16 BULLETIN" 79, U. S. DEPARTMENT OF AGRICULTURE. 



are again practically free from starch and reducing sugars, except 

 where the curing was incomplete. The difference as regards protein 

 is similar to those noted in the cured and uncured leaves in the pre- 

 ceding experiments. The differences with reference to amid and 

 amido compounds are somewhat variable, but it is evident that the 

 cured leaf does not contain appreciably larger quantities of these 

 constituents, relatively, than the green leaf, and the same is true as 

 to ammonia. It is clear that the cured leaves contain considerably 

 less total nitrogen than the green leaves. 



Analyses of cured samples of our more important commercial types 

 of leaf tobacco have been published by several investigators, 1 but 

 none of them has included the comparative composition of the corre- 

 sponding uncured leaf. The results of Moore and of Carpenter indi- 

 cate that the cured leaf of the bright flue-cured type is quite low in 

 ash content, and it should be added that we have had occasion to 

 examine a number of samples grown in eastern North Carolina which 

 contained only 6 or 7 per cent of crude ash in the leaf web. In this 

 type the cured leaf appears to be practically free from starch, but the 

 content of reducing sugars is quite high (16 to 18 per cent), while the 

 content of cellulose is decidedly low, particularly in the leaf web. 

 The leaf contains moderate quantities of nicotine, practically no 

 nitrate, and is very low in protein, as would be expected from the 

 light color. White Burley, which is an air-cured type, is uniformly 

 high in ash content, according to these authors. The cured leaf 

 appears to be free from starch and reducing sugars and is relatively 

 high in content of cellulose. The content of nicotine is high, the 

 content of nitrate is considerable, and the content of protein is high. 

 It is interesting to note that Burley closely resembles the cigar- 

 wrapper-leaf types in composition in respect to all of the above- 

 mentioned constituents. It is also interesting to note that the peculiar 

 chlorotic appearance of this type when growing in the field is not 

 associated with a low content of organic nitrogenous substances. 

 The dark fire-cured export types of Virginia, Kentucky, and Tennessee 

 are rather high in ash content, free from^ starch, low in reducing 

 sugars, 2 and somewhat low in cellulose. These types are quite high 

 in nicotine, usually low in nitrate, and high in protein, as is to be 

 expected from the dark color of the cured leaf. The one sample of 



1 Moore, G. E. Report on the chemistry of American tobaccos. In Killebrew, J. B., Report on the 

 culture and curing of tobaccos in the United States, p. 269. U. S. Department of the Interior, Census 

 Office, Report on the Productions of Agriculture, Tenth Census, 1880. 1883. 



Chemical changes in tobacco during fermentation. Connecticut Agricultural Experiment Station, 16th 

 Annual Report, 1892, p. 29-30. 1893. 



Winton, A. L., Ogden, A. W., Mitchell, W. L., and Jenkins, E. H. Effects of fertilizers on the compo- 

 sition of wrapper leaf tobacco. Connecticut Agricultural Experiment Station, 20th Annual Report, 1896, 

 p. 325-326. 1897. 



Carpenter, F. B. Types of tobacco and their analyses. North Carolina Agricultural Experiment 

 Station, Bulletin 122, p. 331-366, 1895. 



* Only two samples reported as to starch and sugars. 



