He poin­ted out—writ­ing in a fool­ish, fa­cetious tone—that the per­fec­tion of mech­an­ical ap­pli­ances must ul­ti­mately su­per­sede limbs; the per­fec­tion of chem­ical devices, di­ges­tion; that such or­gans as hair, ex­ternal nose, teeth, ears, and chin were no longer es­sen­tial parts of the hu­man be­ing, and that the tend­ency of nat­ural se­lec­tion would lie in the dir­ec­tion of their steady di­minu­tion through the com­ing ages.