310 SEALE. 



USES OF ISINGLASS. 



Probably the chief use of isinglass is in fining liquors of various sorts, 

 especially the best grades of wine. It is also used in the preparation of creams 

 and jellies, in stiflFening fabrics, and in lustering ribbons. Isinglass is also used 

 in the manufacture of court plaster, artificial pearls, diamond cement, and 

 imitation glass. 



It is true that owing to the expense of securing pure fish isinglass, agar-agar 

 prepared from seaweed, is used largely as a substitute. However, there is no 

 question that pure, fish isinglass is more desirable and gives better results in 

 almost all cases than the vegetable product. 



FISHES FBOM WHICH ISINGLASS IS SECURED. 



The best grade of isinglass is secured from the sturgeon and is put up 

 in Eussia. In the Malay Archipelago a Yery fair grade of isinglass is 

 secured from the fishes called thread-fin and from certain species of cat- 

 fish and croakers. In the Philippines, a profitable source of isinglass 

 could be found in the thread-fin, Polydadylus pleheius (Brouss.), called 

 mamali in Tagalog, and tatik in Moro. It is a verj' common fish in 

 the Manila markets, and ranges in length from 35 to 50 centimeters. 

 The common catfish {Netuma nasuia Bl.), called kanduli in Tagalog, 

 which is very abundant, especially in Laguna de Bay, also supplies a good 

 grade of isinglass. In addition, there are several species of croakers, 

 (Otolithes argenteus Kuhl & Van Hasselt), (Otolithes leuciscus Gunth.), 

 and Johnius behngeii C. & V.), and at least two species of Umbrina, from 

 all of which isinglass can be secured. The above are all common market- 

 fish and it has been estimated that the isinglass thrown away from them 

 is greater in value than the price secured by the fisherman for the entire 

 fish. 



VALUE OF ISINGLASS. 



The current value of isinglass quoted from a late trade journal is as 

 follows : 



Russian isinglass, 2.75 to 3 dollars per pound; American isinglass, 0.73 to 

 0.75 dollar per pound; 14,000 pounds were imported into New York during the 

 month of April, 1911. 



There seems to be no local demand for this proditct, but, owing to 

 the recent tariff regulation, it would enter the United States duty free ; 

 consequently, it could be exported from the Philippines with profit. 



IX. PREPARING SKINS OF AQUATIC AXIiLiLS FOR LEATHER. 



CATilAN OB CROCODILE SKIN. 



(.Crocodilus porosus Schneider and C. palustris Lesson.) 



Foi- commercial purposes, skins of the medium-sized eajTnan, of about 

 3 meters. (9 feet) length, are the most desirable as they are easier to tan, 

 and make the best leather. The skin should be cut along the middle line 

 of the bellv from the chin to the tip of the tail and carefully removed 



