THE RECAPITULATION THEORY IN BIOLOGY: A 

 SKETCH OF ITS HISTORY 



1. Other Names for the Theory. 



"This has been named by Hatschek the 'morphogenetic 

 theory,' by Hyatt the 'law of morphogenesis,' by Haeckel the 

 'biogenetic law,' by Cope the 'doctrine of parallelism,' and by 

 Morgan the 'repetition theory.' Sometimes it has been alluded 

 to as the 'law of von Baer,' but incorrectly, for von Baer was 

 its severest critic." * 



2. Anticipations of the Recapitulation Idea. 



The idea that embryos of higher forms pass through the 

 adult stages of the lower animals is a very old one and no one 

 name is associated with its origin. The first clear reference 

 to it appeared at the end of the eighteenth and the beginning 

 of the nineteenth centuries. The system of classification then 

 in vogue was that of Linnaeus, which placed the various groups 

 one above the other in a single scale or series from the lowest 

 to the highest. .In this scale the worms held the lowest rank, 

 and then in order, the insects, fishes, amphibia, birds, mammals. 

 The allusions to the animal series in the extracts which follow 

 are therefore to this uniserial system. 



In these early expressions embryonic or developmental 

 stages were naturally found to resemble the mature forms of 

 existing lower animals, evolution as yet being a conception 

 of a very few prophetic minds. One of the earliest of these 

 expressions, however, was that of such a prophetic mind. Lor- 

 enzo Oken, a speculative evolutionist and a popularizer of the 

 science of the time, wrote in 1805, 



"Each animal 'metamorphoses itself through all animal 

 forms. The frog appears first under the form of a mollusk in 

 order to pass from this stage to a higher one. The tadpole 



1 Montgomery. Analysis of Racial Descent in Animals, 1906, p. 177. 



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