88 Vegetable Physiology, 



has had the misfortune to handle a nettle. This kind of hair 

 is analagous to the poison fang of a serpent. The prickles of 



Fig. 8. 



a b c d e f g 



the Rose, Raspberry, and other shrubs, are also appendages of 

 the cuticle, which, when stripped off, carries them with it. They 

 are thus easily distinguished from spines, which are prolonga- 

 tions of the woody tissue, and do not come off with the bark. 

 They occur on many parts of plants, but are rarely found 

 except on the stems. Scales are thin, flat, scurf-like pro- 

 cesses, composed of cellular tissue, and one/orm of them is found 

 in great abundance on the stalks and leaves of ferns. A gland 

 is a small prominence in the tissue just beneath the cuticle, 

 which it causes to project. Sometimes it is furnished with a 

 little pedicel, by which it is elevated somewhat above the sur- 

 face of the cuticle. Glands frequently secrete a peculiar fluid. 

 Those which are so abundant in the rind of the Orange and 

 Lemon contain the volatile oil which gives it its odor and flavor. 

 The turpentine of resinous woods is collected in similar glands. 

 We have been compelled to leave unnoticed many of the 

 different forms which result from the combination of membrane 

 and fibre, and the foregoing remarks afford but a bare sketch 

 of what might be very 'widely extended. We hope, never- 

 theless, that the reader has not failed to observe the simplicity 

 of the plan by which so many different results are effected, so 

 many functions necessary to vegetable economy performed. 

 Nature is a better artificer than man. While the most elabo- 

 rate works of the latter are found, the more closely they are 

 scrutinized, the more full of defects, those of the former dis- 

 play new beauties at every examination, and the more tho- 

 roughly their intricacies are penetrated, the more perfect do 

 they appear. 



