194. PROTEINS AND CARBOHYDRATES 
CHsCH2OHCOOH. The other has the formula CHn.OHCH2sCOOH. 
The last-mentioned lactic acid since it does not possess an asymetric 
carbon atom is not optically active. The ethylidene lactic acids possess 
asymetric carbon atoms and are therefore optically active. 
Thomas (1916) has shown that the lactic acid produced by Matzoon 
in synthetic culture media is inactive but that it may be resolved into 
two active components. According to Heinemann (1907) milk which 
sours naturally at room temperature contains chiefly d-acid; at 37° C. 
chiefly r-acid with l-acid in excess if allowed to stand a few days. He 
also found that the kind of organism present determined the kind of 
lactic acid which was formed. The temperature was also believed to 
have an effect. 
Alcoholic Fermentation. These are those changes in sugar and 
decomposition products of sugar which result in the formation of large 
amounts of alcohol. Historically it has been known for a very long 
time and was not thoroughly analyzed until Pasteur proved that it was a 
biological phenomenon. The chemistry of alcoholic fermentation is 
now fairly well understood and there is much data available ‘in the 
literature to review at this time. Kruse believes that dextrose breaks 
up in a series of reactions while Harden maintains that this takes place 
in one reaction. Kruse’s reactions will add up to equal that of Harden’s: 
3Ce6H1206 = 2C2Hs0H +2CQz; 
2C6H1206 = 83CH3COOH; 
6C6H1206 = 2C3H603; 
CeH1206+6H20 =6CO2+6H20; 
12C6H1206+H2O = 12C3H603+6C2H5;0H-+6 CH3~—-COOH 
+12COe2e+12H20. 
Eruyt Auconou. Jodoform Reaction. Add about an equal amount 
of iodine solution to the sample and treat with sodium hydroxide until 
decolorized. Warm the mixture very carefully and try to detect the 
odor of iodoform. A yellow precipitate of iodoform may result. This 
test is not specific as it is given by acetone, aldehyde, acetic ester, and 
other similar substances. 
Acetaldehyde Reaction. Add a few drops of potassium dichromate 
and‘ dilute sulphuric acid to the sample and heat. An odor of aldehyde 
will be observed if ethyl alcohol is present. 
