THE DOGSBANE. 63 



means of valves or contractions, the tube remaining 

 open ; but the creature cannot crawl up by reason of 

 the inverted spines, and to prevent its escape by flying 

 up the tube, the flower makes an extraordinary curve, 

 bending up like a horn, so that any winged creature 

 must be beaten back by striking against the roof of this 

 neck as often as it attempts to mount, and falling back 

 to the bulbous prison at the base of the flower, dies by 

 confinement and starvation, and there we find them : a 

 certain number of these perishing, the blossom fades 

 and drops off. 



All the varieties of this snapdragon have the power 

 of maintaining a state of vegetation in great droughts, 

 when most other plants yield to the influence of the 

 weather; and it is the more remarkable in these plants, 

 as the places in which they chiefly delight to vegetate 

 are particularly exposed to the influence of the sun. In 

 that hot dry summer of 1825, when vegetation was in 

 general burned up and withered away, yet did this plant 

 continue to exist on parched walls, and draw nutriment 

 from sources apparently unable' to afford it; not in full 

 vigor certainly, but in a state of verdure beyond any 

 of its associates. The common burnet (poterium san- 

 guisorba) of our pastures, in a remarkable degree, like- 

 wise possesses this faculty of preserving its verdure, 

 and flourishing amid surrounding aridity and exhaustion. 

 It is probable that these plants, and some others, have 

 the power of imbibing that insensible moisture, which 

 arises from the earth even in the driest weather, or from 

 the air which passes over them. The immense evapora- 

 tion proceeding from the earth, even in the hottest sea- 

 son, supplies the air constantly with moisture ; and as 

 every square foot of this element can sustain eleven 

 grains of water, an abundant provision is made for every 

 demand. We can do little more than note these facts : 

 to attempt to reason upon the causes, why particular 

 plants are endowed with peculiar faculties, would be 

 mere idleness ; yet, in remarking this, we cannot pass 

 over the conviction, that the continual escape of mois- 

 ture from one body, and its imbibition by another, this 

 unremitting motion and circulation of matter, are parts 



