354 ELEMENTARY ORGANS. CHAP. III. 



are also to be met with in woody plants, whether 

 As occur- shrubs or trees. If the stalk of a plant of the 

 acfous 1 1 " liliaceous tribe, or a tender shoot of the Elder, is 

 plants. taken and partly cut across, and then gently broken 

 or twisted asunder, the spiral tubes may be seen 

 even with the naked eye, uncoiled somewhat, but 

 remaining still entire even after all the other parts 

 have given way ; and if the inferior portion of the 

 stalk is not very large, it may be kept suspended 

 for some considerable time merely by the strength 

 of the tubes ; which, though now almost entirely 

 uncoiled by means of the weight they support, 

 will, when they finally break, suddenly wind up 

 at each extremity, and again resume their spiral 

 form. 



First de- Grew and Malpighi, who first discovered and 

 Grew and described them, represented them as resembling 

 Malpighi, m their appearance the Trachea, or windpipe of 

 And animals, and designated them by the same term ; 

 "racheL an a PP e ^ at i n by which they are still very gene- 

 rally known. Du Hamel endeavoured to convey 

 an idea of their form by comparing it to that of 

 a piece of riband rolled round a small cylinder, 

 and then gently pulled off in the direction of its 

 longitudinal axis. The figure of the riband be- 

 comes, thus, loosely spiral. This is a very good 

 illustration of the figure of the spiral tubes in their 

 uncoiled state ; but it does not represent them very 

 correctly as they exist in the plant. But the best 

 illustration of this kind is perhaps that of Dr. 



