cap, some effusion of lymph was found under the arachnoid membrane covering the left side of the brain, along with turgescence of that, and the other hemisphere; both divisions being pale, and exhibiting a watery aspect, although their texture was firm and compacted. The ventricles of the brain seemed large, particularly the left; and about two ounces of serum were effused in these cavities; the foramen commune being at the same time larger than natural. The arachnoid tissue extending over the pons Varolii adhered to the parietal layer of that membrane; but no tumour, or any other change of structure was found either in the brain or cerebellum, excepting that the latter organ appeared anemic, and rather softer in texture than ordinary.

On opening the thorax, every part seemed quite healthy, although the pleura pulmonalis on the left side of the chest, adhered firmly to the pleura costalis, by a few strong bands, some of which were apparently of considerable standing. The abdominal viscera likewise appeared very little changed from their natural condition, the liver, stomach and intestines being free from disease: with the exception of the kidneys, which were somewhat enlarged, anemic, and exhibited marks of chronic inflammation on the internal membrane of the pelvis and infundibula. The omentum and some of the small intestines also adhered to the bladder by strong bands, whilst that viscus was much diminished in magnitude, felt very hard to the touch, and on cutting into its cavity, it actually appeared not

larger than the interior of an ordinary sized walnut, its muscular coat being unusually thickened. The mucous membrane was dark-coloured and rugous on the surface.

Having carefully laid open the vertebral column, throughout its whole length, the theca, corresponding to the three or four lower cervical vertebræ, was found to be much distended; and on being cut into, the arachnoid cavity, with the sub-arachnoid tissue, appeared filled with lymph, which evidently had been some time effused; as the membranes were thereby united to each other, and also to the cord. On making a more minute examination of the parts, the adhesions of the membranes to the cord were discovered to be much firmer at its anterior, than posterior portion; indeed, they were actually so strong, as to be inseparable from the medulla without rupture. At this particular part, the medulla also appeared larger than usual, felt soft and pulpy to the touch, and on being divided by the knife, its substance seemed to be in an almost diffluent state, infiltrated with serum, but exhibiting a natural colour. For the extent of half an inch above the point just described, the cord had a dusky red tinge, appearing however, of the ordinary consistence. In the anterior and posterior columns, not much difference was observable to the naked eye, at the first superficial examination of the diseased part of the medulla; although both divisions of the cord seemed considerably softened, infiltrated and disorganised, particularly in the posterior columns; whilst as well above,

as below the affected portion, the medulla was healthy, and quite natural in appearance.

Since it is often very difficult by the ordinary means of investigation, to describe accurately all the minute alterations of structure, which disease may induce in so delicate a texture as the spinal cord, the microscope becomes an important auxiliary to scientific anatomists. Indeed, without the aid of that useful instrument, it would in many cases be difficult, if not impossible, to ascertain correctly the actual pathological changes of structure, which have taken place in that organ, so as to be able to explain the phenomena and symptoms characterising cases like the one now under consideration.

Fortunately on the present occasion, such a desideratum has been supplied; as I am enabled to exhibit to the Fellows of the Society, not only the diseased portion of the cord, but likewise to add a minute and valuable account of its microscopical examination, which that able physiologist, Professor Todd, of King's College, has had the kindness to make, for the express purpose of being appended to the present communication. In the letter that gentleman did me the honour to write, after examining the diseased part of the medulla transmitted to him for investigation, he says, "The portion of spinal cord submitted to me by Dr. Webster, appears to consist of the greater part of the cervical segment. I find great destruction (from softening) of the medullary substance of the posterior columns, especially

that of the right side; the antero-lateral columns seem to have been also the seat of the softening process to a less degree, but I do not find that they have suffered any loss of substance. In examining the softened parts by the microscope, I detected very few of the proper nerve-tubes; and those which I did observe, were much altered from their natural appearance; they had become opaque, and had assumed an indistinctly fibrous aspect. I was unable to find any trace of grey matter. The posterior horns must have shared in the great destruction of the posterior columns, and probably the anterior ones experienced a similar fate. It is right, however, to observe, that the specimen had been preserved some time in spirits, before it came into my hands. I found throughout the diseased part, numerous small scales, (cholesterine ?) such as are very commonly met with in portions of the nervous centres preserved in spirits."

Dr. Todd then makes the subsequent very important remarks:-"I consider this case of the greatest physiological interest, as affording unequivocal proof, that the posterior columns cannot perform the office assigned to them by some physiologists, namely, that of conducting sensitive impressions to the brain, or at least, that they are not the only channels of this communication. It is also important in an anatomical point of view, as showing that the posterior roots of the nerves are independent of the posterior columns of the spinal cord; for although the latter were destroyed

to so great an extent, the former did not appear to have suffered in any degree."

Observations. This instructive and interesting example of disease of the nervous system excited, as it well might, much attention in all those who witnessed its progress; and they, along with myself, confidently hoped, that the pathological appearances met with on dissection would be such as to explain satisfactorily the rationale of the peculiar symptoms, which the malady exhibited during the patient's protracted and severe sufferings; more especially, in regard to those remarkable features characterising the case, namely, that whilst sensation remained unimpaired, voluntary motion was totally suspended. Because, should these anticipations be realized by the post mortem examination, some important pathological facts, worthy of being recorded, would thereby be added to the points already established, as well regarding the actual seat, as likewise the courses of transmission of those functions. The autopsy, with the microscopical inspection of the diseased part of the medullary cord now given, although they sufficiently account for the loss of motion, do not explain why the patient's sensations remained not only unimpaired, but even appeared to be more acute than natural.

Physiologists might undoubtedly urge, since there appeared more indications of inflammation having existed in the anterior than in the posterior columns of the cord, as shown by the firmer adhesions of the membranes to them and to each other, at the