40 
MANURES. 
ing urine is the same in man and animals. Now if 
we reason here, as we surely may, from analogy, then 
the effect of age and sex upon the quantity, of the 
essence of urine or urea, will appear from the results 
of one hundred and twenty analyses of urine. 
In 24 hours there are disch’d by men, 432 grs. of urea. 
By women, ..... 293 u u 
By old men, from 76 to 80 yrs. of age, 122 u “ 
By children, 8 years of age, . . 208 “ “ 
By children, 4 years of age, . . 70 u u 
It will be recollected, that each grain of urea is 
equal to a grain of carbonate of ammonia of the shops, 
so that a healthy man discharges daily about an ounce 
of this salt. If, then, other animals are affected by 
age and sex, as is the human species, then we may 
say that bulls and oxen give a better urine than cows, 
steers better than calves, and a venerable old cow 
gives as much of the essence of urine as two calves. 
Food affects the quantity of water, and that acting 
merely to dilute the urine, renders it weaker in salts 
for a given amount, though perhaps not the daily 
amount of salts. Supposing the animal well fed, so 
as to keep up the wear and tear of his blood and flesh, 
then as the urine derives its chief value from the worn- 
out materials of the body, the actual amount of urea 
daily discharged may be the same, though the amount 
of the urine may vary considerably. We may in¬ 
crease the amount of salts and acids by particular 
food, but this can never be continued long enough to 
change materially the character of urine as a manure. 
Difference of animal has also a great effect on the 
quality of urine. The more active, the greater the 
wear and tear of the flesh, the better the urine in 
working animals. Where the animal is stall-fed, 
there, no doubt, the urine is still richer, and the urine 
of fattening animals is still more valuable. Hence, of 
all animals, commend me to swine, as manufacturers! 
