TOBACCO 255 



researches by Loew and other chemists of the United States 

 Board of Agriculture, lead to the conclusion that the changes are 

 essentially due to enzyme action; oxidases and peroxidases 

 have been detected, and especially a soluble and insoluble 

 catalase, an enzyme capable of decomposing hydrogen 

 peroxide. The changes taking place in the curing of tobacco 

 consist, in the first place, in the elimination of starch and 

 sugar, by the continued respiration of the plant cells during 

 drying. The ethereal extract and the percentage of tannin 

 also decrease. During the fermentation the nicotine also 

 decreases, and the colour and aroma improve. The effect of 

 the character of the soil on the quality of tobacco is, of course, 

 well known, and greater control of the quality, in parts of the 

 world which hitherto have not yielded the finest brands of 

 tobacco, must be sought in investigations similar to those 

 which have been described in connection with indigo and 

 with tea. 



