14 HUMAN PHYSIOLOGY. 



Maltose crystallizes in the form of white needles, which are soluble 

 in water and in dilute alcohol. It is dextro-rotary. In the presence 

 of ferments and dilute acids maltose undergoes hydration and decom- 

 position, giving rise to two molecules of dextrose. It has a reducing 

 action on cupric oxid. Fermentation is readily caused by yeast, but 

 whether directly or indirectly by inversion is somewhat uncertain. 



Osazones. All the sugars which possess the power of reducing 

 cupric oxid are capable of combining with phenyl-hydrazin, with the 

 formation of compounds termed osazones. The osazones so formed 

 are crystalline in structure, but have different melting points, varying 

 degrees of solubility and optic properties, all of which serve to detect 

 the various sugars and to distinguish one from the other. Of the 

 different osazones, phenyl-glucosazone is the most characteristic, and 

 occurs in the form of long, yellow needles. It may be obtained from 

 dextrose by the following method : To fifty c.c. of a dextrose solution 

 add 2 gm. of phenyl-hydrazin and two gm. of sodium acetate, and 

 boil for an hour. On cooling, the osazone crystallizes in the form 

 of long, yellow needles. 



THE FATS. 



The fats constitute a group of organic bodies found in the tissues 

 of both vegetables and animals. In the vegetable world they are 

 largely found in fruits, seeds, and nuts, where they probably originate 

 from a transformation of the carbohydrates. In the animal body the 

 fats are found largely in the subcutaneous tissue, in the marrow of 

 bones, in and around various internal organs and in milk. In these 

 situations fat is contained in small, round or polygon-shaped vesicles, 

 which are united by areolar tissue and surrounded by blood-vessels. 

 At the temperature of the body the fat is liquid, but after death it 

 soon solidifies from the loss of heat. 



The fats are compounds consisting of carbon, hydrogen, and oxy- 

 gen, of which the first is the chief ingredient, forming by weight 

 about seventy-five per cent., while the last is present only in small 

 quantity. The fat, as found in animals, is a mixture, in varying 

 proportions in different animals, of three neutral fats stearin, pal- 

 mitin, and olein. Each fat is a derivative of glycerin and the par- 

 ticular acid indicated by its name e. g., stearic acid, in the case of 



