i7o PLANT AND ORGANIC CHEMISTRY 
gauge the progression or retrogression of a plant, species, or 
genus, and would accentuate the characters of progression, 
adaptation, and filiation. 
5. Variations in chemical constituents would be detected by 
analysis earlier than consequent variations of organs or tissues. 
6. It is a law of internal influences controlling function and 
modifying forms rather than of external forces, hence a study 
of the elements of the innermost structure of plant life is a 
study of that law and of life itself. 
Not all chemical constituents will answer as means of clas¬ 
sification for the same great evolutionary plane, though any 
compound might be found to furnish a basis for the division 
of plants into classes, orders, sub-orders, genera, and species. 
Albuminous compounds and chlorophyll are less likely to 
be serviceable as compounds of classification. They are inti¬ 
mately associated with the manifestation and continuance of the 
conditions of life, though they are not regarded as the essen¬ 
tial factors in development. 
The chemical study of plants is meant to include micro¬ 
chemistry in its application to histology and physiology, in de¬ 
termining the position in the cell of any chemical compound, 
and qualitative and quantitative analysis to be practiced in 
accordance with the schemes of Dragendorff and others. I 
should suggest that analysis be made of each part of the plant, 
as of the root, stem, bark, wood, leaf, flower, and seeds; also 
of the separate organs of plants, i.e ., in the flower, of the sta¬ 
mens, pistils, petals, calyxes, and of various plants under 
various conditions of age, climate, soil, and seasons. Under 
these conditions a comparison of chemical constituents with 
plant structure would lead to a comprehension of the corre¬ 
lation between morphology and chemistry. 
