THE CAUSATION OF DISEASE. 301 



various conditions, not altogether good for us ; yet, at least through 

 a long series of years, if we do not trespass beyond certain limits, 

 no apparent harm comes of it. And this should form part of the 

 answer to be given to the very frequent inquiry whether this or 

 that thing is wholesome or injurious. Many of these things are not 

 strictly beneficial, but the contrary; and yet, in moderation, they 

 may be indulged in, because, during life, there is a power in reserve 

 which enables us to cope with these comparatively insignificant 

 effects, and to overcome them again and again, without, for the most 

 part, any permanent injury. Take the case of alcohol. It is diffi- 

 cult to show that there is any advantage whatever in its habitual use 

 by a healthy man ; and yet it is equally difficult, in most instances, 

 to demonstrate any evil effect from moderate indulgence in it 



through lifetime. Or, take the instance of tobacco That the 



influence of these habits is rather injurious than otherwise to most 

 men, is suggested by the fact that when an effect appears at all it is 

 usually on the side of evil. But the explanation of the impunity 

 with which these and other practices are indulged in is probably to 

 be found in the fact that, in most of us, there is a power in reserve 

 — analogous, perhaps, to that of repair in the case of wound or 

 injury — by which mischief is, in great degree, resisted or overcome. 

 Yet, withal, it must be borne in mind that various habits may work 

 much evil in the long run, without the relation of cause to effect 

 becoming at any time apparent" — Introduction to " The Book of 

 Health," by W. S. Savory. 



Here Mr. Savory assumes a power of reserve by virtue of 

 which the body is capable of resisting more or less effectually 

 certain nocuous influences. I am more inclined, however, to 

 regard a particular agent as nocuous or innocuous in respect of a 

 particular individual only. Mr. Savory assumes that alcohol 

 and tobacco, even in small quantities, are injurious to every 

 one, but that the body possesses a "reserve power"' capable of 

 fighting against their ill effects. According to my view, each 

 man is a law in himself as regards the influence of any specific 

 E — e.g., alcohol and tobacco — upon him : a quantity of such E 

 that to one might be injurious, might to another be quite 

 harmless — nay, even beneficial. I say, the thing is either 

 doing him injury, or it is not ; and if it is not doing him 

 injury, I see no occasion to call upon any reserve power. In 

 those cases where alcohol and tobacco — notably the former — 



