42 Mr. J. N. tangley [March 14, 



understand, the most liable to misconception, and have attempted to 

 show that they resemble fundamentally certain simpler phenomena 

 which can be observed in lower animals. I have further attempted to 

 string together the various facts upon a thread of theory, which may 

 be briefly summed up as follows : — 



Tlie primary condition of mesmerism is an inhibition of a particular 

 mode of activity of the cortex of the brain, in consequence of which the 

 will can no longer be made effective. 



This inhibition may be brought about by nervous impulses coming 

 from certain sensory nerves, as those of sight, touch, hearing. 



It may also be brought about by impulses or changes arising in the 

 cortex itself. 



The inhibited cortex, and probably also inhibited lower centres of the 

 brain, send out inhibitory impulses to all other parts of the central 

 nervous system, so that the mesmerised man or animal gradually passes 

 into a state of torpor, or even of complete ancesthesia. 



The phenomena of the excitable stage of mesmerism are proximately 

 determined by the possibility of exciting any particular centre alone, 

 without exciting at the same time other centres by which its activity is 

 normally controlled. In lower animals this stage is less marked in 

 consequence of a greater interdependence of the various parts of the 

 central nervous system. 



I would expressly state that I regard this theory only as pro- 

 visional. Further, I am quite conscious that it is very imperfect. 

 A complete explanation of the phenomena of mesmerism and of its 

 allied states can only be given when we have a complete knowledge 

 of the structure and functions of all parts of the central nervous 

 system. But I have not much doubt that the explanation of the main 

 features of mesmerism will be found when we are able to answer the 

 question — What is inhibition ? And it is some comfort to think that 

 the answer awaits us in the comparatively simple nervous system of 

 the lower animals. I would not be understood to mean that varia- 

 tion of blood supply and various other events are of no influence in 

 producing mesmeric phenomena ; I think, however, that these events 

 are of secondary importance only. 



Finally, I would say a word about the attitude of physiologists to 

 animal magnetisers and mesmerists. It has sometimes been made a 

 subject of reproach to physiologists that they have not concerned 

 themselves more actively in investigating mesmeric phenomena. 

 The reproach has very little foundation. The knowledge which has 

 been gained on the subject has been gained almost entirely by 

 medical practitioners and by physiologists, and it must be remembered 

 that until lately most physiologists were also medical practitioners ; 

 the division of labour is of recent date. 



It is, however, true that in the beginning and middle part of this 

 century there were many scientific men who regarded the subject 

 with a contempt which intrinsically it did not deserve. But in my 



