BEGINNINGS IN SCIENCE AT MUG BY SCHOOL. 63 



has its own pattern of scale, and that yon could tell a species of 

 fish by its scales ? 



The paper showed that the scales of fishes were composed of 

 the same material, chitine, as the feathers of birds, or the hair and 

 nails of animals — a kind of substance only found in the anibaal 

 kingdom, and never in the vegetable ; that these scales are devel- 

 oped in little pockets in the fish's skin, which you can plainly 

 see for yourself when a herring is scaled. They are arranged 

 all over the fish's body like the tiles covering a roof, partly over- 

 lapping each other, as is seen by one part of the scale being often 

 different from the other. 



Jack looked through 

 the microscope and was 

 delighted. He was always 

 a reverent - minded boy, 

 and the sight broke on 

 his mind like a new reve- 

 lation. How exquisitely 

 chaste and beautiful were 

 the markings, lines, dots, 

 and other peculiarities ! 

 Then the scales which run 

 along the middle line of the 

 fish were shown him, and 

 theducts perforating them, 

 out of which the mucus 

 flows to anoint the fish's 

 body, and thus reduce the 

 friction of its rapid move- 

 ment through the water. 

 The lad was half bewil- 

 dered at the possibility 

 of the new knowledge. 

 " Could anybody get to 

 know about these things ? " he asked Willie, who told him of 

 course he could, if he would only take a little trouble. 



"But," said his young friend, "I would advise you to get a 

 pocket-magnifier first, and begin to examine with that. Some 

 fellows begin right off with a powerful microscope they get their 

 governors to buy them, and they work it like mad for a month or 

 two, and then get tired of it. Fact is, they never learned the art 

 of observing." 



" What do you mean by that ? " said Jack. 



" Why, getting into the habit of looking about you, keeping 

 your eyes open, and quickly spotting anything unusual. Fancy a 

 fellow beginning to use magnifying glasses of thousands of times 



Fig. 12.— Scale of Pike. 



