50 Alfred J. Ewart: 



present in it. The action apparently continues for some time, 

 and suffices to maintain a hijjh percentage in the surface soil of 

 September, in spite of the previous rains. Even in December 

 the average is higher than in any of the three preceding plots. 

 Prei^umably the blood-manure sets up active nitrification in 

 the soil, and this involves a considerable corlversion of diffi- 

 cultly soluble or insoluble earthy and alkaline bases into readily 

 soluble nitrates. One part by weight of the nitrogen of the 

 blood-manure is capable of producing 6 parts of calcium nit- 

 rate, or 10^ parts of potassium nitrate. The effect on the crop 

 was similar to that of the nitrate of soda on plot II. 



If stock owners would abandon the practice common in cer- 

 tain parts of allow^ing dead stock to rot in creeks Ijy running 

 water, or to decay where they fall, and instead to bury nil dead 

 animals so that they are covered by a.t least a foot of soil, 

 the nitrogen and phosphates of the carcase will enrich the soil, 

 instead of being wasted, and the land-owner will benefit instead 

 of the streams being polluted, or the land disfigured. The bene- 

 fits of burying do not merely consist in the s.aiving of nitrogen 

 for the soil, but also apply to the phosphates of the bones which 

 become much f^ooner available for plant use when the carcase 

 is buried than when the bones left on the surface to bleach and 

 weather quite hard. Bare bones when buried rot slowly, es- 

 pecially in calcareous soil, but if surrounded by flesh their 

 disintegration is hastened. Hence the carcase should be buried 

 while still fresh for practical, as well as for sesthetical, reasons. 



Changes in the Acid-Soluble Constituents. — For complete com- 

 parison, a knowledge of the changes in the acid soluble t-on- 

 stituents of the soil is necessary, for these are in a continual 

 process of solution, absorption, and reprecipitation, and undergo 

 an increase during the slow disintegration of the soil, as well as 

 being liable to decreases of chemical or piiysical origin (pre- 

 cipitation, formation of double (u- dehydrated salts, allotro- 

 pic changes, etc.). The use of drastic solvent agencies is 

 inadvisable, since these could quite readily give a false impression 

 as to the condition of the soil. Hence for tlie extraction, 2 litres 

 of very dilute hydrochloric acid of approximately decinormal 

 strength were added to each kilogram nf dry soil. One litre of 

 the clear filtered liquid was evaporated t(i dryness, and the 



