Page:Popular Science Monthly Volume 81.djvu/159

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OLD storage is but one of many methods of conserving foods. There is a period of plenty for every food substance, during which time much would go to waste if there were no provision for conservation, and when prices are low to the consumer and profits large to the producer. During the balance of the year food is scarce and must of necessity bring exorbitant prices, if within reach at all. Usually the period of plenty covers but a fraction of the year and bears to some extent a definite relation to climatic and soil conditions. The gap between the periods of plenty and scarcity is felt least in the centers of population, where transportation facilities make many foods available throughout the year. There, for instance, berries are obtainable before and after the natural period of supply has expired, the provisions being carried in refrigerator cars from southern and northern climates, where conditions favor their production. Also many fruits, such as oranges, grapefruit and pineapple, are carried successfully from tropic and subtropic countries to parts of the world where they can not be grown. These conditions are made possible by efficient transportation. Undoubtedly within the near future transportation facilities will be improved so as to encourage the raising of crops in tropical climates to such an extent that fruits and vegetables will be available in northern countries throughout the year. Many luxuries of the table could not now be obtained, were it not for the systematic conservation of food articles.

There are more than 3,000 million dollars worth of foods placed in cold storage annually, of which about one half is meat. Capitalists are expending money and scientists are giving their time to the exploitation of this promising field. Although the problem is still in its infancy, ways and means of furthering cold storage are being investigated. The chief problems to be investigated are the handling of foods previous to placing them in cold storage; the chemical changes taking place during storage; the study of the microorganisms that produce these changes; the sanitary conditions of cold storage warehouses, and the care of foods after leaving cold storage.

Many foods that constitute a regular and almost necessary part of the diet of civilized man are really nothing but the results of