OF MALARIA. 33 



industriously ; to brush away the whole labor of the lives 

 of many eminent men, and to reflect upon the time and 

 talent lavished wastefully upon mere day-dreams. We 

 cannot also fail to perceive the great fallibility of human 

 opinion, as thus exemplified, nor can we avoid the dread 

 that we ourselves may have to mourn hereafter, over the 

 unproductive labors of our own lives, or leave to our 

 children the thankless office of removing our worthless 

 mental rubbish, to make way for perhaps not more sub- 

 stantial edifices. Be this as it may, we derive from the 

 review the useful lesson of philosophic humility, which 

 teaches us to state or receive new doctrines with becoming 

 hesitation, and to bring them into practical application 

 with prudent caution, and then only when sustained by 

 the prolonged observation of many persons in many 

 places, and at various times. 



