14 THE SALTING OF FISH. 



permeability of a fisli to salt. The fat of different fishes varies widely 

 in chemical composition and physical constants. Some fats may 

 spoil more readily than others and thus affect the keeping qualities 

 of the fish. Fish of different species vary in chemical composition. 

 Everyone knows that some fish soften and spoil much more readily 

 than others. Fish of the same and different species vary gi"eatly in 

 size. The surface exposed to the salt depends upon the size and 

 shape. 



MODE OF PROCEDURE IN EXPERIMENTAL WORK. 



The chemical changes which fat undergoes during salting and 

 storage were not studied, so that any points presented on this sub- 

 ject are merely casual observations which the experimenter noted 

 during his work. The writer used but four species of fish in this 

 work; naturally, therefore, it is not certain that the work applies 

 to all varieties of fish. Most of the work was done with the sque- 

 teague {Cynoscion regalis) and the alewives {Pomolohus aestivalis 

 and pseudoharengus) . No marked differences were observed in the 

 changes taking place during the salting of these fish. The writer 

 ventures the opinion that the rules observed as to the protein decom- 

 position (flesh decomposition) will apply to nearly every species 

 of fish; but he doubts whether any observations concerning the 

 chemical changes occurring in the fat of one species will hold good 

 for all others, for the various fat constants of the oil of different 

 species vary considerably. The rate of oxidation of these fats would 

 vary nearly as much as the composition, because certain fish oils are 

 much less saturated than others and would oxidize much more 

 readily. 



With the exception of the chemical changes taking place in the 

 fat and the fact that the species studied were few in number, the 

 writer believes that he has covered in this paper all of the most 

 important factors influencing the salting of fish. The two factors 

 not studied in detail embrace such a large amount of work that 

 they were considered as separate problems. 



Few important chemical investigations concerning the salting of 

 fish have been carried out. Previously the problem had been con- 

 sidered mainly from the bacteriological standpoint. Various investi- 

 gations concerning bacteriological problems had been attempted, 

 but no methods of estimating the rate of salting, the rate of protein 

 decomposition, or the freshness of fish were to be found in the litera- 

 ture. The investigator had, therefore, to work out and standardize 

 methods applicable for his purpose. This in itself was no small 

 task. The writer does not claim that the methods used are perfect 

 or that other procedures could not be used to better advantage but 

 rather admits that they may be improved upon. However, the pro- 

 cedure was uniform, and the results obtained checked satisfactorily in 

 most cases. They must, therefore, be accepted as relative if not exact. 



It seems obvious that the more rapidly salt penetrates the flesh 

 of the fish the sooner decomposition of the tissue will stop. This 

 statement is based on the assumption that decomposition of the 

 tissue ceases when the fish is thoroughly salted. But this is not 

 exactly the case. Decomposition is not stopped; it proceeds almost 



