242 William Christopher Krauss 



nomonic of progressive muscular atrophy, as was formerly 

 supposed, but has been observed in other aifections of the 

 muscular system, and even in the healthy muscle. 



Loss of Myotatic Irritability. Tapping a healthy muscle 

 produces a slight contraction of the fibers, which calls forth 

 the performance of its function. In the diseased muscle the 

 reflex arc is broken, the centripetal-sensory path remaining 

 undisturbed, while the centrifugal-motor path is broken. 

 The loss of tendon reflexes, in some forms, occurs quite early, 

 even before any serious damage has taken place in the mus- 

 cular fibers. The patellar and elbow reflexes are the ones 

 most generally tested.* 



Electrical Irritability .—"To Duchenne (de Boulogne) must 

 be given the credit of having first employed electricity as a 

 diagnostic and therapeutic agent. His method of localizing 

 the electrical current, published in 1850, has served as the 

 foundation for all later electrical researches in medicine. The 

 elder Reraak appeared against him, disputing some of his 

 conclusions, particularly as to whether the contraction of the 

 muscle was produced by irritating the bulk of the muscle, or 

 the entrance of the motor nerve into the muscle. Von Ziems- 

 sen, taking advantage of this breach, made experiments upon 

 dying patients, and, by careful dissection afterward, discov- 

 ered that the motor points were those points where the motor 

 nerve approached nearest the surface (1857). The natural 

 law of muscular contraction under the influence of the gal- 

 vanic or faradic current, shows the superiority of the cathode 

 over the anode, the contractions being short, sharp and 

 quick. The wasted muscle presents changes of electrical irri- 

 tability dependent upon the degree and extent of the degener- 

 ation. Erb and V. Ziemssen conducted a series of experi- 

 ments upon diseased muscles, and arrived at practically the 

 same conclusions at exactly the same time — 186S. 



Their law, called the Entartungs Reaction, reaction of de- 

 generation, is as follows : First degree, or partial reaction ; 



* See author's paper on Tendon Reflexes, Buffalo Medical and Surgi- 

 cal Journal, December, 1892. 



