108 ARISTOTLE THE FIRST SCALE-READER 
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 ! and its rediscovery as 
regards the carp in 1899 by Hoffbauer,? the Gadide and 
Pleuronectide in 1900-03 by J. Stuart Thomson, and the 
Salmonide about 1904 by H. W. Johnston and others.4 
He tells usin The Natural History, I. 1,that “what the feather 
is in a bird, the scale is in a fish ”’ ; in III. 11,5 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 szze”’ (note this !) “‘and the hardness 
of their scales.”’ & 
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,’’? 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 
1 Select Works, vol. i. p. 69. London, 1798-1801. 
2 «Die Altersbestimmung des Karpfen an seiner Schuppe,”’ in the R. Jahyves- 
ber. des Schlesischen Fischeret-Vereins ftv 1899. 
3 “The periodic growth of Scales in Gadide and Pleuronectide as an 
Index of Age,” in the Journal of the Marine Biolog. Assoc. (1900-03), VI. 
373-375: 
4 Reports of Scottish Fishery Board, 1904, 1906, 1907. 
& Ch. Anim, Gen., V. 3. 
8 ByAo1 8 of yépovres abrav TH peyeber Tav Aewidwv kal TH cKAnpéTnTt. Professor 
D’Arcy Thompson, in his translation, renders this sentence “‘ the age of a scaly 
fish may be told by the size and hardness of the scales.’’ It is most probable, 
though not a certainty, from contextual reasons, from Aristotle’s habit of 
casually harking back, and from Pliny in his translation of it (N. H., IX. 33) 
applying it generally, that this sentence applies to all fish, and not solely to 
the Tunny. 
7V.15. h yep moppipa wept Ern &, nal Kab’ Exaoroy éviauTdy pavepd eotrw 7 
avinots rots diaoThuact Trois év Tq daTpdxw Tis EAtKos. The translation above is 
taken from Professor D’Arcy Thompson (ibid.), to whose kindness I owe the 
following reference and much else in this chapter. Pliny, IX. 60, makes the 
Murex live seven years. 
8 Select Works, I. 69, London, 1798-180t, 
