De Potter is one of the noblest-looking men I ever saw. He is quite bald, with a broad, ample, majestic head, the very model of dignity and intellect. Dr. Spurzheim considers his head one of the most extraordinary he has met. _Firmness_ is the great development of its organs. His tone and manner are calm and very impressive, and he looks made for great occasions--a man stamped with the superiority which others acknowledge when circumstances demand it. He employs himself in literary pursuits at Paris, and has just published a pamphlet on "the manner of conducting a revolution, so that no after-revolution shall be necessary." I have translated the title awkwardly, but that is the subject. I have since heard Dr. Spurzheim lecture twice, and have been with him to a meeting of the "Anthropological Society" (of which he is the president and De Potter the secretary), where I witnessed the dissection of the human brain. It was a most interesting and satisfactory experiment, as an illustration of phrenology. David the sculptor is a member of the society, and was present. He looks more like a soldier than an artist, however--wearing the cross of the Legion of Honor, with a military frock coat, and an erect, stern, military carriage. Spurzheim lectures in a free, easy, unconstrained style, with occasionally a little humor, and draws his arguments from admitted facts only. Nothing could be more reasonable than his premises, and nothing more like an axiom than the results, as far as I have heard him. At any rate, true or false, his theory is one of extreme interest, and no time can be wasted in examining it; for it is the study of man, and therefore the most important of studies. I have had several long conversations with Dr. Spurzheim about America, and have at last obtained his positive assurance that he would visit it. He gave me permission this morning to say (what I am sure all lovers of knowledge will be pleased to hear) that he should sail for New York in the course of the ensuing summer, and pass a year or more in lecturing and travelling in the United States. He is a man to obtain the immediate confidence and respect of a people like ours, of the highest moral worth, and the most candid and open mind. LETTER XXI. DEPARTURE FROM PARIS--DESULTORY REMARKS.