92 HISTORY OF GEINE. 



lytical tact chemists generally place the utmost confidence, 

 has examined the various forms of geine. He has now pub- 

 lished the elaborate results of his long labor. The follow- 

 ing sketch of these, which shed such a new light over this 

 complicated subject, is chiefly drawn from Berzelius's Report 

 for 1841, in which he speaks of them in high praise. While 

 it will be seen that Mulder refers to the various forms of 

 geine, under names used by Berzelius, he confirms the fact 

 that their great difference depends upon their being soluble 

 or insoluble in alkalies, and has added a crowd of new facts, 

 which connect all the forms in a beautiful and consistent 

 manner. Malaguti had procured, by boiling sugar with 

 dilute acid, ulmic acid in distinct crystals. By long boiling 

 in water, it is converted into ulmin, losing its solubility in 

 alkali without any change of composition. 



Stein had already, by repeating the experiments of Mala- 

 guti, arrived at products whose analytical results diflfered from 

 Malaguti's. Mulder, repeating the process of boiling sugar 

 with weak acid, and examining the product, has confirmed 

 Stein's results, and also what has been advanced, that the 

 forms of geine thus produced are, as Malaguti had observed, 

 identical in composition; and has shown that the various 

 forms depend on the circumstances of the manipulation. 



The catalytic action of weak acid, boiled upon sugar, pro- 

 duces first ulmin, and ulmic acid. It is remarkable that these 

 products are not formed in vacuo. This is due, not to the 

 want of oxygen, but to the want of pressure. Boiled, under 

 the pressure of hydrogen, or nitrogen gas, ulmin and its 

 acid are produced. The products formed from sugar and 

 weak acids, in a vacuum, are humin, and humic acid. Ulmin, 

 and ulmic acid, are therefore the primary products of this 

 action in air or under pressure. If these are separated and 

 again boiled with weak acid, in contact with air, they are 



