There are only two reasonable solutions of this exceedingly curious fact. The one is, that men of highly original ideas, like the mythical Prometheus, arose from time to time in the dawn of human progress, and left their respective marks on the world by being the first to subjugate the camel, the llama, the reindeer, the horse, the ox, the sheep, the hog, the dog, or some other animal to the service of man. The other hypothesis is that only a few species of animals are fitted by their nature to become domestic, and that these were discovered long ago through the exercise of no higher intelligence than is to be found among barbarous tribes of the present day. The failure of civilised man to add to the number of domesticated species would on this supposition be due to the fact that all the suitable material whence domestic animals could be derived has been long since worked out. I submit that the latter hypothesis is the true one for the reasons about to be given; and if so, the finality of the process of domestication must be accepted as one of the most striking instances of the inflexibility of natural disposition, and of the limitations thereby imposed upon the [15] choice of careers for animals, and by analogy for those of men. [Footnote 15: _Transactionsof the Ethnological Society_, 1865, with an alteration in the opening and concluding paragraphs, and with a few verbal emendations. If I had discussed the subject now for the first time I should have given extracts from the and with a few verbal emendations. If I had discussed the subject now for the first time I should have given extracts from the works of the travellers of the day, but it seemed needless to reopen the inquiry merely to give it a more modern air. I have also preferred to let the chapter stand as it was written, because considerable portions of it have been quoted by various authors (_e.g._ Bagehot, _Economic Studies_, pp. 161 to 166: Longman, 1880), and the original memoir is not easily accessible.] My argument will be this:--All savages maintain pet animals, many tribes have sacred ones, and kings of ancient states have imported captive animals on a vast scale, for purposes of show, from neighbouring countries. I infer that every animal, of any pretensions, has been tamed over and over again, and has had numerous opportunities of becoming domesticated. But the cases are rare in which these opportunities have led to any result. No animal is fitted for domestication unless it fulfils certain stringent conditions, which I will endeavour to state and to discuss. My conclusion is, that all domesticable animals of any note have long ago fallen under the yoke of man. In short, that the animal creation has been pretty thoroughly, though half unconsciously, explored, by the every-day habits of rude races and simple civilisations.