CHAPTER III. PARALLELISM, 



IT IS now generally recognized that the successive 

 types of organic beings present characters which 

 are traversed in the embryonic life of those which at- 

 tain the greatest complexity of development, and which 

 occupy the highest places in the scale of life. This 

 fact was observed by the early embryologists, as Von 

 Baer and Agassiz, who did not admit its bearing on 

 the doctrine of evolution. But Darwin and Spencer 

 understood its significance, and Haeckel, Hyatt, and 

 the writer applied it directly to the explanation of phy- 

 logeny. At the present time one of the chief aims of 

 the science of embryology is to discover the record of 

 the history of the past, recapitulated in the stages of 

 embryonic life, and to unravel the phylogenesis of 

 plants and animals by this method. The utility of 

 these researches is attested by the results which they 

 have attained, though for obvious reasons, these are 

 not as definite and conclusive as those which are de- 

 rived from paleontology. The general conclusion is 

 however justified, i. e., that the records of embryology 

 and paleontology are closely similar, and that any dis- 

 cordance between them may be explained on compre- 

 hensible principles. 



