of the moft ftately trees, that have never probably felt the a*, and are cœeval with the creation. Such is the entertainment which Mr. Pennant has prepared for the public taste. It con fifts of a variety of dishes, highly feafoned with the rich fpices of India; and out naturalift has alfo ferved up a defert from its luxurious garden, upon which we have no doubt the curious in its produce will banquet with unfatiated appetite.

ART. XIII. An Inquiry into the Nature and Origin of Mental Derangement; comprehending a concife Syftem of the Phyfiology and Patheology of the Human Mind; and a Hiftory of the Paffions, and their Effects. By Alexander Crichton, M D. Phyfician to the Weftminster Hofpital, and Public Lecturer on the Theory and Practice of Phyfic, and on Chemistry. Two Vols. 8vo. 129. Cadell and Davies. 1798.

HE task the author has impofed upon himself is one of the

THE

moft difficult that could have been felected from the wholerange of human fcience; it is what has never yet been completely performed, as he rightly obferves; nor, in our prefent ftate of knowledge, does it feem to be within the scope of human power to accomplish it. For where will the man be found who is capable, to ufe our author's words, Preface, p. 9,

"Of abftracting his own mind from himself, and placing it before him, as it were, fo as to examine it with the freedom, and with the impartiality of a natural hiftorian; to take a calm and clear view of every caufe which tends to affect the healthy operations of the mind, and to trace their effects; to go back to childhood, and obferve how the mind is modelled by inftruction?”

And yet,

"He who cannot do this," the author goes on to fay, "will never proceed farther in knowledge than what he has acquired by books, or by tuition; and how very limited this knowledge is, in regard to the pathology of the human mind, need not be mentioned."

If the author therefore has failed in accomplishing this object, no blame will attach to him on that account; he has failed where no one has, or perhaps ever will fucceed; and as fome benefit may incidentally arife from the attempt, for that advantage, which is by no means trifling, he will be entitled to thanks. Previous to entering on his fubject, the author gives an account of irritability and its laws. This occupies the first chapter, and fills 52 pages. But as irritability has been largely

treated

treated of by Brown, Darwin, and other late writers, and as we perceive little new on the fubject, we fhall pass to chapter the fecond, which treats of fenfibility.

The impreffions made by external objects on our frame, are, according to our author, of three kinds, or rather have three Itages. The impreffion on the extremity of the nerves, a correfpondent or confequent impreffion thence made on the brain, and the impreffion made by the brain on the mind. The first the author calls nervous impreflion; the fecond fenforial impreffion; the third mental perception. As impreffions are communicated from the extremities of the nerves to the fenforium, and thence to the mind, fo the mind acting on different parts of the fenforium, puts in motion thofe parts of the body whofe action depends upon the part acted upon. The author next inquires into the manner in which external bodies act in producing nervous impreffion. After examining the different theories that have been promulgated on this fubject, he concludes that it is by means of a fluid contained in the nerves, but does not think it neceffary that this fluid fhould poffefs any remarkable tenuity or finenefs (p. 67), as thofe authors fuppofed, who imagined' it might be æther, or the electric fluid; neither does he think it must neceffarily be contained in tubes or veifels, it is fufficient that it be continued from one extremity to the other of the nerve; neither is it neceffary that the particles of this fluid thould be in actual contact, or touch each other, it is fufficient that they be fo difpofed as to be each of them fenfible of any impulfe given to the particle before or behind it. This fluid is fuppofed to be fecreted by the brain, and to be the medium through which all impreffions are communicated, from the extremities of the nerves to the fenforium, and thence to the mind. The difference in our fenfations by which we diftinguith one object from another; arifes from the varied and different impreffions made by external objects on the extremities of the nerves. As this fluid must be wafted or expended by long continued action, or recruited by rest, and added nourishment, hence fenfibility may be weakened or diminithed, increafed or accumulated, in the fame manner as irritability is found to be. Next follow dif fertations on the fenfes of tafte, fmell, touch, hearing, and feeing. Thefe are examined and explained with confiderable ingenuity, but will not bear being compreffed into fuch a space as would fuit our mifcellany. We thal! pafs. therefore to chapter the third, p. 110, which treats of the fenfe called caenefthefis, or felf-feeling. Tais includes all the impreffions made, or fenfations felt, from the action of bodies of any X.

BRIT. CRIT. VOL. XII, SEPT. 1798.

kind

kind upon the extremities of the nerves of the ftomach, liver, bladder, uterus, &c. whether fuch fenfations be pleasing or painful. When the ftomach is fatisfied, and the organs of the body are in a healthy and found ftate, we are cheerful, alert, lively; when the contrary, dull, heavy, melancholy. For this part the author acknowledges himfelf to be indebted to Mr. Hubner, and other German writers, who have treated the fubject at confiderable length. The fame object is continued through the next chapter to p. 136; and the arguments, illuftrated with examples, the latt of which, from Meibomius de ufu flagrorum, as it was not neceffary to explain the author's. ideas, and is extremely indelicate, might have been omitted. Having got over this preliminary matter, the author proceeds, in chapter the fifth, to give a methodical inquiry into the nature and phyfical caufes of delirium, particularly the deli rium of lunatics."

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"All delirious people," he obferves, " differ from those in a found mind in this refpect, that they have certain difeafed perceptions and notions, in the reality of which they firmly believe, and which confequently become motives of many actions and expreffions which appear unreasonable to the reft of mankind;"

and which we prefume the author means to fay, are actually extravagant and unreasonable. The author thinks the term difeafed perceptions, or notions, better than erroneous notions, which other writers have ufed; "becaufe," he fays, p. 138, "the ideas in all kinds of delirium whatever arife from a difeafed state of the brain or nerves, or both." That is, the inftrument or organ being difeafed, every thing proceeding from it must be fo likewife. This feems reafonable; but marks of injury have been found in the brains of perfons who never were delirious or maniacal; and the brains of perfons who have died maniacal, have been found to be very little altered from a healthy ftate, or the difeafed appearances have been fuch, as feemed rather the effects than the cause of the deJirium. The term erroneous also appears more applicable to perverfe and wrong ideas than difeafed, which feems to require a fubftratum, or fomething more fubftantial than a notion for its habitation. Having fettled the definition of delirium, and confidered it in its various modifications, as it appears in different perfons, the author proceeds to investigate its caufe. This he thinks confifts in the diseased action of the fibrils of the brain, or, to ufe his own words, p. 168, "it must arise from a peculiar morbid action of the vellets which fecrete nerYous matter, efpecially the fluid in queftion." Nervous difcafes, and maniacal affections, have always been ranked among

them;

them; have, at all times, been attributed to fomething injuring the brain, and thence difturbing its functions, or to fome depravity of the nervous fluid, our author, adopting the modern phyfiology, thinks they should be attributed to "a fpecific difeafed action of the fine veffels which fecrete the nervous fluid in the brain." P. 174. In the fame manner, we prefume, as one fpecies of difeafed action is fuppofed to produce fcrofula, another to propagate fiphylis, &c. If our author thinks he has a clear notion of what he means by a specific diseased action, we have no objection to his ufing the term, but we see no relation between the cause and the effect; that is, we can no way conceive or account, why any modification of action or motion in the fibrils of the brain, thould make one man imagine he fees bears, lions, or devils, rufhing upon him, or another conceive that his father, brother, or wife, intend to poifonor ftab him. We must alfo obferve, that neither the exiftence of a nervous fluid, or of the specific action of the fibrils of the brain, here contended for, have been, or, we believe, are capable of being demonftrated.

Chapter the fixth contains the hiftory of hypochondriasm. The feat of this disease is generally found to be in the stomach, or fome other of the abdominal vifcera, and it is occafioned by a morbid fenfibility of the nerves.

"It is alfo often brought on," our author obferves, p. 200, "by affections of the mind; fuch as deep and long continued grief and melancholy. These mental affections produce hypochondriafis, by creating a diforder in the ftomach and inteftines, and in the nervous fyftem; fo that in every inftance it arifes either directly or indirectly from this fource."

Accounting for the illufions of hypochondriacs, the author obferves, p. 208,

"That the fources of almost all our perceptions, while we are in health, lies in external objects; for the nerves of the external fenfes are the only ones of our whole frame which convey clear impreffions to the intellectual part. Hence we acquire a natural habit of afcribing all ftrong impreflions to fome external caufe. In cafes, therefore, where the caufe of the fenfation cannot be examined, a falfe judgment may easily atife. The languor and pain, and various uneafy fenfations which a hypochondriac feels, naturally withdraw his attention from furrounding objects, and as the exercife of his judgment is weakened by the fame circumstances, he does not examine the unreasonable ideas with accuracy when they are first prefented to his mind. Painful feelings are affociated with melancholy thoughts; and new and uncommon feelings, upon the fame principle, are afcribed to strange and ancommon caufes. The weaknefs therefore which a hypochondriac feels in his limbs, makes him imagine they are unable to fupport him; but if they cannot do fo, he concludes they must bend or break; the idea of fragility or flexibility however is often derived from fuch fubftances

X 2

as wax and glass, and he therefore believes that his limbs are made of fimilar materials."

This chapter is concluded with a variety of appofite cafes, which illuftrate this explanation.

The fecond book contains the natural history of the mental faculties, with defcriptions of the difeafes to which they are fubjected. In the firft chapter of this book, the author fhows that mind or spirit is forething distinct from body or matter, by nearly the fame arguments Mr. Locke has ufed; which he farther illuftrates, by introducing examples of perfons far advanced in years, whofe bodies were enervated, but whofe minds ftill preferved their full vigour and energy, which could not happen, he thinks, if they were one and the fame fubflance. In the next chapter the author treats of attention and its difeafs.

"When any object of external fenfe or of thought, occupies the mind in fuch a degree that a perfon does not receive a clear perception from any other, he is faid to attend to it. The principle that is excited in his mind by a perception or thought, is commonly called the faculty of attention; a faculty," the author goes on to obferve, p. 254, which may be justly faid to be the parent of all our knowledge."

46

We cannot help here noticing, that the author treats of attention prior to perception, which latter is the fubject of the next chapter; and yet it is evident, an object mult be perceived before we can attend to it. There feems an impropriety in calling attention a faculty, as it implies the exercife of all the faculties of the mind conjointly. When a perfon is faid to be attentive or to pay attention to an object, we mean he confiders, thinks, or reflects upon it, examines it, investigates its properties, compares it with other objects, to find its affinity or difcrepancy. To keep the mind fixed upon an object as it at first prefents itself, without confidering its qualities, relations, and dependencies, is rather a mark of idiotifm than of fanity. Children and perfons of weak understanding do not attend, because they are incapable, or not uf d to reflect. And this feems confonant to our author's idea of attention, as he calls it the parcut of all our knowledge."

Chapter the third treats of mental perception and its difeafes.

"When an object acts on any of the nerves which fupply the organs of external fenfe, and our attention is not strongly engaged at the time by any other object, we immediately become contcious of the prefence of the external body, and we obtain a mental perception, or reprefentation of it."

As Doctor Reid entertained different ideas of the manner in which external objects are represented to the mind, to those - laid down in this work, our author thought it neceffary to exa· 5. mine