[385] SCIENTIFIC MANUAL. 99 



1. That of no two varieties of animals is alike in chem- 

 ical composition. 



2. That from the same animal varies with the character 

 of the food consumed. 



3. That from young growing animals is less valuable, 

 especially in phosphoric acid, than that from grown ani- 

 mals. 



4. That from fat animals is richer in nitrogen than that 

 from those in a lean condition, where much of the food 

 consumed is appropriated to the restoration of flesh as well 

 as fat. 



5. That from fowls is richer than that of animals, be- 

 cause the solid and liquid excrements are combined. 



6. Liquid excrement of all animals is richer in plant- 

 food than the solid, and should, as far as practicable, be 

 saved by farmers. 



Flesh, blood, horns, hoofs and hair are rich in nitrogen, 

 and are used by manufacturers of commercial fertilizers to 

 supply that important element to their compounds. The 

 percentage of nitrogen contained in them ranges from six 

 to sixteen. Dried flesh and blood are very extensively 

 used as sources of ammonia, by manufacturers of fertili- 

 zers. The dried flesh is derived principally from countries 

 where animals are killed in large numbers for their hides, 

 horns and tallow, and the flesh boiled for extract of meat. 

 ''The fibrinous residue, when dried, becomes a most ad- 

 vantageous nitrogenous material for use in the manu- 

 facture of ammoniatecl fertilizers." 



Dried blood is derived from the extensive slaughter- 

 houses of the United States, and other countries, where 

 millions of animals are slaughtered for food. The blood 

 is either dried, or solidified by coagulation, and thus is 

 formed a condensed mass, exceedingly rich in nitrogen. 

 Dried ox-blood contains from fifteen to seventeen per 

 cent, of nitrogen. 



Mineral fertilizers are those substances which, derived 



