562 Mr. Graham Brown. Alleged Specific Instance of [Dec. 9, 



year tracings of the scratching movements — both of the Brown-Sequard 

 phenomenon and of the narcosis scratch — were recorded, and the great 

 sciatic nerve was again divided and a part removed at the level of the 

 great trochanter of the femur. In this second operation the narcosis 

 scratch occurred, and was recorded graphically both before and after the 

 division of the nerve. Subsequent to the operation the scratching move- 

 ments of the Brown-Sdquard phenomenon might still be obtained and were 

 recorded. 



At the time of the second operation the Brown-Sequard phenomenon was 

 " incomplete." The rhythm of the " beats " of the scratching movements 

 was between 11 and 13 per second. After the second operation it was 

 slightly more difficult to induce the phenomenon, and the rhythm of the 

 beats was the same. 



The scratching movements of the narcosis scratch before the second 

 operation occurred chiefly upon the side which exhibited the Brown- 

 Sequard phenomenon (the right side of the animal). After the operation 

 the same was the case. There was no important difference between the 

 records taken before and after the second division of the nerve, and the 

 rhythms of the " beats " were similar. 



This experiment shews that a continued irritation arising from the central 

 stump of the severed nerve is not the cause of the Brown-Sequard 

 phenomenon. 



(d) Occurrence of the Phenomenon in a Case of Accidental Injury to the 

 Foot, — Brown-Sequard noticed that accidental injury of the nature of 

 fracture of the bones might produce the phenomenon. He attributed this 

 effect to the implication of the nerve in the callus produced during the 

 process of repair of the broken bones. 



The following instance of the appearance of the phenomenon after another 

 kind of accidental injury is of some interest : — 



Guinea-pig 55. — This animal was operated upon on May 7, 1909, for 

 another purpose (section of the corpus callosum) not connected with the 

 Brown-Sequard phenomenon. One morning, a few days later, it was found 

 that a wisp of straw had become entangled tightly round one foot. This 

 was at once removed, but it was found that the foot had become anaesthetic, 

 and the foot subsequently became swollen. As the animal obviously 

 suffered no inconvenience and was perfectly healthy it was decided to keep 

 it. The foot was carefully treated, but sensation was not restored and 

 it withered. On July 2, 1909, a well-marked " complete " Brown-Sequard 

 phenomenon could be obtained on either side by stimulation of the skin of 

 the face or neck. 



