We have already noticed the method recommended by Professor Cossar
Ewart of preserving fresh fish with boracic acid and salt. Mr Roosen
of Hamburg has patented another method, which was lately tested in
Edinburgh. The process consists in the salmon being placed in an
air-tight compartment among a solution of boracic acid, salt, and
water, and a heavy pressure being applied, the solution penetrates and
thoroughly disinfects the fish, which are prevented from decaying, and
retain all their strength and nourishment. On the 15th of February, a
steel barrel, made for the purpose, and capable of holding about three
hundred pounds of fish, was filled with salt water containing about
fifty per cent. of boracic acid, and into this compound five splendid
salmon, fresh from the Tay, were placed. The air having been entirely
withdrawn, the barrel was hermetically sealed, a pressure of six
atmospheres, or ninety pounds to the square inch, being applied. After
standing for seventeen days, the barrel was opened on the 4th of March,
and all the salmon were found in as fresh and healthy a condition as
when they were first placed among the solution. The flesh of the fish
was of a beautiful colour, and could not be distinguished from that of
a fresh salmon placed alongside of it, while the blood began to flow
freely immediately on the salmon being cut up. The salmon was served up
at a luncheon, on the following day, in different forms of cooking, and
the general opinion was that the new method of preservation was upon
the whole successful. The fish was of good flavour and colour; it could
be separated in nice flakes, and the curd was well preserved.