SIMPLE PURITY AND ADULTERATION TESTS 239 



Against the large end of a fresh egg, between the shell and the 

 lining membrane, a small air cell should be distinctly visible. In 

 an egg which is not perfectly fresh this space is filled by the egg sub- 

 stance, unless the egg has been stored with the large end up. 



FIG. 148. Egg test as determined by Bureau of Chemistry, U. S. Dept. of 

 Agriculture. Hold an egg before a candle, gas or electric light. 1. If it 

 looks like the first egg it is fresh. 2. If it looks like the second egg (top row), 

 showing a red spot, it is slightly stale. 3. If it looks like 'the third egg 

 (top row), settled at the bottom, it is stale. 4. The first egg (bottom row) 

 is stale and the yolk is adhering to the shell. 5. The second egg (bot- 

 tom row) shows a blood ring. 6. The last egg shows a black mold. It 

 is stale and bad. 



Salt solution test: As the density of an egg increases by the 

 evaporation of moisture, its freshness may be approximately esti- 

 mated by placing it in brine. Prepare the salt solution by dissolving 

 two ounces of salt to one pint of water. Immerse the egg in the 



