116 Dr L. Mancll on the Scales of Fishes. 



sensible, by such examples, how much the study of the micro- 

 scope retrograded at the close of the eighteenth century. 

 Nearly all the authors of the second half of that century pro- 

 duced only very meagre observations, when compared with the 

 researches of those that preceded them, although they also, 

 like Leuwenhoek and Hooke, constructed their own instru- 

 ments. 



The puerility of Ledermiiller is conspicuous in the descrip- 

 tions he gives of the -scales of fishes ( Amusemens microsco- 

 piques, Nuremb. 1764, pi. 29, 38, 59, 93). " I believe, he 

 says, that whoever Avould take the trouble to examine and 

 make drawings of the scales of all sorts of small fishes, might 

 form a cabinet of coquillages as pretty as curious." -Of their 

 structure he had formed no idea ; as a proof of this we may 

 mention the scale of the eel, which, according to him, is co- 

 vered " with an infinity of large and small plates of an oval 

 figure." We shall spare our readers the history of paste, 

 and the considerations of this author on the " authentic proof 

 of the infinite wisdom of the Almighty." 



Fontana ( Lui le Venin de la Viptre, Florence, 1781, vol. ii. 

 p. 254) communicated a few microscopical observations on 

 the gluten of eels, which are possessed of no value. He be- 

 lieves it to be formed of small bladders filled with very minute 

 spherical corpuscules. When dried on glass, these become more 

 irregular, and a corpuscule appears in their interior. Finally, 

 on breaking these bladders, a great quantity of minute corpus- 

 cules were seen to issue. 



In a memoir On the scales of many species of fishes which are 

 commonly believed to he destitute of these parts (Journ. de 

 Physiq. 1787, t. xxxi. p. 12), Broussonet merely describes the 

 form of some scales as seen by the naked eye, or by the mi- 

 croscope. In that article we observe the following statement : 

 " The peasantry of many northern countries were acquainted 

 with the scales of the eel long before Leuwenhoek, since 

 they collected them with care, in order to mix them with the 

 white-wash which they put on the walls of their houses, as 

 they thereby acquired a vei*y agreeable lustre, particularly 

 when the sun shone on them." 



Heusinger (Histologic, vol. i, Histographie, Eisenach, 1822) 



