92 J. A. ARCHER ON TOBACCO. 



few club-shaped hairs, the extremities of which are divided so as 

 to form a mimber of small cells containing within their cavities a 

 dark brown colouring matter. These short hairs are found on all 

 parts of the leaf, but are more numerous on the midrib and veins, 

 but are not very abundant. {Fig. la, pi. 5.) 



The author of the paper directed attention, in passing, to the 

 subject of vegetable hairs generally, with the especial object of 

 ascertaining their particular use in the economy of the plant, the 

 existing theories concerning which appear to be very vague. 



The cellular tissues of tobacco may be said to consist of three 

 kinds : — 



First. Cells of an hexagonal or octagonal form, found in the 

 transverse section of the midrib. 



Second. Elongated hollow cells, joined together, found in the 

 epidermis of the under surface of the midrib. 



Third. Cells, with waved borders, found on the upper and 

 under surface of the lamina of the leaf. 



Tobacco contains no raphides, but in the green state a minute 

 quantity of starch is found, the granules of which are very small, 

 and are found near the midrib. In form, these granules are round 

 and irregularly oval, in some instances present a flattened surface, 

 and occasionally they present a very minute hilum in a central 

 position. 



In consequence of the high duty on tobacco, a considerable temp- 

 tation is offered to adulterate the staple, both in its raw and 

 manufactured state. To prevent the practice, a penalty of 

 £200 may be enforced for the introduction of anything but water. 

 The principal adulterants are mechanical, and may be readily 

 detected by the use of the microscope. Among the substances 

 used are the leaves of rhubarb, dock, burdock, coltsfoot, foxglove, 

 thorn apple, cabbage, lettuce, and chicory. Also, sugar, treacle, 

 molasses, liquorice, gum dextrine, Irish moss, common salt, copperas, 

 and flour. In snuff have been found ground dye woods, such as 

 fustic, logwood, Brazil wood, and sumach ; peat moss, ground 

 pine, beech, and birch ; the starches or flour of maize, orris root, 

 wheat, oats, potatoes, &c. ; chalk, oxide of iron, yellow ochre, and 

 probably many others. 



The following are a few instances : — 



1. Rhubarb. — This is distinguished from tobacco by the bundles 

 of woody fibres being scattered irregularly, instead of being 



