Formed Constituents of Organisms 171 



condensation of energy theUy we would suggest, are the important 

 factors at the foundation of all organic as of all inorganic change. 



But the quite remarkable evolution of hundreds — possibly 

 thousands — of secondary chemical products, the glucosides, 

 alkaloids, acids, tannins, crystals, hydrocarbons like terpenes, 

 resins, and volatile oils in plants, seems in marked contrast to 

 the above continuous uniformity of substance. As already 

 indicated, however, we believe that the explanation is not far 

 to seek. Green plants have evolved along a sedentary hne, 

 where fixation for life alongside predatory fungi or animals 

 means either extermination, or varied and effective means of 

 defense for warding off attack. Animals on the other hand 

 have evolved along a motile line, where increasing alertness 

 and activity, combined with protective coverings of a defensive 

 — more rarely color-protective or warning — kind have served 

 best in the struggle for existence. 



No one who has wandered over the Alps of Europe or other 

 lands, over the southern savannahs or the prairies of the west, 

 has failed to observe how severe is the struggle between evolving 

 plant hfe and predatory animals — including therein insects, 

 slugs, birds, and mammals — of herbivorous habit. When we 

 add to these the increasingly severe attacks of parasitic fungi, 

 as these have passed more and more from a facultative to a 

 holoparasitic stage, and have branched off into new race- 

 forms, varietal forms, and specific forms, we begin to appreciate 

 how the individuals of a species, and the species of a tribe, 

 have selected and conserved every accessory and at first for- 

 tuitous by-product of the cell laboratory that the better enabled 

 it to practise selective survival. Even the by-products of food 

 elaboration in animals could be better expended in movements, 

 in surface coverings, or in surface pigments. Hence we believe 

 the relative poverty of animals in diffused accessory chemical 

 constituents. 



We would by no means deny that in some cases these ac- 

 cessory products in plants may also have been utilized either 

 as food formers or transformers, or as contact bodies in effecting 

 metabolic change. It would seem decidedly peculiar if the 



