Dried Blood 



difficult to assimilate, sometimes being added. Its 

 purity should be guaranteed. 



Dried blood contains normally about 13 1 per cent, 

 water. It should never be bought except under 

 guarantee of analysis, because the amount of 

 nitrogen can alter so considerably between the 

 moment of manufacture and that of delivery. 



Dried blood contains from 10 to 13 per cent, 

 nitrogen, sometimes 17 per cent. ; phosphoric acid 

 as tricalcic i"io to 3*25 per cent. ; potash [K2O] o*6 

 to 07 per cent. It is an organic nitrogenous 

 manure of rapid action, because under the influ- 

 ence of bacterial fermentations the organic nitrogen 

 is converted first into ammonia and then into nitric 

 acid — hence the usefulness, or even the necessity 

 of lime in the soil. If lime is not present naturally 

 it must be introduced, so that the operations of 

 transformation can be facilitated and the nitric 

 acid quickly converted into nitrate of lime. 



Our opinion is that too high a price is often paid 

 for dried blood, and that the different blood manures, 

 though they may be good, are not always worth what 

 is asked for them. 



The value of the unit of nitrogen which the 

 material contains in its pure state is a little inferior 

 in value to that of nitrate of soda and sulphate of 

 ammonia, but it is comparable to that of guano of 

 Peru. 



Dried blood is freely employed for such crops as 

 com, hops, turnips, mangolds, or even for pastures, 

 and, in the colonies, for sugar cane and coffee. 



117 



