FISH ISINGLASS AXD GLUE. 7 



Cod sounds are smaller than those of hake and of poorer quality. 

 One ton of fish yields 15 to 20 pounds of sounds. As they are more 

 firmly attached to the backbone than are hake sounds, they are cut 

 off with part of the backbone, scraped, washed, and salted. They 

 are then washed and dried on shore. Cod sounds yield only about 

 50 per cent gelatin, so that they are much less valuable than hake 

 sounds. 



Sounds of the squeteague, which fish occurs along the Atlantic 

 seaboard, are at present only little utilized. One ton of fish yields 

 about 20 pounds of sounds, which are of as good quality as cod 

 sounds. Over 30 years ago about 15 tons of dried sounds of the 

 squeteague were sold annually, but the production since that time 

 has dwindled to a negligible amount. 



The production and value of fish sounds in the United States as 

 reported in the census of 1908 (Fisheries of the United States, 1908, 

 p. 43) are presented in the following table: 



The sounds of many fresh and salt water fishes are at present un- 

 utilized. 



TILEFISH-SOUND TEST. 



The sound of the tilefish {LopholatUus chainceleonticeps) was 

 tested by the writer to determine the character of its principal con- 

 stituent and its possible utility. The sound was cut open and a 

 portion treated as follows : After thorough washing with water the 

 tissue was allowed to stand under a large excess of 0.1 per cent 

 sodium hydroxide solution at room temperature so that mucin, haemo- 

 globin decomposition products, etc., might be dissolved. The resi- 

 due was thoroughly washed with water and then subjected to the 

 action of an active trypsin solution containing 0.2 per cent sodium 

 hydroxide for 24 hours, the temperature being maintained at 37.5° 

 C. and in the presence of chloroform to prevent putrefaction. The 

 tissue was largely unaffected, and after washing with water was 

 treated successively w^th alcohol and ether to remove any lipoids. 

 The residue, after drying at 70° C, was creamy white, and thin 

 layers were transparent. 



On continued boiling with water, much more quickly by the addi- 

 tion of a trace of acid, the treated tissue dissolved and the solution 



