Much thought has been given by naturalists to the exact origin of the various races of domesticated animals. Speaking in general terms, it may be said that Asia is the great original home of domesticated animals as a class. Possibly the dog may be the descendant of some European wolf, and he had perhaps become the companion of man before that great hypothetical eastward migration of the Aryans took place, which the modern ethnologist believes to have preceded the Asiatic settlement of that race. The cat also may not unlikely be a descendant of the European wild cat, but the sheep, the cow, the donkey, and the horse, as well as the barnyard fowl, are almost unquestionably of Asiatic origin. Of these the horse was probably the last to be domesticated, since we find that the Egyptians did not employ this animal until a relatively late stage of the historic period, namely, about the twentieth century B.C. This does not mean that the horse was unknown to the Asiatic nations until so late a period, but it suggests a relatively recent use of this animal as compared, for example, with the use of cattle, which had been introduced into Egypt before the beginning of the historic period. No animal of importance and only one bird--the turkey--has been added to the list of domesticated creatures since the dawn of history. _Sixth. Agriculture._ The studies of the philologists make it certain that long periods of time elapsed after man had entered on a pastoral life before he became an agriculturist. The proof of this is found, for example, in the fact that the Greeks and Romans use words obviously of the same derivation for the names of various domesticated animals, while a similar uniformity does not pertain to their names for cultivated cereals or for implements of agriculture. Theoretical considerations of the probable state of pastoral man would lead to the same conclusion, for the gap between the wandering habits of the owners of flocks, whose chief care was to find pasture, and the fixed abode of an agricultural people, is indeed a wide one. To be sure, the earliest agriculturist may not have been a strictly permanent resident of any particular district; he might migrate like the bird with the seasons, and change the region of his abode utterly from year to year, but he must in the nature of the case have remained in one place for several months together, that is to say, from sowing to harvest time; and to people of nomadic instincts this interference with their desires might be extremely irksome, to say nothing of the work involved in cultivating the soil. But once the advantages of producing a vegetable food supply, according to a preconceived plan, instead of depending upon the precarious supply of nature, were fully understood and appreciated, another great forward movement had been made in the direction of ultimate civilisation. Incidentally it may be added that another incentive had been given one tribe to prey upon another, and conversely