80 TOBACCO LEAF. 



plant reaches maturity, but every part contains some 

 trace of this alkaloid. The percentage of nicotine is 

 greater just as the leaf reaches maturity, than in either 

 the green or overripe leaves. Apparently the formation 

 and accumulation of nicotine in the leaf continue as 

 long as there is growth. The effect of nicotine, after 

 plant growth ceases, is not understood, nor is the office 

 of nicotine in the economy of the plant definitely stated. 

 The amount of nicotine in the whole leaf (exclusive of 

 the stem or midribs), of American-grown tobacco, ranges 

 from less than one per cent to nearly six per cent of the 

 chemically dry substance. 



"This variation in the percentage of nicotine," 

 says Carpenter, "is due, in some measure, to different 

 varieties, but whatever variety is grown, or what other 

 conditions prevail, it is almost always noticed that those 

 influences which tend to produce a coarse, rank growth, 

 containing a large percentage of albuminoids, also pro- 

 duce a comparatively large amount of nicotine. The 

 climate, nature of soil and fertilizers, treatment of crop, 

 etc., all have their influence. Of all these conditions, 

 that of soil and fertilizers seems to be the most impor- 

 tant. A rich, heavy soil, fertilized with a strong nitrog- 

 enous manure, is apparently favorable to the produc- 

 tion of a high percentage of nicotine, while the reverse 

 is true of a light, sandy soil containing little organic 

 matter. Havana-grown tobacco, which contains a low 

 percentage, has, in addition to soil, the benefit of a very 

 moist atmosphere. 



"For this reason, some have attributed the reverse 

 conditions as favorable to the production of nicotine. 

 From the results of the investigation of tobaccos grown 

 in the United States, we can find no ground for this as- 

 sertion. Tobacco of the seedleaf variety grown in Con- 

 necticut, on a rich loam, gave over four per cent of nic- 

 otine, while that grown on a sandy loam soil contained 



