210 Agassiz's Contributions to the 
ving great activity and thoroughness to the investigation. 
he answer to the simple problem would be, some hundreds i 
not thousands; and yet, notwithstanding all the chances, and all 
the labor thus far. bestowed, not a specimen has been found. _ 
There being some system of progress, the great question 18, 
What is that system ? 
Is it a law of uniform progress for the Animal Kingdom asa 
whole? No:—for each of the four Branches, as Professor Agassiz 
observes, are wholly independent of each other in their whole 
system of structure and progress. 
Is it a law of uniform progress for each of these Branches? or 
for each of the Classes they contain, as for the class of fishes, oF 
_ of birds, or of mammals, ‘ete.? The same argument which 1s 
used above for the Branches, holds in fact against any such kind 
and which certainly holds as a general truth. We shou 
fore no more look for lineal progression between different Orders 
An a Class, or different Classes in a Branch, than between dif 
ferent systems in the heavens. : Re fd 
In addition to this, a class has not generally been first intro 
duced through the creation of its very simplest specie 
8, 
On this point, Professor Agassiz says: “he earliest repT® 
sentatives of these classes do not always seem to be the low 
et through all the intricate relations, there runs an evident te 
dency towards the production of higher and higher types, until, 
at last, man crowns the series.” And he closes this aragraph 
with the sentiment which seems to be ever dwelling in his mint. 
Who can look upon such series, and not read in them the suc’ 
cessive manifestations of a thought expressed at different 29 
in ever new forms, and yet tending to the same end, onwal 
hesied in the 
~ 
“ee 
ares 
