air, light and proper food.  He ridiculed, too, the notion of unhealthy places.  “It is like,” he wrote to Mr. Birch, “the old idea that every child must have measles, and the sooner the better.”  To the same correspondent, who was contemplating going into virgin forests and who expressed his fear of malaria, he replied:  “There is no special danger of malaria or other diseases in a dense forest region.  I am sure this is a delusion, and the dense virgin forests, even when swampy, are, in a state of nature, perfectly healthy to live in.  It is man’s tampering with them, and man’s own bad habits of living, that render them unhealthy.  Having now gone over all Spruce’s journals and letters during his twelve years’ life in and about the Amazonian forests, I am sure this is so.  And even where a place is said to be notoriously ‘malarious,’ it is mostly due not to infection only but to predisposition due to malnutrition or some bad mode of living.  A person living healthily may, for the most part, laugh at such terrors.  Neither I nor Spruce ever got fevers when we lived in the forests and were able to get wholesome food.”  “Health,” he said to the present writer, “is the best resistant to disease, and not the artificial giving of a mild form of a disease in order to render the body immune to it for a season.  Vaccination is not only condemned upon the statistics which are used to uphold it, but it is a false principle—­unscientific, and therefore doomed to fail in the end.”  Besides which, he believed in mental healing, and had recorded definite and certain benefit from spiritual “healers.”  And he reminded himself that amongst doctors (witness the blind opposition encountered by Lister’s discoveries) were found from time to time not a few enemies of the true healing art, and obstinate defenders of many forms of quackery.  Wallace made no claim to be an original investigator.  He knew his limitations, and said again and again that he could not have conducted the slow and minute researches or have accumulated the vast amount of detailed evidence to which Darwin, with infinite patience, devoted his life.  He was genuinely glad that it had not fallen to his lot to write “The Origin of Species.”  He felt that his chief faculty was to reason from facts which others discovered.  Yet he had that original insight and creative faculty which enabled him to see, often as by flashlight, the explanation which had remained hidden from the eyes of the man who was most familiar with the particular facts, and he elaborated it with quickening pulse, anxious to put down the whole conception which filled his mind lest some portion of it should escape him.  Therein lay one secret of his great genius.  He often said that he was an idler, but we know that he was a patient and industrious worker.  His idleness was his way of describing his long musings, waiting the bidding of her whom God inspires—­Truth, who often hides her face from the clouded eyes of man.  For hours, days, weeks, he was disinclined