AMERICAN TOBACCO TYPES, USES, AND MARKETS Oo 
achieve these desired characteristics the tobacco is raised on the hght 
sandy soils of the southeastern seaboard. The same varieties, if 
raised on heavier soils such as those of limestone origin would yield 
heavier-bodied tobacco not suited to the uses for which flue-cured 
tobacco is in demand, and would not make the same response to flue- 
curing technique. Although many of the varieties or strains of tobacco 
in the fire-cured, dark air-cured, and flue-cured classes were derived 
from the same parent stock, they owe their present wide divergence to 
differences in environment, and to generations of selection and 
breeding. 
The curing methods employed in any district are such as will con- 
tribute to the desired qualities of leaf, and the varieties or strains 
selected are those that respond best to the curing methods and soil 
types and best meet manufacturmg requirements. Curing is pri- 
marily a chemical process. By regulation of the drying process cer- 
tain changes in the composition of the leaf take place during the 
period when the cells remain alive. These changes and the rate at 
which they take place have important effects upon the texture, color, 
and other properties of the tobacco. Beyond this, the curing process 
consists of the further drying of the tobacco, fixing the color, and 
imparting finish. Involved in this process are chemical changes 
that extend through the fermentation or aging period. (See The 
Aging of Tobacco, p. 85). 
Classes of tobacco vary from each other to some extent in chemical 
properties. Chemical analyses have been made of several classes of 
tobacco, but the methods employed have not been uniform and the 
results are not strictly comparable. In many respects the differences 
appear to be of minor importance. As to some, the differences are 
marked. The outstanding differences relate to quantity of nitroge- 
nous constituents, including nicotine; quantity and form of carbo- 
hydrate; the ash or mineral content. The cigar types, though differ- 
ing somewhat among themselves, are characterized on the whole by 
a high content of nitrogen and their content of mineral matter also 
is high, whereas their relative content of carbohydrates is quite low. 
These characteristics apply more especially to the wrapper types and 
the binder types grown on lght soils. Of the domestic cigarette 
types, the flue-cured leaf is in a class by itself with respect to its 
very high content of sugar, which frequently exceeds 20 percent of 
the dry weight. On the other hand, Maryland contains an excep- 
tionally high percentage of cellulose and pectin but very little sugar. 
Both flue-cured and Maryland are low in total nitrogen and mineral 
matter and the Maryland has a low content of nicotine. In chemical 
composition, Burley is intermediate between the cigar types and the 
Maryland and flue-cured types. Not many data are available on the 
dark air-cured and fire-cured types but they appear to resemble 
Burley in content of nitrogen and ash or mineral matter and they 
are rather outstandingly high in nicotine. 
Variations between the types composing any given class of tobacco 
are not so great as those which distinguish one class from another. 
They may consist of differences in color, body, quality in a general 
sense, or in their response to fermentation and aging during storage. 
These differences, which are important from a manufacturing stand- 
point, result mainly from differences in soil and climate, since the 
