120 THE POPLAK AND THE WILLOW. 



the forms called alba and Russelliana, which, last is 

 a variety of ihefragilisj and of that valuable tonic 

 medicine called salicine, extracted by chemical pro- 

 cess from the bark of the Eusselliana and some 

 others, and which has been found equally efficacious 

 with quinine, extracted from " Peruvian bark/' 

 which is supplied in turn by various species of 

 Cinchona. Even a strong infusion of willow-bark 

 in boiling water, left to stand with the bark in it 

 until cold, is nearly as efficacious as the elaborately 

 prepared salicine itself; and in rural districts might 

 often be advantageously employed without the 

 trouble and expense of " sending for the doctor." 

 The wood, which is elastic, tough, and durable, and 

 not liable to split by any sudden shock, is much 

 used for lining the rough carts and barrows used for 

 the conveyance of stone; it is excellent also for 

 various applications in connection with machinery. 



