(diastatic matter) cannot be separated, also that the lac contains 

 acetic acid. The lac is of a grayish color. On exposure to air 

 it rapidly darkens, but if undisturbed an impervious membrane 

 soon forms on the surface thus preventing further change. The 

 blackening of the lac is due to the action of oxydase or "Lac- 

 case," a soluble oxydizing enzyme, in the presence of moisture. 

 The lac may also be darkened by other means, as, by the action 

 of alkalies. For example, a piece of wood was coated with fresh 

 lac; a second piece was coated with lac, sterilized by suspending 

 a tube containing lac in boiling water for half an hour; and a 

 third was coated with sterilized lac containing a small portion 

 of potassium hydroxide ; each piece of wood was covered with 

 wet filter paper. The first rapidly changed to a dark brown color 

 and in 24 hours the coating was black and hard. The second 

 remained unchanged. The third immediately changed to black 

 but remained moist for several days. 



LACRESINS, THE URUSHIC ACID OF YOSHIDA, THE; LACCOIy OF 

 BERTRAND. 



It was desirous to separate the resinous portion from the 

 gum and enzyme with the least exposure to the air, therefore 

 the can containing lac was connected with a flask by means of 

 a tube extending to the bottom of each. The flask was partially 

 filled with alcohol and the lac drawn into the alcohol by suction. 

 The contents of the flask were then agitated, filtered and the 

 residue exhausted with alcohol. The alcoholic solution was 

 strongly acid and had a peculiar aromatic odor which upon evap- 

 oration of the alcohol suggested the odor of acetic acid. The 

 oily residue left after distillation of the alcohol was washed by 

 shaking out with water. The watery solution was neutralized 

 with potassium hydroxide and heated, when a fine black precipi- 

 tate formed. This was removed by filtration and the filtrate evap- 

 orated to dryness. The residue with sulphuric acid gave an un- 

 mistakable odor of acetic acid, also when heated with sulphuric 

 acid and alcohol the odor of acetic ether was developed. It also 

 gave the cacodyl odor when heated with alkali and with arsenic 

 trioxide. To prove that the presence of acetic acid was not due 

 to the oxidation of the alcohol, a fresh portion of lac was ex- 

 tracted with ether, and the ether residue treated as above with 

 the same results. It is therefore evident that the lac contains acetic 



