(he was a great believer in the healing powers of cheerfulness, if not of open mirth). Yet he had some faults, and one was a habit of dosing himself, generally from a spirit of enquiry, as in his period of inhaling large quantities of the nitrous oxide and of the vapour of hemp, to say nothing of tobacco, bhang in all its charming varieties in India, betel in Java and the neighbouring islands, qat in the Red Sea, and hallucinating cacti in South America, but sometimes for relief from distress, as when he became addicted to opium in one form or another; and now he was busily poisoning himself with coca-leaves, whose virtue he had learnt in Peru.