56 



ANTIMONY. 



This lias also l;)ccn rc])ortcd in foods, 1:)iit has never come under 

 our observation. As a certain amount of organic matter does not 

 interfere ■ with the "Mansh Test", it can be tested for, by that 

 method, the difference between arsenic and antimony being that 

 the arsenic mirror dissolves in sodium hypochlorite, and the antim- 

 ony mirror does not. This substance is also of rare occurrence 

 in condimentals. 



CALCIUM CARBONATE. 



The particles of this substance, when it is found in stock foods, 

 are usually large enough to be picked out with the forceps. They 

 are white in color and do not possess any particular taste or odor. 

 Small particles of the suspected substance may be picked out 

 and placed on a slide containing a couple of drops of water. A 

 drop of dilute hydrochloric acid is added from a stirring rod and an 

 effervescence of carbon dioxid indicates the presence of calcium 

 carbonate. If it is necessary to prove calcium present, the same 

 solution is rendered alkaline with ammonia and a small amount 

 of ammonium oxalate is added. A white cloudiness or precipi- 

 tate indicates calcium. As a confirmatory test for calcium, a 

 small particle may be held in a colorless flame; calcium is indi- 

 cated in the absence of other compounds by the yellowish red 

 color imparted to the flame. 



CALCIUM PHOSPHATE. 



If the presence of this substance is suspected, a little of it may 

 be mounted in glycerine on the slide and small tetragonal and cubi- 

 cal crystals arc sometimes observed. When the suspected crystals 

 are treated with a little nitric acid (dilute) and then a few drops of 

 ammonium molybdate solution are added, diamond shaped yellow 

 crystals of small size may be obtained, or at least a yellow color 

 will be observed. 



CHARCOAL. 



Charcoal very often occurs in stock and chick feeds. It is 

 used partly as an absorbent for the odors arising from the other 

 constituents. In stock feeds it is usually ground fine, but in 



