802 THE SPINAL CORD. 



lesions of the muscles and nerves of the leg that it results when the tension 

 of the antagonist muscles is abnormally low. He regards it as due to the loss 

 of a reflex inhibition of muscular contraction, arising in afferent nerves of the 

 "muscular sense" order. It is therefore an ataxic effect. In swimming, 

 although synchronous bilateral strokes are sometimes taken, the frog usually 

 swims with the apsesthetic limb in permanent active extension. When both 

 hind-limbs are apsesthetic, the frog does still occasionally swim with syn- 

 chronous extensor strokes. Apsesthesia of the fore-limbs in the frog causes the 

 frog to sit supported, not on the fore-feet, but on the fore-arm, often with the 

 digits bent underneath. The spring is less high than usual, and for that reason 

 less wide. Whefi all four limbs have been rendered insensitive, the animal 

 can still spring, but only a short distance, and often in attempting to spring 

 upsets itself, rolling over sideways. Bickel l has made observations on 

 combination of apsesthesia of one or more limbs with removal of one labyrinth. 

 The forced postures regularly assumed after removal of a labyrinth were, as a 

 rule, far less marked in the apaesthetic than in the normal limbs. Baldi 2 

 in Luciani's laboratory observed dogs for long periods after severance of afferent 

 roots of one or both limbs. When one hind-limb is apsesthetic, it is not at 

 first used for walking ; it seems unable to bear the weight of the body ; it is 

 kept more or less flexed at hip and knee, and full extension is rarely executed 

 by it. Later, it is used for walking, but is lifted too high, and sometimes set 

 too far. With both hind-limbs apaesthetic, the fore-limbs at first simply drag 

 the hind-limbs after them, these trailing with the dorsal aspect of the foot to 

 ground. Later, as the hind-limbs are trailed, they make alternate movements 

 of extension and flexion, and ultimately they may to some extent support the 

 body, crawling as it were with very flexed knees, so that the rump droops too 

 low. When the lowest three cervical and the first thoracic are the afferent roots 

 cut, the animal limps, lifting the apsesthetic fore-limb from the ground. Later 

 it comes at times to be used for progression, but the dorsum of the foot frequently 

 doubles under, causing a fall or stumble. Baldi considers the ataxy the most 

 marked symptom, and refers the chief gravamen of the lesion to rupture of 

 the afferent channels from the peripheral organs of muscular sense. Combina- 

 tion of extirpation of one labyrinth with apaesthesia of the hind-limbs in the 

 dog leads, when the latter operation precedes the former at a long interval, to a 

 recrudescence of symptoms from which the apsesthetic limbs had partly 

 recovered. After extirpation of both labyrinths, there appears far less power to 

 compensate the disturbance of motility of apsesthetic limbs. 3 An important 

 observation by Bickel is that extirpation of one labyrinth causes the apsesthetic 

 tail to be twisted 90 on its axis, and that this twist at once disappears when, 

 weeks later, the other labyrinth is removed. Hering 4 and Bickel have pointed 

 out that the residual disturbance of motility, due to apsesthesia of both hind- 

 limbs, is much increased by excluding retinal sensations, by bandaging the eyes 

 or placing the animal in the dark. 



Observations on the symptomatology of apsesthesia of the limbs 

 in the monkey 5 show even more striking defects of motility. When the 

 whole series of afferent roots of a limb are divided, the lirnb is useless for 

 progression. The animals never use the apsesthetic limb in climbing 

 either down or up a rope. The limb is chiefly moved in association with 

 vigorous movements of the fellow normal limb. In climbing, while 

 the normal movements are being executed by the normal arm, the 

 apsesthetic, semiflexed at elbow, is often flung up behind the head. 



1 Arch.f. d. ges. PhysioL, Bonn, 1897, Ed. Ixvii. S. 299. 



2 Sperimentale, Firenze, Sept. 1885. 3 Bickel, loc. cit. 



4 Neurol. Centralbl., Leipzig, 1897, No. 23 ; A. Margulies, Monatschr. f. Psych, u. 

 Neuroi: 1897, Bd. i. S. 4. 



5 Mott and Sherrington, Proc. Roy. Soc. London, 1895, vol. Ivii. p. 481. 



