82 TOBACCO LEAF. 



flavor of the leaf. The nitrogen-containing substances 

 or albuminoids, also form an important constituent, the 

 effect of which is but little understood, and the same is 

 true of the acids in tobacco nitric, citric, acetic and 

 pectic. There are other organic or carbonaceous sub- 

 stances, of which still less is known. 



Ash or Mineral Ingredients make up a large part of 

 the tobacco plant. The ash constitutes from 15 to 25 

 per cent of the chemically dry leaf, 5 to 15 per cent of 

 the stalk, and from 5 to 15 per cent of the root. The 

 quantity and character of the mineral ingredients have 

 a profound influence on the quality of leaf, especially 

 for smoking. These mineral ingredients vary widely in 

 different varieties, and also in the same variety under 

 different conditions (see Table IV, Pages 112 and 113). 

 Potash and lime each constitute about one-third of the 

 ash, the other third being composed of phosphoric acid, 

 magnesia, soda, sulphuric acid, carbonic acid, chlorine, 

 silica (sand), alumina (clay) and iron (ferric oxide). 



Effect of Constituents. The principal ingredients 

 that are supposed to most affect quality are, nicotine, 

 nitrogen, potash, lime, magnesia and chlorine. The 

 quantity of nicotine in the leaf is governed, to some ex- 

 tent, by the amount and character of the nitrogenous 

 substances the plant feeds upon. The other elements 

 also vary in amount with variety, soil, climate and fer- 

 tilizer. One cannot speak positively of their effect upon 

 the curing or chewing quality of the leaf. 



Why certain crops of leaves of tobacco burn well 

 and others burn badly, is not fully understood. Nessler 

 demonstrated that tobacco which contains large quanti- 

 ties of chlorides does not burn well, especially when the 

 quantity of potash present is small. Nessler found, 

 from examination of forty-six samples of tobacco grown 

 in different parts of Baden, on soils of diverse character, 

 that the more potash and the less chlorine a leaf con- 



