964 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



swamping the bait-house, and great trouble thus caused by damaged 

 bait. I do not believe cold-dried bait will demand any more care than 

 salt or frozen bait, but the chances of its prompt, beneficial and econom- 

 ical introduction depend on care and foresight in the first trials, and until 

 the fishermen become familiar with its use. The nearest approach to live 

 bait will be the carefully -preserved dry fish, which, on being submerged, 

 may promptly regain plumpness, should drying have to be continued so 

 long as to shrink them perceptibly. 



X.— PEESERYATIOX OF SALMOX, COD, HALIBUT, &C. 



Appert's method of cooking in hermetically-sealed tin cans has proved 

 a great boon to fisheries. The salmon-canneries on the Columbia and 

 Sacramento Rivers, not to speak of the sardine-trade in France and 

 elsewhere, the canned oysters of Baltimore, canned lobsters, &c., in- 

 dicate how indispensable a cheap mode of fish-preservation is found 

 in supplying the people's food. This subject deserves attention, and 

 it would be well to know why canned fish, like canned meats and 

 fruits, tend in the long run to nauseate, or, at all events, not to be 

 eaten with the same relish as on first trials. I believe it will be an 

 immense advantage if the cost and inconveniences of tinning can be set 

 aside ; and on sanitary grounds this may be very desirable. The con- 

 tents of cans, containing cooked fish of all sorts, should be subjected to 

 analysis, making a selection of different dates, so as to ascertain what 

 the influence may be of protracted preservation in contact with metals. 

 In the Chemical Xews of July 5, 1878, page 5, Mr. Albert E. Menke, of 

 the chemical laboratory. King's College, London, writes as follows : "In 

 opening a tin can of pine-apples I found that at the place where the tin 

 had been soldered corrosion had taken place, which induced me to test 

 for tin, having found indications of it, and made a quantitative analy- 

 sis with the following results: I first poured the syrup off, and squeeze^ 

 tlie juice from the fruit, then oxidized with chlorate of potash and hydro- 

 chloric acid, boiled, and then reduced the tin to the stannous state with 

 sulphate of soda ; sulphuretted hydrogen was then passed through the 

 liquid, the tin sulphide was then filtered off", dissolved in strong hydro- 

 chloric acid, largely diluted and titrated with potassium permanganate. 

 0,151335 gramme of tin was found in a tin of pineapple which weighed 

 If pounds. I next tried lobster and apples, and found in the lobster 

 0.010089 gramme, and in the apples, 0.00672 gramme of tin, showing that 

 the pine-apple was the worst, which would support the theory that it 

 was due to corrosion." 



Salting, smoking, and drying by the sun or at ordinary temperatures, are 

 tlie commonest methods of fish-preservation, which are attended with 

 great difficulties in the summer season, when unexpectedly large catches 

 demand more hands, more time and conveniences than have been usually 

 provided. Thus a successful haul is sometimes a cause of loss rather 



