I EMBRYOLOGICAL ARGUMENTS 31 



the real relation between forms sometimes very dis- 

 similar in adult age, it shows also the probable origin 

 of the group or species under consideration. Why 

 should a tadpole begin as a fish having' gills and 

 the circulatory system belonging to fishes although 

 destined to become something very different from a fish, 

 if there is not some intimate relationship between am- 

 phibians and fishes, if amphibians have not their origin 

 in fishes, if amphibians are not transformed fishes ? 



And, if we turn towards man, who, according to the 

 evolutionary hypothesis, is no more than the last result 

 of the evolution of higher vertebrates, we meet with 

 facts identical in nature, but more surprising still. 

 Mammals must be considered as having been evolved 

 out of lower vertebrates, exactly as amphibians must 

 have been evolved out of fishes, and as all vertebrates 

 must, in different lines, have been evolved from fishes, 

 man's development or embryology should retain some 

 trace of this long and varied ancestry. And it does 

 retain such traces ; this is a very plain and precise fact. 

 Haeckel, in his History of Natural Creation, and in 

 his AntJiropogenie, has well summarized the facts bear- 

 ing on this question, and it is useless to go over the 

 details which are familiar to all. In the course of 

 the few months during which the primitive egg-cell be- 

 comes evolved into a new-born child, the human organ- 

 ism offers unmistakable evidence of its animal ancestry 



