Latin scholars would have felt far more hesitation in introducing the old _d_ of the ablative in Plautus, if the analogy of Sanskrit had not so clearly proved its legitimacy. On the other hand, we, comparative philologists, should readily ask and gladly accept the advice and help of our classical colleagues. Without their guidance, we can never advance securely; their warnings are to us of the greatest advantage, their approval our best reward. We are often too bold, we do not see all the difficulties that stand in the way of our speculations, we are too apt to forget that, in addition to its general Aryan character, every language has its peculiar genius. Let us all be on our guard against omniscience and infallibility. Only through a frank, honest, and truly brotherly coöperation can we hope for a true advancement of knowledge. We all want the same thing; we all are _etymologists_--that is, lovers of truth. For this, before all things, the spirit of truth, which is the living spirit of all science, must dwell within us. Whoever cannot yield to the voice of truth, whoever cannot say, “I was wrong,” knows little as yet of the true spirit of science. Allow me, in conclusion, to recall to your remembrance another passage from Niebuhr. He belongs to the good old race of German scholars. “Above all things,” he writes, “we must in all scientific pursuits preserve our truthfulness so pure that we thoroughly eschew every false appearance; that we represent not even the smallest thing as certain of which we are not completely convinced; that if we have to propose a conjecture, we spare no effort in representing the exact degree of its probability. If we do not ourselves, when it is possible, indicate our errors, even such as no one else is likely to discover; if, in laying down our pen, we cannot say in the sight of God, ‘Upon strict examination, I have knowingly written nothing that is not true;’ and if, without deceiving either ourselves or others, we have not presented even our most odious opponents in such a light only that we could justify it upon our death-beds--if we cannot do this, study and literature serve only to make us unrighteous and sinful.” Few, I fear, could add, with Niebuhr: “In this I am convinced that I do not require from others anything of which a higher spirit, if He could read my soul, could convict me of having done the contrary.” But all of us, young as well as old, should keep these words before our eyes and in our hearts. Thus, and thus only, will our studies not miss their highest goal: thus, and thus only, may we hope to become true etymologists--_i.e._, true lovers, seekers, and, I trust, finders of truth. NOTES. NOTE A. Θεός AND DEUS.