The following are unessential, and, to a certain extent, merely accidental combinations: hypostatic congestions of the lungs, lobular pneumonias, slight pleuritic exudations, enlargement of the liver, etc. Intussusceptions are very frequently met with in the intestines: but, although Abercrombie attributes them to the same cause as the vomiting which occurs in the course of the disease, they have certainly not existed for any length of time, and must rather have arisen during the agony; for they present no trace of any congestion or swelling of the bowels from the strangulation of those vessels of the mesentery which are invaginated with the bowel.

Terminations Of Acute Hydrocephalus

The great fatality of acute hydrocephalus is well known, and may be accounted for. The first of the two forms, when a tubercular process, is undoubtedly always fatal; but when it is a simple meningitis, it may, as well as the second form, be outlived and cured, provided it be moderate in degree, and especially if the brain have escaped complete destruction by white softening.

This termination, in a more or less complete cure, may be reduced to the following particulars:

(1.) The products of the process may be entirely reabsorbed, and the brain be restored to its natural consistence, size, and figure.

(2.) A part of the effused fluid, or the whole of it, may remain in the ventricles, and both they and the skull may be permanently enlarged. This can only be conceived to take place in the child just before the skull is completely ossified. The acute hydrocephalus thus becomes a chronic accumulation, which is capable even of further gradual increase.

(3.) In that case, the lining membrane of the ventricles very often remains thickened in various forms and degrees. The quantity and density of its tissue are increased, and the plastic exudations remaining upon its surfaces become converted into a cellular or fibroid tissue, and covered with a layer of tesselated epithelium; thus both contribute to the thickening of the wall of the ventricle. The new tissue assumes various forms, similar to the false membranes which occur on serous surfaces.

As its presence on so delicate a substratum as the ependyma is of some interest, and as it may be the means of leading to a more accurate examination of the cases in question, I will give a more detailed description of it.

a. The lining membrane sometimes appears covered with a granular film, like the finest sand, which has a transparent crystalline, or an opaque, grayish-white appearance, and can be detected only by looking carefully while the light falls favorably upon it. It may occasionally be seen at every part of the lateral, third or fourth ventricles, but it is generally most developed at particular spots, as the corpus striatum, and taenia semicircularis, and especially in the anterior cornu of the lateral ventricle.

B. More rarely it forms coarser granulations, which are then more prominent, and in time become nodules attached by a pedicle. These granulations, more particularly, are analogous to the false growths of the same kind, which occur on other serous membranes, and to the Pacchionian bodies on the arachnoid.

r. Sometimes the new tissue is smooth, membranous, and superficially attached, and forms separate, round, white, opaque, islands, or "plaques," which are not unfrequently thinner in their middle, and, as it were, perforated (gefenstert, latticed): this form is analogous to the tendinous spots.

d. At other times the tissue is similar in its character, but instead of forming separate islands, it is continuous, and the whole seems knitted or areolar, and forms an adherent network of false membrane, which may generally be easily raised from the surface.

e. Or, lastly, it forms false membranes of considerable and nearly uniform thickness, which are for the most part, intimately united with the lining membrane.

In these last sometimes bony concretions are developed.

In some very rare cases of chronic hydrocephalus in children, especially of congenital but advancing hydrocephalus, in which, also, the thickenings just described exist, a peculiar appearance is met with on the walls of the ventricle. The cerebral substance protrudes into the ventricle at various spots, probably those where the ependyma is relatively thinner, and forms rounded, smooth bosses, with broad bases, as large as hempseed or peas. I have had two opportunities of observing this peculiarity.

(4.) Does it happen, as Otto, I believe, first asserted, that hydrocephalus (of course I mean the second form, that which is allied to chronic hydrocephalus), is ever cured by the supervention of hypertrophy of the brain? I have already (p. 272) considered the combination of hydrocephalus and hypertrophy of the brain, which is occasioned by rickets: I believe, further, that the hydrocephalus (the hydrocephalic process) may itself sometimes give the first impulse to hypertrophy of the brain: but that any compensation for, or cure of, hydrocephalus is effected by hypertrophy, appears to be altogether problematical. Such an opinion is founded upon the fact, that in some large skulls, of hydrocephalic shape, the brain exceeds the normal size and weight. But, I believe, that these are cases in which the hypertrophy having taken place in childhood, has continued ever since; and that belief is confirmed by the resemblance, in shape, which subsists between the skull in hypertrophy and the hydrocephalic skull, as well as by the difficulty which the similarity in the symptoms of hypertrophy and hydrocephalus imposes, upon our determining positively what disease of the brain did exist in childhood. So far as I am aware, the morbid increase in the volume of the brain in hydrocephalus, as well as its normal growth, takes place always in the neighborhood of the enlarged ventricles; it is a peripheral deposition around them: and the skull goes on increasing in size to whatever extent its closure may be prevented by the hydrocephalus.

B. Chronic hydrocephalus may be subdivided into congenital hydrocephalus, and that which commences at various periods of extra-uterine life: besides these, there is a third and entirely different form, hydrocephalus ex vacuo. The distinction between the first two forms is not made by any essential difference between them, for in the most important particular, viz., their cause, they are undoubtedly alike; but congenital hydrocephalus presents such very marked peculiarities that the distinction appears justifiable.

The general anatomical characters of chronic hydrocephalus are a large accumulation in the ventricles of clear and colorless serum, which contains very little animal matter, and a thickening and toughness of their lining membrane, for the most part to a considerable degree.