Bad Eggs

Eaters of eggs were gratified to learn last week from the American Chemical Society that Paul Francis Sharp and Charles Kelly Powell of the Department of Dairy Industry & Poultry Husbandry at Cornell University have, through study of measurements and temperature data, refined the science of keeping eggs fresh.

Egg merchants determine the freshness of their wares by candling--observing the size and condition of the air cell, the visibility of the yolk. Sufficiently accurate for commercial grading, candling does not give data detailed enough for scientists who wish to study methods of egg preservation.

When subjected to unfavorable conditions egg yolks begin to flatten, because water from the white passes into the yolk. Paul Sharp and Charles Powell worked with many eggs, subjected them to different conditions, measured the height and width of the yolks. They divided the height by the width, got a numerical index of yolk-flattening. Yolks of freshest eggs had highest index. Temperature, not age, was found to be the most important factor in deterioration. Eggs kept for three days at 37DEG C. had the same numerical index as eggs kept for eight days at 25DEG C., 23 days at 16DEG C., 65 days at 7DEG C.

Significance of this mathematical measurement of egg freshness lies in its value as a standard for determining efficient conditions for storage. Most general method used today for large scale preservation is refrigeration. Stored at freezing point, eggs are kept in good condition for several months, imported from long distance. Many a European housewife bakes cakes with South African eggs. Critical temperature for eggs is --6DEG C. Below this temperature, an egg is so frozen it can never recover its normal transparency.

Small scale preservation methods are based on the principle of keeping air from penetrating the egg shell. Most U. S. farmers keep eggs in water-glass. Others bury them in bran or sawdust, sometimes grease them with vaseline.

Curiosity seekers, poultry men, the Duke of York and many a hen last week eyed the world's strangest hen, at the Fourth World's Poultry Congress, London (TIME, Aug. 4). Unperturbed she stared back out of her one shining glass eye, patiently explained how eggs are made.

Built by the U. S. Department of Agriculture, she is 7 ft. tall, made of wood and wallboard. She is fully equipped with gullet, crop, copper-lined stomach, rubber intestines, a two-valved pump for a heart, all exposed to the public view. While her audience watched, she ate food, ground it, digested it, distributed it, laid a big egg, explained--in a polite voice with a U. S. accent--each step of her internal working as it took place.

Electric motors behind the exhibit furnish operating power. Rate of egg-laying can be increased by speeding up a small motor which operates the lathe on which the eggs are turned. A phonograph record and amplifying apparatus make it possible for the great hen to speak. Upon its return from London, the exhibit will be sent to U. S. state fairs.

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