GRADING EGGS 457 
(c) Leakers. Eggs whose shells and shell membranes are suffi- 
ciently broken to permit a portion of their contents to escape. 
(d) Dirties. Eggs, the shells of which have become soiled from un- 
clean nests, etc. 
(e) Weak Eggs. In this grade are placed all eggs in which the 
albumen has become weak or watery, due to high or varying tempera- 
ture. 
Leakers and dirties present the greatest problem to food bacteriol- 
ogists since they allow the ingress of bacteria. The leakers are either 
sold for local consumption or are broken for drying. Table XLIX pre- 
sents some data on commercial samples of leaking eggs secured by 
Pennington et al. (1914). 
Dirties appear during wet weather and sometimes during hot 
weather when moisture from the hen’s body allows more dirt to adhere 
to the shell. Many of these are used for local consumption or for 
drying since they do not keep well. In the examination of eggs with 
dirty shells Pennington (1914) secured widely divergent results. The 
minimum number of bacteria was 400 and the maximum number 
1,600,000 per gram at 20° C. The number of B. col: varied from 
10 to 10,000 in six samples. It has been reported by many 
investigators that dirty eggs do not keep well. Often these eggs 
are washed but this process reduces the keeping quality since it 
removes the delicate membrane or film of mucus on the surface 
of the shell. 
Spots. All eggs which show a spot before the candle are put into 
this class. These may be due to bacterial, meat, blood or mold spots. 
The term ‘ spot-rot”’ is applied to a heated egg caused by decom- 
position of the dead germ. Molds often develop in eggs and the hyphe 
extend toward the air cell. To prevent this eggs must be stored in a 
dry place. Kossowicz found that old eggs were more susceptible to 
mold invasion than are fresh eggs; this is somewhat to be expected. 
Postolka (1916) confirmed this opinion. Marked growth of molds took 
place after either natural or artificial infection in the testacea but rarely 
in the yolk. Natural infection was caused by Penicillewm glaucum and 
Cladosporium herbarum. Under experimental conditions almost any 
mold will attack and penetrate the egg. Postolka states that with 
even great infection with molds, no putrefaction takes place. Meat 
spots are caused by broken-down tissue of the hen’s oviduct. In 
the candling process they appear as small floating bodies and 
are usually near the shell. Blood clots result from injuries to 
