THEIR ABSORBING FORCE. 19 



become incapable of passing fluid through their sides ; and 

 when very young and soft, there is probably but little difference 

 between their action and that of the spongelets themselves ; 

 for it is to be remembered that the latter are not special organs, 

 but are only the very youngest part of the root. 



The absorbent power of the spongelets must be much greater 

 than would have been supposed, if we consider that it is almost 

 entirely through their action that the enormous waste of fluid, 

 which takes place in plants by perspiration, is made good ; and 

 hence their importance to plants, and the danger of destroying 

 them, become manifest. 



Boots being furnished with the power of perpetually adding 

 new living matter to their points, are thus enabled to pierce 

 the solid earth in which they grow, to insinuate themselves 

 between the most minute crevices, and to pass on from place 

 to place as fast as the food in contact with them is consumed. 

 So that plants, although not locomotive like animals, do per- 

 petually shift their mouths in search of fresh pasturage, although 

 their bodies remain stationary. 



Many examples of tMs migLt be adduced. The foUowing are, however, 

 sufBLcient. In a Garden at Tumham Green, a Popnlus monilifera 

 (Canadian Poplar) was found to have sent a root thirty feet horizontally, 

 including its dip beneath the foundations of a waU, and then to have 

 passed into an old well to the depth of eighteen feet, having then broken 

 up into a mass of fibres so finely divided as to resemble yarn. 



In another case, a root of the Deciduous Cypress was foimd by the 

 author, eleven feet long, which had passed nearly to that length without 

 division in search of water. 



Mr. Tyso, a Florist at WaUingford, mentions the case of a Mignonette 

 plant which had penetrated through several courses of bricks, and 

 descended far into a wine cellar. Over the cellar, which was outside 

 the dweUing-house, was a brick pavement, between the joints of which 

 Mignonette seed had been sown from year to year. At the extreme end 

 a small portion of soil was allowed, and here a plant or two grew more 

 vigorously than the rest, though not so luxuriantly as is often found in 

 a common border. ' The roots of these plants had penetrated through 

 eighteen inches of brickwork, and some of them were hanging inside the 

 arched roof, nourished by the damp atmosphere only. A few, more 

 favourably situated, were attached to the end wall of the cellar, and had 

 descended five feet five inches down the waU into the decaying sawdust 

 of the wine-bin. Others were beautifully spread over the wall, with a 



2 



