97 Schulz (Deutsches Archiv für klinische Medizin, Band xxiii.) and Strümpell (Archiv für Psychiatrie, x.).
98 Journal of Anatomy and Physiology, xv. p. 510.
99 Archiv für Psychiatrie, xv. p. 246.
100 Another feature which antagonizes the development of spastic phenomena in paretic dementia is the lesion of the posterior columns which often ensues. In proportion as this is developed it neutralizes the exaggerated knee-jerk, stiffness, and spastic gait.
101 Archiv für Psychiatrie, xiii. p. 155.
102 It has been claimed against this view that if this were so the degeneration of the pyramid tract should be accompanied by degeneration of the cells in the anterior horn. This claim assumes that the cells and the pyramid tract are directly continuous, but the most modern researches, those of Von Monakow, confirming an older observation of Homén's, show that a system of small cells in the lateral reticular processes is interpolated; which I can confirm. It is certainly compatible with an atrophy from disuse of the voluntary tract that the cells themselves, presiding over reflex and nutritive functions not necessarily disturbed in paretic dementia, should remain nearly intact.
There is another respect in which the two conditions differ. Spastic paralysis is usually an ascending affection, the lower extremities being involved first, the trunk next, and the upper extremities last. But in paretic dementia the spastic phenomena develop in both upper and lower extremities simultaneously, and there are universal tremors, probably of irritative origin. The lower extremities are not commonly in the extension contracture of spastic paralysis, but in the same flexed position as the arms, the adductors usually preceding the flexors in becoming rigid. If it be added to this that the lateral-column lesion in paretic dementia appears to answer all the requirements which could be made of the lesion on theoretical grounds were the case one of pure spastic paralysis—that is, that its area decreases upward—the inconsistency of the observed anatomical and clinical facts becomes strongly evident. Thus far, the attributing of spastic paralysis to a primary lesion of the pyramid tract rests in a few contested cases, on a number of doubtful analogies, and on the undoubted fact that sclerosis of this tract in the event of a myelitis is followed by pronounced spastic symptoms in all those muscles which derive their voluntary innervation from the part of the tract which lies below the level of the lesion.
The situation of this tract, which was not discovered by Türck and Flechsig, as is usually supposed, but accurately known to Burdach103 in 1819, may be roughly stated as follows: It lies in the dorsal half of the lateral column, making up the bulk and core of this part of the column. It is separated from the pia mater by the direct cerebellar tract, and from the posterior gray horn by a narrow zone of fibres differentiated by Lissauer (see Tabes). It is connected with the lateral reticular processes, and in its cephalo-caudal course becomes gradually attenuated, giving off its fibres to these processes, thus to be exhausted in the lower part of the lumbar enlargement of the cord, where it approaches, if it does not actually reach, the surface. The fibres controlling the voluntary motions of the lower limbs, and which have a longer course to run before they reach the brain than those which mediate the voluntary control of the arms, are situated nearest the lateral boundary of the cord. Where the spastic phenomena are mainly marked in the lower limbs the sclerotic process has been found most marked in the corresponding area.
103 Vom Bau und Leben des Gehirns. This gifted author says that the crossed-pyramid tract lies in the lateral column of the cord, behind a line corresponding to the attachment of the ligamenta denticulata and removed from the surface.
The progress of this affection has not been materially modified in any case by treatment. The same measures employed in sclerotic processes generally, particularly galvanism and warm baths, are recommended. It is difficult to understand what good effect ergotin, which is mentioned by a number of the German writers, can have in a disease of this nature.