas with visible objects, arranged in order; and as these objects were at will summoned before the imagination, they would naturally bring with them the ideas with which they had been previously associated, and without confusion, as we shall presently demonstrate. We find in Quintilian the following minute account of the topical memory* in use among the

ancients :

They (the students of topical memory) become intimately acquainted with the arrangement of particular situations of considerable extent, for instance, of a spacious mansion divided into many apartments; every marked object contained in this building is attentively impressed upon their mind, that the memory may recur to the individual parts of it, without the smallest delay or hesitation.

In the next place, whatever they have written, or reflected on, they connect with a casual association, by which they may be reminded of it.

This association may either relate to universals, as for example, to navigation or war, or to particular words; for if they lose the train of their ideas, they are enabled to recover them, by the prompted suggestion of one individual word, whether this be the type of navigation, as an anchor, or of war, as a particular weapon; they therefore arrange these objects of association in order, and assign the first place, or the first idea, which they wish to remember, to the portico, the second to the hall; then they go round the inner courts: nor do they only commit these associations progressively to the bed-rooms and antirooms, but even to their furniture. When they have performed the

Many interesting remarks on this subject occur in Cicero, who describes the ap plication and advantages of this artificial mode of assisting the memory, with great neatness and perspicuity.-Rhetor. lib. iii. 16.

circuit,

circuit, and are anxious to recollect the associations, they recur mentally to those places in order from the beginning, they regain every sensible type which they had entrusted to each particular spot, and this type at once suggests the idea connected with it.'

In considering this scheme of topical memory, we must advert to an extraordinary property of the mind, viz. that without a certain degree of volition, these associations will not operate. If we were unconsciously to revisit a scene, which had once been familiar to us, but of which we only retained a general impression, we should probably pass by a number of objects, to which our attention might be partially or even earnestly directed, without experiencing the revival of any ideas; but if at last we discovered where we had been, and retraced our steps with anxious curiosity, those objects which in the first instance had not awakened any ideas, would inevitably arouse our dormant associations, when the mind was exerting a particular act of volition. We were induced to remark this property, with the view of anticipating an objection, that the association of an infinite variety of trains of thought with the same series of objects, would be liable to generate confusion; whereas the volition of the mind to pursue a particular train of thought, of itself awakens the ideas belonging to that train, and this without confusion or mistake. It is from this principle in the constitution of our minds, that we are enabled to recollect an infinite number of lines in poetry, of the same measure and subject, or to remember distinctly a variety of tunes, which are in the same time and key, and which correspond in general effect of harmony. If an orator had associated a series of arguments upon a particular question of law, with a series of apartments, and at the same time had also associated a series of arguments upon a political question, there would be no danger of confusion. The volition which the mind would exert in the first instance would suggest the first train of associations, distinct and separate, and equally so in the second case; in fact, if the two arrangements were both upon legal points not essentially different, the train would not even then be confused.

We have long been disposed to think that it would be impossible to convey in writing an adequate and practical explanation of the system of mnemonics arranged by Feinaigle.* The present publication, which is illustrated by plates and diagrams, and is not deficient in merit, tends to confirm our opinion. If we attempted to define this system, we should call it, a method of re

*We could not say 'invented,' for a reference to a work published in 1617, entitled, Ravellini Ars Memoriæ,' will convince the reader that he has few claims to invention.

calling