76 THE HARMONIES OF NATURE. 



instantaneously clap together, the bristles on both sides fitting 

 into each other, so that if a fly settles on an opened leaf it is 

 immediately caught as in a trap, and forced to remain in its 

 highly uncomfortable position as long as life lasts, for the least 

 movement stimulates the contraction of the leaf. 



In the Hedysarum gyrans, a leguminous plant of the East 

 Indies, we even find something like voluntary motion, as the 

 wings of the ternate leaves are constantly oscillating upwards 

 and downwards, quite independently of any external stimulus, 

 so that this wonderful plant seems absolutely invested with one 

 of the chief attributes of animal life. 



Thus, even in the vegetable kingdom, we find glimpses of a 

 higher order of existence ; as in our own natures we are able to 

 trace the dawn of a superior spiritual world. 



In consequence of the delicacy of their structure the leaves 

 are exposed to innumerable hostile attacks ; but it may well be 

 supposed that organs of such vital importance have not been 

 left unprotected, and that bounds have been set to the voracity 

 of their enemies. Many are invested with a thick tomentose or 

 cottony covering, others with hairs, bristles, or prickles. Some- 

 times these hairs bear little glandular bodies at their extremities, 

 by the secretion of which a peculiar viscidity is given to the 

 surface of the leaf, as in the Sundew (Drosera) ; in other in- 

 stances the hair has a glandular body at its base, whose secre- 

 tion is of an irritating quality, as, for instance in the Nettle, 

 where the extremity of the hollow sting, being extremely brittle, 

 breaks at the slightest touch, and suffers this corrosive fluid to 

 escape. 



The sharp, bitter, or acrid juices with which the substance of 

 many leaves is saturated, as well as the strongly-scented volatile 

 oils which others exhale from their surface, no doubt serve also 

 as powerful means of passive defence. 



Another circumstance favourable to the leaves is, that the 

 attacks of many of their enemies are limited to a short space of 

 time. Some insects feed only upon the first tender foliage of 

 spring, so that a rapid vegetation outstrips their ravages : others 

 make their first appearance towards the end of summer. Dur- 

 ing all these attacks the plant is incessantly active in repairing 

 its incessant losses ; its leaves are constantly extending their 

 surface, or new ones are sprouting forth to replace those that 



