Sometimes it happens that the starting-point of hypochondriac pains, simulating neuralgia, is a blow, or other bodily injury acting on a predisposed nervous system. Another of my patients at the Westminster Hospital was a policeman, who had received a severe kick in the groin; he suffered pains which at first seemed to wear all the characters of true neuralgia in the pudic nerve, but afterward shifted to other places and exhibited all the intractability of hypochondriasis; the patient also developed the regular appearance and the characteristic hallucinations of the latter disease. On the last occasion when I saw him, he struck me as likely to become really insane, in the melancholic form; and the probability is that the casualty which he suffered was only accidentally the starting-point of a malady which was inherent in him since birth, and would have been developed, in any case, at some period of his life.
Considering the vast amount that has been written about this disease during the last few years, it might be thought superfluous for me to give any description of its general features. But it unfortunately happens that there is still great divergence of opinion among authorities as to the true limitation of the group of cases that can properly be ranked under this title, and, indeed, as to the propriety of employing the title at all. The phrase ataxie locomotrice progressive, as every one knows, was applied by Duchenne de Boulogne to a class of cases which really only form a subdivision of the group known under the older title of _tabes dorsalis_ and the most advanced German pathologists maintain that the old word was better, and that Duchenne was altogether wrong in making the one symptom, ataxy of locomotion, the bases of a new phraseology;[49] more especially as his theory as to the seat of the morbid changes was undoubtedly erroneous.
In this country, however, there is as yet no disposition to give up the phrase locomotor ataxy, and it only remains to define with sufficient care the class of cases to which the word is here meant to apply. The disease is understood to depend upon a degeneration of the spinal cord, of which the following description is given by Lockhart Clarke:[50] "In true locomotor ataxy, the spinal cord is invariably altered in structure. Its membranes, however, are sometimes apparently unaffected, or affected only in a slight degree; but generally they are much congested, and I have seen them thickened posteriorly by exudations, and adherent, not only to each other, but to the posterior surface of the cord. The posterior columns, including the posterior nerve-roots, are the parts of the cord which are chiefly altered in structure. This alteration is peculiar, and consists of atrophy and degeneration of the nerve fibres to a greater or less extent, with hypertrophy of the connective tissue, which give to the columns a grayish and more transparent aspect; in this tissue are embedded a multitude of corpora amylacea. Many of the blood vessels that travel the columns are loaded or surrounded to a variable depth by oil-globules of various sizes. For the production of ataxy, it seems to be necessary that the changes extend along a certain length, from one to two inches of the cord. The posterior nerve-roots, both within and without the cord, are frequently affected by the same kind of degeneration, which sometimes extends to the surface even of the lateral columns, and occasionally along the edges of the anterior. Not unfrequently the extremity of the posterior cornua, and even deeper parts of the gray substance, are more or less damaged by areas of disintegration. The morbid process appears to travel from centre to periphery, that is, from the spinal cord to the posterior roots. In the cerebral nerves, on the contrary, the morbid change seems to travel in the opposite direction, that is, from the periphery toward the centres. From the optic nerves it has been found to extend as far as the corpora geniculata, but seldom as far as the corpora quadrigemina. With the exception of the fifth, seventh, and eighth pair, all the cerebral nerves have occasionally been found more or less altered in structure."