68 THE HISTORY OF CREATION. 



and phylogeny, which I have abeady (p. 10) claimed as 

 one of the strongest pillars of the Theory of Descent. No 

 one before had so distinctly stated as Agassiz did, that, of 

 the Vertebrate animals, fishes alone existed, at first, that 

 amphibious animals came later, and that birds and mam- 

 mals appeared only at a much later period, further, that 

 among mammals, as among fishes, imperfect and lower 

 orders had appeared first, but more perfect and higher 

 orders at a later period. Agassiz, therefore, showed that 

 the palseontological development of the whole Vertebrate 

 group was not only parallel with the embryonic, but also 

 with the systematic development, that is, with the gi^aduated 

 series which we see everywhere in the system, ascending 

 from the lower to the higher classes, orders, etc. 



In the earth's history lower forms appeared first, the 

 higher forms later. This important fact, as well as the 

 agTeement of the embryonic and palaeontological develop- 

 ment, is explained quite simply and naturally by the 

 Doctrine of Descent, and without it is perfectly inex- 

 plicable. This cause holds good also in the great law of 

 'progressive development, that is, of the historical progress 

 of organization, which is traceable, broadly and as a whole, 

 in the historical succession of all organisms, as well as in 

 the special perfecting of individual parts of animal bodies. 

 Thus, for example, the skeleton of Vertebrate animals 

 acquired at first slowly, and by degrees, that high degree 

 of perfection which it now possesses in man and the other 

 higher Vertebrate animals. This progress, acknowledged 

 in point of fact by Agassiz, necessarily follows from Dar- 

 win's Doctrine of Descent, which demonstrates its active 

 causes. If this doctrine is correct, the perfecting and diver- 



