H4 Of the Scales of Fifhes. 
If a fnail be fuffered to creep upon a bit of glafs, you 
may by the naked eye (but better if you apply the hand- 
glafs of your microfcope to view it through) obferve a 
little cloudy ftream pacing from its tail to the head, that 
never returns the fame way j and this as long as the fnail 
is in motion. 
Of the fcales of fifhes. 
T HE outfide coverings of fifhes are fcales, formed 
with inconceivable beauty and regularity; fome 
longifh, fome round, fome triangular, fome fquare, and 
feme or other of all the variety of fhapes imaginable: 
forne again are armed with fharp prickles, as thofe of the 
perch, foal, &c. others have fmooth edges, as the cod- 
fifh, carp, tench, &c. There is like wife a great variety 
even in the fame fifh; for the fcales taken from the 
belly, the back, the fides, the head, and all the other parts* 
-afe very different from each other. 
The fcale of a foal fifh is delineated, as it appear’d in 
.the microfcope, at fig. 176. whereof CDEF repre¬ 
sents that part of the fcale which fhews itfelf on the 
outfide of the fifh, and A B C D, the part which ad¬ 
heres to the fkin, being as it were furrowed, that it 
might hold the fafter, * each of which is terminated on 
the outfide by pointed fpikes, and every other of thefe 
jnuch longer than the interjacent ones. 
Mr. Leeuwenhoek fuppofes thefe fcales not to be filed 
during the whole life of the animal; but to have an an¬ 
nual addition qf a new fcale growing over the old one* 
and extending every way beyond its edges, in propor¬ 
tion to the fifhes growth : fomewhat in the fame man¬ 
ner 
5 Hook’s Micro, p. 16?} 
