Among vertebrate animals we similarly trace up, along with advance in structures and functions, this advance in conduct. A fish roaming about at hazard in search of something to eat, able to detect it by smell or sight only within short distances, and now and again rushing away in alarm on the approach of a bigger fish, makes adjustments of acts to ends that are relatively few and simple in their kinds; and shows us, as a consequence, how small is the average duration of life. So few survive to maturity that, to make up for destruction of unhatched young and small fry and half-grown individuals, a million ova have to be spawned by a cod-fish that two may reach the spawning age. Conversely, by a highly-evolved mammal, such as an elephant, those general actions performed in common with the fish are far better adjusted to their ends. By sight as well, probably, as by odor, it detects food at relatively great distances; and when, at intervals, there arises a need for escape, relatively great speed is attained. But the chief difference arises from the addition of new sets of adjustments. We have combined actions which facilitate nutrition--the breaking off of succulent and fruit-bearing branches, the selecting of edible growths throughout a comparatively wide reach; and, in case of danger, safety can be achieved not by flight only, but, if necessary, by defence or attack: bringing into combined use tusks, trunk and ponderous feet. Further, we see various subsidiary acts adjusted to subsidiary ends--now the going into a river for coolness, and using the trunk as a means of projecting water over the body; now the employment of a bough for sweeping away flies from the back; now the making of signal sounds to alarm the herd, and adapting the actions to such sounds when made by others. Evidently, the effect of this more highly-evolved conduct is to secure the balance of the organic actions throughout far longer periods.