still some complaint of headach, which varies much in degree from one day to another, never severe, but never quite gone; the pulse continuing a little frequent. Amid these remissions and aggravations, eight or ten days may pass before the disease has assumed any decided character. It is not perhaps before the sixth or seventh day, that even an attentive observer begins to remark, that the degree of headach, though not severe, is greater and more permanent than corresponds with the general symptoms of fever; that the tongue is becoming clean, the pulse coming down, and the appetite improving, while the headach continues, with an unwillingness to be disturbed, and a degree of oppression which is not accounted for by the degree of fever. In this manner the disease may go on for several days more, until, perhaps about the 12th or 14th day, the pulse suddenly falls to the natural standard, or below it, while the headach is increased, with an evident tendency to stupor. This instantly marks a head affection of the most dangerous character, and the patient now lies for several days in a state of considerable stupor, sometimes with convulsion, often with squinting and double vision. The pulse then begins to rise again, and about this time there is frequently a deceitful interval of apparent amendment, sometimes the squinting goes off, and the eye appears quite natural, the stupor is lessened, and the patient appears easy and intelligent, but soon relapses into perfect coma, and dies in three or four days."

5. The FIFTH FORM of the disease is usually observed in adults, and begins with violent head-ache unaccompanied by fever. The patient lies in bed oppressed and unwilling to be disturbed, or tossing about from the violence of the pain. The pulse is natural, or even below 60—face sometimes flushed, sometimes pale-eye sometimes natural, in others morbidly sensible, with contracted pupil. The headache is usually acute and deepseated, frequently appearing to shoot from temple to temple, or is referred to one ear. Sometimes vomiting occurs. Delirium frequently appears at an early period, varying in intensity from day to day, till, in five or six days, it passes into coma, the pulse continuing from 70 to 80 all the time. Sometimes the vision is unaffected-sometimes there is squinting with double vision. These latter symptoms occasionally disappear to return no more, but the disease goes on to a fatal termination. In every case, there is more or less delirum; but sometimes it is slight and transient. This condition, when unaccompanied by fever, is always characteristic of a dangerous affection of the brain. The speech is sometimes embarrassed, apparrently from want of recollection of words. There is generally more or less of coma towards the close of the disease.

In all these forms, there is a great variety in the symptoms, and much attention is necessary, in order that the practitioner may not be thrown off his guard against the nature of the insidious disease. "Even in those cases which have assumed the most formidable aspect, every alarming symptom may subside," and during a deceitful interval, we indulge sanguine hopes—nay, the patient will sometimes dismiss his medical attendant. He falls into a drowsy state, which is considered favourable-he then sleeps almost constantly-and, in another day this sleep terminates in coma!

In this description, our author informs us that he has been entirely PRACHe has not stopped to inquire whether all these forms are to be considered as primary idiopathic affections of the brain-or whether some

TICAL.

of them may be looked upon as secondary or symptomatic. There can be no doubt that many of them are secondary, supervening on other diseases, especially on continued fever-scarlatini-hooping cough-measles-pneumonia-phthisis, and diseases of the kidney. The following is a brief summary of those symptoms which, in the course of any disease, indicate a tendency to dangerous cerebral affection.

"IN THE HEAD.-Violent headach with throbbing and giddiness-tinnitus-sense of weight and fullness-stupor-a great propensity to sleep. In many obscure and insidious cases, a constant feeling of giddiness is the only remarkable symptom.

"IN THE EYE.-Impatience of light-unusual contraction or dilatation of the pupildouble vision-squinting--blindness-distortion of the eyes outwards-paralysis of the muscles of the eyelids, producing, according to the muscle that is affected, either the shut eye, or the gaping eye-transient attacks of blindness or double vision-objects seen that do not exist-a long-sighted person suddenly recovering ordinary vision.” "IN THE EAR-Transient attacks of deafness-great noise in the ears-unusual acuteness of hearing.

"IN THE SPEECH-Indistinct or difficult articulation--unusual quickness of speech, or unusual slowness.

"IN THE PULSE.-Slowness and remarkable variations in frequency.

"IN THE MIND--High delirium-transient fits of incoherence-peculiar confusion of thought, and forgetfulness on particular topics.

"IN THE MUSCLES.--Parlytic and convulsive affections-sometimes confined to one limb, or even part of a limb; and a state of rigid contraction of particular limbs.

"IN THE URINE.-There frequently occurs a remarkable diminution of the secretion-sometimes nearly amounting to complete suppression; and connected with this diminution there is often a frequent desire to pass urine, occasioned probably by the increased acrimony, as the quantity diminishes."

So much for symptomatology-an important division of the study of diseases. We have presented a very full view of this part of our author's work, as it may prove a useful reference in the hurry of practice. We must now proceed to the second section, embracing the seats and terminations of the disease.

SECT. II.-SEATS AND TERMINATIONS.

The varieties in the seat of the inflammation, may be referred to the following heads-dura mater-pia mater and arachnoid-substance of the hemispheres-dense white matter forming the central parts of the brain. In respect to the terminations, the disease may end fatally in the INFLAMMATORY STAGE, whether the inflammation be seated in the brain itself or in its coverings. In the most distinctly marked cases of such early termination, however, the phlogosis has been found in the cerebral substance. The other terminations are, as mentioned a few pages back, by SEROUS EFFUSION DEPOSITION OF FALSE MEMBRANE-SUPPURATION--SOFTENING. On each of these terminations, the author makes a few remarks, and then proceeds to illustration by numerous cases.

1. Serous Effusion. Too much importance was attached to this by the earlier investigators, as if it alone constituted the disease called acute hydrocephalus. The symptoms were ascribed to the compressing influence of the effused fluid, and the practice was consequently directed to the removal of the effect, while the cause was neglected. It is now very generally admitted that the effusion in acute hydrocephalus is one of the terminations of inflammation, though there are certainly other causes from which serous effusion in these parts may arise.

Increased effusion from a serous membrane appears to take place under two very different conditions of the part. FIRST-from inflammation of the membrane itself or ajacent structures, as we see in the cavities of the pleura and peritoneum. The effused fluid varies very much, being limpidopake, milky, flocculent, or nearly purulent. Who can tell on what these varieties depend? Dr. A. does not seem inclined to undertake this taskbut he thinks we are authorised to conclude, that these various fluids, which are found in the head as well as in other cavities of the body, are the products of inflammation, in all those acute affections included under the term

ACUTE HYDROCEPHALUS.

But there is another source of serous effusion entirely distinct from the above, viz. interruption of venous circulation. In this manner, we see a tightly bandaged limb become œdematous below the seat of pressure—and anasarca of the whole or part of a limb produced by the pressure of tumours-while ascites results from induration of the liver. Such a state of impeded circulation evidently takes place in the brain, from a variety of causes; such as pressure of tumours, chronic disease of the sinuses, tumours on the neck, certain diseases of the lungs and of the heart-and, probably, from that very remarkable condition of the brain, to which I have proposed to give the name of simple apoplexy." From serous effusions produced by such causes as these, probably arise those affections which have been called CHRONIC HYDROCEPHALUS, and serous APOPLEXY.

2. Deposition of False Membrane. This is a product of inflammation as well ascertained as effusion. It is found sometimes between the dura mater and bone-sometimes between the dura mater and arachnoid-but most commonly it is under the arachnoid, where it is often found of great extent communicating a yellow colour to a considerable surface of the hemisphere. It is occasionally found within the ventricles, covering the surface of the choroid plexus-and a very common seat of it is the upper surface of the tentorium.

3. Suppuration. A thin uniform layer of puriform matter is often found under the arachniod, and occasionally betwixt the arachnoid and the dura It is also to be met with mater, or even betwixt the dura mater and bone.

in distinct small cavities formed by partial adhesions of the membranes to the bone or to each other. It is occasionally found in the ventricles.

5. Ramollissement. We think Dr. A might just as well have used the English term SOFTENING, as the French one ramollissement, which conveys precisely the same meaning. This morbid condition of the brain consists in a part of the cerebral substance being broken down into a soft pulpy mass, retaining its natural colour, but having lost its cohesion and consistence. It differs entirely from suppuration, having neither the colour nor the fetor of pus-for the white parts of the brain, in which it is most commonly observed, retain their pure miky whiteness. The corpus callosum, fornix, and septum lucidum, are the more usual seats of this peculiar disorganization.

In former communications, Dr. A. noticed this disease, and had no hesitation in attributing it to preceding inflammation. Since that time, the subject has undergone laborious investigation by the French pathologists, some of whom, especially M. Rostan, look upon this affection of the brain as one sui generis-sometimes, but not generally, the result of inflammation. Dr. A. now thinks that it occurs under two modifications, differing essentially from each other.

"In the cases of M. Rostan, the disorganization was observed chiefly in the external parts of the brain; it occured almost entirely in very old people, few of his cases being under sixty years of age, many of them seventy, seventy-five, and eighty. It was found in connexion with attacks of a paralytic or apoplectic kind, many of them protracted; and was often found combined with extravasation of blood, or surrounding old apoplectic cysts. On the contrary, the affection which I had been anxious to investigate, was found chiefly in the dense central parts of the brain, the fornix, septem lucidum, and corpus callosum, or in the cerebral matter immediately surrounding the ventricles; and occurred in persons of various ages, but chiefly in young people and children. It took place in connexion with attacks of an acute character chiefly the character of acute hydrocephalus; and it was in many cases distinctly combined with appearances of an inflammatory kind, such as deep redness of the cerebral matter surrounding it, suppuration bordering upon it, and deposition of false membrane in the membranous parts most nearly connected with it. We may even observe in different parts of the same diseased mass, one part in the state of ramollissement, another forming an abscess, while a third retains the characters of active inflammation, and probably exhibits, as we trace it from one extremity to the other, the inflamed state passing gradually into the state of softening. Remarkable examples of this will be given in the sequel, and another of a different nature, in which an opening in the septum lucidum produced by the ramollissement, was entirely surrounded by a ring of inflammation. This is the affection which I have endeavoured to investigate, and which I consider as one of primary importance in the pathology of acute affections of the brain, and upon the grounds now shortly referred to, I cannot hesitate to consider it as a result of inflammation."

These facts being compared with the observations of M. Rostan, Dr.A thinks we may arrive at a principle by which the apparent difference may be reconciled. Dr. A. considers the peculiar softening of cerebral matter as analogous to gangrene in other parts of the body—and that, like gan grene, it may arise from two very different causes-inflammation, and failure of the circulation from disease of the arteries. The former (phlogosis) Dr. A. conceives to be the origin of the affection which he has described -and the latter (defect of circulation) to be the source of the appearances

described by M. Rostan. If this doctrine be admitted, the difficulty is removed. Gangrene from inflammation is familiar to every one--and equally familiar, though very different in origin and concomitant symptoms, is gangrene from a diseased state of the arteries. Ossification of the cerebral arteries is very common in elderly people--and, indeed, M. Rostan distinctly points to this, as the cause of his, ramollisement. In young people, however, and after acute diseases, we may fairly attribute the phenomenon in question to inflammation. It is often combined with suppuration in other parts of the brain, and still oftener with effusion into the ventricles. In some cases it is, however, confined to a very small spot, as the septum lucidum and fornix, without any other disease in the encephalon.

6. Chronic Form of Encephalitis. Among the terminations of the chronic form, we may remark thickening of the membranes, contraction and obliteration of the sinuses, caries of the bones, and some other affections of the external parts. In respect to acute hydrocephalus, we cannot but admit, that the serous effusion is only one of the terminations of that inflammatory condition of the brain. Some of the other terminations are scarcely less frequent-especially the softening of the central parts, which is sometimes met with as the only morbid appearance, and is found combined with the effusion in a very large proportion of the ordinary cases of hydrocephalus. Other cases, in which the symptoms closely resemble those of hydrocephalus, will be found to terminate by the undefined suppuration, or by this combined with serous effusion, or with the ramollisement of the central parts. In fact, we but seldom meet with any one of the terminations uncombined—and it is impossible to anticipate, by the symptoms, in what way the inflammation may terminate in any given case.

Of these various terminations, Dr. Abercrombie has given numerous examples-these cases occupying the greater portion of the volume under review. It is not our intention to attempt the exhibition of any specimens of the cases. We shall entirely confine ourselves, in this analysis, to an enumeration of principles and precepts.

MENINGITIS. Passing over the illustrations of inflammation of the dura mater, one instance only of which, as purely idiopathic, has been seen by our author, we come to inflammation of the arachnoid and pia mater, from which we shall extract the following passage.

"Inflammation of the arachnoid, and of the pia mater, may be taken together. It is very difficult to distinguish them in practice, and as the affections are generally combined, it is probable that no important purpose can be answered by attempts to discriminate between their symptoms. The disease terminates most commonly by a deposition of false membrane betwixt the arachnoid and the pia mater. When this this is found to spread uniformly over the surface of the convolutions, we may suppose that it has been produced from the arachnoid; when it dips considerably between them, it is probable that the pia mater has been affected; but, in point of fact, it is very often remarked in these cases, that the pia mater presents a most VOL. VIII. No. 16. 45