"When I was a boy, I was very fond of music, and I am so now; and it so happened that I had the opportunity of hearing much good music. Among other things, I had abundant opportunities of hearing that great old master, Sebastian Bach. I remember perfectly well--although I knew nothing about music then, and, I may add, know nothing whatever about it now--the intense satisfaction and delight which I had in listening, by the hour together, to Bach's fugues. It is a pleasure which remains with me, I am glad to think; but, of late years, I have tried to find out the why and wherefore, and it has often occurred to me that the pleasure derived from musical compositions of this kind is essentially of the same nature as that which is derived from pursuits which are commonly regarded as purely intellectual. I mean, that the source of pleasure is exactly the same as in most of my problems in morphology--that you have the theme in one of the old masters' works followed out in all its endless variations, always appearing and always reminding you of unity in variety." He had a hot temper, and did not readily brook opposition, especially when that seemed to him to be the result of stupidity or of prejudice rather than of reason, and his own reason was of a very clear, decided, and exact order. He had little sympathy with vacillation of any kind, whether it arose from mere infirmity of purpose or from the temperament which delights in balancing opposing considerations. He said on one occasion: "A great lawyer-statesman and philosopher of a former age--I mean Francis Bacon--said that truth came out of error much more rapidly than out of confusion. There is a wonderful truth in that saying. Next to being right in this world, the best of all things is to be clearly and definitely wrong, because you will come out somewhere. If you go buzzing about between right and wrong, vibrating and fluctuating, you come out nowhere; but if you are absolutely and thoroughly and persistently wrong, you must, some of these days, have the extreme good fortune of knocking your head against a fact, and that sets you all straight again. So I will not trouble myself as to whether I may be right or wrong in what I am about to say, but at any rate I hope to be clear and definite; and then you will be able to judge for yourselves whether, in following out the train of thought I have to introduce, you knock your heads against facts or not."