HIGHER AND LOWER PLANTS 
265 
from a gelatinous or undifferentiated compound to a polymer, 
or a substance of the same chemical formula, having a solid 
or crystalline form. 
2. In their succession of changes, which may be observed 
during the different stages of the individual plant’s growth, 
and the relation of these chemical changes to other com¬ 
pounds present in the plant. 
3. The location as predominant of some one or associated 
compounds only in certain plants on similar evolutionary 
planes. 
These three conditions correspond to what was stated at 
the beginning, that a law of universal progression may be 
traced wherever matter or force exists. 
There is no absolutely certain knowledge of the precise 
character of the chemical changes which these plant compounds 
undergo, though we have some information about them. In¬ 
vestigations are being vigorously pushed in this department 
of plant life, and it may be reasonably inferred that definite 
facts will be obtained on many of these subjects. 
It would seem from the latest researches that the albumi¬ 
nous or proteid compounds to which life is essentially linked 
are formed from a compound containing nitrogen, called an 
amide, and some carbohydrate; its sulphur and phosphorus 
supply being derived from inorganic sources. This amide is 
probably asparagine or a related body. Various suggestions 
have been offered to explain its formation in the plant, from 
the breaking down of protoplasm to its construction from 
simple nitrogenous and carbon compounds, and among the 
latest investigations 1 the results show that the formation of 
asparagine is independent of carbohydrates, and that the 
amide formed is not a by-product of the interchange of mat¬ 
ter within the plant. The author of these experiments con¬ 
siders that asparagine is formed by the union of inorganic 
nitrogen compounds and malic acid within the plant, the acid 
being derived from the carbohydrates. 
Other nitrogenous compounds, as the alkaloids, for example, 
1 O. Müller, “Landw. Versuch. Stat,” 1886, 326-335; Jour. Chem. Soc. } p. 
70, January, 1887. 
