Chap. V. ROOT-CLIMBERS. 187 



of softening indurated caoutchouc, I soaked in it 

 during a short time several rootlets of a plant which 

 had grown up a plaistered wall ; and I then found 

 many extremely thin threads of transparent, not viscid, 

 excessively elastic matter, precisely like caoutchouc, 

 attached to two sets of rootlets on the same branch. 

 These threads proceeded from the bark of the rootlet 

 at one end, and at the other end were firmly attached 

 to particles of silex or mortar from the wall. There 

 could be no mistake in this observation, as I played 

 with the threads for a long time under the microscope, 

 drawing them out with my dissecting-needles and 

 letting them spring back again. Yet I looked re- 

 peatedly at other rootlets similarly treated, and could 

 never again discover these elastic threads. I there- 

 fore infer that the branch in question must have been 

 slightly moved from the wall at some critical period, 

 whilst the secretion was in the act of drying, through 

 the absorption of its watery parts. The genus Fie us 

 abounds with caoutchouc, and we may conclude from 

 the facts just given that this substance, at first in 

 solution and ultimately modified into an unelastic 

 cement,* is used by the Ficus rejpens to cement its 

 rootlets to any surface which it ascends. Whether 

 other plants, which climb by their rootlets, emit 

 any cement I do not know ; but the rootlets of the 



* Mr. Spill rr has recently shown a fine state of division to the air, 



(Chemical Society, Feb. 16, 1865), giadually becomes converted into 



in a paper on the oxidation of hi ittle, resinous matter, very similar 



india-rubber or caoutchouc, that to ^hell-lac. 

 this eubbtance, wlien exposed in 



