CHAPTER III 



HUMAN INFANCY AND THE RECAPITULATION 

 THEORY 



1. Human Embryogeny. 



The ancestral significance of the facts of human foetal develop- 

 ment was carefully considered by Duckworth in " Morphology and 

 Anthropology" (1904). This author made comparisons with 

 respect to external features, topographical and systematic ana- 

 tomy, between the human foetus at birth, also at a point about 

 half way through embryonic development, and the human adult 

 and existing primates. His conclusions are briefly as follows. 

 With respect to the external features of the human foetus a 

 small number of simian characters are recognizable in both 

 stages studied, although the younger stage does not show these 

 in any greater frequency. This is practically the result of the 

 comparison based on topographical anatomy. Some of the 

 points of difference from the adult human condition constitute 

 resemblances to conditions obtaining among the primates. No 

 special primate form is indicated. The conclusions regarding 

 systematic anatomy are given in the words of the author. The 

 observations regarding the ninth month foetal stage are arranged 

 with respect to descent in three groups. 



"First of all, there are to be noticed characters, such as the 

 relatively large size of the liver, of the hypogastric arteries, or 

 of the fontanelles, which appear to be quite irrelevant; these are 

 in fact, conditions associated with, and determined by the par- 

 ticular and peculiar mode of development in the higher Eutheria, 

 and, therefore, they may be expected to obtain in all these 

 animals alike. Secondly, there are a number of characters, 

 such as the great size of the head and of the cerebrum, which 

 are related to the specific and peculiar characters of the Homin- 

 idae, and which might well be expected to be so impressed in 

 their organization as to appear prematurely, so to speak, in his 

 individual development. . . . These two classes constitute 

 a very considerable number of characters which do not bear 

 upon the question of descent and must be carefully eliminated. 



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