MIt,K SUGAR. 19 



formed which on coohng separates out in golden yellow 

 needles. The same reaction is effected by heating the 

 sugar solution with two parts of phenylhydrazine hydro- 

 chloride and three parts of sodium acetate crystals. By 

 recrystallization out of hot water pure lactosazone may 

 be obtained, melting at 200 degrees C. (The osazone of 

 grape sugar, glucosazone, melts at 205 degrees C.) 



5. Milk sugar does not undergo alcoholic ferment- 

 ation directly, but by boiling with dilute sulphuric acid 

 for an hour and neutralizing with calcium carbonate, the 

 resulting solution will ferment upon the addition of yeast. 



6. Lactose turns the plane of polarized light to the 

 right, (a) D equals 52.5 degrees. The rotation will be 

 greater when the solution is boiled for half an hour with 

 dilute acid and made up to its former volume. 



7. Unlike grape sugar, solutions of milk sugar will 

 not produce cuprous oxide by boiling with copper ace- 

 tate and acetic acid. 



8. The reaction of nitric acid : To 5 grams of the sugar 

 add 20 c. c. of concentrated nitric acid and cautiously heat 

 the mixture. A very vigorous reaction takes place, pro- 

 ducing dense red fumes. When the action of the acid has 

 ceased the reaction product is allowed to stand in a cool 

 place for some time. From the solution mucic acid sepa- 

 rates as a crystallized mass. The crystals are thoroughly 

 dried, dissolved in ammonia, and the solution then placed 

 on a water bath and evaporated to dryness. The dried 

 substance when heated in a test tube yields pyrrol, the 

 vapor of which will color dark red a pine splinter previ- 

 ously moistened with hydrochloric acid. Grape sugar, 

 when treated in a similar manner, with nitric acid yields 

 oxalic acid but no mucic acid. 



Besides the already mentioned difference in the per- 

 centage of volatile fatty acids contained in the fat of milk 

 from different animals, one may decide (according to 



