After crossing the river, we soon reached Pital, where I had a cup of tea and got a fresh mule. We now turned nearly at right angles to our former course, and struck into the dark forest, the road through which I have already described. It was very wet and muddy. In some places, although it was only the commencement of the wet season, the mules sank above their knees. On this occasion, as on many others, I had often to notice how well the mule remembered places where in some former year it had avoided a particularly bad part by making a detour. I was riding a mule that had tender feet, having just recovered from the bite of a spider, that had occasioned the loss of one of its hoofs, and when it came near to a place where it could escape the deep mud by going over a stony part it would slacken its pace and look first at the mud, then at the stones, evidently balancing in its mind which was the lesser evil. Sometimes, too, when it came to a very bad place, which was better at the sides, I left it to itself, and it would be so undecided which side was the best, that making towards one it would look towards the other, and end by getting into the worst of the mud. It was just like many men who cannot decide which of two courses to take, and end by a middle one, which is worse than either. And just as in men, so in mules, there is every variety of disposition and ability. Some are easily led, others most obstinate and headstrong; some wise and prudent, others foolish and rash. The memory of localities is much stronger in horses and mules than in man. When travelling along a road that they have been over only once, and that some years before, where there are numerous branch roads and turnings, they will never make a mistake, even in the dark; and I have often, at night, when I could not make out the road myself, left them to their own guidance, and they have taken me safely to my destination. Only once was I misled, and that through the too good memory of my mule. Many years before it had been taken to a pasture of good grass, and recollecting this, it took me several miles out of my road towards its old feeding-ground, causing me to be benighted in consequence. I reached the mines at nine o'clock, and found that during my absence it had been raining almost continuously, although at Juigalpa there had been only a few slight showers. CHAPTER 11. Start on journey to Segovia. Rocky mountain road. A poor lodging. The rock of Cuapo. The use of large beaks in some birds. Comoapa. A native doctor. Vultures. Flight of birds that soar. Natives live from generation to generation on the same spot. Do not give distinctive names to the rivers. Caribs barter guns and iron pots for dogs. The hairless dogs of tropical America. Difference between artificial and natural selection. The cause of sterility between allied species considered. The disadvantages of a covering of hair to a domesticated animal in a tropical country.