Suspecting that this herb was the cause of their contumacy, we took a young hippopotamus, and kept him without food till he became quite ravenous. Some of the tender herbs were then brought, but he would not touch them, and evinced other symptoms of antipathy, while he showed his ravenousness by trying to seize the keeper. He was still kept without food, and the herbs were left within his reach, but he would not approach them, though, as soon as some of his usual food was brought, he greedily devoured it.
These beasts formerly infested the rivers which run through our cities; and a very powerful solution from the herb, which they could scent at a considerable distance, was prepared by our chemists. We have great locks at the entrances of our rivers. In these are concave places in which the preparation is deposited, and the dangerous beasts are thus kept at a great distance.
In our world the hippopotami are very fond of freshwater rivers. There is a large stream called the Aoe, the waters of which have a peculiar attraction for these beasts, and I have seen it covered with them for miles.
The waters of this river are very prejudicial to man; perhaps the qualities which make them agreeable to the beast render them antipathetic to man's constitution.
In their native state, the beasts like the land as much as the water, preferring it indeed during the prevalence of certain winds. I could tell, by the direction of these, whether few or many of the animals would come ashore. From my observatory, I have seen thousands together a long way off, looking like countless swarms of flies, and all moving in a compact mass, as though they were gregarious to the highest degree. When seen from a short distance, they look like a moving lead-colour bog. I have sent to caution the hunters, for on occasion the large herds are dangerous.
There are times when the hippopotami seek to be invisible; they then bury themselves in the sand, and not one can be seen. At other times, miles of country are covered with them.
When the wind is in a particular quarter it causes a remarkable musical sound in its passage through the hollow rocks, which seems particularly sympathetic to the hippopotami. If, at the time the "musical sound" is heard, the sun shines, they with great rapidity place the young ones together, running round them as round a central point in a succession of circles. They jump and bound, pass and repass each other, and as it were dance with joy, in a state of great excitement continuing their energetic gambols all the time the musical sound is heard, until, exhausted with their exertions, they lie down and sleep.