His knowledge of the Mediterranean fishes not only exceeded that of any ancient writer, but also, if Belon, Rondolet, and Salviani be excepted, that of any writer before Risso and Cuvier. However true may be the criticism of Dr. Günther that Aristotle’s “ideas of specific distinction were as vague as those of the fishermen whose nomenclature he adopted,” the fact cannot be gainsaid that Aristotle was, and remains, a very great Naturalist as well as a very great Biologist. To him[244] by right belongs the distinction, which (except incidentally in Mr. Lones’ work[245]) I have so far failed to find attributed to him, of being the first writer to note, certainly the first to point out, that its scales make possible a shrewd, in the case of the _murex_ an exact, computation of the age of a fish. If from lack of the microscope he did not in all particulars antedate, he certainly blazed the trail for the discovery of scale-reading at the close of the eighteenth century by the Dutch microscopist van Leeuwenhoek[246] and its rediscovery as regards the carp in 1899 by Hoffbauer,[247] the _Gadidæ_ and _Pleuronectidæ_ in 1900-03 by J. Stuart Thomson,[248] and the _Salmonidæ_ about 1904 by H. W. Johnston and others.[249] He tells us in _The Natural History_, I. 1, that “what the feather is in a bird, the scale is in a fish”; in III. 11,[250] that “the scales of fish become harder and thicker, and in those which are wasting or aging, become still harder”; in VIII. 30, that “the old fish are distinguishable by the _size_” (note this!) “and the hardness of their scales.”[251] He then buttresses this discovery of annual growth of scale by another fact resulting from his observation that “the _Murex_ lives for about six years, and the yearly increase is indicated by a distinct interval in the spiral convolution of the shell,”[252] or as Bohn renders the words, “its annual increase is seen in the divisions on the helix of its shell.” In Leeuwenhoek we read that, in the examination by a rough self-made microscope of the scales of a large tame carp, he counted the component _scale-layers_ lying one above the other, “as if glued together,” and found without exception that a new layer larger than the one of the preceding year is added. The carp, accidentally killed when forty years old, possessed forty such layers in each scale. He adds pathetically—anticipating perhaps Lytton’s— “A Reformer, a creed by posterity learnt A century after its author is burnt”— that “many people accused me of telling lies on the matter!”[253] One cannot help being struck with acute astonishment that for over the 2000 years between Aristotle and Leeuwenhoek we obtain, with the exception[254] of nine words in Pliny (IX. 33), _Senectutis indicium squamarum duritia, quæ non sunt omnibus similes_, cribbed and condensed, as was often his wont, from Aristotle, little, if any, addition to our knowledge of scale-reading.