THE CAUSATION OF DISEASE. 317 



own diversion, such change does not work the same exhilarating 

 effect upon it as diversity of external surroundings. It is better 

 that the change should strike through the senses ; and there 

 can be no doubt that the good effect of travel upon health 

 is in very large measure due to change of scene, social sur- 

 roundings, and general mode of life. Reading, to take the 

 commonest form of mental diversion, is essentially a subjective 

 process ; when occupied with it, the mind is largely bent in 

 upon itself ; the thoughts do not actively go out to surrounding 

 objects. It is true that by many kinds of reading the indi- 

 vidual is to a large extent drawn out of himself, but by no 

 means to the same extent as by actual observation of the outer 

 world. But if his surroundings are quite new, and at the 

 same time capable of commanding his rapt attention, then 

 indeed he becomes self-forgetful, and has little opportunity to 

 harbour gloomy thoughts, which depress the vital processes 

 and retard recovery. It is very remarkable what a potent 

 influence the mind has upon the body. A careful study 

 of Dr. Tuke's book on this subject will bring this truth 

 forcibly home to the reader. There are many ways of in- 

 fluencing mind ; but when our object is to draw the individual 

 out of himself, there is no method so effectual as that of sending 

 him away from home, and, by so doing, diverting the current 

 of his thoughts out of the channel in which they have too long 

 stagnated. The altered mental state that rapidly ensues reacts 

 upon the body ; there is increase of appetite, a quickening of 

 the circulation, better sleep, a rapid improvement in general 

 bodily health. No doubt such improvement is due in large 

 measure to the direct effect of changed locality upon the body ; 

 nevertheless, all will allow that the mental effect of the 

 altered surroundings often plays a very considerable — in some 

 cases the chief — share in the process, and it is indeed very 

 remarkable that those subtle cortical changes which are the 

 concomitants of thought should be capable of working such 

 marked effect upon the body — turning the balance, it may be, 

 in favour of Life or Death ! 



