LOCOMOTOR ATAXY. 303 



their disease. There is no doubt that many of the patients attacked 

 have been addicted to excess in venery, but there is just as little doubt 

 that many patients with tabes dorsualis have led an exemplary life, while 

 others who have been unbounded in their excesses escape the disease. 



From the great frequency of lewd habits, and from the difficulty of 

 deciding the amount in any given case, I consider the dependence of 

 tabes on venereal excess as not yet proved. 2. On the other hand, 

 there appears to me no doubt of the influence of catching cold and 

 bodily fatigue, especially when they act together, in inducing tabes 

 dorsualis. The disease occurs with remarkable frequency among those 

 who, wearied and heated by severe marches or other bodily exertions, 

 have stretched themselves on the damp earth to rest. 3. Many patients 

 ascribe their disease to suppressed perspiration of the feet. We can- 

 not generally lay much weight on these accounts, for the laity give 

 suppression of habitual perspiration as a very common cause of dis- 

 ease. Doubtless in most cases where the occurrence of a disease is 

 accompanied by the absence of habitual perspiration of the feet, it is 

 because the latter has ceased with the appearance of the disease. But 

 I think it is going. too far to deny the possibility of a genetic connec- 

 tion between the arrest of perspiration of the feet and tabes dorsualis. 

 At all events, many patients with tabes have previously suffered much 

 from, perspiring feet. 4. Lastly, the disease appears occasionally to 

 be of syphilitic origin, a supposition chiefly supported by the fact that 

 some tabes patients who had previously suffered from syphilis were 

 benefited by an antisyphilitic treatment. 



ANATOMICAL APPEARANCES. The usual appearance of the spinal 

 medulla and its membranes, in decided cases of tabes dorsualis, is as 

 follows: The dura mater is either unchanged or its posterior half is 

 slightly thickened, the arachnoid is moderately opaque, if the medulla 

 be atrophied the fluid in the subarachnoid space is increased; on the 

 posterior surface the pia mater is constantly thickened, clouded, and 

 more or less adherent to the posterior columns. 



In the early stages, where no decrease of volume of the spinal medulla 

 is as yet observable, there is a peculiar degeneration of the posterior 

 columns ; this always begins in the immediate vicinity of the posterior 

 fissure, close under the pia mater, and thence spreads toward the sides 

 and the gray commissure ; the diseased part always retains the shape 

 of a wedge, with the base directed toward the pia mater. The degen- 

 eration consists in a transformation of the white substance of the pos- 

 terior columns into a gray or grayish-red, half-translucent, soft mass. 

 On microscopical examination of the latter we only find a few nerve- 

 filaments, partly in various stages of atrophy ; most of them have com- 

 pletely disappeared, and between the atrophied cells there is a richly 



