EVOLUTION BEFORE DARWIN Ig 
quired by the parents, all seemed well. There is a 
tendency now to insist once more that slowly and 
gradually, in some perhaps as yet unexplained way, 
external factors do influence even egg cells, and grad- 
ually acquired characters do reappear in the offspring. 
The blighting setback these views suffered came 
from the criticisms of Baron Cuvier. This genu- 
inely remarkable man had built up the study of com- 
parative anatomy. To him students flocked from all 
sides. Among these one of the most brilliant was 
Agassiz, the Swiss naturalist, who later came to this 
country, filled with Cuvier’s ideas. This great teacher 
believed that species are fixed. He knew better than 
any man of his times the wonderful similarity in 
structure between animals of a given class. He at- 
tributed this not to any real blood relationship be- 
tween the animals. They were alike because they 
had been made by the same Creator. This great 
Artificer worked along four main lines, and hence 
animals could be divided into four groups. Many 
who have studied text books on zodlogy written in 
this country by Agassiz and his followers will remem- 
ber the four classes—Radiates, Articulates, Mol- 
lusks, and Vertebrates. Agassiz was such a wonder- 
ful teacher and so genial and so lovable a man that 
his opposition to evolution held back the advance of 
the Darwinian idea in America as Cuvier’s influence 
