34 PHYSIOLOGICAL CHEMISTRY. 



from mare's milk, and kephir, from cow's milk, are made in 

 this way. In digestion lactose splits up into glucose and 

 galactose readily, while cane sugar yields glucose and fructose, 

 but less readily. With phenyl hydrazine a yellow lactosazone 

 is formed. 



Milk sugar is much less soluble in water than is cane sugar 

 and has but a slightly sweet taste. It is used mainly in the 

 production of infant and invalid foods and in manufacturing 

 pharmacy in tablets, pills, etc. 



MALTOSE, or the sugar of malt, is produced by the action 

 of malt diastase on starch. It therefore occurs in germinating 

 seeds and grains, and is present wherever a diastase acts on 

 starch. In the action of weak acids on starch paste malt sugar 

 is produced as a transition stage, glucose finally resulting by 

 inversion. In this country malt sugar is not a common article 

 of commerce, but in several European countries it has been 

 produced in considerable quantities to be used as an article 

 of food in the place of glucose or cane sugar. The manufac- 

 ture of a relatively pure sugar by the use of malt diastase and 

 a starchy material, such as corn, seems to be attended, how- 

 ever, with great practical difficulties. 



Maltose is readily soluble in water, sweet, but not to the 

 same degree as cane-sugar, and is not directly fermentable. 

 But an inverting enzyme in common yeast changes it so 

 quickly that it was long classed among the true fermenting 

 sugars. The view is now generally held that the disaccha- 

 rides must first be converted into monosaccharides before real 

 fermentation can take place. In the industries malt sugar 

 is thus fermented on the large scale. Toward oxidizing solu- 

 tions its behavior is like that of glucose, although its reducing 

 power is not quite as great. With phenyl hydrazine it forms 

 a maltosazone, and on polarized light its rotating power is very 

 great, the specific rotation being at 20 C. []# + 137. 

 In the body maltose is changed into glucose by action of an 

 inverting enzyme occurring both in the pancreas and in the 

 true intestinal juice. This inversion seems to take place much 



