222 THE TROPICAL WORLD. 



wakeful vigilance, is necessary ; for, though destroyed by 

 thousands, new legions ever make their appearance, and to 

 repose after a victory is equivalent to a defeat. 



In our temperate zone, where a higher cultivation of the 

 ground tends to keep down the number of the lower animals, 

 their persecutions, though frequently annoying, may still be 

 borne with patience ; but in many of the tropical regions, where 

 man is either too indolent or not sufficiently numerous to set 

 bounds to their increase, the insects constitute one of the great 

 plagues of life. 



Along the low river-banks, near stagnant waters, and 

 everywhere on hot and swampy grounds, the 

 blood-thirsty Mosquitoes appear periodically 

 in countless multitudes, the dread of all who 

 are exposed to their attacks. 



Not satisfied with piercing the flesh with 



their sharp proboscis, which at the same time 



forms a kind of syphon through which the 



blood flows, these malignant gnats, of which 



MOSQUITO. there are many species, inject a poison into 



the wound, which causes inflammation, and prolongs the 



pain. 



In Angola, Dr. Livingstone found the banks of the river 

 Seuza infested by legions of the most ferocious mosquitoes he 

 ever met with during the course of his long travels. ' Not one 

 of our party could get a snatch of sleep. I was taken into the 

 house of a Portuguese, but was soon glad to make my escape, 

 and lie across the path on the lee-side of the fire, where the 

 smoke blew over my body. My host wondered at my want of 

 taste, and I at his want of feeling ; for, to our astonishment, he 

 and the other inhabitants had actually become used to what 

 was at least equal to a nail through the heel of one's boot, or 

 the tooth-ache.' 



' He who has never sailed on one of the great rivers of tropical 

 America, the Orinoco, or the Magdalena,' says Humboldt, ' can 

 form no idea of the torments inflicted by the mosquitoes. How- 

 ever accustomed the naturalist may be to suffer pain without 

 complaining, however his attention may be riveted by the ex- 

 amination of some interesting object, he is unavoidably disturbed 

 when Mosquitoes, Zancudos, Zejens, and Tempraneros cover his 



