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



the whole of the cerebral hemispheres had been removed, mechanical 

 pressure applied to the skin of the neck evoked a distinct scratch-reflex in 

 the hind limbs (fig. 3). 



This observation demonstrates that a true scratch-reflex may be evoked 

 in the guinea-pig. And a comparison between graphic records of it, and of 

 the scratching movements of the Brown-Sequard phenomenon, demonstrates 

 their similarity. 



" Voluntary " scratching occurs in guinea-pigs as in most other mammals. 



III. Conclusions Concerning the Nature of the Brown- Sdquard Phenomenon. 



It is somewhat remarkable that comparatively little attention has 

 previously been directed to the nature of the condition. This question is 

 of great importance in relation to the value of the experiments in demon- 

 strating the transmission of an acquired character. For it is obviously 

 important to know if the phenomenon is one inherent in all guinea-pigs, 

 and released by the special conditions of the experiments ; or if it arises 

 de novo as a result of the experimental interference. 



The present author (45) has demonstrated the close similarity between 

 the scratching movements of the Brown-Sequard phenomenon and the 

 movements of the scratch-reflex as observed by Sherrington in the spinal 

 dog (43, 44). Graphic records of the phenomenon in guinea-pigs demon- 

 strate all the especial characteristics of the scratch-reflex. 



We have now before us evidence of the characteristics of three scratching 

 phenomena in the guinea-pig — the true scratch-reflex, the scratching 

 movements of the Brown-Sequard phenomenon, and the scratching move- 

 ments of the " narcosis scratch." The records, in general, exhibit the same 

 characteristics in all three cases. 



But more than this. In all three conditions there are concomitant 

 phenomena, in other parts of the body, which accompany the scratching 

 movements. Such are the bending of the back and neck, movements of 

 the ears and eyes, movements of the fore limbs, etc. In all three conditions 

 these also are present, although in differing degree. 



It must, I think, be definitely admitted that the movements in the 

 "incomplete" form of the Brown-Sequard phenomenon, in a scratching 

 phase of the " narcosis scratch," and in the true scratch-reflex of the guinea- 

 pig, are all exhibitions of the activity of one and the same mechanism. 

 The " incomplete " Brown-Sequard phenomenon is, in fact, no more and no 

 less than an example of the scratch-reflex in the guinea-pig. 



The phenomena of the "complete" form of the condition at first sight 

 raise certain difficulties. In the scratch-reflex of such a preparation as the 



