Lecture on Toim Seicagc. 
467 
Ilcnce, if we want to get any crop at all, we must apply a bulky 
manure anrl an abundant supply of food. Now sewage is well cal- 
culated to furnish this food, provided we apply it largely, and not, 
as has been proposed, in quantities amounting to 3000 or 4000 tons 
per acre. Those who recommend such a small quantity forget 
that in 300 tons of London sewage we have in reality not more than 
the fasces of five persons — a supply for which it never can be worth 
while to lay down pipes or to make any provision whatever. I hold 
with the most ardent advocate of the use of sewage, that it is a pity 
that a liquid which contains an enormous quantity of fertilising 
matter, and which may be used with very great advantage on sandy 
soils, should be let run to waste. Yet, if we wish to derive any 
material benefit from it, we must use it largely — that is to say, as 
ordinary water is used for irrigation, in quantities amounting to 
from 8000 to 10,000 tons per acre, in, say, five dressings, averaging 
1400 tons apiece. But even then it will not benefit every descrip- 
tion of crop, but, as has been proposed, may well be restricted to 
Italian ryegrass and other grass-crops. 
Grass is especially benefited by the sewage of towns, because it 
is a quick-growing crop, which allows us to apply a fresh fertilising 
matter as soon as a given quantity is exhausted. Grass-land 
may be manured repeatedly, but not so the cereal crops. Our 
wheat would never ripen if, after it has passed through its grassy 
stage and approached maturity, we were to apply sewage to it : 
the grain would never get formed. Neither is sewage generally 
applicable to market produce ; it has a tendency to enci'ust the 
soil and to close up its pores, which is a great practical inconveni- 
ence. Btit apart from this objection, I question whether we could 
dispose of the sewage of a large town in market gardens, because it 
must be dealt with at all times of the year, and in very large 
quantities. 
With regard to the grass grown by the application of sewage, 
it is stated in many treatises that the produce from in-igated 
meadows, more especially meadows irrigated by sewage manure, 
is superior, inasmuch as it is richer in nitrogenous matter than 
ordinary farm produce ; but I believe that this is a mistake, and 
that in nutritive quality the grass from the irrigated meadow will 
be found inferior to that from natural pastures, the produce of 
meadows irrigated by sewage being in a still higher degree inferior. 
In fact, the more rapidly prodiice is grown the less mature it is, 
and the more likely to produce disorders in the animal economy ; 
whilst, bulk for bulk, the poorer the meadow the more scanty the 
herbage, and the more slowly it grows, the better and more nutri- 
tiorts it is. Of course it does not follow that we shoiild leave off 
manuring our fields and grow a scanty increase for fear of inferior 
prodiice. 
Notwithstanding all these drawbacks, however, great sums have 
been realised by the application of large quantities of sewage to 
meadow land. And, after all, the most satisfactory way of arriving 
at a fair and just estimate of the value of sewage is to inquire of 
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