Two methods are at present followed by chemists for the analysis of organic bodies containing nitrogen. In the first of these the nitrogen is directly separated from the substance, and measured in a pure state; while in the second method it is converted into ammonia, collected and weighed, its amount being calculated from the known composition of this latter substance.

In accordance with the first-named mode of proceeding, the substance is burned at a high temperature, in contact with oxide of copper, chromate of lead, or some other body capable of yielding oxygen, when the carbon of the organic substance becomes converted into carbonic acid, and its hydrogen into water, while all the nitrogen is given off in a free state.