To letter-writing he had a great aversion.  I have never seen a letter or note from him to which his signature was attached.  The autograph-fanciers, therefore, will find a scanty harvest when they come to forage after the name of Percival.  His handwriting corresponded in some sense with his character.  It was fine; the lines straight and parallel; the letters completely formed, though without fulness of curve; no flourishes, and no unnecessary prolongations of stroke, above or below the general run of the line.  There were few erasures, the punctuation was perfect, and the manuscript was fit for the press as it left his hand.

Literary criticism he rarely indulged in, being too disinclined to praise or blame, and too intensely devoted to the acquisition of positive knowledge.  If he commented severely upon anything, it was usually the slovenly diction of some of our State Surveys, or the inaccuracies of translations from foreign languages.

His only published criticism, of which I am aware, was discharged at a phrenological lecturer, whose extraordinary assumptions and ad-captandum style had excited his disgust.  Percival did not reverence the science of bumps, and believed, in the words of William Von Humboldt, that “it is one of those discoveries which, when stripped of all the charlatanerie that surrounds them, will show but a very meagre portion of truth.”  Dr. Barber, an Englishman, and a somewhat noted teacher of elocution, having been converted to the phrenological faith, delivered certain magniloquent lectures on the same to the citizens of New Haven, and took pay therefor, after the manner of his sect.  Percival responded with a sharp newspaper pasquinade, entitled “A Lecture on Nosology.”  At the head of the article was a wood-cut of a gigantic nose, mapped out into faculties.  “Gentlemen, the nose is the most prominent feature in this bill,” commenced the parody.  “The nose is the true seat of the mind; and therefore, gentlemen, Nosology, or the science of the nose, is the true phrenology.  He, who knows his nose, foreknows; for he knows that which is before him.  Therefore Nosology is the surest guide to conduct.  Whatever progress an individual may make, his nose is always in advance.  But society is only a congeries of individuals; consequently its nose is always in advance,—­therefore its proper guide.  The nose, rightly understood, will assuredly work wonders in the cause of improvement; for it is always going ahead, always first in every undertaking, always soonest at the goal.  The ancients did not neglect the nose.  Look at their busts and statues!  What magnification and abduction in Jove!  What insinuation and elongation in the Apollo!  Then [Greek:  nous] (intellect) was surely the nose,—­[Greek:  gnosis] (knowledge) noses,—­[Greek:  Minos] my nose.  What intussusception, what potation, and, as a necessary consequence, alas! what rubification!  But I have seen such noses.  Beware of them!—­they