THE CULTURE OF TOBACCO. 79 



nun-la lower on the windward side of the barn than elsewhere, and 

 thus pi'event an even curing of the contents. The ventilation of 

 the barn must also be under perfect control. It is perhaps need- 

 less to say that, wheie so much heat is used, a thermometei' is a 

 necessity. This should be hung in the centre of the barn, and in 

 such a position that it may be easily read from the dour. 



The tobacco may be cured on the .stalk, oi- may lie cured by 

 the single leaf system. If the single leaf system is used, more 

 pounds may be placed in the barn, and each barn's contents will 

 be largely of the same degree of ripeness and of the same grade. 

 The stalk system will require more time in the curing, but le.ss 

 time in the harvesting. The sap (jf the stalk is also, to a eeitain 

 extent, ti'ansloeated to the leaf, giving the leaf greater vi'eight and 

 gumminess. 



Wliethei' the Isaf oi' tlie stalk method lie adopted, the same 

 four foot curing sticks are used. 



As soon as the barn is filled the fire is started, and fiom that 

 time until the bam is finished, at the end of four oi' five days, it 

 is lint allowed to die down oi' go iiut. The curing pi'ocess may be 

 divided into three stages. 



The first stage is known as the "yellowing" or "wilting" 

 stage. The heat is kept at OO'"" fi:ir from eighteen to twenty houi's, or 

 until the tobacco has reached the pi-opei- colour and lo.st a piortion 

 of its moisture. Some cui'ers hasten this pi'ocess by holding the 

 temperature at 90^ for but three hours and then i-apidly incieasing 

 to 120", and as soc^n as that point is reached dropping back to 90° 

 for another six or eight hours. During this stage certain life 

 chemical changes take place in the leaf ; there is a desti'uctiijn ijf 

 chlorophyll and staich, and the creation of enzymns. 



Tile .second stage is for the purpose of "fixing" the '-'ilour. 

 The yellow colour is already in the leaf, but would, by oxidation 

 of the cell contents, change to a In-own oi- led, unless it be fixed 

 bj' the application of heat and the exhau,stioii fif moisture. This 

 loss of moisture and the application of heat destro}^ the oxidising 

 enzymns that ai-e responsiljle for the change in the cell contents, 

 and the brown colour. To destroy this enzymii, and fix the colour, 

 requires a temperature starting at 100" and gradually rising to 

 120° during a period of aljout twenty hours. 



The next stage is what is known as "killing" the leaf by the 

 final exhausting of the moisture. The temperature is held foi- 

 some time at 120°, and then gradually rises to as high as 135° and 

 even 140^ This process takes about forty-eight hours, at the end 

 of wliic;h time the leaf is so dry that it will ci'umble to po\A-dei- in 

 the hand. If the single leaf method is used, this high temperature 

 must lie maintained, oi- even increased, until the stem is perfectly 

 dry and bi-ittle. 



If the tobacco is being cured on the stalk, a fourth stage is 

 necessary, and is known as "killing the stalk." The temperature 

 is gi-adually increased at a regular rate per hour, until it reaches 

 as high as 160° or 175°, and the stalk is thoroughly cured out. If 

 the stalk be not thoroughly cured as soon as the temperature is 

 lowered, its sap will spread into the leaves and form red places in 

 the region of the veins. 



Many dilTerent modifications of this flue-curing system are in 

 use, differing from each other largely in the degree of temperature 



