CHAPTEE VII 



PHOSPHATES AND NITROGEN" 



" " T) HOSPHOEUS, which is a dangerous poison, as 

 A we have seen, is nevertheless found in abun- 

 dance in the bodies of all animals. It occurs in the 

 urine, whence Brandt was the first to extract it ; it is 

 found still more plentifully in the bones, and from 

 thence it is now obtained. There is some in meat, 

 in milk, and in cheese ; also in plants, notably cereals ; 

 hence flour and bread contain it. But do not be 

 alarmed: we shall not die of poison like the rats 

 that have nibbled crusts smeared with grease and 

 phosphorus. ' ' 



"But why not," asked Emile, "if we eat it as the 

 rats do?" 



' ' I will try to explain, ' ' replied his uncle. ' ' When 

 two or more substances are mixed together, they lose 

 their original properties, while the new substance 

 obtained by their combination is found to possess 

 new properties having nothing in common with the 

 old ones. Thus carbon, when combined with the air 

 that we breathe, becomes an invisible gas, subtle, and 

 unfit for breathing. In like manner lime, burning to 

 the taste, is converted by union with carbonic acid 

 gas into chalk, a calcareous stone void of taste. Fur- 

 thermore, poisonous substances, deadly in a very 



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