A FEW FACTS ABOUT ZOOLOGY. 



and reverently exclaim, "I think God's thoughts; I trace his 

 designs." " Classification, rightly understood," says Agassiz, 

 " means simply the creative plan of God, as he has expressed 

 it in the forms of life that surround us." The first details 

 may be tedious, but our patience, if we persevere, will be 

 rewarded, and, in the language of this great naturalist, 

 " the long and tedious road will bring us suddenly to a 

 glorious prospect and a clearer mental atmosphere, and a 

 new intellectual sensation will amply reward us for a little 

 weariness in the out let." 



Upon what must our classification be founded? Upon 

 external resemblance or internal structure? Let us illus- 

 trate : The flat roof and the colonnade are the types which 

 distinguish all Grecian temples; they may be built of marble, 

 granite, or wood; their columns may be adorned with the 

 elaborate Corinthian embellishments, or finished in a plainer 

 Doric style; we do not inquire, in order to decide whether it 

 is a Greek temple, about the materials, or the ornamentation; 

 we class all temples as Greek which are built according to 

 the Greek plan — the flat roof and colonnade. Cnvier was 

 the first to adopt and apply the principle of internal structure, 

 rather than external resemblance. After years of ripe study 

 he thus announced his conclusions : 



" Looking at animals only with reference to their nature 

 and organization, excluding their size, their utility, our 

 greater or less familiarity with them, and all other accessory 

 circumstances, we shall find that there exist four principal 

 forms — four general plan?, if Ave may so express it — in accord- 

 ance with which all animals seem to be molded." 



The publication of this statement at first created an ex- 

 traordinary excitement throughout the scientific world, but, 

 after many investigations, it became accepted by many as a 

 scientific truth. Baer, a German naturalist, went a step 

 farther. Cuvier showed us the four plans as they exist in 

 the adult animal ; Baer showed us, not only that they were 



D 



