i LIVING MATTER 37 



acetate of phenyl-hydrazine ; characteristic yellow crystals (needles) 

 of phenyl-glucosazone are formed (E. Fischer). 



The biological test is based on the fact that beer yeast is able 

 to provoke alcoholic fermentation in a solution of glucose. 



We shall give the quantitative tests for glucose in dealing 

 with urine. 



(6) Di-saccharides have the formula C 12 H 22 O U , which represents 

 the combination of two molecules of a monosaccharide with 

 elimination of a molecule of water. The most important are cane 

 sugar (saccharose) arid milk sugar (lactose). On warming with 

 dilute mineral acids, and under the action of certain bacteria, the 

 di-saccharides are inverted, i.e. transformed into monosaccharides. 

 Under the fermentative action of the Bacterium lacticum these last 

 are transformed into lactic acid (C 6 H 12 6 = 2C 3 H 6 3 ). With 

 Bacillus butyricus lactic acid undergoes further decomposition, 

 giving rise to butyric acid, carbonic acid, and hydrogen : 



2C 3 H 3 = C 4 H 8 2 + 2C0 2 + 4H. 



(c) Poly sacchar ides are also anhydrides of monosaccharides, 

 and result from the combination of several molecules ; they there- 

 fore have a high molecular weight, which differs in different 

 compounds of the group. Their general formula is wC 6 H 10 5 . 

 They do not taste sweet, are generally amorphous, are partly 

 soluble, partly insoluble in water, and are convertible into 

 monosaccharides by various means. They include a series of 

 bodies widely distributed in both plant and animal cells. The 

 most important are starch, which in the form of stratified 

 corpuscles is found in the protoplasm of many plant cells ; glycogen 

 or animal starch, which occurs in almost all animal tissues, but 

 particularly in the amorphous granules of the hepatic cells, as also 

 in muscle fibre, embryonic tissue, and proliferating cells in general ; 

 animal and vegetable gums; cellulose, which is the principal 

 component of the cellular membranes of plants, and is also found 

 in the animal kingdom in the mantle of Tunicata and the 

 chitinous skeleton of insects. 



Polysaccharides behave variously to solutions of iodine. The 

 starches turn blue, glycogen brown ; cellulose does not stain at all 

 with iodine, and only assumes a bluish tint on treatment with 

 sulphuric acid. 



In addition to free carbohydrates, living protoplasm contains 

 other compounds such as mucin and chitin, as is shown in their 

 derivatives and decomposition products (dextrin, sugar, lactic acid, 

 butyric acid, etc.). 



The inorganic substance of elementary organisms consists of 

 water, salts, and gases. 



Water is indispensable to the activity of living matter, since 



