ACIPENSERID^ THE STURGEONS 23 



smoked sturgeon in the United States was given in 1898 as about 

 4,000,000 tb, annually. The smoked flesh usually keeps only from 

 one to two weeks. It is not kept in cold storage because of its ten- 

 dency to mold. Sturgeon is canned on a small scale, and the roe, pre- 

 served in brine and sold in tight packages under the name of caviar, 

 is an expensive food product highly relished by many. The method 

 of preparing caviar is simple, the first essential being to work the eggs 

 loose from the membranous tissue in which they are embedded. 

 When once separated they are mixed with Liineburg salt, with a 

 small addition of one of the ordinary preservatives. The eggs are 

 then sieved and drained for 12 to 20 hours, after which they are 

 ready for packing. Caviar is usually packed in small oaken kegs, 

 although it is also sealed in small tins for the retail trade. The 

 Russian output amounts to about 8,000,000 tb annually, most of it 

 prepared on the Volga and the Caspian. The American product is 

 about 300,000 tb annually (1898), about f of it being exported 

 Sturgeon bladders are used in the manufacture of isinglass, and oil 

 is made from the offal and softer parts. Sturgeon skin has been 

 somewhat used of late for an ornamental leather. The skin is 

 exceptionally durable and has been used for laces for mill-belts. 



Owing to their great commercial importance, the artificial 

 propagation of sturgeon has long been a subject of more or less 

 interest in this country and in Europe. Up to the present time, 

 however, although the artificial fertilization of the eggs and the 

 successful hatching of the young has been accomplished experi- 

 mentally*, it has not been practiced on a large scale anywhere, the 

 difficulty of obtaining ripe roe and milt at the same time, the ad 

 hesiveness of the eggs and their tendency to mold, and the difficulty 

 of finding food for the young (which live on microscopic organ 

 isms), having proved serious obstacles. It has, however, been the 

 opinion of all who have investigated the subject that if artificial 

 culture were once undertaken, these difficulties would soon be 

 greatly diminished. It may be said that the number of eggs pro- 

 duced by the Atlantic sturgeon is from 1,000,000 to 2,500,000 to a 

 single adult female— a fact of much importance to its artificial 

 culture. 



* The eggs were fertilized dry by Dean (Bull. U. S. Fish Comm., 1893, p. 335), 

 and then put into water and allowed to adhere in a single layer to a sheet of cloth 

 stretched over a frame. They were hatched out in the current of the river, the 

 loss by fungus being only 5 per cent. Artificial propagation was tried by the 

 Germans in 1888 with fair success, and in America by Ryder (1889), who lost 

 most of his eggs. Some success has been more recently obtained by the Russian 

 government, operating on the Ural. 



