2 U. S. BUREAU OF FISHERIES. 



them the arts of sousing and pickling fish. The descendants of the 

 Pilgrims are still pickling fish around Cape Cod and particularly 

 at Gloucester. 



To a great many people it may seem that science has contributed 

 little or nothing to the improvement of methods of preserving fish 

 by salt. Perhaps this view is shared by a considerable number of 

 people who are engaged in the business of salting fish. To them it 

 may appear that salting fish is just salting fish, and " that's all there 

 is to it." It may be admitted readily that science has not so per- 

 vaded and dominated the fish-pickling industry as it has other an- 

 cient arts, but it has contributed something and is capable of con- 

 tributing a great deal more, and here lies the purpose of this paper. 

 That purpose is to present the rationale of salting and pickling fish, 

 so that the reasons for the various steps and modifications will be 

 readily understood and appreciated, to the end that the art may be 

 practiced more intelligently and successfully. It is a further pur- 

 pose of this paper, by showing what the few attempts made by 

 science have done for the art, to convince and persuade those on 

 whom the industry depends for its existence and progress that science 

 can be expected to do a great deal more than it ever has done if it 

 is energetically studied and applied. 



HOW SALT PRESERVES. 



Salt preserves by extracting water. Spoiling is a series of chem- 

 ical activities for which water is necessary; remove the water and 

 spoiling is arrested. The removal of water by means of salt is in 

 some senses a truer dehydration than actual drying in air, for changes 

 of an undesirable sort take place in air drying that are never cor- 

 rected, while salting may be done in such a way that few changes 

 other than removal of water are brought about. The statement that 

 salt preserves by extracting water is to be taken strictly and liter- 

 ally, for salt has no peculiar preserving or antiseptic quality, as 

 many people seem to think. Things live, die, and putrefy in the sea, 

 which is one-tenth saturated Avith salt. But by sufficient concentra- 

 tion salt, an otherwise almost inert, harmless substance, becomes a 

 powerful preservative, merely because, if concentrated sufficiently, 

 it extracts water. 



The process of transferring water from one place to another, as 

 from the inside of a fish to the outside, under the influence of con- 

 centrated solutions, is known to physicists and chemists as osmosis. 

 This principle of osmosis is of almost universal application in 

 nature and is used by men in the arts, but a good understanding of it 

 is not common. By osmosis our food is taken from the intestines 

 to the blood without any communicating opening. By osmosis 

 oxygen is taken from the air into the blood Avithout any leakage 

 of blood. By the same principle the kidney tubules remove unde- 

 sirable substances from the body while holding back all desirable 

 substances. By osmosis the roots of plants select the necessary 

 minerals from the soil. A weak sugar solution will readily ferment, 

 but if made concentrated it destroys yeast and bacteria by osmosis 

 and is therefore an excellent preservative of fruits. Salt is also a 

 preservative by virtue of its concentration. Any other neutral min- 



