226 THE WEALTH OF THE SEA 



it is marketed. These trade names refer simply to the 

 form and method of packing the product for the 

 market. 



American isinglass is prepared principally in 

 Massachusetts, where the quaint old town of Rock- 

 port is the principal center of the industry. This 

 isinglass is marketed chiefly in the form of ribbons. 

 Such isinglass is prepared by soaking the previously 

 dried sounds in water until they become soft, after 

 which they are chopped into pieces and rolled many 

 times until they are converted into a very thin ribbon, 

 which is wound on a wooden spool. 



Isinglass is often considered to be gelatinous or 

 gluey in nature; but, although it may be converted 

 into glue or gelatin by boiling with water, it is 

 neither glue nor gelatin. It is similar in composition 

 to fish skin. It does not dissolve in water unless it is 

 heated, whereupon it takes on gelatinous properties, 

 forming a tough jelly when cooled. It is used in the 

 clarification of fine wines and other beverages. 

 Formerly it was used for the preparation of edible 

 jellies and in the manufacture of marshmallows and 

 other candies, but since gelatin has become so inex- 

 pensive these uses have become obsolete. It also finds 

 use in the preparation of high-grade glues and 

 special cements. Some is still used in the preparation 

 of high-grade court-plaster. 



Shark and Other Leathers or Marine Origin 



Although the skins of certain marine animals 

 (seals and walruses) have been tanned for many cen- 

 turies, it is only recently that any attention has been 



