184 SECTIONAL ADDRESSES. 



fed on a synthetic diet act as a poison, but if the rats are fed on bread 

 and milk the effect of the ergosterol is negligible. In real life we do not 

 live on a completely synthetic diet ; nearly everyone takes some if not 

 an abundance of fresh food, so the practical value of this type of experi- 

 ment may be over-estimated, though it is of considerable academical 

 interest. 



Civilisation has brought bad sanitation in houses, and even our windows 

 may be depriving us of fresh air and filtering out certain rays of light, 

 bringing its attendant tuberculosis — for tuberculosis is a disease of houses. 

 Science is now engaged in endeavouring to remedy the evil effects which 

 it has produced. 



Civilisation is associated with wealth, indoor life, luxury, and some- 

 times excessive mental exercise. These are conditions which lead to 

 exaggerated nervous sensibility, and this is a much commoner feature 

 in those engaged in a mental indoor life than in those engaged in an outdoor 

 physical life. It is not difiicult then to understand the excessive use of 

 tobacco in some of these people, since one effect of tobacco — and perhaps 

 its most beneficent effect — is to increase the threshold of sensation in 

 those who are supersensitive. When this supersensitiveness reaches 

 extreme limits these people are referred to as ' neurotic' They are so 

 highly reflex, so easily responsive to external impressions, that the asso- 

 ciations set loose by any ordinary stimulus cause such a complexity of 

 cerebration that the ordinary affairs of life become a burden ; they are 

 not phlegmatic and uninteresting, but are often possessed of quick 

 perception, a rapid response, and other higher attributes of mind which 

 go to make up high breeding and culture. They easily weary of the strain 

 and anxiety involved in the fight for existence, and anything that gives 

 relief from their cares and anxieties is seized with avidity. Now it is 

 these higher faculties of mind which are most responsive to narcotic 

 poisons, which influence these long before those concerned with movement 

 and ordinary sensation — so that the supersensitive people under the 

 influence of narcotics lose the exaggerated effect of their sensations, 

 and become more like normal people ; the everyday trifles and incon- 

 veniences of life are no longer exaggerated out of proportion to their 

 significance, and life, instead of being oppressive and anxious, becomes 

 pleasant and free from worry. Sometimes the very acuity of their 

 intellect is their undoing. Perhaps in a few special instances persons 

 possessed of such vivid sensations may benefit by a narcotic which limits 

 these conflicting impulses by allowing a freer play of some of the higher 

 mental faculties ; certainly the records of De Quincey and Coleridge 

 suggest such a possibility. Hence it is easy to understand the modern 

 tendency in some highly civilised nations to indulge in narcotic drugs 

 like morphine, heroine, and cocaine. 



It is another curious fact that it is just these supersensitive people who 

 drink the caffeine beverages, like tea and coffee, in excess. Since the 

 seventeenth century the use of the caffeine beverages has slowly increased, 

 whilst that of beer and allied drinks has slowly diminished. Beer, from 

 its essential oils and alcohol, is a soothing beverage ; it depresses the 

 higher faculties of mind, it does not exaggerate their activity. Caffeine, 

 on the other hand, relieves drowsiness and fatigue by direct stimulation 



