76 EXCREMENTS AND URINE. 



worthless and loathsome substances, in very many- 

 localities, the exclusive means of manure for our 

 fields. Hence it will be altogether in order if they 

 are taken first into consideration. 



How do the faeces of the several species of animals 

 operate ? For what crops are they the most ser- 

 viceable manure ? What amount is yearly obtained 

 from a horse, a cow, a sheep, or from a given quan- 

 tity of provender ? What is the worth of these dif- 

 ferent excrements when compared with each other? 

 These and similar inquiries of extreme importance 

 to the practical agriculturist have been already an- 

 swered with the greatest fulness of detail in agricul- 

 tural writings, but the answers unfortunately differ 

 so widely from each other, as to impart little assist- 

 ance to the farmer ; since in most cases he will be in 

 doubt which of these statements is best entitled to 

 belief. Fresh and accurate experiments are here 

 greatly needed, in order confidently to decide which 

 of the figures given as the respective equivalents of 

 the food and manure, the quantity and quality of the 

 latter, etc., rest merely on conjecture, and which are 

 founded upon the results of actual experience. If, 

 however, such experiments are to lead to reliable re- 

 sults, the circumstances under which they were insti- 

 tuted must be also specified with thorough exactness, 

 and the constituent elements of the food and the faeces 

 it produces must be no less carefully ascertained. 

 The path leading to this goal is laborious, and many 

 years will probably expire before the principal ques- 



