54 DR. R. ANGUS SMITH ON THE EXAMINATION 



extent of several per cent. The quantity given out (at 140° 

 Centigrade) is between 8 and 16 per cent. It requires 

 195° to free them from water. '^ 



P. 167. " The power of ulmic^ humic, and geic acids to 

 condense ammonia is so strong, that the acid made by 

 acting on sugar with hydrochloric acid almost always 

 contains ammonia if air is not kept away.^^ 



P. 169. ^^ These acids combine so intimately with am- 

 monia, that they have the character of an organic com- 

 pound of four elements by treatment with potash ; at a 

 higher temperature they lose the ammonia completely/^ 



In the ^ Handworterbuch der Chemie/ under " Humus/^ 

 it is said that by constant digestion with hydrochloric 

 acid, ammonia was not removed. It is also added that 

 boiled with an alkali the ammonia is not removed. 



This accounts for the opinion held by Berzelius and 

 others, that nitrogen existed in these substances; and 

 certainly it is not clearly shown that they are only ammo- 

 niacal salts. At the same time they may certainly be 

 something between the purely organic compound albumen 

 and the alkali ammonia. Independently of this supposi- 

 tion, I am quite disposed to think that Professor Wanklyn 

 is right in thinking that the substance may in some cases 

 be albumen ; but I am not disposed to think him right in 

 calling it putrescible. Is there any albumen not putres- 

 cible? That is an open point; but we know that there 

 are bodies beside which albumen will not putrefy, even if 

 putrescible when alone. 



Berzelius gives Hermann^s old analysis of crenic acid 

 as containing nitrogen ; and until we can finally settle the 

 composition of these substances, we may be allowed to 

 doubt. I think we may find in these facts sufficient reason 

 to believe that even the organic nitrogen is not a measure 

 of the dangerous quality of water, whether that nitrogen 

 exist in a non-putrescent condition or association of the 



