No. 7. DEPARTMENT OF AGRICULTURE. 103 



A receuliy described nielliod fur preserving' eggs, whicli is claimed 

 to give results so satisfactory that eggs six months old may be 

 poached and are otherwise indistinguishable from fresh laid eggs, 

 is as follows : The eggs are first placed in a vacuum and then 

 iniiiiersed iu melled paraillu wax, which tiuis enters the pores of 

 the shell upon admission of the atmospheric pressure and her- 

 metically seals it. Evaporation of the egg contents, which is 

 responsible for much of the alteration seen in storage eggs, is thus 

 prevented, and if the process is properly carried out, the egg 

 remains in practically a sterile condition until used. 



Properly applied, cold storage seems to be the best method by 

 which eggs may be preserved for some months and still be fit for 

 food purposes. It has been found that the temperature at which 

 the eggs are stored has a great deal to do, not only with the keeping 

 quality of the eggs while iu storage, but also with the length of time 

 they will keep after being removed from storage. A temperaturt 

 of from 31° to. 34° F, seems, to give the most satisfactory results in 

 practice. Eggs which have been stored at a temperature of 30° or 

 below mast be used immediately after removal from storage, while 

 those stored at temperatures of from 32° to 40° will keep for a 

 considerable time after removal to normal temperature. 



The changes which eggs undergo iu cold storage are almost en- 

 tirely due to coiiditicns brought about by the porosity of the shell, 

 whereb}' water is lost by evaporation of the egg content, thus favor- 

 ing the growth of micro-organisms which penetrate the shell and 

 start putrefactive changes. The loss of moisture by evaporation 

 from eggs when standing, either at ordinary temperatures or in 

 cold storage is so decided and such a constant factor that the age 

 of an egg may be approximately ascertained by its deviation from 

 the normal average specific gravity, found in the fresh egg to be 

 1.090, while after thirty days' keeping the figure is reduced to 1.035. 

 The actual loss of weight at the end of thirty days is about 5 per 

 cent, at ordinary temperatures. At cold storage temperatures the 

 loss is more gradual but just as certain, and at the end of one year 

 the loss is 10 per cent. A difference between cold storage and fresh 

 eggs is noted in the relative weights before and after boiling. 

 Fresh eggs lose in weight upon being boiled, while cold storage 

 eggs appreciably gain in weight. 



If eggs in storage are turned at least twice a week to prevent the 

 yolk from adhering to the shell, the proportion of eggs that spoil 

 can materially be reduced, as the point from which the area of 

 infection proceeds in an egg technically known as a ''spot" egg 

 is the point at which the yolk has begun to adhere to the lining 

 membrane of the shell. 



In sorting storage eggs for purposes of selection of those which 

 are sound and fit for food purposes, the operation known as 

 "candling" is resorted to. This is done by workmen who are skilled 

 in the art of selecting rapidly and unerringly the good eggs from 

 those known technically as "rots" and "spots" respectively. An 

 egg which is classified as a "rot" is one in which the decomposition 

 has proceeded so far that the egg content is no longer differentiated 

 into yolk and white, but is one homogeneous mass of putrefying 

 material, sometimes fluid but often semi-fluid or even solid. 

 "Rots" are divider! into "red rots" and "black rots", according to 

 the color of the egg contents. Such an egg may not have present 



