34 Mr, J. N, Langley [March 14, 



hand, when a centre is inhibited, an irradiation of inhibitory impulses 

 is apt to take place, and the whole nervous system is in consequence 

 apt to be inhibited. Hence the activity or suppression of activity 

 of particular parts of the central nervous system, which forms so 

 conspicuous a feature of mesmerism in man, can be only partially 

 produced in the lower vertebrates. Even in man there is very con- 

 siderable difference, in different individuals, in the ease with which par- 

 ticular nerve centres can be excited or inhibited without other centres 

 being similarly affected. But apart from this the fundamental 

 features are the same, whether a man or a frog be mesmerised. The 

 primary point is, as I have said, the paralysis of the will, that is, the 

 inhibition of a certain activity of the nerve cells of the cortex of the 

 cerebrum. 



In man, as in the frog, this inhibition may be brought about either 

 by impulses proceeding from the peripheral organs of sense, or by 

 impulses originating in the cortex itself. Of the former class, tactile 

 and visual impulses are most effective, although the mesmeric state 

 may be produced by auditory and probably by other impulses. A 

 man may, then, be mesmerised by passing the hands over or close 

 to the skin, or by making him look steadily at an object, or listen 

 intently to a sound. 



Whether the inhibitory impulses so set up produce inhibition or 

 not, depends upon the condition of the whole of the nervous system. 

 The effect of the inhibitory impulses may be counteracted by exciting 

 impulses coming from other parts of the central nervous system. In 

 many people the exciting impulses are always sufficiently strong to 

 overpower the inhibitory ones, and such people cannot be mesmerised. 

 In others, the inhibitory impulses must be kept up for a long time, 

 and repeated on successive days, before they acquire sufficient force 

 to overcome the exciting ones. Such people are mesmerised with 

 great difficulty. 



The great majority of people cannot be mesmerised unless they 

 consent to fix their attention on some particular object. This fixing 

 of the attention, speaking generally, seems to be a voluntary exclusion 

 of exciting impulses, leaving thus the inhibitory ones an open field. 

 Idiots, who, on account of the lack of co-ordination of their nerve 

 centres, cannot fix their attention for any length of time on any one 

 object, cannot as far as I know be mesmerised. Now this, now that part 

 of the brain becomes active, and exciting impulses are sent out which 

 overpower the inhibitory ones.* Inhibition from impulses arising in 

 the cortex itself are rare unless the patient has been previously mes- 

 merised. Some such cases, however, do occur. But in people who 

 have been previously mesmerised inhibition in this manner is of not 

 unfrequent occurrence ; within limits, the more often the changes in 



* It is said tliat some persons, whilst they arc sleeping, can be brought by 

 means of passes into the mesmeric state. It would be interesting to observe if 

 this can also be done with insane people. 



