SULPHUR 15 



Sulphur. — (See Ex. IV. ) Another important element 

 in our body compounds is sulphur. Most of us have seen 

 this element in its pure state and recall its yellow color. 

 The sulphm' used on sulphur matches is the element in 

 its pure state, and wc may recall the fact that when it 

 burns it gives off suffocating fumes and a blue flame. In 

 its free state, this element is found only around volcanic 

 regions. Combined with other elements (chemical com- 

 pounds of sulphur) it is extremely abundant. Muscle is 

 such a compound of sulphur with other elements. Pure 

 sulphur is odorless and tasteless. 



When flesh decays it gives off a disagreeable odor. This 

 odor is a property of a gas called hydrogen sulphide, 

 which the sulphur forms as flesh decays, by combining 

 with the element hydrogen. The ordinary hen's egg con- 

 tains sulphur, and in decay this gas is formed abundantly. 

 The blackening of a silver spoon used in eating an egg is 

 due to a black compound called sulphide of silver, which 

 the sulphur of the egg forms with the element silver. 



The fumes from burning sulphur (a compound of sul- 

 phur and oxygen), the bad smelling gas (sulphur and 

 hydrogen) and the black compound (sulphur and silver) 

 bring out the fact that a chemical element may have an 

 affinity for more than one element. The fact that it occurs 

 free in the air and yet combines with oxygen to form a 

 compound when heated is an illustration of the way in 

 which external conditions may affect the affinity of an 

 element, while the blue flame which results when sulphur 

 combines with oxygen and which is absent in the forma- 

 tion of the other two compounds, shows that the amount 

 of heat generated by the union of two elements may vary 

 greatly with the elements. 



