The lives of authors and artists exhibit a most painful disease in that jealousy which is the perpetual fever of their existence. Why does PLATO never mention XENOPHON, and why does XENOPHON inveigh against PLATO, studiously collecting every little rumour which may detract from his fame? They wrote on the same subject! The studied affectation of ARISTOTLE to differ from the doctrines of his master PLATO while he was following them, led him into ambiguities and contradictions which have been remarked. The two fathers of our poetry, CHAUCER and GOWER, suffered their friendship to be interrupted towards the close of their lives. Chaucer bitterly reflects on his friend for the indelicacy of some of his tales: "Of all such _cursed stories_ I say fy!" and GOWER, evidently in return, erased those verses in praise of his friend which he had inserted in the first copy of his "Confessio Amantis." Why did CORNEILLE, tottering to the grave, when RACINE consulted him on his first tragedy, advise the author never to write another? Why does VOLTAIRE continually detract from the sublimity of Corneille, the sweetness of Racine, and the fire of Crebillon? Why did DRYDEN never speak of OTWAY with kindness but when in his grave, then acknowledging that Otway excelled him in the pathetic? Why did LEIBNITZ speak slightingly of LOCKE's Essay, and meditate on nothing less than the complete overthrow of NEWTON'S system? Why, when Boccaccio sent to PETRARCH a copy of DANTE, declaring that the work was like a first light which had illuminated his mind, did Petrarch boldly observe that he had not been anxious to inquire after it, for intending himself to compose in the vernacular idiom, he had no wish to be considered as a plagiary? and he only allows Dante's superiority from having written in the vulgar idiom, which he did not consider an enviable merit. Thus frigidly Petrarch could behold the solitary AEtna before him, in the "Inferno," while he shrunk into himself with the painful consciousness of the existence of another poet, obscuring his own majesty. It is curious to observe Lord SHAFTESBURY treating with the most acrimonious contempt the great writers of his own times--Cowley, Dryden, Addison, and Prior. We cannot imagine that his lordship was so entirely destitute of every feeling of wit and genius as would appear by this damnatory criticism on all the wit and genius of his age. It is not, indeed, difficult to comprehend a different motive for this extravagant censure in the jealousy which even a great writer often experiences when he comes in contact with his living rivals, and hardily, if not impudently, practises those arts of critical detraction to raise a moment's delusion, which can gratify no one but himself.