OlSrUTILIZED FISHES. 41 



settle a matter of this kind. A fair bounty, to be sure, would stimu- 

 late the fishermen in their eiforts to catch the dogfish. But if one will 

 stop to consider that the number of dogfish just off the eastern 

 American shores probably runs up into the hundreds of millions, per- 

 haps billions, he can realize how great would be the expense involved 

 in this method for simply reducing the number by 5 per cent. A 

 bounty placed on the dogfish would prove to be more expensive, more 

 useless, and more absurd than a bounty placed on the English spar- 

 row. The most sensible and practical suggestion given above is no. 

 7. This method makes the dogfish to some degTee pay the expense of 

 bringing about its own destruction. But why not make the dogfish 

 pay the whole bill, besides yielding a comfortable income to those 

 who engage in the fishery? A consideration of the useful products 

 which may be obtained from the dogfishes will help to show that this 

 is possible. 



POSSIBLE USES OF DOGFISHES. 



Goode (1884) says that the smooth dogfish constitutes an important 

 bait in the local fisheries of Bermuda. According to Cunningham 

 (189f)), the horned dogfish is salted down for bait by the English fish- 

 ermen in some localities. It has also been dried and used for fuel on 

 some parts of Cape Cod. 



SKIN. 



The skin of the dogfish is in itself a useful product. It is durable, 

 nonporous, and covered with numerous small, pointed denticles closely 

 set together. The denticles are spinelike in form and similar in 

 structure to mammalian teeth, consisting of an inner portion of den- 

 tine covered by an outer layer of enamel. Each is inserted firmly into 

 a plate of osseus tissue which lies within the skin. In other sharks 

 the denticles are larger and much less numerous. This durable ma- 

 terial has been used in numerous ways. Turners, cabinetmakers, 

 and carpenters of Europe have used it for scraping and smoothing 

 their work before polishing. Metal workers and others have used 

 it to advantage, for polishing purposes. Fishermen have long used 

 it for polishing their metallic mackerel jigs and the woodwork on 

 shipboard. In the East it is used for polishing ivory. In France 

 the skin, when prepared with the placoid scales in place and dyed, 

 usually green, is used for covering cardcases, jewel boxes, sword 

 sheaths, desk ornaments, etc., and may also be used to advantage as a 

 covering for the handles of such articles as swords and tennis rackets, 

 on which it is desirable to get a firm grip. This commodity is called 

 " galuchat." 



When prepared for polishing purposes, the shark or dogfish skins 

 are merely dried after being thoroughly cleaned of all adhering 



