788 TraksactioiXS of the American Institute. 



of the dung is carbon, and of little value as plant nutriment, whereas 

 the solid matter of urine is wholly made up of mineral and nitro- 

 genized substances that enter directly into the structure of vegeta- 

 tion. The dung and the urine together contain all the enriching 

 materials which the vegetable food of the animals originally derived 

 from the earth, and which it is the office of the farmer to restore to 

 it for the growth of future crops. But the dung contains one por- 

 tion of these enriching materials, and the liquid manure another and 

 very diiferent substance. Hence, if we waste the latter, the balance 

 or proportion in the different kinds of plant food required for thrifty 

 growth will be destroyed. It is a maxim of agricultural chemistry 

 that all of the essential elements of plants must be present in due 

 quantities, not one must be absent or diminished ; for if it is the 

 power of the plant to absorb and assimilate, the others will be 

 reduced in a corresponding ratio. From this it is evident that by 

 wasting the liquids we not only lose just so much of the elements of 

 fertility necessary in the soil, but we impair the capacity of the solid 

 manure to give its full eifect. In other words, a perfect manure is 

 simply an animal manure, which includes the natural proportions of 

 both solid and liquid excrement. By the ordinary practice the liquid 

 is mostly lost ; it is the province of muck to save it. Nothing comes 

 from nothing. The manure is the food taken in another form from 

 the ground, and which must be returned to it if its fertility is main- 

 tained. The undigested or unmasticated part of the food passes from 

 the animal in a more or less solid form. That which is digested 

 passes into the system, undergoes its round of duty in the animal 

 organization, and, being filtered through the kidneys, is thrown out 

 in a solution. The dung is rich in soluble silica, in jiotash and 

 phosphoric acid, and also in lime, soda, magnesia, sulphuric acid and 

 the like ; the urine contains alkaline salts of various kinds, but is 

 especially rich in a substance termed urea, capable of evolving 

 ammonia when decomposed, and from which tl>e greater part of the 

 manurial value of the liquid is derived. This is so marked that 

 Boussingault states the amount of ammonia in the urine of a horse 

 as three times that of the dung, and that of the cow as twice as 

 much. The value of muck in absorbing and retaining the liquid is 

 therefore very great, and, in reality, by this saving, enables the 

 farmer to double the quantity of plant food or true manure from hi8 

 stables, as compared with that obtained by the usual slovenly prac- 

 tice. No definite rule can be laid down concerning the proportion 



