132 It is from this field that has come a new argument for the spinal nature of lead-paralysis, from its peculiar grouping, and from analogy with that of anterior poliomyelitis of the upper extremities (Remak, “Ueber die Local. Atropa. Spinal Lahm.,” Archiv für Psych., Bd. ix.; also, Ferrier, loc. cit.).
Relation between Limitation of Myelitis and Age.—From the relative frequency of anterior poliomyelitis in childhood, as compared with its much greater rarity in adult life, we must infer the existence of some special conditions in childhood which tend to limit the morbid process to such a portion of the cord. The theory of a primitive spontaneous atrophy of the motor cells would serve, indeed, to explain this limitation. The reasons already alleged for regarding the morbid process as a systematic myelitis decisively hinder the acceptance of such an explanation as it stands. On the assumption, however, that the myelitis is usually of functional origin, and starts, therefore, in the elements of the anterior cornua essentially involved in the motor functions, the morbid susceptibility of these elements may be ranked with the liability to disease of the entire locomotor system which is known to be so predominant in children. From pathological evidence, even without anatomical proof, we may reasonably infer an incompleteness of development in the anterior cornua of the cord correlative with that well demonstrated in the bones and functionally inexperienced muscles. If the antero-posterior fibres which connect the anterior cornua with the central and posterior gray masses be also incomplete, the radiation of irritations, and consequent vascular irritation, would also be arrested within the boundaries of the original lesion. Thus a peculiarly circumscribed, instead of the common diffused, myelitis of adults.
Money133 points out that for the gray matter of the cord, as of the brain, the centre or maximum force of the circulation is on the periphery, and the nutritive supply of the centre is thus easily cut off. Moreover, while the blood-vessels of the cervical and dorsal regions of the cord pass to it transversely, the vessels of the lumbar region are compelled to describe a somewhat prolonged vertical course before reaching their point of distribution. From these circumstances, even transitory congestions in the circulation of the cord are easily followed by irreparable injury of its delicate elements.
133 Loc. cit., Path. Trans., 1884.
Finally, in all discussions on pathogeny must not be forgotten the doctrine of Leyden134 that infantile paralysis, also progressive muscular atrophy, is a disease which may begin at the periphery and extend to the centres, as well as the reverse. It must also be remembered that, as yet, only very scanty evidence exists to support this, in itself, plausible theory.
134 See loc. cit., ut supra.
COURSE OF INFANTILE PARALYSIS.—The most ordinary course of infantile paralysis is that already described as typical—namely, extremely rapid development to a maximum degree of intensity, then apparent convalescence, retrocession of paralysis, atrophy, and ultimate deformities in limbs in which paralysis persists.
Several variations from this typical course are observed. Complete recovery may take place, as in the so-called temporary paralysis of Kennedy135 and of Frey.136 These cases are very rare. But their possibility seriously complicates the estimate we may make of the efficacy of therapeutic measures.137
135 Dublin Quarterly Journal, 1840.
136 Berlin. Klin. Wochensch., 1874. I have described one such temporary case in the article already quoted. These cases seem about as frequent in adults. (See Frey, loc. cit.; also case of Miles, etc. etc.)