310 SEALE. 



USES OP 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 stiffening fabrics, and in lustering ribbons. Isinglass is also used 

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

 imitation glass. 



It ia 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 FROM 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 very fair grade of isinglass is 

 secured from the iishes 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, Polydactylus plebeius (Brouss.), called 

 mamali in Tagalog, and tatih in Moro. It is a very common fish in 

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

 The common catfish (Netuma nasuta 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), {Otolithcs leuciscus Gunth.), 

 and Johnius bclcngeri C. & Y.), and at least two species of TJmbrina, from 

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

 fish and U lias been estimated that the isinglass thrown atuay from them 

 is greater in value than the price secured iy 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. 2.7S 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 product, 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 ANIMjVLS FOR LEATHER. 



CAYMAN OR CROCODILE SKIN. 



(CrnroiUlus porosus Schneicler and C. palustris Lesson.) 



For commercial purposes, skins of the medium-sized cayman, 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 belly from the chin to the tip of the tail and carefully removed 



