56 
BULLETIN 51, U. S. DEPAETMENT OF AGEICULTTJRE. 
BLACK ROTS. 
Black rots receive their name from the black appearance which 
they present before the candle. Out of the shell they are a homo- 
geneous olive green liquid with an offensive odor resembling that 
of hydrogen sulphid. It is often possible to pick out a black rot 
from receipts by the odor and gra^dsh tint of the shell. The results 
of two samples consisting of from four to eight of these rots showed 
counts of more than a billion bacteria and an amount of ammoniacal 
nitrogen much greater than that found in any previous type of egg 
discussed (see Table 25). Black rots^ therefore, represent eggs in 
the last stages of decomposition. Their only value is for fertilizer 
purposes. 
Table 25. — Small samples of hlack rots. 
Sample 
No. 
Source. 
Date of 
collec- 
tion. 
Number of bacteria per 
gram at — 
Number 
of gas-pro- 
ducing 
bacteria 
per gram 
in lac- 
tose bne. 
Gelatin 
liquefy- 
ing or- 
ganisms 
per gram. 
Percentage 
of ammon- 
iacal nitro- 
gen, Folin 
method. - 
Per 
cent 
of 
mois- 
tvue. 
Size of 
sample. 
20° C. 
37° C. 
Wet 
basis. 
Dry 
basis. 
4421 
D2 
D5 
1912. 
May 28 
July 31 
1,100,000,000 
2,300,000,000 
310,000.000 
2,300,000.000 
10,000,000 
10,000,000 
99,000,000 
72.31 
71.40 
4 eggs. 
8 eggs. 
4873 
0.0229 
0. 0800 
DETERIORATED EGGS NOT DISTINGUISHABLE BY CANDLING. 
The eggs previously discussed have been recognizable before the 
candle or distinguishable by other characteristics, such as dirty or 
cracked shells. Some eggs, however, which are distinctly undesir- 
able, can not be detected by candling and must be eliminated by the 
breaker. These are recognized when out of the shell by color, odor, 
or general appearance. The great majority of them belong to three 
groups : Eggs having a green white, often called " grass " eggs by 
the trade; eggs having a pungent, characteristic odor, commonly 
known as " sour " ; and eggs which are " musty," that is, having an 
odor which is exceedingly penetrating, very characteristic, and often 
suggesting that of the -common jimson weed. This odor increases 
when heat is applied, so that a single musty egg in 100 pounds of 
good egg will spoil it for bakers' purposes. 
A number of eggs have distinctive odors when out of the shell, 
though there may be no visible signs of deterioration. Sometimes 
the eggs absorb these odors, such as the fruity odor which comes when 
eggs and apples are held in a closed space together, or that of straw- 
board from the fillers in which they are packed. Unless these ab- 
sorbed odors carry with them an objectionable taste there would seem 
to be no reason for discarding the eggs. Other odors, apparently 
