HIGHER AND LOWER PLANTS 265 



from a gelatinous or undifTerentiated 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. Miiller, "Landw. Versuch. Stat.," 1886, 326-335; Jour. Chem. Soc., p. 

 70, January, 1887. 



