DEVICES FOR USE IN FISH HATCHERIES AND AQUARIA. 



1035 



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fiecfptac/e 



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To a board, i meter long and 0.30 meter wide, edged with a strip 0.02 meter 

 high to keep the pulp of the spleen from falling over the sides, is affixed at each 

 end a transverse support to raise it above the surface of the table on which the 

 scraper is used. One support should be sufficiently high to permit a small recep- 

 tacle to be placed somewhat under the board, at a height of o.io meter approxi- 

 mately, while for the other support a height of 0.03 meter would be sufficient. 

 The board will thus be inclined. 



At the lower end a narrow board is attached fiat by means of a hinge at the 

 farther side. This small board is 0.05 to 0.06 meter wide, of the same thickness 

 as the big board, and in it are fixed 10 to 12 sharp points 0.02 meter long, spaced 

 0.015 meter apart. This board 



swung back, the spleen is placed /fe cepiac/ec = Board 



flat on the larger board, some 0.03 

 or 0.04 meter of it falling over the 

 end. The small board is then 

 swung forward and its points, 

 piercing the spleen, will keep the 

 latter in place during the scrap- 

 ing. A small hook at the end 

 holds the small board in position 

 to keep the spleen from slipping. 

 The thin skin around the spleen is 

 taken off with a knife and the 

 spleen is cut longitudinally sev- 

 eral times. 



The scraper is manipulated 

 in the manner of a plane. The 

 spleen should be turned end for 

 end, if need be, to scrape the part 

 which had been held under the 

 toothed board. 



This implement may seem an odd device, but it is remarkable how rapidly 

 the spleen pulp is extracted. Two to three minutes are sufficient for the opera- 

 tion, with a spleen weighing 0.80 kilogram. It should be added that this pulp 

 does not contain any remnants of spleen cells, as might be supposed. 



If the spleen is frozen in winter and it is not feared that the nutritive quali- 

 ties of the raw flesh or the spleen pulp might be decreased, it may be immersed 

 for a few minutes in hot water before being scraped and the operation will be 

 still more rapid. 



Several establishments make use of this scraper because their proprietors 

 have seen me use mine. I have ordered several from a manufacturing firm. 



Fig. 6. — Scraper for preparing fish food. 



