More care is required in processing at high temperatures, than at boiling. A high internal pressure is developed inside the cans or jars, due to the expansion of the contents and of the enclosed gases, which has a tendency to loosen or blow off the covers. This tendency may be overcome by applying air or water pressure on the outside of the cans or jars to counteract that generated within. This is done while they are inside the retort and by means of automatic pressure controllers. There is no essential difference in the sterilizing and cooling of tin cans and glass jars, both forms of containers are responsive to treatment with high temperatures and both require proper care and handling. As with pickled olives, however, glass jars permit the purchaser to see the size and the condition of the fruit. The canning of ripe olives in California was originated by F. T. Bioletti, zymologist in the University of California, and came about through an [Illustration: Packing Olives in Jars] investigation in 1889 on the spoiling of olives. When pickled olives were held, the quality deteriorated in some of them, they softened during the summer, and seldom remained in an edible condition for a year. As a result of his experiments on methods of keeping, he found that the olives could be sterilized in sealed containers and be kept in edible condition indefinitely. The commercial application of the method and the popularizing of the ripe olive is due to Mrs. Freda Ehmann, a pioneer olive grower, who applied scientific methods, with marked success, to both the development and canning of the olive. The sustained scientific work along developmental and preserving lines in this country, has been done mainly by Wickson, Bioletti, and Cruess of the state university staff to whom great credit is due for the advancement made. Many improvements have naturally been made by manufacturers in the preparation of the ripe olive but are held by the factories for their own use solely. Recently Cruess has developed methods for treating the ripe olive with aerated hot solutions which have permitted the preliminary treatments to be done in 3 to 6 days, instead of as formerly in 3 to 6 weeks. The methods promise to be of great economic value, and have been patented for the benefit of the public. The olives which are too small or misshapen to be used in the regular pack are sometimes used for other purposes besides oil extraction in which size and appearance are not factors. The flesh is ground and seasoned and thus furnishes a mixture for relishes and sandwich filling, or the flesh is mixed with pickled cucumbers, capers, pimiento, tomato, etc., in various combinations for the same purposes or to flavor sauces. The appetizing ways in which olives may be used alone or in combination, and the attractive dishes which can be prepared from them are endless.