310 CONSERVATIVE ORGANS. [LECT. VII. 



hollow articulations connected by knots; which 

 in their growth appear to rise from within each 

 other ; the new one always carrying with it the 

 central bud, which in the last of the series termi- 

 nates in the inflorescence. The leaves are sheath- 

 ing and given off only at the knots, which are 

 solid, or rather are filled up with a dense cellular 

 substance, containing at first a saccharine nutri- 

 tious juice, which Darwin asserts to be essential 

 to the growth of the next joint, for it is absorbed 

 or at least disappears as that is perfected. The 

 vascular cords, which run in straight lines 

 throughout the length of each joint, divide as they 

 approach the knot, forming an inosculated plexus, 

 and send off branches to the leaf and to the new 

 articulation, to which the cellular substance, that 

 forms the diaphragm interposed between the 

 cavity of each articulation, actually belongs ; 

 giving to the basis of the new joint the appearance 

 as if it rose from a bulb. It was this appearance, 

 as seen by the naked eye, which suggested the 

 theory advanced by Dr. Darwin, that each joint 

 of these stems is a distinct individual; and that 

 the whole of a stem of any grass, Wheat for ex- 

 ample, is a successive series of leaf-bulbs and 

 leaf-buds produced in one year, and terminating 

 in a flowering bulb. " At the first joint of the 

 " stem of Wheat," says the Doctor, " on or 



