130-(KX)) GRADATION IN ANIMAL LIFE. 



while intimate internal structure is alone worthy to be 

 the basis of broad generalization. And it is in the spirit 

 of such profound investigation, that nothing is taken for 

 granted. Even the old idea, axiomatic with the earlier 

 philosophers, that man is in every respect superior among 

 created existences is denied any claim as a necessary 

 truth. Man himself is brought before the bar of judg- 

 ment, tried by the same principles that are applied to the 

 rest of the animal kingdom, and classified according to 

 the results of this judicial process. Not that modern 

 science has attacked the obvious supremacy of man, but 

 it has in the first place required that supremacy in its 

 esveral details to be proved by established general prin- 

 ciples, and in the second place, as the result of this pro- 

 cess, it has denied the completeness of that supremacy in 

 some directions. 



It is time to consider some of the more prominent and 

 interesting principles or criteria of rank, among animals, 

 as developed by modern science. I will mention first, 

 two grand principles of extensive bearing, brought 

 forward by two of our most eminent scientific philoso- 

 phers. The first was developed by the the master zoolo- 

 gist, Agassiz, and may be stated as follows . In the de- 

 velopment of any species of animals, from the embryo to 

 maturity, earlier forms are obviously inferior to later 

 forms. Consequently, species whose mature forms are 

 similar to any such earlier stages, are inferior to species 

 whose mature forms are similar to those of any later 

 stages of such development. This law, like that of grav- 

 itation, has required ages of human progress, and the 

 thinking of a rarely profound mind for its formulation. 

 Yet it is so grandly simple, that it can be readily explain- 

 ed to a child. It is very far-reaching. It has solved 

 easily many problems of rank, and it is constantly solv- 

 ing more. 



As illustrative of the working of this law, let me cite 

 the following passage from another eminent authority, 

 Prof. J. 1). Dana. He says : "As a many-jointed lar- 

 va, without any distinction of thorax and abdomen, is 

 the young state of an insect, therefore myriapods or cen- 

 tipedes, which have the same general form, are inferior 

 to insects. As a young living gar has a vertebrated cau- 

 dal lobe which it loses on becoming adult, therefore the 



