CARBOHYDRATES 181 



The potassium salt of indoxyl sulphuric acid is known 

 as indican. 



It follows from the origin of the ethereal sulphates that 

 the extent to which they are excreted is a measure of the 

 amount of intestinal putrefaction. 



6.— CARBOHYDRATES 



A carbohydrate is a substance containing carbon, hydro- 

 gen and oxygen, the hydrogen and oxygen being in the 

 same proportions as in water. 



The principal carbohydrates fall into the following 

 groups : — 



A. Monosaccharides or Hexoses (CeH^oOg). 



Glucose (dextrose). 

 Laevulose (fructose). 

 Galactose. 



The relation of these sugars to one another is seen from 

 their formulse. 



