28 EVOLUTIONS OF ORGANIZATION. 



of modern science." Rather, I apprehend, the 

 method of true science, modern or not, would be to 

 study each evolution separately, attending to all the 

 phenomena, and investigating its limits, and the 

 action of every possible factor in its production. 

 Thus, truly, it is of importance to study the opera- 

 tion of circumstances of environment at the present 

 day, that we may understand the effects of environ- 

 ment in the past; and science is enormously indebted 

 to Darwin for the stimulus which he has given to 

 that inquiry. But just as in the evolution of lan- 

 guage, although environment plays an all-important 

 part, the fundamental factors are the existence of 

 ideas to communicate and a parallelism of things 

 of different order, rendering it possible for ideas to 

 be represented by signs, so also in the evolutions of 

 organization there is a non-material element in the 

 definitely directed impulse, and there is a physiog- 

 nomic propriety in organic forms, a class of facts 

 appreciated by both Oken and Dana, telling of 

 spirit which pervades the whole. 



It is certain that the evolutions of form after 

 passing through periods of activity do cease ; for 

 while all the most curious forms of invertebrate 

 life, polyzoa, echinodermata, lamellibranchs, brach- 

 iopoda and cephalopoda, are formed already in 

 palaeozoic times, the vertebrates have in the same 



