MARKETING AND GRADING EGGS 



157 



" Rots : Eggs which are absolutely unfit for food. 

 The dififerent classes of rots may be defined as 

 follows : 



" (a) Black rot : This is the easiest class of rots 

 to recognize and, consequently the best known. 

 When the egg is held before the candle the contents 

 have a blackish appearance, and in most cases the 

 air cell is very prominent. The formation of hydro- 

 gen-sulphide gas in the egg causes the contents to 

 blacken and gives rise to the characteristic rotten 

 egg smell, and sometimes causes the egg to explode. 



"(b) White rot: These eggs have a character- 

 istic sour smell. The contents become watery, the 

 yolk and white mixed, and the whole egg offensive 

 to both the sight and the smell. It is also known 

 as the 'mixed rot.' 



"(c) Spot rot: In this the foreign growth has 

 not contaminated the entire egg, but has remained 

 near the point of entrance. Such eggs are readily 

 picked out with the candle, and when broken show 

 lumpy particles adhering to the inside of the shell. 

 These lumps are of various colors and appearances. 

 It is probable that spot rots are caused as much by 

 mold as bacteria, but for practical purposes the dis- 

 tinction is unnecessary. 



"To all intents and purposes the spot rot, as 

 explained above, is practically the same as the 

 brown and black spots described under the general 

 head of ' spots.' The spot rot is also placed under 



