SUGAK. 45 



woody fibre. These substances exist in the same 

 proportion as in woody fibre. 



Another important orj^anic substance is sugar. Its 

 properties of easy solubility and sweetness need scarce- 

 ly be mentioned here, neither will they require illus- 

 tration by the teacher. 



There are several kinds of suffar present in plants, 

 but the kind called cane sugar is most abundant and 

 important. It is that which exists in the stalk of the 

 sugar cane, the root of the sugar beet, the trunk of the 

 sugar maple, etc. etc. Sugar blackens and becomes 

 a species of charcoal when burned : it consists of 

 carbon, hydrogen and oxygen. These same three 

 substances also form the gums, resins, and oily matters 

 which exist so abundantly in certain trees, as the 

 pines, and in certain seeds, as linseed. 



Thus by far the larger portion of plants is made up 

 of sub«!tanrps containinfj only these three gases. We 

 no" ict, hinted at with relation 



to I Ml the early part of this sec- 



tion : the hydrogen and oxygen in woody fibre, starch, 

 sugar and many gums, are m the proper proportions 

 to form water. The plant then can make these bo- 

 dies without difficulty, for we have seen that it absorbs 

 both carbonic acid and water through its leaves : if 

 now the oxygen of the carbonic acid be i T 



through the leaves during the day, as we ha\ • v 



mentioned that it is, there remains only carbon and 

 water, or carbon, oxygen and hydrogen, iust the sub- 

 stances to form those bodies which we have named 

 aboTc. 



In the case of woody fibre, sugar, starch and gum, 

 the quantity of carbon and of f! ' ' Is 



the same, so that they are in 

 position. How V 

 in properties ! \'> 

 yet the chemist i^ able to make sugar from either 



