There were probably a greater number of tropic birds than of any others. They would not got out of our way as we walked along, allowing us to shove them over rather than move.  We literally also took their eggs from under them, without their attempting to make any defence.  This apathy, as we called it, we thought arose from stupidity, but the doctor examined one of them, and showed us how weak its legs were, while its feet were adapted only for swimming.  Its wings, however, were very long and powerful.  Therefore, had it been up in the air, or skimming along over the summit of the waves, it would probably have acted in a very different way.  "Never judge of people till you know the sphere of life in which they have been accustomed to move," remarked the doctor.  "A really sensible, clever man, may appear very stupid and dull, just as these poor birds do, simply because he is out of his element."