A third objection has been brought forward by Leyden, and is really an enlargement on the second. It is, that various lesions or morbid processes may underlie the same clinical history. In four autopsies of cases presenting all the clinical history of acute anterior poliomyelitis this author has found three different lesions. In one an extensive lepto-meningitis, together with irregular focal sclerosis of the white columns, evidently depended upon the latter, and in turn caused sclerosis of the anterior cornua with consequent destruction of their cells.114 In two other cases an anterior poliomyelitis was accompanied by diffused lesions of the central canal. Finally, in a fourth case the lesions were limited to the anterior cornua, as is most usual.
114 This case of Leyden's throws light on the two autopsies by Laborde with sclerosis of the white columns and intact cornua. It seems probable that a process originating in the cornua had then been arrested or had receded, while continuing its evolution in the white columns.
The theory of acute atrophy of ganglionic cells is not sensibly different from that of a parenchymatous myelitis.115 But all the objections which can be urged against the former theory apply to the latter also, with the exception that the hypothesis of inflammation suggests a cause for the otherwise inexplicable atrophy. Observation of the pathological appearances alone could not decide whether the irritation started in the parenchymatous or interstitial tissues. Reference to the etiology of the disease shows that of the two most frequent apparent causes, blood-poisoning and traumatisms, the first would indicate that the inflammation started in the connective tissue supporting the blood-vessels; the second suggests that the irritation began in the spinal elements constituting the origin of the nerves.
115 Hammond assumes such a form of myelitis in his classification of inflammations limited to the anterior part of the gray matter of the spinal cord:
1. Inflammation of motor and trophic nerve-cells: (a) Infantile spinal paralysis; (b) Spinal paralysis of adults; (c) Pseudo-hypertrophic spinal paralysis.
2. Inflammation of motor cells: (a) Glosso-labia-laryngeal paralysis.
3. Inflammation of trophic cells: (a) Progressive muscular atrophy; (b) Progressive facial atrophy (Dis. Nerv. Syst., 6th ed., p. 464).
We think this classification open to several fundamental criticisms.
Whatever be the starting-point, however, it is very evident that the morbid process soon involves all the tissues contained in the gray matter of the anterior horns, and constitutes, therefore, a real anterior poliomyelitis.
A question of much interest is the relation to this of the lesions of the anterior roots and of the white columns. Is the atrophy of nerve-tubes a passive consequence of their separation from the ganglionic cells, the sclerosis a secondary consequence of this? or is the sclerosis the cause of the atrophy, itself the result of an irritation propagated downward from the myelitic focus, according to the usual law for secondary degenerations in motor tracts? or, finally, is it a residuum of a leucomyelitis (or of the white substance), complicating by simple extension the inflammation of the gray substance?