134 American Fisheries Society 



perature, the more rapid the striking through, a difference too 

 great to be accounted for by temperature variations of osmotic 

 pressure. The cell-membrane itself must change. Whether any- 

 more free permeability caused by warm temperature is perma- 

 nent after the fish is chilled again is not known, but the ques- 

 tion would be well worth investigating. Cold, when in the 

 neighborhood of freezing, also promotes permeability, as has 

 been proved by various experiments. It is quite possible that 

 fish chilled to a point near freezing would strike through much 

 more quickly than fish at the customary warmer temperature. 

 This matter also should be investigated. 



Stale fish, i. e., fish whose cell-membranes have died, are 

 more permeable than fresh fish. The past spring some fish 

 were held in the laboratory all day at a temperature of about 

 75° F., and toward night were salted in pure salt and put in 

 an incubator at 100° F. By the next day they were struck 

 through. The combination of stale fish, high temperature, and 

 pure salt brought about extraordinarily rapid penetration. 



LOSS BY FISH OF NUTRIENTS IN BRINE 



The liquid that comes from fish during the salting process 

 is not pure water, as every fisherman knows, but contains a 

 quantity of material derived from the fish. Most of the nitroge- 

 nous matter found in brine represents just so much good 

 food gone to waste, and just so many pounds of fish that might 

 fetch a good price gone overboard. The quantity of protein 

 that escapes into the brine is highly variable, for reasons that 

 will appear later. That some idea may be had of the magnitude 

 of the loss of fish substance in brine, the following figures 

 are given; these figures were obtained in the course of inves- 

 tigation on the recovery of valuable materials from old brine. 



