This was a robust and powerful man of about forty years of age, with long, black hair, high forehead, sallow complexion; intellectual expression, and most intelligent countenance, He approached the doctor, and said to him, in a tone of exquisite politeness, although slightly constrained, "Doctor, I ought, in my turn, to have the right of conversing and walking with the blind man; I have the honor of observing to you that there is a flagrant injustice in depriving this unfortunate man of my conversation, to deliver him" (and the madman smiled with bitter disdain) "to the stupid incoherences of an idiot, who is completely a stranger (I hazard nothing in saying it)--completely a stranger to the least notions of any science whatever, while my conversation might divert the attention of the blind man. Thus," added he, with extreme volubility, "I would have told him my opinion on the isothermal and orthogonal superficies, causing him to observe that the equations of partial differences, of which the geometrical explanation is summed up in two orthogonal superficies, cannot generally be integral on account of their complication. I should have proved to him that the united superficies are all necessarily isothermal, and together we would have sought what superficies are capable of composing a trebly isothermal system. If I do not deceive myself, sir, compare this recreation with the stupid nonsense with which they entertain this blind man," added the lunatic, taking breath, "and tell me, is it not a pity to deprive him of my conversation?" "Do not take what he has just said, madame, for the wanderings of a madman," whispered the doctor; "he handles in this way sometimes the most difficult questions of geometry or astronomy, with an acuteness which would do honor to the most illustrious learned men. His knowledge is great. He speaks all the living languages, but he is, alas! a martyr to his thirst for erudition and pride of learning. He imagines that he has absorbed all human knowledge, and that, by retaining him here, humanity is thrown back into the darkness of the most profound ignorance." The doctor replied aloud to the lunatic, who seemed to await his reply with a respectful anxiety, "My dear M. Charles, your complaint appears to me very just, and this poor blind man, who, I believe, is dumb, but, happily, is not deaf, will have great delight in the conversation of a man as learned as you are. I will see that you have justice done you." "Besides, by retaining me here, you deprive the universe of all human knowledge, which I have appropriated to myself by assimilation," said the madman, becoming animated by degrees, and commencing to gesticulate with great violence.