The Rat is so thoroughly omnivorous that it would be equally absurd to attempt a list of its food: there is nothing that can be eaten that the Rat will not eat. Therefore, there is no possibility of starving him out. Rat-killing campaigns that do not cover every square yard of the country can only have the effect of temporarily mitigating the nuisance; for the Rats' fertility is so great and so rapid that the loss of nine-tenths of a generation is quickly made good. A continental statistician has worked out the theoretical progeny of a single pair of Rats after ten years as reaching the appalling figure of 48,319,698,843,030,344,720! Of course, there is no great value in such a calculation, for it proceeds upon the assumption that every individual lives to become a parent, whereas in fact the mortality in all creatures of such fecundity is enormous, and there are few if any more survivors this year than there were last year. In other words, the great fertility of a race only suffices to make up the wastage from enemy attacks. But the figures serve to show what might happen if the natural control by Weasels, Stoats, Hawks, and Owls were suspended for a short time. But Rats are disseminators of bubonic plague with the aid of their special species of flea. *Water Vole* (_Arvicola amphibius_, Linn.). In certain directions it appears that failure is the lot of those who have spent the greater part of their lives in trying to spread enlightened views as to the true nature of our native animals and plants. Among a number of such failures two or three may be briefly cited here: you cannot persuade a countryman that a slow-worm is not a snake, that all snakes are not poisonous and to be killed at sight, and that the comparatively inoffensive rodent now to be described is not a rat and of rat-like nature. The name of Water Rat is general as a true folk-name.