68 STRONG DRINK AND TOBACCO SMOKE. 



cells, joined end to end, ending occasionally with a 

 single oval cell, perfectly colourless, but more frequently 

 with one that is slightly curved, like that of chicory. 

 It is, however, readily distinguished from that hair by 

 the form and structure at its base and lower series of 

 cells ; but, like it, the foxglove hair has a compound 

 base. 



Another of our wild plants, comfrey (Plate 10, fig. 6), 

 found growing on hedge-banks and in marshy places, is 

 furnished with two forms of hair, both of them very 

 singular in their appearance. On this leaf are a pro- 

 fusion of unicellular hairs, with compound bases, and 

 very sharp points, the whole surface of the hair being 

 wrinkled or striated (as we found in doch but much 

 more coarsely). This is the first instance we have seen of 

 a single-celled hair with a compound base, which in this 

 instance is very prominent. The length and sharp point 

 of this hair readily distinguish it from the club-shaped 

 ones of doch The second form of hair on comfrey leaf 

 is also single-celled and curved, ending in a sharp point, 

 which gives it a form somewhat resembling a fish-hook. 

 The surfaces of these hairs are not striated, and their 

 bases are simple. 



The leaf of the Jerusalem artichoke furnislies in 

 abmidance examples of beautiful compound haii^s with 

 recurved points and compound bases ; their surfaces being 

 covered with minute warts (Plate 10, fig. 9). The student 

 may usefully compare the horizontal section of the midrib 

 of this leaf; first, with that of chicory, which it most 



