142 
SECOND BOOK. 
2. “ That is just what I want them to do,” said 
Miss Brooks. “ Do you see how black they are 
turning now. They are as black as the charred 
piece of wood that has fallen from the fire, and for 
the same reason, for they contain the same kind of 
substance as that which burns in the wood.” 
3. “ And what is that, please?” 
“ It is carbon — one of the names you read 
out to me yesterday. Don’t you remember the 
list? Carbon, hydrogen, oxygen, and nitrogen. 
4 . “ Now the corn-flour is really starch, and 
neither starch nor sugar has any nitrogen in it. 
They are both heat-giving foods; the foods con- 
taining nitrogen are the flesh-formers. So I think 
'the difference between the two kinds is easy to 
understand. 
5 . “I want to talk with you just now about the 
heat-givers. They are called carbonaceous foods 
by some people, because they have so much carbon. 
“ I must tell you that our blood is of the same 
heat whether we live in a hot or a cold country; 
the inside of our bodies is warm even when we feel 
cold. This warmth is made by the slow burning 
of the carbon foods which we eat.” 
6 . “ I did not know that we ate starch,” said May. 
“Indeed we do!” was the reply. “It is one of 
the commonest of the heat-giving foods. We eat 
plenty of it in arrow-root, tapioca, rice, and com, 
as well as in yams, cocoes, and other vegetables. 
