Money-value of Nifiht-Soil rtvd oflicr Mcnnirea. 
125 
At this rate, tlie mauuiial value of cooked meat is about 
l-15th of a penny per lb., or 1-lOOtli of its cost, if it be valued 
at about Qhd. per lb., — a low price for cooked meat. 
But if these great staples of human food fail the " bulls " of 
the sewage question, what shall we say for the odd pennyworths 
of vegetables, &c., bought at a town-market or from the green- 
grocer, when the price paid is quite fictitious ! The probability, 
therefore, is very great that such calculations based on the cost of 
man's food will be wide of the mark ; and that this is the case 
when a yearly value of 3/. to 4/. per head is arrived at, is pretty 
certain. Even the more moderate estimate of 1/. per head is 
contrary to the opinion of our best agricultural chemists, who 
seem thoroughly agreed in fixing on a much lower value, viz. 
that of %s. per head, supposing all the constituents contained 
both in the liquid and solid excreta to be preserved without any 
waste, that valuation being made at the customary rates em- 
ployed in connexion with analyses of guano. Both Mr. Lawes 
and Dr. Voelcker have favoured me with independent but con- 
curring information on this point ; whilst Professor Way, when 
questioned on the subject by the Sewage Committee, referred to 
Mr. Lawes' calculations with approval ; the teaching of Professor 
Anderson also, so far as I have become acquainted with it, 
decidedly takes the same direction. 
Our leading scientific authorities, then, are agreed on this 
point ; and why should we gainsay their conclusions ; and what 
jnore trustworthy evidence have we to build upon ? Would 
they not all have felt much more satisfaction in giving a reply 
more favoumble to the march of improvements Avhich Science 
regards as in some degree her own bantlings ? Shall we listen 
for a moment to an insinuation that interested motives have 
actuated them in consequence of their connexion, more or less 
direct, with the market for imported manures which might suffer 
from new competition ? 
Surely such opinions, based on careful scientific investiga- 
tions, must prevail, at least until they are encountered by con- 
clusions drawn from a greater amount of accurate and repeated 
experiments than we are yet furnished with. 
As to the bulk of these excreta, there can be no doubt. 
According to Liebig, the annual fluid and solid excrement of 
a million inhabitants of large cities (men, women, and children) 
weigh in the dry pulverulent state 45,000,000 lbs., in which are 
contained 10,300,000 lbs. of mineral substances, mostly ash 
constituents of bread and meat. "These human excrements 
alone contain 4,580,000 lbs. of phosphates." * 
* See Liebig's ' Letters on Modern Agriculture,' 1859, admirably rendered into 
English by Dr. Blythe, of Queen's College, Cork, 
