J. PISCICULTURE AND THE FISHERIES 419 



J. PISCICULTURE AND THE FISHERIES. 



OIL FROM SHARKS' LIVERS. 



The preparation of oil from the livers of sharks, rays, saw- 

 fish, etc., is conducted on a large scale on various portions of 

 the sea-coast of India. For this purpose the fish are usually 

 taken in October and November, the livers being then in 

 their best condition. Although the quality does not vary 

 with the season, the amount is about three times as great in 

 autumn as in spring. The most esteemed livers are firm and 

 rose-colored, while those which are whitish and flabby are re- 

 jected. 



The first operation consists in removing the gall-bladders; 

 the livers are next slashed in various places, and washed to 

 remove the blood. They are then placed in a large earthen 

 vessel, with enough water to cover them ; are heated for fif- 

 teen or twenty minutes, and then allowed to cool. The oil 

 which floats on the surface is gathered in ladles and poured 

 into glazed earthen jars ; it is next passed through a sieve, 

 and all which does not pass through is thrown away. Three 

 or four days later it is again filtered through a thick strainer 

 to separate the deposit of stearine, this operation being re- 

 peated three or four times at intervals of twenty to twenty- 

 five days. The oil then remains clear, of a fine straw color, 

 smelling very much like cod-liver oil. An inferior quality 

 of oil is made by simply heating the livers, without previous- 

 ly washing or picking them. The better quality of this oil 

 is used for medical purposes. That of the shad is similarly 

 used in China. 17 A, March 1, 1874, 40. 



FISHERIES AND SEA TEMPERATURES. 



The Scotch Meteorological Society instituted, nearly twenty 

 years ago, a series of valuable observations on sea tempera- 

 ture, the observations being taken at the uniform depth of 

 six feet, and special observations were made at greater 

 depths, extending even to fifty feet, while a highly important 

 series of hourly observations, continued during four years, 

 were made at the depth of sixty feet. During the past year 



