Orga'nic Ferments. 221 



A molecule of glucose being C 6 H 12 6 , if we conceived it being 

 halved, each half molecule will be C Q EL 0, . ( That is also a molecule 



363 x 



of lactic acid. The} r are therefore isomeric.) If from this a mole- 

 cule of carbonic acid be taken ; viz., C 2 , there will be left C 2 H 6 0, 

 which is a molecule of common ( or Ethylic) alcohol. Such a split evi- 

 dently occurs in fermentation. 



After glucose and cane sugar have been " altered," they are liable to 

 a fermentation called Viscous or Mannitic. It transforms them into 

 carbonic dioxide, mannite and gum. This sort of fermentation occurs 

 in certain wines, in the sugary juices of plants, such as beets, carrots, 

 onions, &c. , and in solutions containing sugar and nitrogenous matter. 

 The organisms concerned in this fermentation are small globules united 

 together, the diameter of which varies from .0012 mm. (or .000047 of 

 an inch ) to .0014 mm. (or .000055 of an inch). ( See Fig. 104, I) 



FIG. 104. 



FIG. 104. L Viscous ferment of wine. m. Lactic ferment. 



n. Vinegar ferment. ( Mycoderma Aceti.) 



This ferment sown in 100 parts dissolved sugar give Mannite 51.09 r 

 Gum 45.48, Carbonic dioxide 6.18. 



Lactic Fermentation. 



This consists in the transformation of certain sugars, as sugar of 

 milk and grape sugar, into an acid, sirupy and soluble in water, called 

 lactic acid. A molecule of lactic acid is only a half molecule of sugar 

 and the process appears to be simply the splitting of the molecule 

 thus : 



C 6 H 12 O 6 = 2 C 3 H 6 O 3 

 Sugar 1 molecule. Lactic acid 2 molecules. 



Lactic acid exists in sour skimmed milk, the water of fermentation of 

 peas and French beans, in the sour water of baker's yeast, in the sour 

 water of starch manufacturers, and in sour kraut. 



Lactic fermentation requires the presence of nitrogenous albuminous 

 matter in process of decomposition. A mass of lactic ferment germs 

 has much the appearance of ordinary yeast drained of water and pressed. 

 (See Fig. 104, m. ) It is rather viscid and of a gray color. Lactic 

 fermentation sets itself up spontaneously in the proper medium and is 

 more rapid often than alcoholic fermentation. Best temperature is 35 

 C. ( 95 F.) Lactic ferment often occurs along side of alcoholic in the 

 same mixture, if it is favorable sometimes occurs with beer yeast fer- 

 mentation. In general, the sugars which are most easily fermented by 

 alcoholic fermentation are the most difficult to lactic, and vice versa. 



