INORGANIC PRINCIPLES 93 



vegetable kingdom, in diabetic urine, in the blood, etc. It is usually ob- 

 tained from grape-juice, honey, beet-root, or carrots. As prepared, it really 

 is a mixture of two isomeric bodies, Dextrose or grape-sugar, which turns 

 a ray of polarized light to the right (-f- 56), and L&vulose or fruit-sugar, 

 which turns the ray to the left. 



It is easily soluble in water and in alcohol; not so sweet as cane-sugar; 

 the relation of its sweetness to that of cane-sugar is as 3 to 5. It is not so 

 easily charred by strong sulphuric acid as cane-sugar. It is not entirely 

 soluble in alcohol. It undergoes alcoholic fermentation with yeast. 



Dextrose is the characteristic carbohydrate of the blood. It has the 

 power of reducing the salts of silver, bismuth, mercury, and copper, either 

 to the form of the metal in the first three cases, or to the form of the sub- 

 oxide in the case with cuprous salts. Upon this property the chief tests for 

 the sugar, e.g., Trommer's and Bottcher's, depend. It undergoes alcoholic 

 fermentation with yeast, and lactic-acid fermentation with bacteria lactis. 

 It forms caramel when strongly heated, and is also charred with strong acids. 



Levulose is one of the products of the decomposition of cane-sugar by 

 means of dilute mineral acids, or by means of the ferment invertin in the 

 alimentary canal. It reacts to the same test as glucose, but is non-crystal- 

 lizable, and is laevo-rotatory. It is soluble in water and in alcohol. Its com- 

 pound with lime is solid, whereas that with dextrose is not. 



Galactose. This monosaccharid is formed from lactose by the 

 action of dilute mineral acids, or inverting ferments; it may also be ob- 

 tained from cerebrin. It undergoes alcoholic fermentation, and reduces 

 copper salts to the suboxide. 



Inosite. Inosite occurs in the heart and voluntary muscles, as 

 well as in beans and other plants. It crystallizes in the form of large color- 

 less monoclinic tables, which are soluble in water, but insoluble in alcohol 

 or ether. It has the formula of glucose, but is not a sugar. Inosite may 

 be detected by evaporating the solution containing it nearly to dryness, and 

 by then adding a small drop of solution of mercuric nitrate, and afterward 

 evaporating carefully to dryness, a yellowish-white residue is obtained; 

 on further cautiously heating, the yellow changes to a deep rose-color, which 

 disappears on cooling, but reappears on heating. If the inosite be almost 

 pure, its solution may be evaporated nearly to dryness. After, the addition 

 of nitric acid, the residue mixed with a little ammonia and calcium chloride, 

 and again evaporated, yields a rose-red coloration. 



INORGANIC PRINCIPLES. 



Salts. The inorganic principles of the human body are numerous. 

 They are derived, for the most part, directly from food and drink, and pass 

 through the system unaltered. But some salts are decomposed on their 



