•212 CHAPTER XII 



If fermentation is properly carried out the le^f will be 

 much improved as to colour, flavour and aroma. Durmg this 

 process it might easily be ruined, and the operation should 

 only be undertaken by those thoroughly experienced. 



Composition. — The following analyses of air-dried 

 samples, furnished by the Union l3epartment of Agriculture, 

 give some idea of the variation in composition found in 

 ordinary tobacco : — 



Sample. Nicotine. H,0. Ash. Ca. Mg. K,0. P^O,. N. 



Strong, good Piet- Retief leaf 4.34 5.24 18.05 2.09 5.19 6.83 0.43 3.92 

 Yellow Kat Eiver leaf ... 0.87 0.57 22.59 4.41 1.02 5.30 0.79 1.26 



Tobacco evidently feeds heavily on nitrogen and potash, 

 but only to a small extent on phosphorus — since, on the aver- 

 age, one ton removes nitrogen, potash, and phosphorus respec- 

 tively, as follows — expressed as sodium nitrate, 300 to 400 

 pounds; expressed as potassium sulphate, 200 pounds; and, 

 expressed as phosphoric oxide, 6 pounds — the necessity for 

 generous applications of fertilisers is apparent. 



Nicotine and the Kelation of Nicotine to Quality. — 

 Koughly speaking, the nicotine content in South African 

 tobaccos varies from "75 to 5'5 per cent., but in N. rustica 

 the content may be as high as 8 per cent. At present, the 

 profitable production of extract is limited by the small quan- 

 tity of waste available. However, the high nicotine content 

 of Pondo tobacco might warrant the cultivation of this type 

 solely for the purpose of nicotine extraction. 



The percentage of nicotine contained in the leaf increases 

 with the growth of the plant until it reaches maturity. " Pro- 

 ductive soils, heavily fertilised with nitrogenous manures, are 

 held to produce tobacco having a high percentage of nicotine. 

 There is also a varietal variation in the percentage of this 

 alkaloid. As curing proceeds the percentage decreases. The 

 finest grades of tobacco contain only moderate, and even 

 relatively small, amounts of this principle. The term 

 strength ' is frequently used to designate the degree of 

 physiological reaction of the system to the use of the tobacco 

 in question, and when thus restricted the strength of a sample 

 depends on the amount of nicotine present. But this term 

 is also frequently applied -to the more direct effect of the 

 tobacco or its smoke on the mucous membrane of the throat 

 and nose. The true physiological action which constitutes 

 the satisfying effect to the consumer, so strikingly exemplified 



