THE ROOTS AND STEMS OF TREES 149 



which increases its holding power, and the thumb has 

 disappeared from the hand. These are the Spider-monkeys, 

 of which there are several species. Their wonderful leap- 

 ing powers are familiar to visitors to the Zoological Gardens, 

 who can now and then see a Spider-monkey hanging by the 

 tail alone. 



It is said that the Capuchin-monkey when he is pleased 

 can make a singing or whistling noise, but I have never 

 heard this. 



The monkey of fable, the monkey that Galen dissected, 

 the monkey that was two hundred years ago a favourite 

 pet of fashionable ladies, was not the organ-grinder's 

 monkey, nor any American species, but the Barbary ape, 

 a tailless Macaque, native to northern Africa and Gibraltar ; 

 it has yellowish-grey hair, a flesh-coloured face, cheek- 

 pouches and callosities. Many other monkeys have been 

 caught young and tamed, but this more than the rest may 

 be said to have made a place for itself in the history of 

 mankind. 



XXX. THE ROOTS AND STEMS OF TREES. 



A balsam-poplar in my garden, having become hollow 

 in the trunk by decay of the wood, had the top lopped off. 

 Many vigorous shoots were sent off from the top of the 

 stump, and after a time roots made their way down the 

 hollow trunk to the ground. A much more perfect 

 example of the same thing was pointed out to me by Mr. E. 

 M. Langley in a pollard-willow growing on the bank of the 

 river Ouse at Bedford. The birch in Norway is often 

 lopped for the sake of its foliage, which is given to cattle, 

 or for its wood, which is used for fuel, or for its sticks and 

 withs, out of which the farmer makes upright hurdles for 

 drying his hay. The mutilated trunk generally rots, and 

 through the shell large twisted air-roots may pass down to 

 the ground. The famous yews at Fountains Abbey, sole 



