THE SALTING OF FISH. 15 



infinitely more slowly. The decomposition products are also 

 changed in nature, but no toxic compounds are developed. Later 

 the salted fish may spoil because of unfavorable storage conditions, 

 but it is not likely that the spoiled fish will produce harmful results 

 if eaten. In order, therefore, to learn how fast salt penetrates a fish, 

 a method was required which would enable the experimenter to 

 determine the rate of penetration. This should enable him to judge, 

 at least from one standpoint, the value of different salts. 



The rate of penetration of salt into fish was followed by cutting 

 sections of the fish at different depths from the surface. These sec- 

 tions were ashed and the amount of chlorine in them determined. 

 The amount of chlorine in the dry salt fish was then calculated. 

 ,This was done from day to day, and thus the increase in salt con- 

 tent of the inner sections was determined. The rate of penetra- 

 tion of any salt into fish is not an absolutely accurate criterion for 

 judging the quality of that salt, for certain impurities in the salt 

 might have a preservative action surpassing that of the salt. 



Then it was necessary for the experimenter to learn the best method 

 of cleaning fish prej^aratory for salting and to judge the necessity of 

 absolute freshness. The rate of penetration does not afford a means 

 of judging between two methods of application of the salt. It 

 Avas necessary, therefore, to choose some means of estimating the de- 

 composition of the flesh of fish and to adapt it for use with salt 

 fish. A wide choice was not permissible, for a very large number of 

 determinations must be run simultaneously and quickly. The ap- 

 paratus required had to be simple and easily transported, as it was 

 necessary to take the laboratory to the fish, as it were, in order to 

 obtain fresh fish. The estimation of the rate of amino-acid forma- 

 tion was chosen as an indicator of the rate of protein decomposition. 

 The reasons for this choice will be explained further on. 



A limited amount of histological work was carried on in order 

 to determine if possible the difference between the effect on the cell 

 structure of the salted fish of pure sodium chloride and of sodium 

 chloride adulterated with other chlorides. A complete record was 

 kept of the macroscopic changes of each lot of fish. All the ordi- 

 nary qualities were observed, such as color, odor, hardness, brittle- 

 ness, taste, and general appearance. For the sake of brevity only 

 the most notable changes are recorded in this paper. All edible 

 samples of salted fish were cooked at the end of the experiments and 

 their palatability noted. In these culinary experiments the fish 

 were cooked in such a way that their flavor was in no way disguised. 



The writer presents in this paper only those conclusions that seem 

 to him to have been proved beyond doubt. The results may be ac- 

 cepted as facts for the river herring and the squeteague. It is very 

 probable that they hold for other fish, but further work must bei done 

 to prove this point beyond doubt. In no case are the figures abso- 

 lutely exact; but there is little doubt that they are relative to each 

 other and that they may be compared with confidence. The 

 writer hopes that this research will create such an interest in the 

 chemistry of fish salting that other researches of a similar nature 

 will be instituted. 



