HISTORY OF GEINE. 99 



These are beautiful and valuable results. Executed by 

 one of the great masters in organic analysis, they show a 

 wonderful coincidence between the artificial and natural 

 products. This has a direct connection with agriculture. 

 The source of the nitrogen of plants depends upon these 

 compounds of ammonia with the geine of soil. The compo- 

 sition of that substance shows that, by making it soluble, the 

 farmer commands the same beneficial effects which may be 

 produced by nitre. But the researches of Mulder do not 

 terminate with the analyses. He has examined the com- 

 pounds which these forms of geine produce with other acids, 

 particularly with muriatic and nitric. The compound of 

 nitric and humic acids is called nitro-humic acid ; ulmin and 

 ulmic, humin and humic acid are decomposed by weak nitric 

 acid. They are converted by gentle heat immediately into 

 a rust-colored powder, and by prolonged action evolve oxalic 

 and formic acids and nitrate of ammonia. Nitro-humic 

 acid, the rusty brown powder above, is soluble in water. 

 Alkalies evolve ammonia from it. Late researches have 

 shown that this compound is apocrenate of ammonia. 



It is highly probable that this product is connected with the 

 action of nitrates, or saltpetre in agriculture. All these 

 products, observes Berzelius, are connected by an unknown 

 thread. These black and almost insoluble acids, have a 

 very weak saturating power, in comparison with their oxy- 

 gen. This last exceeds that of the base, by 10, 12, or 14 

 times. Hence, Berzelius suggests that all these organic acids 

 may have a composition analogous to sulpho-benzoic acid. 



Notwithstanding the objections raised by Berzelius, 

 founded upon a want of correspondence between the oxygen 

 and saturating power of some of these forms of geine, they 

 are probably modifications of one principle, differing not so 

 much m their physical properties as do fibrine, albumen, and 



