But they were all undone at last, only there was one immensely wealthy old merman who was never quite sure in his mind that he had got back his own proper curly fish’s tail, and not that of some other gentleman, so that all the rest of his life he was in a puzzle as to at least half his personal identity. This incident so vexed him that he did not give anything to the college funds, as he had fully intended. This circumstance and a few other accidents had so annoyed the professor that instead of going to the North Seas with his grandson he shut himself up in the house and began to write a book. The book was in opposition to a theory put forth by a learned merman in the Baltic Sea that human beings were undeveloped mermen. The professor, however, declared that they were no such thing, but simply undeveloped walruses. He began his first chapter by saying that, while he had the highest respect for the Baltic merman’s acquirements, intellect, penetration and general infallibility, he nevertheless felt himself obliged to declare that none but an idiot or a madman could come to the conclusion of the learned man aforesaid. He (the professor) wished to lay down his platform in the beginnings and state that he differed from the opinions of the learned author on this and all other conceivable points. “You’d a good deal better go along with me, grandfather,” said the young merman, swimming into the room where the professor was sitting with his big books all about him. “Think how nice and cool it will be among the icebergs this hot weather. Hadn’t you better come?” “I won’t,” said the old professor, snapping and switching his tail angrily round in the water, for the houses there are full of water, as ours are of air. “I didn’t say you would, sir,” said the young merman; “I said you’d better.” “Did you ever know me say I would do a thing when I did?” returned the professor, angrily. “I mean, did you ever know me say I did do a thing when I would? Pooh! Pshaw! That isn’t what I mean.” “Yes, sir!” said his grandson, respectfully. “What do you mean by that?” said the professor, sharply. “There’s that catfish mewing at the door. Get up and let her in, do, and make yourself useful for once in your life.” The young merman got up and opened the door for the catfish, which came swimming in, followed by two little kitten fish. These, frisking playfully around the room, soon overset the professor’s inkstand. “There!” said the professor to his grandson. “That’s all your fault! What did you let them in for? Open the windows and let in some fresh water, do. Scat! scat! you little torments! I don’t believe the cook has given them their dinner; she never does unless I see to it myself; your sisters forget them. No, I’m not going to the North Seas; I can’t spare the time.” “Don’t you think you can, sir?” said the young merman. “What odds does it make about those forked creatures on land?”