Then if I am an experiment, am I the whole of it? No, I think not; I think the rest of it is part of it. I am the main part of it, but I think the rest of it has its share in the matter. Is my position assured, or do I have to watch it and take care of it? The latter, perhaps. Some instinct tells me that eternal vigilance is the price of supremacy. [That is a good phrase, I think, for one so young.] [...]
I followed the other Experiment around, yesterday afternoon, at a distance, to see what it might be for, if I could. But I was not able to make out. I think it is a man. I had never seen a man, but it looked like one, and I feel sure that that is what it is. I realize that I feel more curiosity about it than about any of the other reptiles. If it is a reptile, and I suppose it is; for it has frowzy hair and blue eyes, and looks like a reptile. It has no hips; it tapers like a carrot; when it stands, it spreads itself apart like a derrick; so I think it is a reptile, though it may be architecture.
I was afraid of it at first, and started to run every time it turned around, for I thought it was going to chase me; but by and by I found it was only trying to get away, so after that I was not timid any more, but tracked it along, several hours, about twenty yards behind, which made it nervous and unhappy. At last it was a good deal worried, and climbed a tree. I waited a good while, then gave it up and went home.
Today the same thing over. I've got it up the tree again.
[M.Twain, Eve's diary]