SANITARY INSPECTORS. 161 
all decay! Hail to eternal youth! Let every creature die which lives 
beyond a day !” 
Observe that the furious eagerness of the winged insects, which 
seem to be the agents of death, is frequently a cause of life. By an 
incessant persecution of the sick flocks, enfeebled by hot damp airs, 
they ensure their safety. Otherwise they would remain stupidly re- 
signed, and hour after hour grow less capable of motion, gloomier and 
more morbid in the bonds of fever, until they could rise no more. 
The inexorable spur knows, however, the secret of putting them on their 
legs; though with trembling limbs, they take to flight ; the insect never 
quits them, presses them, urges them, and conducts them, bleeding, to 
the wholesome regions of the dry lands and the living waters, where, 
growing discontented, their furious guide abandons them, and returns 
to the pestilent vapours, to its realm of death. 
In the Soudan, in Africa, a little insect, the Nam fly, directs with a 
sovereign authority the migrations of the flocks. In the dry season it 
rages against the camel; it audaciously ventures into the ear of the 
elephant. The giant is-resistlessly driven forward by its winged shep- 
herds, to escape the fires of the south, and to seek the fresh winds of the 
north. On the other hand, the oxen, through its management, remain 
with their Arab master peacefully in the genial southern pastures. 
The most terrible of insects—the great Guiana ants—are valued 
precisely for their devouring power. Without them, no effectual means 
would exist of thoroughly cleansing the homes of man of all the obscure 
broods which infest the shadows, and swarm in the timbers and frame- 
work, in the most imperceptible crevices. One morning the black 
army appears at the door of the house: an army of sanitary inspectors. 
gives place to them, and evacuates his dwelling. “ Enter, 
Man retires, 
ladies ; come and go at your pleasure ; make yourselves quite at home.” 
It would not be safe for the owner to remain, since it is a law with 
these scrupulous visitors to leave no living thing in the track of their 
march. In the first place, every imsect,—the largest as well as the 
minutest,—and their eggs, however well-concealed, perish. Then the 
smaller animals—frogs, adders, field-mice ;—none escape. The place is 
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