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



to the loss of consciousness or the absence of loss of consciousness which 

 Brown-Sequard described. Thus a " double " attack may yet be " incom- 

 plete" according to him. But the phenomenon of loss of consciousness 

 cannot accurately be investigated, and it is better to use the terms- 

 " complete " and " incomplete " in the sense in which Brown-Sequard used 

 " double " and " single." This has been the practice of the present author 

 in previous papers, and in it he has been followed by Taft. 



Brown-Sequard seems to have considered these different varieties of the 

 phenomenon as essentially of the same nature, and he states (36) that 

 " epilepsy " which exists in guinea-pigs after the various lesions is 

 absolutely equivalent to ideopathic epilepsy or epilepsy of cerebral origin 

 in man. He thought (21, 22) that the primary cause of the former 

 condition was the irritation of the central stump of the cut sciatic nerve. 

 The secondary alterations (of the posterior columns of the spinal cord on 

 the same side, of the hair in the " epileptogenous zone " on the face and 

 neck, and presumably the "epileptic faculty" itself) do not depend upon 

 the transmission of the morbid organic state by Continuity of tissue, but 

 upon the propagation of a morbid influence exercised at a distance by the- 

 irritated fibres of the central stump of the cut nerve. 



Weismann (34, 41) apparently accepted Brown-Sequard's view of the 

 nature of the condition, for he states that epilepsy is not a morphological 

 character but a disease, and he supposes that the condition might be caused 

 by an unknown microbe which might pass to the young, and in them 

 produce the same phenomena. 



This view was vigorously combated by Brown-Sequard (37), who failed to- 

 find a specific micro-organism. He also points out that the condition never 

 follows certain lesions (such as section of the brachial plexus), although 

 it always follows certain other lesions of a similar nature (section of the 

 trunk of the great sciatic nerve). And, in addition, the phenomenon 

 may appear when the sciatic nerve is injured without breaking the skin, 

 as when it is involved in the callus thrown out when there is a fracture of 

 the bones. 



(b) The Occurrence of the Phenomenon in Relation to Trophic Changes in the- 

 Feet. — After section of the great sciatic nerve, a large part of the surface 

 of the skin of the foot and leg is rendered anaesthetic. Guinea-pigs in which 

 this anaesthesia is produced commonly acquire the habit of nibbling the 

 insensitive parts until they may destroy the two outer toes, or even a 

 greater part of the limb. This habit may be controlled by placing fluids 

 which have a bitter taste upon the foot. It is hardly necessary to say that 

 the animal itself can feel no pain. 



