August 1951. Chicken eggs and their preservation. A new laid egg is produced with a constitution fitted to withstand infection to a marked degree, and will remain in an edible condition for a considerable period. At the broad end of the egg there is an air space. If the egg is stored with the broad end upwards the air space prevents the yolk rising to the shell, which it tends to do. The albumen itself has slight prophylatic properties, which the yolk lacks. It is, therefore, important that when packing an egg it should be done so as to reduce the possibility of the yolk reaching the shell. Once this takes place, infection can rapidly reach the yolk and a bad egg results. There is always the tendency for the water in the albumen to evaporate through the pores of the shell. This can be prevented by storing the egg in a moist, cool room. By so doing the rate of evaporation is substantially reduced, the air-space increases but slowly, while, if the egg is stored with the broad end upward, this and the lowered rate of evaporation retain the yolk in a fairly central position, and so deterioration of the contents can be delayed for a period up to, and often exceeding, two months. The rate of evaporation can still be slowed down by packing the egg in bran or similar material.
More satisfactory systems of egg preservation are the use of water-glass and lime-water. For the housewife the former method is probably the most convenient, and proprietary brands of water-glass can be purchased readily. The principle involved is that the sodium silicate in the water-glass prevents any evaporation at all from the egg. If, therefore, the eggs are immersed in the water-glass when in a fresh condition, and kept completely immersed with, if possible, the broad ends upwards (althought this is not essential) they may be kept stored and will remain in an edible condition for periods up to twelve months.