COMPOSITION OF SOLID EXCRETA. 5 



This may be accounted for by the interesting and well- 

 known fact that a large percentage of potash is to be 

 found in the wool of sheep. 1 



The solid excrement of the sheep is, therefore, 

 weight for weight, the most valuable as a manure, as 

 it contains more nitrogen and phosphates than the 

 others, and, at the same time, is much drier. 



If, however, we compare the composition of the 

 solid excreta in a dry state, we shall find that the 

 following are the results (basing our calculation on 

 Stoeckhardt's analyses) : 



Horse . 

 Cow . 

 Pig . . 

 Sheep . 



It will be seen from the above that the dry substance 

 of the solid excreta of the pig is richest in fertilis- 

 ing substances. Too much stress, however, as has 

 already been pointed out, must not be put on any 

 single analysis, as so much depends on various 

 conditions, especially the food. 2 The most reliable 

 method of studying this question, therefore, is to 

 study it in its relation to the food consumed. Wolff 

 has calculated from numerous investigations that, 



1 "The large amount of potash in unwashed wool is very remark- 

 able ; a fleece must sometimes contain more potash than the whole 

 body of the shorn sheep." Warington's 'Chemistry of the Farm,' 

 p. 78. 



2 See Appendix, Note II., p. 53. 



