fication might, in course of time, be expected, the present truth should be most carefully made out, and having been accurately recorded and published, observation, after a certain length of time, should again be focussed on the same points, and this being renewed every ten, twenty, fifty, or a hundred years, the results could be compared. For instance, our green woodpecker feeds now largely upon ants in their nests, whilst it both fights and copulates upon the ground. How interesting would it be if we had a continuous record of observations of this bird's habits, dating, say, from William the Conqueror or the days of the Saxon Heptarchy, and if we found that no mention was made of these peculiarities, by the field naturalists of those times, but that they first began to be doubtfully recorded in the reign of Henry the Fifth, or Richard the Third. No doubt a connected chain of evidence of this kind will gradually grow up, owing to the accumulation of works of natural history, but it would, I think, be a great deal more satisfactory if the object were kept steadily in view, and I am quite sure that observations made in this spirit would produce much more interesting matter than that which is to be found in the ordinary bird or beast book. For the great idea would then be to compare the present with the past habits of any creature, in order to see whether, or in what degree, they have changed, and this could only be done by continual re-observation, which would assuredly lead to novelty of some sort, instead of mere repetition, which is what we