126 American Fisheries Society 



protein does not escape, but the salt does. This exchange is 

 carried to a point where the meat is again plump and the desir- 

 able quantity of salt left in. 



Thus, we have, by exposing the meat of fish to salt, removed 

 the water and caused some salt to enter the meat; we have 

 stored the fish; we have then by exposing the fish to water, 

 put water back in the cells and taken out the excess salt. The 

 actual food material of the fish, the cell protein, is still where 

 it was, for practical purposes, unchanged. If every step has 

 been scientifically correct we have at the end very nearly the 

 fresh fish we had to start with. But there is the rub. At every 

 turn it is possible to depart from the scientifically correct. 



The principles of osmosis here very briefly stated are the 

 fundamentals of the art of salting fish. They are the starting 

 point for the investigations for which the writer has been 

 responsible. In all that follows there will be frequent 

 occasion to refer to osmosis. 



FACTORS AFFECTING PERMEABILITY OF FISH CELLS 



The preservation of fish by salt is practiced extensively in 

 the cooler parts of the United States, but very little has been 

 done south of Chesapeake Bay. The reason fish have not been 

 salted in the warmer part of the country is that the process has 

 not been satisfactory. Repeated efforts to salt ale wives on the 

 St. Johns river in Florida previous to 1920 uniformly resulted 

 in failure. In 1918 research on this problem was undertaken 

 under the immediate direction of the writer. The results of a 

 part of this program were published this year,* but continu- 

 ation of the program planned is held up for lack of funds. 



The hypotheses which guided this work were somewhat as 

 follows : During the course of "striking through" the fish, two 

 things are happening, ( 1 ) the flesh is breaking down by auto- 

 lysis (a process to be explained later) and (2) the salt is pene- 

 trating the flesh. Salt arrests autolysis when it arrives, but con- 



*Tressler, D. K. Some Considerations Concerning the Salting of Fish. Report of 

 the U. S. Commissioner of Fisheries for 19:9, Appendix IV, 54 pp., 1920, Washington. 



