104 ANNUAL REPORT OF THE Off. Doc. 



Ihc gasses hydfogen sulphide and hydrogen phosphide, which are 

 mainly responsible for (he disagreeable odor of a decomposing or 

 rotten egg. The presence of these gases is pO'Sitive evidence of the 

 decomposition of the egg, as they are liberated when the complex 

 proteids containing sulphur and phosphorus are broken up by putre- 

 factive changes. After a time these gases escape and the egg 

 content becomes almost inodorous, although greatly changed in its 

 appearance as w^ell as in its chemical composition. In China, duck 

 eggs are sometimes buried in the ground and allowed to. remain for 

 years; total decomposition ensues, the gases rux)ture the shell and 

 escape into the soil where they become absorbed. The eggs are then 

 dug and used for food purposes, being esteemed a great delicacy 

 by the orientals. 



An egg which is known as a "spot'' egg is, as previously stated, 

 one in which there is a localized point of infection, usually charac- 

 terized by the adherence of the yolk to the lining membrane of the 

 shell, and which upon close examination, is found to be accom- 

 panied by the presence of an active growth of a micro-organism, 

 usually one of the more resistant fungi. A "spot" egg is also one 

 in which incubation has begun. In its early stages, a "spot'' egg 

 upon opening, has an appearance as though the yolk had been 

 partly cooked where it adheres to the lining membrane of the shell. 

 Later this spot becomes black and mould spores are readily recog- 

 nized upon microscopic examination. Such an egg always possesses 

 a characteristic, usually disagreeable odor, and is not a wholesome 

 article of food. Chemical and physical examinations of the remain- 

 ing egg content show a splitting up of the proteid compounds nor- 

 nmlly present with the liberation of new and frequently- poisonous 

 organic bodies. 



Candling, as actually practiced, consists in observing the appear- 

 ance of the egg, viewed by transmitted light when held against a 

 bright flame. A candle may be used, but an incandescent light is 

 more frequently employed in the larger establishments, and when 

 the operation is carried on in a dark room where the only light pro- 

 ceeds from the one that is. used for the examination of the eggs, a 

 skilled workman can candle and separate the eggs into their various 

 classes as rapidly as he can pick them up and handle them. 



A normal or fresh egg, when observed by transmitted light under 

 these conditions, shows an almost uniformly illuminated appear- 

 ance, shading slightly from the darker center occupied by the yolk. 

 A "rot" is recognized at once by its opaque, almost black appeaiance 

 throughout, while a "spot" is readily known by the dark localized 

 area at one particular point against the inside of the shell. An 

 egg which has been in storage for more than six months can readily 

 be recognized by the expert candler, as the air space is much larger 

 and rapidly changes its position as the egg is moved around before 

 the light, due to the greater fluidity of the egg content. When the 

 egg has been in storage for from 7 to months it has acnuired a 

 degree of fluidity which renders the se]jaration of the yolk from the 

 white of an opened egg almost impossible, and if such an egg in tlie 

 whole si ate be agitated, it will be found upon opening that the 

 white and yolk have become almost entirely blended. This is not 

 true of a fresli egg, in v/hich the most violent agitation usually fs'.ils 

 to produce any mixture of the yolk and white. This condition of 



