364 OBSERVATIONS ON GUANO 
collect, with what avidity the smallest quantity of 
manure is collected in countries where it is scarce, 
it seems hardly possible to calculate the enormous 
annual loss hitherto sustained by this country, 
owing to the excrementitious matters derived 
from a vast metropolis like London, being all de- 
posited uselessly in the Thames.” 
“‘ Owing to this waste, it is a curious fact, that 
cattle are slaughtered in South America, often for 
no other purpose, than that their bones ground 
into dust should be sent over to manure the tur- 
nip fields of England; so that our commerce has 
been hitherto compelled to supply from a great 
distance a material, which an application of che- 
mical skill at home now promises to secure to us.” 
Night-soil possesses the same freedom from 
weeds as Guano; but this is not the case with 
horse-manure. Dr. Daubeny also remarks, “when 
the excrements of the horse or ox are employed, 
we are obliged to allow of their undergoing a long 
previous process of fermentation, by which a large 
portion of their valuable matter is got rid of, in 
order as much as possible, to destroy the vitality 
of the seeds, which pass undigested along with 
the feces. And after all many still remain, and 
