POSSIBLE CONTROL OF MINUTE LIFE. 125 
being inhabited by it. The conversion of woodland into pas¬ 
turage, of pasture into plough land, of swamp or of shallow 
sea into dry ground, the rotations of cultivated crops, must 
prove fatal to millions of living things upon every rood of 
surface thus deranged by man, and must, at the same time, 
more or less fully compensate this destruction of life by pro¬ 
moting the growth and multiplication of other tribes equally 
minute in dimensions. 
I do not know that man has yet endeavored to avail him¬ 
self, by artificial contrivances, of the agency of these wonder¬ 
ful architects and manufacturers. We are hardly well enough 
acquainted with their natural economy to devise means to turn 
their industry to profitable account, and they are in very 
many cases too slow in producing visible results for an age so 
impatient as ours. The over-civilization of the nineteenth cen¬ 
tury cannot wait for wealth to be amassed by infinitesimal 
gains, and we are in haste to speculate upon the powers of 
nature, as we do upon objects of bargain and sale in our traf¬ 
ficking one with another. But there are still some cases where 
the little we know of a life, whose workings are invisible to 
the naked eye, suggests the possibility of advantageously 
directing the efforts of troops of artisans that we cannot see. 
Upon coasts occupied by the corallines, the reef-building ani¬ 
malcule does not work near the mouth of rivers. Hence the 
change of the outlet of a stream, often a very easy matter, may 
promote the construction of a barrier to coast navigation at one 
point, and check the formation of a reef at another, by divert¬ 
ing a current of fresh water from the former and pouring it 
into the sea at the latter. Cases may probably be found in 
tropical seas, where rivers have prevented the working of the 
coral animalcules in straits separating islands from each other 
or from the mainland. The diversion of such streams might 
remove this obstacle, and reefs consequently be formed which 
should convert an archipelago into a single large island, and 
finally join that to the neighboring continent. 
Quatrefages proposed to destroy the teredo in harbors by 
impregnating the water with a mineral solution fatal to them. 
