Hypertrophy of the spinal marrow is exceedingly rare when compared with that of the brain. Although some of the many cases which have been adduced as hypertrophy are certainly of a different nature, and others appear to be at least doubtful, yet there can be no doubt that such a disease really does occur. It affects in some instances the whole cord, and is then almost always combined with hypertrophy of the brain, which forms the more prominent feature in the case: in other instances it is partial, and especially affects the enlargements of the cord; or at least they appear to be its original seat, and from them the disease extends to the other parts of the cord.

Ollivier holds the swelling which the marrow presents near a part that has been subject to pressure, especially above such a part, to be hypertrophy. If this swelling be not produced by some distension of the medullary tubes, by an enlargement resulting from the displacement of their contents out of the compressed part, yet it may resemble the secondary form of hypertrophy of the brain, that, for example, which arises from the irritation of growths in the brain; or perhaps, more commonly still, it may be a condition in which congestive swelling, oedema, and hypertrophy all meet together. It reminds us of the hypertrophy which the brain undergoes when the medulla oblongata is subjected to pressure (p. 285).

The character of the spinal marrow, when hypertrophied, is, on the whole, analogous to that of the hypertrophied brain: its form becomes round and plump, and its grooves seem smoothed out; it has a peculiar turgescence, while at the same time the cord and the pia mater are anaemic; its consistence appears to be firm, but when the membranes are removed and the cord itself is pulled asunder, it is found to have the consistence of dough.

It occurs mostly in children, and sometimes even in the foetus. Ollivier has noticed it in several cases affecting the gray substance.

A more frequent and a better-marked affection of the cord is atrophy, and diminution of volume to which it gives rise. Atrophy occupies either the whole cord, or merely separate portions of it. Most frequently total atrophy is but partial at first, and gradually extends till it occupies the whole length of the cord.

Total atrophy of the spinal marrow comes on in old age simultaneously with the same affection of the brain (atrophia medullae senilis). Though it is equally a primary disease in the medulla as in the brain, yet it is usually better marked in the latter organ. Its characteristics are identical with those of senile atrophy of the brain, diminution of volume, and dirty whiteness of the fibrous columns, a rusty-brownish, fawn tint of the gray substance, and toughness of the white substance, even to a degree like that of leather. Chronic effusions of serum in the sac of the arachnoid accompany it, and opacity, thickening, and ossification of that membrane. Not unfrequently the cord, discolored as before mentioned, is infiltrated with serum, and its substance is then soft and withered. Like the corresponding atrophy of the brain, it may come on as a premature marasmus.

The partial atrophies are, most probably, in many cases consecutive upon disease at the periphery of the nervous system. They affect particularly the enlargements of the cord. Atrophy of the lumbar portion especially, under the names of Tabes dorsalis, has long obtained the attention of physicians, as a consequence of decay of generative powers, and spermatorrhoea. From thence the wasting gradually extends, as has been said, and becomes a total atrophy.

These atrophies attain various degrees, which are determined simply by the diminution in the volume of the cord. They vary so much, that in one case the wasting is but just discernible, while, in another, the cord may have but half, or scarcely half, its natural thickness. There are differences, also, in other respects: thus the white columns vary in their consistence, sometimes being natural, but more frequently compact, dry, and even as tough as leather.

In some few cases of considerable wasting, the cord is found constricted here and there, and nodose, a series of bulgings being produced by successive constrictions of the cord.

From numerous observations I may assert, generally, that the more advanced degrees of atrophy, such even as are palpable at once, and not those which are discernible only upon comparison with other preparations, are rare.1

The secondary atrophy which the cord undergoes, in consequence of diseases of its texture, especially of inflammation, will be described below.

Lastly, when the cord is subjected, in any part, to the pressure of enlarged, or of dislocated (inflamed and carious) vertebrae, of exostoses, aneurisms, morbid growths, etc, it becomes flattened and thin, in proportion to the amount of pressure. In such cases it is found swollen and thickened, especially above the compressed spot, and, very commonly, below it also. This condition, as I have before remarked, is distinctly asserted by Ollivier to be one of Hypertrophy.

3. Interruptions Of Continuity

Various instruments penetrate to the cord, and inflict upon it incised, punctured, or shot-wounds. Much more frequently it is contused and lacerated by fractured, crushed, comminuted, or dislocated vertebrae: but sometimes these injuries are occasioned merely by excessive stretching and concussion of the spinal column. The most remarkable and important of the injuries which the cord undergoes in consequence of luxation of the vertebrae, is that in which sudden death ensues, immediately upon its being crushed or lacerated; such an event occurs when those bones are dislocated spontaneously, and especially when, in consequence of inflammation and suppuration of the ligamentous apparatus, and of caries, the odontoid process of the second cervical vertebra becomes loose, tears through the dura mater, and is dislocated into the vertebral canal.

1 [The construction of this sentence seems to indicate that a word has been omitted, and that the author would say, such degrees of atrophy are not rare. - Ed].

Sometimes only a part of the cord is bruised: at other times it is changed in its whole thickness, and more or less of its length, into a suffused red pulp; or it is crushed quite through. In the last case, the two ends of the cord are held together by the pia mater; but if that also be torn, they remain opposite to each other, and quite free. The inflammation and yellow softening of the cord, which result from injuries of this kind, usually carry them on to a fatal termination; but sometimes it is by the paralysis and its consequences that life is destroyed.