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 pervaded and dominated the fish-pickling industry as it has other ancient arts, but it has contributed something and is capable of contributing 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 purpose 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 chemical 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 corrected, 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 literally, 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 with salt. But by sufficient concentration 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 concentrated 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 without any leakage of blood. By the same principle the kidney tubules remove undesirable 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-
