B. Other inflamed spots, again, are found deep in the brain, and especially in the white substance, in which the softening, above described, is wanting, and hardness and resistance are the prominent characteristics. This does not appear to depend upon any induration (sclerosis) of the portion of brain which is involved in the inflammation, for it has undergone the same destruction when found in this condition as when softened, at least, in that most important particular, the forcible separation and breaking-down of its elementary structures; but its increased consistence arises from the coagulation of highly plastic fibrinous imflammatory products, and of the small extravasations which are present at the same time. The fact of such spots occurring is unquestionable; indeed, it would be surprising if they did not occur. They either go on to suppuration, in which case these coagulated products become converted into pus; or they change gradually into fibroid tissue, and form a cicatrix. In the latter case, there is never any softening throughout the whole course of the process, with the exception of the looseness of the cerebral tissue, that takes place at the beginning.

In the immediate neighborhood of the diseased spot, a slighter degree of inflammation prevails, and the appearances which it presents illustrate the commencement of the process. This part forms a ready medium for the advance of the disease upon any increase of the inflammatory action.

Changes of much importance occur in the cerebral tissue, still further from the diseased part. They are rarely absent; and thus a gradation of changes exists from the most diseased to the completely healthy structures. The outermost part is generally oedematous, or in a state of yellow softening.

The division of the brain in which the inflammatory process occurs, and, subsequently, even the whole brain, become permanently diseased; and this condition is more marked in proportion to the extent of cerebral substance included in the inflammation. It is forced out. of its natural position by the accumulation of the essential, and of accidental, products of inflammation within it; it appears swollen and fluctuating, and presses upon the cranium, and on other parts of the brain, the latter being compressed by it: the convolutions of the cerebrum become flattened, and pressed against one another, and both cerebral substance and membranes are, in consequence, pale and bloodless. The division of the brain in which the inflammation occurs is of course oedematous, and more or less yellow softening surrounds the inflamed part itself, according to its extent, and the intensity of the process going on in it.

The usual site of the inflammation is the hemispheres of the cerebrum and cerebellum, the former being far more commonly affected than the latter. To speak more particularly, though it is met with somewhat frequently in the white substance of the cerebral hemispheres, yet, when we take into consideration the cases in which it happens at the periphery, there can be no question as to the greater liability of the gray substance to the disease. In that substance it is found both in the central masses of gray matter in the corpus striatum and thalamus opticus, and also on the surface of the hemispheres. And this distinction of an inflammation of the central gray masses and one of the gray matter at the periphery, is, like the same distinction in the case of cerebral hemorrhage, a matter of considerable interest. The resemblance of the two diseases, in respect to locality, is unquestionable, though Durand-Fardel endeavors to disprove it in the instance of the peripheral substance of the brain.

The inflamed spot varies in size from that of a bean or hazel-nut to that of a fist; it is sometimes met with so large as almost to occupy one entire hemisphere. In their early stage these large spots are not usually so extensive, they increase partly by the progressive enlargement of a previously smaller spot, and partly by several of such smaller ones coalescing. In the latter case considerable portions of brain, in a state of yellow softening, usually become involved in the diseased mass. The whole then generally assumes more or less of a rounded form.

The inflammatory action is generally confined to a single spot, though it is not very uncommon to meet with cases in which there are several distinct ones, in the same or in different portions of the brain. Very large spots often originate from the confluence of several smaller ones.

Encephalitis is far from being, as is generally asserted, a very acute disease; in nearly all cases its course is chronic. And this is true, even of traumatic inflammation. When it is the primary cause of death, we may trace this result either to the large extent of brain destroyed, or, as is more commonly the case, to the pressure and anaemia produced by the swelling of the brain, when oedema and yellow softening have come on around the inflamed spot. It destroys life in the same manner sooner or later, by its terminations and consequences; and last of all, by general marasmus, by congestions, especially in the lungs, and hypostatic pneumonia, by sloughs on the sacrum, etc.

a. Encephalitis may terminate in resolution, but only at the beginning of the process, and when it is very slight in degree.

b. It results also in atrophy, - in secondary atrophy. The principal part of the products of the inflammation is absorbed, together with so much of the injured cerebral tissue in which they are contained, as is incapable of being restored to a healthy condition; while a small portion of the products undergoes a change of structure. This termination is in itself one of great importance; but it also requires more especial notice, because its true character as a termination of inflammation has not hitherto been recognized, and it is looked upon by observers as the true softening, and, indeed, as the highest degree of softening of the brain. (See Andral and others.) In the seat of inflammation we find an ex*-tremely delicate, and irregular network,'f a white, grayish, or very pale yellowish-red color; sometimes it is soft, sometimes pretty firm: its interspaces are filled with a fluid, like an emulsion or lime-water, flocculent, white and turbid. Upon minute examination, this delicate network is found to consist of a fine cellular tissue at various stages of development, and of a few vessels. The fluid contains a quantity of separate and conglomerate, elementary corpuscles, fat-globules of different sizes, and a little amorphous pigment, which is not discernible by the naked eye. It constitutes the second stage of Durand-Fardel's chronic softening, and is called by him cellular infiltration. Both it and the following latter stage of the same morbid process occur only in the white matter, or only in those of the cerebral ganglia which contain much white matter. Accordingly, I have observed it unquestionably in the corpus striatum, but, like Durand-Fardel, have never discovered it in the peripheral gray matter. Gradually the fluid becomes clearer, and at last we find at the affected spot a cavity, lined by a layer of delicate cellular tissue, and usually honeycombed, or traversed in different directions by slender filaments of cellular tissue, and containing a clear serous fluid. The cerebral substance immediately surrounding the cavity appears slightly condensed, - sclerosis.