'J 2 htstinct. 



agencies in every species only impresses us more 

 fully with the conviction, that they are the three 

 agencies supplementary to each other by which an- 

 mal life is sustained and has secured to it, its infinite 

 variety of expression. Nothing can well be more 

 unlike than the species that make up the great 

 branches of the animal kingdom. But structure, 

 function and instinct are as perfectly adapted to 

 secure the welfare of individuals belonging to one 

 branch as to another. We may also consider a 

 more complex plan of which these three agencies 

 are but one part. For when we consider the struc- 

 ture, forces and operations of the inorganic world, 

 the structure and function of plants as a whole and 

 the relation of their parts to each other, — the struc- 

 ture, functions, instincts and relations of animals, 

 the plan or system seems to be the same in kind as 

 we see in a single individual or species, but more 

 far-reaching still, embracing as it does the three 

 kingdoms of nature as though they formed an or- 

 ganized whole. But the oneness never impresses 

 us as arising from any likeness of the things among 

 themselves but from the peculiar relationship of the 

 most diverse things to constitute one system, that 

 brings the idea of unity necessarily to every mind 

 that comprehends its parts, relations and opera- 

 tions. Within this one comprehensive plan, by 

 which all beings seem to be related for their mutual 

 good, we may consider the various subordinate 

 plans for specific purposes. These impress us more 

 strongly perhaps because they are specific, especial- 

 ly if they are so different from the general plan as 



